AudioCircle

Industry Circles => GR Research => Topic started by: Jaytor on 9 Aug 2020, 11:40 pm

Title: DIY Amps for NX-Oticas
Post by: Jaytor on 9 Aug 2020, 11:40 pm
I've spent the last few months SLOWLY buidling a pair of monoblock amps to use with my NX-Oticas. I've only been able to work on these on the weekends, and I took my time since this is my first audio electronics build since about 1980. Back then, I built a Pass A-40 and a couple of my own designs until I got heavily involved in digital electronics and never had a chance to get back to audio stuff.

As my first (recent) foray into DIY electronics, I decided to build another amp based on one of Nelson's designs (I have fond memories of the A40). This is what is referred to as an F5 Turbo. It's based on the First Watt F5, but uses higher voltage rails (32v in my case), doubled output transistors, and a cascoded input stage. I also used a power supply with a capacitance multiplier to reduce ripple on the rails. There is also a soft start board under the power supply board, and thermal cutoffs mounted to each heatsink.

Output power is about 60W RMS into 8 ohms. I haven't finalized the bias yet, but I'll probably set the bias to around 1 Amp (which will give me class A to about 25W) to keep the amp running a little cooler. The NX-Oticas are fairly efficient, so this will keep me in class A almost all the time.

The power supply board for each channel has 72,000 microfarads of capacitance in a CRC arrangement, but most of the ripple reduction comes from an active Cap Mx circuit.  I used an Antek 400VA toroidal transformer for each monoblock.

The input circuitry has a switchable Jensen transformer for balanced input. There is also a switchable MiFlex copper cap for lower frequency roll-off since I'm using the powered OB servo subs. For outputs, I've got tube connectors in parallel with Cardas binding posts.

(https://www.audiocircle.com/image.php?id=213036)

(https://www.audiocircle.com/image.php?id=213037)

(https://www.audiocircle.com/image.php?id=213038)

I haven't hooked these up to my NX-Otica's yet. I am running them in on a cheap pair of speakers first, to make sure that they are operating reliably. Once they've burned in for a couple weeks, I'll get them hooked up and let you know how they sound.

I'm currently using a Parasound JC-5, which is a pretty nice sounding amp, so it will be interesting to see how these compare. But I had a blast building these, so I'm sure there will be more DIY audio electronics in my future.
Title: Re: DIY Amps for NX-Oticas
Post by: UtopiaNemo on 9 Aug 2020, 11:58 pm
This is incredible. Before finding this site, the idea of a DIY amp sounded ludicrous to me. I’m so impressed! Please keep us informed as to how it sounds in comparison to your Parasound!
Title: Re: DIY Amps for NX-Oticas
Post by: Early B. on 10 Aug 2020, 12:04 am
I'm currently using a Parasound JC-5, which is a pretty nice sounding amp, so it will be interesting to see how these compare.

It ain't a fair fight. You may as well put your Parasound up for sale. 
Title: Re: DIY Amps for NX-Oticas
Post by: poseidonsvoice on 10 Aug 2020, 01:04 am
The power of DIY! Enjoy the fruits of your labor. I rotate my DIY Sony VFET from time to time and have the Aleph J as well as MOFO monoblocks on the building queue...

Best,
Anand.
Title: Re: DIY Amps for NX-Oticas
Post by: WC on 10 Aug 2020, 01:43 am
Enjoy.

I have a 4 channel Mod-86, Mod-686 monoblocks, M2X Monoblocks, Aleph J monoblocks, Folsom 7297, 3255 evm, and 4 channel 3e 3255 amps all in various stages of construction.

Currently using my ACA 1.1 monoblocks.
Title: Re: DIY Amps for NX-Oticas
Post by: RonP on 10 Aug 2020, 02:18 pm
Keep us posted Jaytor!

Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 10 Aug 2020, 07:46 pm
Thanks everyone.

WC - that's quite a collection of DIY amps. I'm also quite interested in the Neurochrome amps. How did you decide between the Mod-86 and the Mod-186?

- Jay
Title: Re: DIY Amps for NX-Oticas
Post by: Skilly on 10 Aug 2020, 08:10 pm
Jay,

Can I ask what you are budgeting per amp and your parts source?

Scott
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 10 Aug 2020, 09:48 pm
Hi Scott - That's not so easy to figure out since I ended up changing the design a few times along the way and ordered parts I didn't end up using (at least for these amps). I'd guess somewhere between $800 and $1000 for each mono amp.

I bought the chassis on ebay from a vendor in China, the transformers with covers from Antek, the connectors from Parts Connexion, the F5 PCBs from DIYAudio Store, the soft start and power supply PCBs from XRKAudio Etsy store, the Jensen transformers (for balanced input) used from an ebay seller, the Copper input caps from SonicCraft, and all the rest of the parts from Mouser. I had the small PCB boards for the balanced input circuit made by a shop in Taiwan.

Building amps like this isn't a way to save money. In addition to all the parts, I also bought a nice soldering station, a Variable AC transformer, a heat gun for heat shrink, two nice Fluke multimeters (I had a cheap one), and a 4-channel oscilloscope. The scope isn't really necessarily, but everything else is. You can get away without the variable AC transformer, but it significantly reduces the risk of blowing parts and/or starting a small fire if you've got a wiring error, and they are not very expensive.

It's definitely possible to build an amp similar to this for a lot less. For example, the standard FirstWatt F5 uses a single chassis, a shared simple power supply, no soft start (other than a single simple thermistor), no balanced input, no copper input cap (which is used to roll-off the low end for use with OB subs), no tube connectors and no thermal shutoffs. I would expect you could build one of these for well under $1K for a two channel amp.

- Jay
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 10 Aug 2020, 10:07 pm
Enjoy.

I have a 4 channel Mod-86, Mod-686 monoblocks, M2X Monoblocks, Aleph J monoblocks, Folsom 7297, 3255 evm, and 4 channel 3e 3255 amps all in various stages of construction.

Currently using my ACA 1.1 monoblocks.

What are your impressions of the Modulus amps?  I just finished a Folsom 7293 and I am looking at the Modulus 186 as my next build.
Title: Re: DIY Amps for NX-Oticas
Post by: Skilly on 10 Aug 2020, 10:44 pm
Jay,

Great response, thank you. This is a project I have been contemplating since I sold my Nakamichi PA-7. I really like that beast, but I needed to do it. I have been lurking at DIYaudio for some time. They never seem to have complete kits available. Its weird, how they have boards but no parts or parts but then no boards. No links for transformers.

I appreciate your answers.
Title: Re: DIY Amps for NX-Oticas
Post by: WC on 11 Aug 2020, 03:00 am
Thanks everyone.

WC - that's quite a collection of DIY amps. I'm also quite interested in the Neurochrome amps. How did you decide between the Mod-86 and the Mod-186?

- Jay

I bought the Mod86 boards before there were Mod-186 boards. The Mod-186 costs more, but comes as an assembled board and is supposed to be better, but even Tom says they sound very similar.
Title: Re: DIY Amps for NX-Oticas
Post by: WC on 11 Aug 2020, 03:19 am
What are your impressions of the Modulus amps?  I just finished a Folsom 7293 and I am looking at the Modulus 186 as my next build.

Don’t have any impressions yet, since neither of them are yet complete. I am missing parts for both amps. For the Mod-686 I have the partial amp boards, power-86, and transformers. Just need the heat sinks and the rest of the parts for the chassis and the amp boards. For the Mod-86, I have everything except for parts for the Power-686. I move slowly with my builds. Just finished building 2 Rythmik 15” subs and three pair of speakers with full range drivers. Now I can turn my attention and finances to building amps and DACs to use with the speakers and subs.
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 2 Oct 2020, 11:35 pm
Well, after listening to my F5 Turbo monoblocks for a few weeks, I decided I wasn't really happy with them. They had good dynamics and no noise (hum or hiss), but just didn't have the clarity (detail and imaging) I was used to with my Parasound JC-5.

I suspect the quality of the components and/or wires I used was not good enough, and I didn't do an adequate job of component matching. The meters I had when I built these didn't provide any accuracy or precision when measuring small value resistors. I've since purchased a desktop multimeter which has much better precision.

At some point, I'll get around to rebuilding the front-end boards with better quality and matched components, and rewiring with higher quality signal wires to see if I can improve the SQ.

In the meantime, I built another pair of amplifiers based on the Neurochrome Mod-286 with a beefy power supply. These have plenty of power for the NX-Oticas and really sound fabulous. I'd say at least as good as the JC-5 and that's with lesser quality speaker cables. I've just ordered a speaker cable kit from Danny to make some short cables to use with these new amps.

(https://www.audiocircle.com/image.php?id=215398)

(https://www.audiocircle.com/image.php?id=215399)

(https://www.audiocircle.com/image.php?id=215400)
Title: Re: DIY Amps for NX-Oticas
Post by: Rock Ball on 4 Oct 2020, 12:27 pm
In the meantime, I built another pair of amplifiers based on the Neurochrome Mod-286 with a beefy power supply. These have plenty of power for the NX-Oticas and really sound fabulous.

Nice job!  That looks like a fun build.  Was it a kit or did you source all the individual components yourself?

Do you have a build thread for these on any forums?
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 4 Oct 2020, 04:25 pm
Thanks Rock Ball.

These weren't done from a complete kit, but the Modulus-286 amplifier module is sold assembled by Neurochrome.

https://neurochrome.com/products/modulus-286

The chassis is the 3U Mini-Dissipante from ModuShop available through the DIYAudio Store.

https://diyaudiostore.com/collections/chassis/products/mini-dissipante-3u?variant=12173317060

The soft start board is from XRKAudio, available through his Etsy shop. I used this in my FirstWatt F5Turbo as well.

https://www.etsy.com/listing/769363642/soft-as-a-feather-pillow-sfp-solid-state

I bought the power supply boards on Ebay - fairly cheap but fit in the case and provided what I needed. This is a CRC type design - two capacitor banks split by parallel resistors - which provides better ripple reduction than a single capacitor bank supply. I built mine with 2x15,000uF per rail in the first bank and a 22,000uF per rail in the second bank. The board doesn't include a snubber circuit to cancel transformer secondary resonances, so I added this to the back of the board.

https://www.ebay.com/itm/CRC-6-Capacitors-PASS-Amplifier-PSU-Power-Supply-Rectifier-Filter-Bare-PCB-Board/133283479788

All the parts for the soft-start board and power supply board are from Mouser.

The Transformer is the Antek AS-4225 (400VA, dual 25v secondaries). They also sell the steel cover for this transformer.

https://www.antekinc.com/as-4225-400va-25v-transformer/

The power supply is overkill for this amp. In fact, Tom Christiansen, the designer of the Modulus-286, recommends a supply a quarter this size. But I've generally found a larger supply provides better dynamics and fullness in the bass and lower-midrange. And since I don't have to worry about building to a budget, I went with the largest supply I could fit in the enclosure.

This was a fairly easy build because the amp modules are pre-built. The hardest part was getting the case together with the tight fit of all the components, but that was partly because I didn't realize that the mounting holes for the top and bottom covers aren't completely symmetrical and had already drilled the holes in the bottom plate before I figured it out. So the panels didn't go together quite as easily as they would have if I had not made this mistake.

I had Modushop cut the holes in the back panel - they do a great job for a very modest price. I drilled the holes in the bottom panel myself which was fairly easy. Overall, I'd estimate it took me about 30 hours to build the pair, but I like to take my time. This is a hobby, after all.

Next projects - finishing up a preamp for which I'm currently waiting for the case from Modushop which has a LOT more custom machining than these amps had, and then building another pair of monoblocks using the Pufifi 1ET400A class-D modules with a 1000VA linear power supply and a custom triode front-end. Oh, and a pair of Line Forces once Jay (captainhemo) gets the enclosures done for me.
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 4 Oct 2020, 04:34 pm
Its great to see good reviews of the Neurochrome amps.  I'm building a pair of Modulus 186 monos for my Super 7s.  Great job on the build. 
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 21 Nov 2020, 10:58 pm
I finished my latest DIY project - a new preamp. I just got it hooked up to my main system with the NX-Oticas and I'm thrilled with the way it sounds. I think my Parasound JC-2BP will be listed for sale shortly.

The preamp uses a fully balanced Khozmo relay-based input selector and shunt attenuator. All shunt resistors are Takman REY. The series resistor and all signal path resistors are Vishay Z-foils. I'm using AMB Labs alpha 24 balanced line-stage buffers, with an AMB omega 22 supply, with 100VA transformer. A separate supply based on the AMB omega 11 is used for the digital logic, including the OLED display. The Khozmo includes a nice machined metal remote control.

I have two pairs of balanced outputs - one DC coupled directly to the alpha 24, and the other through a set of MiFlex KPCU copper caps which roll off the low end. I've got this latter output feeding my amps into the NX-Oticas, and the single-ended output from the alpha-24 feeds the servo subs.

All audio wiring uses DH Labs solid-core silver with teflon insulation and I'm using Viborg gold over copper XLR connectors.


(https://www.audiocircle.com/image.php?id=217264)

(https://www.audiocircle.com/image.php?id=217265)

(https://www.audiocircle.com/image.php?id=217266)
Title: Re: DIY Amps for NX-Oticas
Post by: RonP on 22 Nov 2020, 01:58 pm
I finished my latest DIY project - a new preamp. I just got it hooked up to my main system with the NX-Oticas and I'm thrilled with the way it sounds. I think my Parasound JC-2BP will be listed for sale shortly.

The preamp uses a fully balanced Khozmo relay-based input selector and shunt attenuator. All shunt resistors are Takman REY. The series resistor and all signal path resistors are Vishay Z-foils. I'm using AMB Labs alpha 24 balanced line-stage buffers, with an AMB omega 22 supply, with 100VA transformer. A separate supply based on the AMB omega 11 is used for the digital logic, including the OLED display. The Khozmo includes a nice machined metal remote control.

I have two pairs of balanced outputs - one DC coupled directly to the alpha 24, and the other through a set of MiFlex KPCU copper caps which roll off the low end. I've got this latter output feeding my amps into the NX-Oticas, and the single-ended output from the alpha-24 feeds the servo subs.

All audio wiring uses DH Labs solid-core silver with teflon insulation and I'm using Viborg gold over copper XLR connectors.


(https://www.audiocircle.com/image.php?id=217264)

(https://www.audiocircle.com/image.php?id=217265)

(https://www.audiocircle.com/image.php?id=217266)

Damn dude! :o Do want!!!  8) :icon_lol:
Title: Re: DIY Amps for NX-Oticas
Post by: rtate on 22 Nov 2020, 04:12 pm
@Jaytor , Any build threads on your projects ?
I'd  love to see the work in progress !!
Title: Re: DIY Amps for NX-Oticas
Post by: Jon L on 22 Nov 2020, 04:48 pm
The series resistor and all signal path resistors are Vishay Z-foils.

Like those Vishay Z-foil resistors, except for the price :thumb:
Title: Re: DIY Amps for NX-Oticas
Post by: Early B. on 22 Nov 2020, 06:12 pm
@Jaytor , Any build threads on your projects ?
I'd  love to see the work in progress !!

Yeah, please tell us more about this preamp.
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 22 Nov 2020, 07:08 pm
I didn't create a build thread, but would be happy to answer any questions.

I used a ModuShop Slimline 2U chassis, 280mm deep with aluminum covers and 10mm front panel. I bought this through the DIYAudio Store. I created drawings using photoshop for the front and rear panels. I wanted something more than just a flat front panel, so I specified a 500mm radius rabbet that is 3mm deep and extends 8mm down from the top and bottom. 

I also specified a rabbet around the control holes so that I could inset the knobs into the front panel. I've got another set of knobs on order that are simpler design and have a sand-blasted look so I think they might look better against the brushed aluminum front panel. It's really hard finding knobs that don't have an indicator line. Since I'm using rotary encoders that don't have a stop, I wanted plain faced knobs.

There is also a rabbet around the cutout in the center of the panel for the OLED display. I found a company (Angel City Lasercraft) on Etsy that made the red acrylic panel that fit perfectly into the opening.

The transformers are from Antek - 100VA 18V, and 50VA 9V (for the 5.2V supply for the attenuator logic). The AMB Labs o11 supply I used for the digital logic is overkill since I only need 1A, but since I wasn't sure when I spec'ed it exactly what I was going to need.

I wanted to use a relay switched attenuator since I think this allows high quality resistors to be used and excellent tracking between four channels (balanced stereo). Originally, I was not planning to have more than one input since I only currently have one source, but after Khozmo told me about this particular product which I really liked since it had the display and remote control, I decided to take advantage of the built in switching and add all the inputs.

The AMB Labs alpha 24 buffer is essentially an instrumentation amp using modern very-low-noise op-amps and is configured to have both balanaced and single-ended outputs. I have to say I'm very impressed with the sound quality. The only challenge with this board is that the op-amps are surface mount and with my old eyes were a bit challenging to solder. I ordered an extra PCB so I could do a little practicing before building the two I used in the preamp. Fortunately, my wife has a dissecting microscope which made it much easier. At this point, I feel pretty comfortable with soldering these (fairly large) SMD components and wouldn't hesitate to use them again.

I used a little ground-break kit from glass-ware.com to connect the analog ground to the chassis ground. In the past, I've hard-wired my own circuit using a bridge rectifier, but this makes it simpler and cleaner.

I decided to use internal panels (modified chassis side panels from Modushop) that I lined with copper sheet around the analog section. I'm not sure if this really helps, but it can't hurt and looks kind of cool.

The Khozmo attenuator was the most expensive part of the project, and a little under $500 for the fully balanced design with Takman REY shunt resistors and Vishay Z-Foil series resistors. That's including shipping to the US. These are made in Poland. Khozmo was really great to work with and very responsive to questions. Included in the price was the customization of the OLED display (I designed the logo, for what it is), and the remote control with engraved logo.

The chassis was also a bit pricey since I had so much machining and printing. This came to about $450.

All in, it probably cost me somewhere between $1800 and $2000, but the SQ is an obvious improvement over my Parasound  (it took seconds to notice the difference) which retails for $4500, the remote works great, and I love the display. And I've got very hlgh quality in-line hi-pass filtering caps built in on a second balanced output.
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 28 Nov 2020, 05:25 pm
I have found both the Folsom 7293 and the Neurochrome Modulus 186 to be great matches for the Super 7.  I owned the NX-Otica monitors for about 2 years so I think both would be a great match for those as well. 

Choose the Modulus 186 if you want a more detailed sound but with slightly set back mids and a deeper soundstage.  The Folsom has aggressive mids, great detail, maybe a more forward sound with great layering front to back.  Both are as transparent as anything you can get. 

Honestly, I like having both, they compliment each other really well.  The Modulus is like Daniel Craig's James Bond while the Folsom is like Ethan Hunt.  Bond is this https://www.youtube.com/watch?v=K2DUFYqc27w&t=1m51s, Hunt is this https://www.youtube.com/watch?v=Sjn3ELLcy2U&t=1m33s. 
Title: Re: DIY Amps for NX-Oticas
Post by: poseidonsvoice on 28 Nov 2020, 07:10 pm
Great builds and descriptions.

My buddy and I both built the Modulus 686 and our own versions of the Orchard Audio Starkrimson. He owns a full fledged NXOtica system with 4 separate subs and a treated room. Loves both amps but for slightly different reasons. We don’t see a reason to purchase commercial amplifiers as our DIY builds seem to trounce them! We have also eliminated our preamps (I used to use my own build of the TAPX with 4 silver autoformers), and go dac direct (Matrix Audio X-Sabre Pro MQA).

I use the AMB linestages in my MOFO and also have Wayne Colburns 2018 preamp for kicks.

Great to see DIY going strong. I will be happy to share pictures if there is interest.

Best,
Anand.
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 28 Nov 2020, 08:00 pm
Great builds and descriptions.

My buddy and I both built the Modulus 686 and our own versions of the Orchard Audio Starkrimson. He owns a full fledged NXOtica system with 4 separate subs and a treated room. Loves both amps but for slightly different reasons. We don’t see a reason to purchase commercial amplifiers as our DIY builds seem to trounce them! We have also eliminated our preamps (I used to use my own build of the TAPX with 4 silver autoformers), and go dac direct (Matrix Audio X-Sabre Pro MQA).

I use the AMB linestages in my MOFO and also have Wayne Colburns 2018 preamp for kicks.

Great to see DIY going strong. I will be happy to share pictures if there is interest.

Best,
Anand.

I am DIY amp all the way from now on for the reason you mentioned.  The fun I have building them is just a added benefit.

I was considering building a AMB preamp but I have heard that they have issues with DC bias over time.  Have you run into that issue?
Title: Re: DIY Amps for NX-Oticas
Post by: Tyson on 28 Nov 2020, 08:32 pm
Great builds and descriptions.

My buddy and I both built the Modulus 686 and our own versions of the Orchard Audio Starkrimson. He owns a full fledged NXOtica system with 4 separate subs and a treated room. Loves both amps but for slightly different reasons. We don’t see a reason to purchase commercial amplifiers as our DIY builds seem to trounce them! We have also eliminated our preamps (I used to use my own build of the TAPX with 4 silver autoformers), and go dac direct (Matrix Audio X-Sabre Pro MQA).

I use the AMB linestages in my MOFO and also have Wayne Colburns 2018 preamp for kicks.

Great to see DIY going strong. I will be happy to share pictures if there is interest.

Best,
Anand.

Oh, there's interest!  Please show :thumb:
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 28 Nov 2020, 08:56 pm
@AKLegal - I would like to build the Folsom amp at some point. I was actually planning to build one this past spring, but ended up building the F5 Turbo instead. I've got most of the parts (and circuit boards) collected for the Folsom, although I'll need to get another chassis and power supply.

As I mentioned, I'm building a Purifi class D amp right now. I started a build thread on DIYAudio. This is another pair of monoblocks, each with a large linear power supply (1500VA). I'm leaving enough room in the chassis to experiment with input buffers, and I plan to build a few different designs to see how it affects the sound. But eventually, I'll get back to building the Folsom chipamp.

Regarding the AMB preamp, I'm using the alpha 24 board which is op-amp based. It is DC coupled, so any input offset will show up on the outputs, but with the inputs grounded, it is very close to 0 offset. This board was perfect for me since I wanted balanced inputs, and both balanced and single ended outputs (the single ended for the servo subs). I am actually currently using my hi-pass output which is AC coupled through Miflex KPCU caps since I don't want to send the lowest couple of octaves to my NX-Oticas, so offset doesn't matter anyway for the balanced outputs.

But I suspect the AMB alpha-20 (which is a discrete design) may be more prone to offset since it uses a trim pot to compensate for differences in the JFETs. Since these are N and P channel devices, they will never have exactly the same transfer function and may drift a bit over time (and temperature).

@poseidonsvoice - I saw photos of your Orchid and Mod-286 builds on DIYAudio - very nice! But I don't think I saw photos of the Mod-686. Are these posted on DIYAudio?
Title: Re: DIY Amps for NX-Oticas
Post by: poseidonsvoice on 29 Nov 2020, 12:33 am
@AKLegal - Yes, what Jaytor said. The AMB Alpha 24 is a very flexible opamp based preamp that is dc coupled using some of the finer opamps out there, fully biased in class A. DC Offset isn't an issue either.
 
The AMB Alpha 20 is a different animal altogether.  It is a discrete design, and has a push pull output stage that needs some bias to stay in Class A for most output loads. Only 30mA is required but you can bias it much higher. I use about 50mA. I have found that at higher gains (10X or more) the DC offset can vary a bit, but it isn't too big of a deal. This is common with JFETs which as discrete devices do vary in matching. The closer matched they are, the better, and that is the issue with *any* discrete design. With opamps, the matching is quite exacting, as such DC offset "drift" is very rarely seen. With the Alpha 20 discrete preamp, the small amount of dc offset even at the 10X gain (20dB)  isn't an issue in my setup because the next stage is capacitor coupled (my MOFO stage). If it troubles you, use a very high quality capacitor on the output of the Alpha 20 preamp (sized enough so that it can pass low frequencies, like 10Hz or so) and you should be fine; or else design a DC servo, etc...

Here is my Class D build:

Front panel with push button switch that glows a very subtle blue when on:

(https://i.imgur.com/NeYjqgs.jpg)

Rear panel, which uses Furutech binding posts, IEC and XLR's. The writing in Cyrillic says: Ayzenshtat Class D which pays homage to the designer, Leo Ayzenshtat who is the owner, and proprietor at Orchard Audio.

(https://i.imgur.com/5tE5Xz0.jpg)

Here are the innards. It uses Neurochrome Audio's SMPS-86 supplies (dual mono), set to +48V. It has it's own soft start, surge protection, and Pi Filter on the output of the MeanWell power supplies and is also compatible with any AC power grid from about 100V to 240V AC. The audio signal wiring is all Neotech. I purchased the Orchard Audio "BOSC" boards as blank boards and had to order and populate the parts myself, all very small SMD! As such, we had to order an SMD stencil to accurately place the parts on the board. Fun stuff. Nowadays, you can order just the boards, fully built which is much easier for the end user, since it is fully tested as well.

(https://i.imgur.com/RM8feig.jpg)

(https://i.imgur.com/pgcNHoF.jpg)

(https://i.imgur.com/qsdo7qV.jpg)

The unit is very light, about 8 lbs, and easily pumps out 100 watts into 8 ohms with astonishingly low distortion figures.  I have comfortably listened to the amps hooked up to my system and achieved SPL levels of 85-95dB at my main listening position of ~ 4 meters. At these SPL levels, I have measured about a minimum of 6watts and max of 20 watts (my impedance varies from 4.8 ohms to 20 ohms from 100Hz on up). Bear in mind that I use a distributed multisub setup for frequencies below ~ 200Hz.

Here is a measurement at 10 watts:

https://www.audiosciencereview.com/forum/index.php?attachments/e215338b-09ca-40e7-8f29-1246f2635a8d-jpeg.83025/ (https://www.audiosciencereview.com/forum/index.php?attachments/e215338b-09ca-40e7-8f29-1246f2635a8d-jpeg.83025/)

@Jaytor - I will at some point post pictures of my Modulus 686 build which puts out more power and is very amenable to more difficult loads like 3 to 4 ohms. It is a phenomenal amplifier in its own right and the finest Class AB amplifier I have heard.

Best,
Anand.
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 29 Nov 2020, 12:38 am
The Folsom is definitely worth building.  Jeremy says he designed the 7293 to be less responsive to input capacitor changes than the older 7297 was but my 7293 sounds like a completely different amp with a pair of Jantzen silvers as opposed to the Jupiter flat stacks I had in there at the start.  The Jupiters make the 7293 sound a bit closer to the Neurochome 186 without the extreme detail retrieval.  I think if I had the space I would try a pair of MiFlex KPCUs but the 2.2 uf variety are 3 inches by 2.75 inches. 

By the way, Poseidonsvoice and Jaytor, you two make my stuff look super pedestrian.  lol

Folsom 7293

(https://www.audiocircle.com/image.php?id=217568)

(https://www.audiocircle.com/image.php?id=217569)

(https://www.audiocircle.com/image.php?id=217570)

Neurochrome Mod 186 monoblocks

(https://www.audiocircle.com/image.php?id=217571)

(https://www.audiocircle.com/image.php?id=217572)

(https://www.audiocircle.com/image.php?id=217573)


   
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 29 Nov 2020, 04:27 pm
@AKLegal - These look fabulous! Which amp did you build first? I've found that with each project, I learn something new and want to go back and rebuild the early ones.
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 29 Nov 2020, 09:44 pm
Thanks for the compliment.  I built the Folsom first.  I originally wanted to make it a pair of monoblocks and I still wish I had but at the time I had concerns about size.  One monoblock would have been almost the same size as the stereo build. After building the Neurochromes in such a small form factor (they disappear on my floor), I don't think I would have minded the larger size.

I have no complaints with the Neurochrome build.  I kind of wish I went all out and built a pair of 686 Monos even though I really don't need the power at all.  The high powered amps I have owned couldn't seem to get out of their own way with high efficiency speakers but I don't that would have been an issue with the 686 given what I have heard of the 186.
Title: Re: DIY Amps for NX-Oticas
Post by: Tyson on 29 Nov 2020, 10:11 pm
Anand,
First rate build, as always.  Makes me want to build something just to up my DIY game :D
Title: Re: DIY Amps for NX-Oticas
Post by: poseidonsvoice on 30 Nov 2020, 02:55 am
@Tyson - Thanks! Honestly, at this point of my life I do DIY purely out of boredom and some need for personalization.

Best,
Anand.
Title: Re: DIY Amps for NX-Oticas
Post by: RonP on 2 Dec 2020, 01:10 am
How good can these DIY sold state amps sound? Apparently better than Parasound brand, but what about higher end brands?

In reading reviews of the Modwright Tube Pre-amp + SS Amp combo, I was liking what I was reading about it, especially the sound of the Amp as described. The price tag is a bit hefty though.  Same with the Bryston Amps. I'd wanna go two mono block amps. If the quality is there, I could build 2 SS monoblock DIYs for probably about the price of ONE Modwight/Bryston amp.

I would appreciate any comments on this. I think I've pushed the sound quality to near max on the my moderately priced amp/preamp combo (Schiit Vidar Amp + Rotel PreAmp). I'm pleased with what's coming out of it so far, but I'm eyeing upgrades of course. I'm looking at the NX-Oticas or higher in Danny's line (upgrade from my X-SLS)

Thanks!
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 2 Dec 2020, 01:46 am
I'm not that happy with the FirstWatt F5 Turbo I built, but this was the first DIY audio electronics project I've done in 40 years, and I don't think I did the best job of matching components or picking the best parts to use. In an amp like this, this matters a lot.

The Neurochrome amp definitely sounds better and is very close in performance to my Parasound JC5. I think the JC5 still has a slight edge. It has a slightly different tonal balance which I slightly prefer - I think this may be because it is operating in class A up to about 10 watts. But the Neurochrome amps are damn good, and I have been happily listening to them exclusively for the past month or so. Also keep in mind that the JC5 is a $6K amplifier and my Neurochrome based monoblocks cost me about 1/4 that to build.

My DIY preamp is definitely a step up from the Parasound JC2 in SQ which I would attribute primarily to the relay switched attenuator, the use of premium resistors (and no caps) in the signal path, and the use of the highest quality wire and connectors. I don't think there is much I could do that would improve this if you are looking for a highly transparent preamp. But it's not going to add much in the way of low-order harmonics which some people prefer. If you're looking for a tube sound, my preamp isn't going to provide it.

To answer your questions from your PM.

Can it be made into a tube version? I think you could certainly use the Khozmo input selector and attenuator to drive a tube buffer stage, and could build a tube based power supply if you wanted to. I think using a tube buffer would have the most value in providing more low-order harmonics assuming that's what you're trying to get.

Can a tape out at line level be added? The Khozmo attenuator I used is actually two completely separate sections. The first is the input selector and the second is the attenuator. You actually have to connect the output of the input selector to the attenuator, and you could easily connect this to it's own output either directly (if you just want passive) or through it's own buffer, for a line-level tape monitor.

Could you add a left/right balance control? You could certainly add this as a separate circuit using a pot. I would think this is something that could also be done in firmware with the controller that Khozmo uses since, in a balanced configuration, the L and R channels are controlled by completely separate attenuators. So it seems like it should be possible to set these to separate levels although it's possible that the way they have the control circuitry connected, this isn't possible. The control cable essentially daisy chains between the two boards. In my system, I have a very slight imbalance between the two channels due to my room layout, so I use the Roon DSP function to tweak the level of one channel by about 1db.  But this isn't an effective solution for recording to recording adjustments. If you are interested in the Khozmo attenuator, I'd contact them to see what they can do.
Title: Re: DIY Amps for NX-Oticas
Post by: RonP on 2 Dec 2020, 01:53 am
Appreciate the info, Jaytor!  :thumb:
Title: Re: DIY Amps for NX-Oticas
Post by: poseidonsvoice on 2 Dec 2020, 02:14 am
Jaytor,

I would encourage you to listen/build the Neurochrome Modulus 686. I would be surprised if it doesn’t replace the JC5. Recall that at low power levels (~ 0.1 watts or so), the 686 is probably still in Class A if that matters to you. After listening to numerous Class A amps myself what I have found is that execution of the design is key, not necessarily Class A, AB, D design ethos. Yes, I have become Class agnostic! I also have a DIYAUDIO Sony VFET and it’s fantastic on its own until you make the comparison (easily eclipsing the Aleph J and Firstwatt F5).

I did a review about 1 year ago of the Vfet vs Neurochrome Modulus vs Orchard Audio Starkrimson/BOSC Class D:

https://www.audionervosa.com/index.php?PHPSESSID=2io2udng20f06ljmmfls623gn0&topic=7264.msg91698#msg91698

Since then I have done loads of measurements on the VFET. It clips at 56 watts/4 ohms so plenty of power for my purposes and even the NX Otica’s. As pretty as the sinewave looks, it didn’t fare as well as I had thought. My buddy with the NX Otica’s probably put only a few hours on it and then switched back to Neurochrome Modulus 686. The difference was stark. He then sent the VFET along with me figuring that I would use it more than he would (indeed I have!!).

Best,
Anand.
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 2 Dec 2020, 02:33 am
How good can these DIY sold state amps sound? Apparently better than Parasound brand, but what about higher end brands?

In reading reviews of the Modwright Tube Pre-amp + SS Amp combo, I was liking what I was reading about it, especially the sound of the Amp as described. The price tag is a bit hefty though.  Same with the Bryston Amps. I'd wanna go two mono block amps. If the quality is there, I could build 2 SS monoblock DIYs for probably about the price of ONE Modwight/Bryston amp.

I would appreciate any comments on this. I think I've pushed the sound quality to near max on the my moderately priced amp/preamp combo (Schiit Vidar Amp + Rotel PreAmp). I'm pleased with what's coming out of it so far, but I'm eyeing upgrades of course. I'm looking at the NX-Oticas or higher in Danny's line (upgrade from my X-SLS)

Thanks!

FWIW I owned the Schiit Aegir for about a month and in my opinion both the Nuerochrome and the Folsom amps are superior.  I think the consensus is that, notwithstanding bass, the Aegir is superior to the Vidar.  The Aegir is really, really good by the way, it bested the Hegel H360 I had at the time.
Title: Re: DIY Amps for NX-Oticas
Post by: sarora9 on 2 Dec 2020, 03:10 am
I have the Folsom 7293 (built in dualmono configuration by pinocchio of diyaudio) and it is fantastic. I don't find it too forward; it feels like sitting in 10th row from the stage. Far superior to the AvaHifi SET 120 it replaced (which was quite good).

 Using with Spatial X3's and Bricasti M1SE dac (used as preamp too).


Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 2 Dec 2020, 03:22 am
I have the Folsom 7293 (built in dualmono configuration by pinocchio of diyaudio) and it is fantastic. I don't find it too forward; it feels like sitting in 10th row from the stage. Far superior to the AvaHifi SET 120 it replaced (which was quite good).

 Using with Spatial X3's and Bricasti M1SE dac (used as preamp too).

I think I saw your amp build on the DIY forums.  Pinocchio does really nice work and he answered all of my stupid questions. 

I really think the 7293 is more sensitive to input cap changes than Jeremy says (although he didnt say the 7293 wasn't sensitive just less so than the 7297).  Mine was laid back with Jupiter flat stack caps and the presentation was somewhat flat, but with Jantzen Silvers I am on the 7th or 8th row with a very 3D like presentation. 
Title: Re: DIY Amps for NX-Oticas
Post by: Hobbsmeerkat on 2 Dec 2020, 03:29 am
I really wanna look into the DIY Folsom amps going forward, I've heard nothing but great things about them.
Title: Re: DIY Amps for NX-Oticas
Post by: electriceye on 3 Dec 2020, 05:16 am
Anyone have a good route to building Folsom or Neurochrome for beginners? I'm pretty great at building kits and following directions, soldering, etc but the diyaudio.com is rocket science to me at this point, the more I read the less I know. I've built some pretty complex preamps successfully (elekit 8500, just fired up successfully on my first time), speakers and guitar pedals but I'm not great at sourcing my own components and wiring without direction. Any builds I could copy with good detail? Or anyone that could mentor? Wouldn't mind throwing a few bucks out for education, I'd prefer to learn to build it myself.
Title: Re: DIY Amps for NX-Oticas
Post by: poseidonsvoice on 3 Dec 2020, 10:49 am
Electriceye,

I will say that the Neurochrome build manuals are some of the finest I have read in the industry (I have built a LOT of diy designs!). Pretty much everything is included except the soldering part. If you are a good at soldering, I would give it a try. The easiest amp to try in the Neurochrome arsenal is the LM3886DR if you want to solder something. Next is the Modulus 86. Both are available as blank boards so you have to get all the parts from Mouser/Digikey, etc... After that, the Neurochrome Modulus 186, 286, and 686 are all presoldered but you should've had a few kits under your belt just so that you know how to configure everything properly, i.e. sofstart board, power supply, chassis, etc...The 686 is the most complex in that regard only because of the physical board dimensions (i.e. larger than any of his other kits) and honestly you want to invest in a nice chassis and have good mechanical skills as it is that good of an amplifier.

If you look on diyaudio.com, there are a ton of documented builds of the Neurochrome variety and I am sure Folsom amplifiers too.

Do understand that there are builders like myself who build for the sake of building and not necessarily ultimate sound quality. Kind of like guys who collect/build cars for the experience of learning. It's more of a journey for us. So asking what is the easiest build and what is the best sounding amp for the money are not really the same question!

Best,
Anand.

P.S. The only other diy company I have dealt with that has exceptional build manuals is AMB audio. But there is practically no hand holding there. You purchase the blank boards and procure the parts but the instructions and parts lists are first rate. The designs are top notch sonically. However, if your soldering capabilities are poor then you are kind of on your own in the debugging department (although AMB's forums are helpful). If you need to get your confidence up first then you need some easier builds. I am sure AudioNote has excellent build manuals but you pay out of the nose for those kits.
Title: Re: DIY Amps for NX-Oticas
Post by: sarora9 on 3 Dec 2020, 07:41 pm
Anyone have a good route to building Folsom or Neurochrome for beginners? I'm pretty great at building kits and following directions, soldering, etc but the diyaudio.com is rocket science to me at this point, the more I read the less I know. I've built some pretty complex preamps successfully (elekit 8500, just fired up successfully on my first time), speakers and guitar pedals but I'm not great at sourcing my own components and wiring without direction. Any builds I could copy with good detail? Or anyone that could mentor? Wouldn't mind throwing a few bucks out for education, I'd prefer to learn to build it myself.

Folsom includes a parts list that you click and voila, you have a filled shopping cart at one of the major stores. The minor annoyance is that stores may be out of stock on a particular item so you have to select an alternative based upon description. 
Title: Re: DIY Amps for NX-Oticas
Post by: sarora9 on 3 Dec 2020, 07:45 pm

I really think the 7293 is more sensitive to input cap changes than Jeremy says (although he didnt say the 7293 wasn't sensitive just less so than the 7297).  Mine was laid back with Jupiter flat stack caps and the presentation was somewhat flat, but with Jantzen Silvers I am on the 7th or 8th row with a very 3D like presentation.

Aargh did you have to say that? Now I'll be tempted to try to experiment. But on second thought, maybe 99% is good enough :)
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 3 Dec 2020, 08:27 pm
I concur with Anand that the Neurochrome amps would be a good choice for your first project that's not a complete kit. Using Tom's prebuilt modules (the Mod 186, 286, or 686) will result in a great amp without a lot that can go wrong. You'd still have to build the power supply boards, source/design the chassis, and wire everything up, but that's much more straightforward than finding all the parts and building the amplifier boards. 

The Modushop chassis that are available through the DIYAudio Store are excellent quality, and they will take your drawings (even hand drawings if you want) and convert them to CAD to drill all the holes, add labels, etc. The Neurochrome monoblocks and preamp photos I posted earlier in this thread use these chassis.
Title: Re: DIY Amps for NX-Oticas
Post by: electriceye on 4 Dec 2020, 06:02 am
Thanks so much for the responses, this board is great as usual.
Title: Re: DIY Amps for NX-Oticas
Post by: DigIndig on 6 Dec 2020, 03:00 am
Folsom includes a parts list that you click and voila, you have a filled shopping cart at one of the major stores. The minor annoyance is that stores may be out of stock on a particular item so you have to select an alternative based upon description.
When I bought my 7293 boards from Jeremy, he provided recommended alternatives for all of the out of stock components, which made it super easy. There was still one out-of-stock item - the photocell -  and he quickly confirmed the store recommended replacement as viable.

The instructions leave a few details out, but between what is there and what is silk-screened onto the boards, it's pretty easy to figure out where each part goes.
Title: Re: DIY Amps for NX-Oticas
Post by: Bullitt5094 on 6 Dec 2020, 04:19 am
I built a Pass B1 Nutube preamp project with several upgrades including a linear power supply. It feeds a Pass F5 power amp. Also with a couple of upgrades implemented as the project progressed. I am very pleased with the combination of the Nutube feeding the F5. Very accurate and with just enough smoothness from the Nutube to make it very natural sounding without the syrupy tube sound I don't really enjoy . Mr. Pass predicted this would be an excellent combination of components and was right IMHO.
Title: Re: DIY Amps for NX-Oticas
Post by: electriceye on 6 Dec 2020, 05:31 am
Good to know, I ended up purchasing some boards for it for a dual mono folsom, feeling pretty confident in my soldering or at least the ability to recognize bad joints when I do them.


When I bought my 7293 boards from Jeremy, he provided recommended alternatives for all of the out of stock components, which made it super easy. There was still one out-of-stock item - the photocell -  and he quickly confirmed the store recommended replacement as viable.

The instructions leave a few details out, but between what is there and what is silk-screened onto the boards, it's pretty easy to figure out where each part goes.
Title: Re: DIY Amps for NX-Oticas
Post by: electriceye on 7 Dec 2020, 05:49 am
Also btw, I planned to do a tube audio system all DIY with a budget of $2,000 for preamp and amp, probably stretching to much more after tubes. I opted for the elikit 8500 built by me for $450 (its working great but only tested as phono stage, and bested my highly regarded budget phono) slightly upgraded with solen fast caps. Im guessing this build will be around $800 putting me at $1250 if all goes well. So, I'll be at a $750 surplus with about $1000 or more to spend on a dac now (dac advice?) . It just has to equal my IDA-16 integrated and I'll be satisfied (or close to it), guessing I'll come at least close, stoked to own an all diy system minus the turntable and dac. I was listening to the nx studios with the ida-16 and remembering when my local audio shop played a 6 figure system and how damn close I am to it already, thanks largely to the nx-studios but also nuprime.
Title: Re: DIY Amps for NX-Oticas
Post by: electriceye on 15 Dec 2020, 02:23 am
Basic question, what is everyone using for internal wiring (both electrical/audio)?

Also, are there any good tutorials for wiring monoblocks specifically for the power supply as it would apply to Folsom EC7293? I bought the dualpoles with the folsom. I plan on reading this: 3 to 10 times: http://www.decdun.me.uk/gainclone_psu.html but thought something more specific would help as well, it's definitely my area I'm most confused in, and seems to be highest stakes. Feeling pretty good about cap/resister placement, I've done that a ton with guitar pedals. purchased the BOM, feeling good about that I think.

Hopefully it is okay to slightly hijack the thread.
Title: Re: DIY Amps for NX-Oticas
Post by: corndog71 on 15 Dec 2020, 06:53 am
I like Kimber TCSS for internal wiring.

https://www.angela.com/kimberkabletcsshookupwireonefoot.aspx?variationId=1589 (https://www.angela.com/kimberkabletcsshookupwireonefoot.aspx?variationId=1589)
Title: Re: DIY Amps for NX-Oticas
Post by: Edgar77 on 30 Dec 2020, 02:28 am
I finished my latest DIY project - a new preamp. I just got it hooked up to my main system with the NX-Oticas and I'm thrilled with the way it sounds. I think my Parasound JC-2BP will be listed for sale shortly.

The preamp uses a fully balanced Khozmo relay-based input selector and shunt attenuator. All shunt resistors are Takman REY. The series resistor and all signal path resistors are Vishay Z-foils. I'm using AMB Labs alpha 24 balanced line-stage buffers, with an AMB omega 22 supply, with 100VA transformer. A separate supply based on the AMB omega 11 is used for the digital logic, including the OLED display. The Khozmo includes a nice machined metal remote control.

I have two pairs of balanced outputs - one DC coupled directly to the alpha 24, and the other through a set of MiFlex KPCU copper caps which roll off the low end. I've got this latter output feeding my amps into the NX-Oticas, and the single-ended output from the alpha-24 feeds the servo subs.

All audio wiring uses DH Labs solid-core silver with teflon insulation and I'm using Viborg gold over copper XLR connectors.


(https://www.audiocircle.com/image.php?id=217264)


I am new in this forum and I try to learn.
Which rack are you using?
Is that something special to minimize vibrations?

And in general: Many of the nice enclosures are also available in 19" width to be mounted in 19" racks. Is that a good idea - at least for someone who starts new and buys his first enclosures?
Here are samples from https://modushop.biz/ :

(https://modushop.biz/site/image/cache/catalog/Dissipante3U-230x230h.jpg)
(https://modushop.biz/site/image/cache/catalog/data/DSC_9642-600x600-600x600.jpg)

Thanks

Edgar
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 31 Dec 2020, 03:56 pm
This is a Hybrid Standard rack from Solid-Tech. The corner posts are hollow aluminum and can be filled with sand (which I did) to provide damping and more mass. Each corner post is spiked and sits in a cup at the top of the post below to provide a mechanical path for vibration. The shelves are all adjustable with aluminum brackets holding MDF shelves. This rack is available in numerous configurations and colors, with different shelf materials including veneered wood, concrete and carbon fiber. It's very well made and relatively easy to put together (it took me the good part of a day including filling the individual corner posts with sand).

(https://www.audiocircle.com/image.php?id=218978)

The wider Modushop enclosures have a front panel width just under 18". This is what I used for my preamp on the top of the rack. It's possible that they have rack-mount tabs available, which are designed to bolt onto a 19" wide rack. I haven't looked into it. Rack mounting is primarily used when you want to get the most equipment packed into the minimum space, and where you want to make sure the equipment can't fall out if the rack is jostled. It's generally not used for home audio installations, particularly if your equipment is in your listening room.

There are a lot of different home audio rack manufacturers. I think Solid-Tech makes some of the better ones, assuming you like the hitech-industrial styling. If you are looking for something in wood, check out Timbernation.
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 31 Dec 2020, 08:54 pm
Jaytor did you find a source for knobs without position marks?
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 31 Dec 2020, 09:34 pm
My original photo showed knobs I got from Parts Express. These are polished aluminum (but without position markers) and didn't match the brushed aluminum from the Modushop chassis very well. I found someone on AliExpress that had knobs (again with no position markers) that have a sand-blasted type finish that matched pretty well with the brushed aluminum. So that is what is shown in the photo I just uploaded. They took forever to ship though. They took a little more than 2 months to get. But they are pretty nice quality.

https://www.aliexpress.com/item/32600707771.html?spm=a2g0s.9042311.0.0.22cc4c4dBABC9s
Title: Re: DIY Amps for NX-Oticas
Post by: Edgar77 on 1 Jan 2021, 06:10 am
Thanks for the info about the Hybrid Standard rack from Solid-Tech.

I looked them up online and I found lots of details. I even found a price list here.
https://drive.google.com/drive/folders/12bYUjzS-Sg1P6Ft8E0h_YJ6PjZxqam6O
But it seems every nut and bolt is listed separately which makes it difficult to get an idea about the price of the whole thing.
Obviously I could ask a shop for a quotation. But maybe you can give me, and maybe others, an idea about the price.
When I look at their nuts and bolts price list and your rack then I guess your rack cost a couple of thousand USD, maybe even more than a thousand per floor level, correct?
Thanks

Happy New Year to everybody!

Edgar
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 1 Jan 2021, 02:28 pm
The rack I have has (or had this past spring) a retail price of $2650. That's including the small floor cups which you wouldn't need on carpet. My dealer gave me a discount off this price.
Title: Re: DIY Amps for NX-Oticas
Post by: Edgar77 on 26 Jan 2021, 11:40 am
About audio power amps for these speakers but also in general.

For a long time I thought it is possible to measure amplifiers and find out which amps have the better technical data and are better.

By now I watched probably at least 100 videos from Danny Richie from GR-Research, Paul from PS Audio and others. And I read lots of articles about power amps especially on the http://neurochrome.com/ website. And now I am confused.

Is there something like a better amp? Or is it more that amps are different but not clearly better?

I like to buy and build for myself a very good audio system. Maybe like in this thread the MX-Oticas with Neurochrome Modulus-286 amps plus subs. In the moment I have Danny's H frames with 2 drivers in my mind.

My intention is not to try two or more different amps, different speakers, different everything. My intention is to buy and build something very good and that's it.
Is that a reasonable and realistic idea?
It seems in this and other threads many audiophiles try constantly different speakers, amps, etc.
I understand the fun factor of playing around with these things but it obviously cost a lot of money.
Why not buy something very good from scratch and that's it?

Coming back to this thread: Are the MX-Oticas with Neurochrome Modulus-286 amps a good combination? Or which other amps would be better?

I consider myself a modern electronics guy. I don't intend to use tubes or vinyl, ever.
Title: Re: DIY Amps for NX-Oticas
Post by: sarora9 on 26 Jan 2021, 02:46 pm
I have not heard the neurochromes but given the set of people who vouch for them I'd guess they will compete with most other amps out there.

I have Folsom 7293 (built by somebody else) and it is amazing too. If you are into DIY please also build yourself some decent cables (power/interconnect/speaker). They  are needed to get the most out of a resolving system.
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 26 Jan 2021, 04:38 pm
Quote
Why not buy something very good from scratch and that's it?

The problem is that everyone hears a little differently. A system that sounds great to you might be disappointing to someone else and vice versa. There is also system synergy to consider. Depending on other components (such as your source, preamp, cables), one amp may sound better than another.  These are the main reasons people tend to try multiple products.

That said, you're more likely to find a good match by starting with a well regarded product. Measurements only tell part of the story. An amplifier that measures really badly will almost certainly sound worse than an amp that measures great, but keep in mind that traditional measurements use one or a few pure tones into test loads. They don't measure performance on real music into real speaker loads.  And the parameters that are measured don't always correlate well with listener's preferences.

As an example, very highly regarded Pass amplifiers have considerably worse measurements than an amp like the Neurochrome Modulus amps, but many audiophiles strongly prefer the sound and are willing to pay many times more money.  The same can be said for most tube amplifiers.

If you want build your own amplifier, and particularly if you don't have a lot of DIY electronics experience, I think the Neurochrome amps are an excellent place to start. Since the amplifier module itself is already assembled, the full amplifier is fairly easy to build and your results are likely to be consistent with other builds. These amps are very clean sounding and fairly neutral, and the Mod-286 provides enough power to drive the NX-Oticas fairly well, particularly when supplemented with the powered subs. For the money required to build them, I doubt you will find anything that will objectively perform any better.

If you can afford it, I'd recommend a dual-mono build (meaning separate transformers and power supplies for each channel) or monoblocks. I haven't personally compared the single supply build of these amps with dual mono, but in my experience with many other amplifiers, separate power supplies provide better imaging and dynamics (sometimes significantly better) than the the same amp built as a single-supply stereo amp.

I currently have a pair of Neurochrome Mod-286 monoblocks in my amplifier rotation used to drive my NX-Oticas and find the sound to be quite good. Is it as good as a $5K or higher amp from Pass, Parasound, Bryston, etc.? Probably not, but it is close in my system. Fortunately, the NX-Oticas are fairly efficient and easy to drive.

But I'll reiterate my first point. Everyone hears a bit differently and will appreciate different aspects of the sound. And system synergy is key. I don't think you will be disappointed at all with the NX-Oticas and subs, but if you have the opportunity to try different electronics and cables, I'd encourage you to do that.

- Jay
Title: Re: DIY Amps for NX-Oticas
Post by: corndog71 on 26 Jan 2021, 08:15 pm
My intention is not to try two or more different amps, different speakers, different everything. My intention is to buy and build something very good and that's it.
Is that a reasonable and realistic idea?

Buy whatever you think will get you there and live with it. 

If it makes you happy then congrats!  You can listen to music and not worry about what others think.

If it doesn’t then you will have learned that audio gear is subjectively different regardless if it measures well and don’t say we didn’t warn you.
Title: Re: DIY Amps for NX-Oticas
Post by: poseidonsvoice on 26 Jan 2021, 08:46 pm
The problem is that everyone hears a little differently. A system that sounds great to you might be disappointing to someone else and vice versa. There is also system synergy to consider. Depending on other components (such as your source, preamp, cables), one amp may sound better than another.  These are the main reasons people tend to try multiple products.

That said, you're more likely to find a good match by starting with a well regarded product. Measurements only tell part of the story. An amplifier that measures really badly will almost certainly sound worse than an amp that measures great, but keep in mind that traditional measurements use one or a few pure tones into test loads. They don't measure performance on real music into real speaker loads.  And the parameters that are measured don't always correlate well with listener's preferences.

As an example, very highly regarded Pass amplifiers have considerably worse measurements than an amp like the Neurochrome Modulus amps, but many audiophiles strongly prefer the sound and are willing to pay many times more money.  The same can be said for most tube amplifiers.

If you want build your own amplifier, and particularly if you don't have a lot of DIY electronics experience, I think the Neurochrome amps are an excellent place to start. Since the amplifier module itself is already assembled, the full amplifier is fairly easy to build and your results are likely to be consistent with other builds. These amps are very clean sounding and fairly neutral, and the Mod-286 provides enough power to drive the NX-Oticas fairly well, particularly when supplemented with the powered subs. For the money required to build them, I doubt you will find anything that will objectively perform any better.

If you can afford it, I'd recommend a dual-mono build (meaning separate transformers and power supplies for each channel) or monoblocks. I haven't personally compared the single supply build of these amps with dual mono, but in my experience with many other amplifiers, separate power supplies provide better imaging and dynamics (sometimes significantly better) than the the same amp built as a single-supply stereo amp.

I currently have a pair of Neurochrome Mod-286 monoblocks in my amplifier rotation used to drive my NX-Oticas and find the sound to be quite good. Is it as good as a $5K or higher amp from Pass, Parasound, Bryston, etc.? Probably not, but it is close in my system. Fortunately, the NX-Oticas are fairly efficient and easy to drive.

But I'll reiterate my first point. Everyone hears a bit differently and will appreciate different aspects of the sound. And system synergy is key. I don't think you will be disappointed at all with the NX-Oticas and subs, but if you have the opportunity to try different electronics and cables, I'd encourage you to do that.

- Jay

Overall I agree with Jay, although I will coax you to look at Neurochrome's 686 design over the 286. There is a just a bit more ease (i.e. lower THD overall at higher wattages) and the costs are roughly similar if you are swinging with a DIY hammer. The 686 I have heard on multiple occasions with the NX Otica's and it is a very fine choice.

Best,
Anand.
Title: Re: DIY Amps for NX-Oticas
Post by: Edgar77 on 27 Jan 2021, 12:19 am
Thanks for all your comments, I appreciate them.

I learned soldering 3 decades ago and recently I bought a hot air station and I did some SMD test boards to learn that. I am pretty sure the electronics part should be manageable for me.
I am normally good enough with mechanics and get things done. I.e. I built two racing quads from scratch, one of them has tiny electronics. I know I have to be careful when I "build" the amplifier mechanics to get everything 100% right.

Obviously it would be good if I could hear different speaker and amp combinations before I buy/build them. The problem is that I live in Bangkok, Thailand and I would be surprised if many of Danny's speakers and Tom's amps are around here. But maybe I should search in the forums - maybe there are others nearby.

I also have to think about building the speakers. I am pretty sure I am able to glue the parts together (see Peter's videos). But I have no experience at all with veneer or high quality painting. Maybe it's better if I find a good furnisher here to do that for me. Let's see.

I will continue reading lots of threads here and in Tom's Neurochrome forum and learn. I am not in a hurry.

Thanks for your advise

Edgar
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 27 Jan 2021, 12:25 am
Check out DIYAudio.com. There are a lot of very sharp audio engineers that are very gracious with their time, and lots of ideas. Of course, the danger of doing this is that you might get sucked into starting lots of projects. :D I'm finishing up my fourth project in the past year (a preamp and three pairs of monoblocks), and have a several more in the planning and parts collection phases.
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 27 Jan 2021, 12:46 am

I consider myself a modern electronics guy. I don't intend to use tubes

That was pretty much my attitude for the last 20 years running the HIFI gauntlet. Now I'm at tubes and not going back. If you must go DIY, go get an Elekit tu-8600s with all the upgrades before they are all gone, plus vcap cutf coupling caps and you will have a truly high end amp. There is a reason why Danny Richie uses one on his NX-Tremes.
Title: Re: DIY Amps for NX-Oticas
Post by: Edgar77 on 27 Jan 2021, 02:32 am
Check out DIYAudio.com. There are a lot of very sharp audio engineers that are very gracious with their time, and lots of ideas. Of course, the danger of doing this is that you might get sucked into starting lots of projects. :D I'm finishing up my fourth project in the past year (a preamp and three pairs of monoblocks), and have a several more in the planning and parts collection phases.

Thanks, I follow already a couple of threads over there about Tom's Neurochrome Amps. That keeps me busy enough in the moment.
New audio projects are fine. I just try not to repeat building the "same" things again.
In the moment I just received all the parts for Tom's H-22 headphone amp. I can't wait to see how that will sound. But I still take my time with it.

Did you or anybody here built a DAC? Are there any DIY DACs out there?
Since I read it I try to keep in mind "The Layout is the Circuit". https://neurochrome.com/pages/grounding
Maybe for some devices, like maybe a DAC and preamps, it's better to let the professionals do the work.
But I keep my mind open about that one.
Title: Re: DIY Amps for NX-Oticas
Post by: Edgar77 on 27 Jan 2021, 02:34 am
That was pretty much my attitude for the last 20 years running the HIFI gauntlet. Now I'm at tubes and not going back. If you must go DIY, go get an Elekit tu-8600s with all the upgrades before they are all gone, plus vcap cutf coupling caps and you will have a truly high end amp. There is a reason why Danny Richie uses one on his NX-Tremes.
Thanks, maybe in 20 years ;)
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 27 Jan 2021, 03:51 am
Quote
Are there any DIY DACs out there?

I haven't built a DIY DAC, but you can check out https://www.amb.org/audio/  (https://www.amb.org/audio/). I've built a few of Ti's designs and they work well.
Title: Re: DIY Amps for NX-Oticas
Post by: madsry on 4 Feb 2021, 05:17 am
First, thank you all for the great thread.

I’m very intrigued with the Neurochrome offerings as well as the Folsom 7293. While I hear and respect Jaytor’s SS preference, I’m curious if anyone has or will be trying a tube preamp in conjunction with Neurochrom or Folsom amps. I’m pretty sure that I’ve been infected with at least some of the tube flavor preference for the foreseeable future, but also have a lot to learn/experience still. Playing with a B1 preamp at the moment, and may have a 6SN7 based preamp to play with soon. Still very open to ideas though.

NXtremes are on the future wish list, but for now, I’m nearly settled on buying NX Studios to go with stereo triple stacks I’m gathering parts for now.
Title: Re: DIY Amps for NX-Oticas
Post by: Edgar77 on 4 Feb 2021, 05:33 am
About Neurochrome and it's owner Tom Christiansen.
A few days ago an interview with Tom was published on YouTube.

https://youtu.be/1VklknumxTA
https://youtu.be/X9xW9OAZpNs

It's interesting. I was surprised about his education, work experience and knowledge.
He philosophy with his amps is clear. Summary: The amps are as transparent as possible. On the output is what was input - just amplified.

Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 6 Feb 2021, 05:39 pm
I finished (well, almost) my latest DIY amplifier build. This is another set of monoblocks - this time based on Bruno Putzeys' Purifi 1ET400A class D amplifier modules.

I tried class D a couple of years ago with the Nord NC500 monoblocks which use a Hypex module. I found the sound to be very clean and clear, but they sounded a bit thin and were not very engaging compared to my Krell FPB-300 (which they replaced after the Krell died after 20+ years) or my Parasound JC5 (which replaced the Nords).

But since I've really gotten into DIY in the past year or so, I decided to give class D another try. I have heard good things about the Purifi modules. I also decided to use a large linear power supply because many of the highly regarded commercial class D implementations take this approach, and because I could build it myself.

Each monoblock uses a 1500VA transformer with custom secondaries (Toroidy Supreme Audio model). There are several linear power supplies for the different voltage requirements. The high voltage rails (about 68V) have 134,000 uF in the capacitor banks in a CRCRC configuration. The low voltage supply which provides power for the input buffer and Purifi input circuits provides 20 volt rails with another 54,000 uF in the cap banks. This feeds a low-noise regulator on the input buffer to generate the required +/- 12V. Finally, one more regulated power supply generates the 15V gate drive (referenced to the negative high voltage rail).

An additional 12V power supply module is included to drive "accessories" which include the power light on the push button, a 32 segment LED power display on the front panel, and a delayed start circuit which allows the power supplies to reach steady state before asserting the AMP_ON signal to the Purifi modules. I have additional switches on the backpanel which can turn off the front panel lights when I don't want the distraction.

I am currently using the Neurochrome input buffer, but my plan is to experiment with other buffers over time.

The only thing that is remaining is to get an smoked acrylic panel which will fit into the front panel over the LED bargraph. The company that I have worked with in the past is moving, but should be able to make this for my in a couple weeks.

The first monoblock has been powered on for 3 weeks and has about 200 hours of music playing on it. The second one has only been on for a week and has probably 60 hours on it.  I expect it will take a few more weeks of playing before the amps are fully burned in, but I'm quite pleased with the sound so far. Very detailed with sweet sounding vocals - more engaging then the Nord amps I had in the past, but virtually everything in my system has changed since then. I'll report back after I've had a few more weeks on them.

(https://www.audiocircle.com/image.php?id=220584)

(https://www.audiocircle.com/image.php?id=220585)

(https://www.audiocircle.com/image.php?id=220586)

(https://www.audiocircle.com/image.php?id=220583)

Title: Re: DIY Amps for NX-Oticas
Post by: Endo2112 on 6 Feb 2021, 06:45 pm

Very nice work!!!

Don
Title: Re: DIY Amps for NX-Oticas
Post by: Edgar77 on 7 Feb 2021, 08:54 am
I finished (well, almost) my latest DIY amplifier build. This is another set of monoblocks - this time based on Bruno Putzeys' Purifi 1ET400A class D amplifier modules.
ps://www.audiocircle.com/image.php?id=220583[/img]

Looks great!
How is the new amp compared to the Neurochrome Class-AB Amp which you described earlier in this thread?
Title: Re: DIY Amps for NX-Oticas
Post by: mlundy57 on 7 Feb 2021, 05:16 pm
Very nice. Here's hoping the sound quality is everything you were expecting and then some.  :thumb:
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 7 Feb 2021, 05:54 pm
Thanks folks. I want to give them a few hundred more hours before I make any critical assessments. Also, I haven't had a chance to readjust my subs for the change in gain and input impedance (I have a series high-pass cap in my preamp). But even without making any adjustments, they are sounding very nice - at least on par with the Mod-286 amps.
Title: Re: DIY Amps for NX-Oticas
Post by: Chilkoot on 7 Feb 2021, 06:41 pm
Has anyone done a NX-Studio and Folsom 7293 combo? I would be interested to hear (read) comments.
Title: Re: DIY Amps for NX-Oticas
Post by: madsry on 7 Feb 2021, 07:36 pm
I too would be very interested in feedback about the NX Studio / 7293 combo (as well as 686).  Even better if anyone has done so with a tube DAC and/or tube preamp.

Jaytor, curious if you’re still content/happy with the Oticas as you as xperiment with different components.  Things could always change, but Oticas or Extremes are still target based on my experience thus far.
Title: Re: DIY Amps for NX-Oticas
Post by: Folsom on 7 Feb 2021, 08:30 pm
I too would be very interested in feedback about the NX Studio / 7293 combo (as well as 686).  Even better if anyone has done so with a tube DAC and/or tube preamp.

Jaytor, curious if you’re still content/happy with the Oticas as you as xperiment with different components.  Things could always change, but Oticas or Extremes are still target based on my experience thus far.

https://www.diyaudio.com/forums/group-buys/338275-folsom-ec7293-pvi-powered-frontend-60-120w-8-4ohm-post6518836.html
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 7 Feb 2021, 09:17 pm
Quote
Jaytor, curious if you’re still content/happy with the Oticas as you as xperiment with different components.  Things could always change, but Oticas or Extremes are still target based on my experience thus far.

I am still very impressed with the NX-Oticas. I think they are the best speakers I have owned (and that includes a number of well regarded speakers over the years including Tympani IVs, Duntech Sovereigns, and Revel Studios).  I don't have the vertical space for the Extremes (my listening room ceiling is about 7'9"), but I am very interested in the Line Forces and would like to build a set sometime soon (I have already collected the NEO 10 drivers).
Title: Re: DIY Amps for NX-Oticas
Post by: mlundy57 on 8 Feb 2021, 08:11 pm
I am still very impressed with the NX-Oticas. I think they are the best speakers I have owned (and that includes a number of well regarded speakers over the years including Tympani IVs, Duntech Sovereigns, and Revel Studios).  I don't have the vertical space for the Extremes (my listening room ceiling is about 7'9"), but I am very interested in the Line Forces and would like to build a set sometime soon (I have already collected the NEO 10 drivers).

If you're not already on the list for the cabinets, get a hold of Jay before he does the next run or you may end up waiting awhile for another run to be cut.
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 8 Feb 2021, 08:20 pm
Thanks Mike. Yes, I'm on the list and have been pestering Jay regularly  :icon_lol:
Title: Re: DIY Amps for NX-Oticas
Post by: JTS410 on 8 Feb 2021, 11:25 pm
About audio power amps for these speakers but also in general.

For a long time I thought it is possible to measure amplifiers and find out which amps have the better technical data and are better.

By now I watched probably at least 100 videos from Danny Richie from GR-Research, Paul from PS Audio and others. And I read lots of articles about power amps especially on the http://neurochrome.com/ website. And now I am confused.

Is there something like a better amp? Or is it more that amps are different but not clearly better?

I like to buy and build for myself a very good audio system. Maybe like in this thread the MX-Oticas with Neurochrome Modulus-286 amps plus subs. In the moment I have Danny's H frames with 2 drivers in my mind.

My intention is not to try two or more different amps, different speakers, different everything. My intention is to buy and build something very good and that's it.
Is that a reasonable and realistic idea?
It seems in this and other threads many audiophiles try constantly different speakers, amps, etc.
I understand the fun factor of playing around with these things but it obviously cost a lot of money.
Why not buy something very good from scratch and that's it?

Coming back to this thread: Are the MX-Oticas with Neurochrome Modulus-286 amps a good combination? Or which other amps would be better?

I consider myself a modern electronics guy. I don't intend to use tubes or vinyl, ever.

Some incredible builds on this thread so far, thought I'd throw in my modest one.  I originally built these fully-balanced monos based on the Hypex NC400 class D modules to power the 15" woofers on my first open baffle build.  As you can see from the oversized cases (lol) the implementation is very straight forward.  I'm running them as my primary amps now full range and they are some of the best I've had in my system.   Only thing is they are very open on top with a lot of detail.....not fatiguing at all with my current speakers but I'm about to pull the trigger on a pair of NX-Otica's so will see how they compare vs. my tube power amp.


(https://www.audiocircle.com/image.php?id=220679)


(https://www.audiocircle.com/image.php?id=220681)


(https://www.audiocircle.com/image.php?id=220682)

Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 8 Feb 2021, 11:43 pm
Nice looking build. You should consider replacing one of the sets of binding posts with tube connectors when you get the NX-Oticas.
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 16 Mar 2021, 11:14 pm
So I decided to build a Neurochrome Modulus-686. After letting it break in for a few days, I’d say it’s about as good as any solid state amp I have heard under $10k. I think my PS Audio BHK300 monos are far better across the board. The closer match is with the Elekit TU-8600s. They are very close in transparency. I like them both equally. I will be building the Folsom EC7293 monos as soon as I can get my hands on some backordered parts.

(https://www.audiocircle.com/image.php?id=222081)
Title: Re: DIY Amps for NX-Oticas
Post by: corndog71 on 17 Mar 2021, 12:04 am
I thought about building the neurochrome amp but it would be cheaper to buy a Schiit Aegir.
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 17 Mar 2021, 12:15 am
I thought about building the neurochrome amp but it would be cheaper to buy a Schiit Aegir.
I haven’t heard the Aegir, but I bet the Neurochrome is a better sounding amp. That said, I am looking at getting a Freya+ to go with the Neurochrome as there is no other balanced tube preamps near its price. Plus it has great reviews.
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 17 Mar 2021, 01:04 am
@mkrawcz - Nice build! It looks like you went all-in with the Neurochrome boards. I'm using Tom's soft-start board on another project. It's a well-executed design.

I'm glad it's sounding good for you. I'm listening to my Mod-286 monoblocks right now while I do some mods on my Purifi amps. I bought a pair of input buffer boards from VTV that use a 6922 triode feeding a pair of Weiss discrete op-amps. I've got the first one installed and plan to finish the second later this week.


(https://www.audiocircle.com/image.php?id=222093)
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 17 Mar 2021, 01:19 am
@Jaytor, yes the soft start board is fantastic. I am planning on using them for the Folsom amp build. It will be interesting to hear your feedback on that 6922 setup.
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 17 Mar 2021, 02:22 pm
I thought about building the neurochrome amp but it would be cheaper to buy a Schiit Aegir.

I've owned both, the Neurochromes are better but you can't go wrong with the Aegir.
Of the four amps I have recently owned the Aegir ranks above the Hegel H360 but below the Folsom EC7293 and The Neurochrome Mod186.
Title: Re: DIY Amps for NX-Oticas
Post by: sunnydaze on 17 Mar 2021, 03:07 pm
I've owned both, the Neurochromes are better but you can't go wrong with the Aegir.
Of the four amps I have recently owned the Aegir ranks above the Hegel H360 but below the Folsom EC7293 and The Neurochrome Mod186.

I haven't heard any of these amps......
And I'm not one that believes that higher price always guarantees better SQ.....within a reasonable $$ range.

But if I read you correctly, are you saying that the Hegel -- which costs approx 5 to 10X more than all these other amps -- sounds inferior to them all?   I find that hard to believe.    :scratch:



Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 17 Mar 2021, 03:54 pm
I haven't heard any of these amps......
And I'm not one that believes that higher price always guarantees better SQ.....within a reasonable $$ range.

But if I read you correctly, are you saying that the Hegel -- which costs approx 5 to 10X more than all these other amps -- sounds inferior to them all?   I find that hard to believe.    :scratch:
The Neurochrome mod-686 is about $3k once you have all the parts so it’s more like half the price. When it comes to price vs performance, these particular DIY amps are better than most retail amps under $10k. They are still flat out not nearly as good as PS Audio BHKs which remain better than any amp I ever heard or demoed by far My previous benchmark was my brothers Krell Evo 403 and even that is not much competition.
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 17 Mar 2021, 04:04 pm
I haven't heard any of these amps......
And I'm not one that believes that higher price always guarantees better SQ.....within a reasonable $$ range.

But if I read you correctly, are you saying that the Hegel -- which costs approx 5 to 10X more than all these other amps -- sounds inferior to them all?   I find that hard to believe.    :scratch:

I wouldn't have sold my H360 in favor of the Folsom amp if it was better. The DIY price performance advantage over manufactured products is quite large. This is why I am building my own preamp using Khozmo parts later this year.

The better question is why a single Schiit Aegir is slightly better than the Hegel with high-efficiency speakers. Unless you need all of that power the Aegir is the no brainer. You can have Aegir monos for less than half the price of a used H360 or H390.
Title: Re: DIY Amps for NX-Oticas
Post by: sunnydaze on 17 Mar 2021, 06:41 pm
I apologize.....I researched real quick and was mistaken in my pricing.    :oops:

Thanks so much for your thoughtful and informative reply.    :thumb:
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 6 Apr 2021, 12:26 am
Quick Neurochrome mod686 update for anyone who has this amp or is considering it. I changed out a little surface mount resister to increase the input gain from 26db to 29db and that seems to have had a dramatic impact on this amps performance. I am using an Elekit TU8500 preamp as a unity gain tube buffer and the combo is really good.
Title: Re: DIY Amps for NX-Oticas
Post by: poseidonsvoice on 6 Apr 2021, 01:03 am
Quick Neurochrome mod686 update for anyone who has this amp or is considering it. I changed out a little surface mount resister to increase the input gain from 26db to 29db and that seems to have had a dramatic impact on this amps performance. I am using an Elekit TU8500 preamp as a unity gain tube buffer and the combo is really good.

In your setup, you may have just needed the extra gain, although your signal to noise ratio will be slightly worse. It’s not a big deal with the 686 since the base SNR is sooo low anyway. It also depends on the output voltage of your source and sensitivity of your speakers.

For example in my setup with a 4-5V RMS source, 96 dB speakers and no preamp (I used to own a TAPX though), the 20dB gain version of the 686 is best.  I removed the same SMD you changed and that dropped the gain from 26dB to 20dB.

It’s all about adjusting things to your liking. One thing is for sure, the 686 isn’t the bottleneck if transparency, neutrality and detail are what you are after.

Best,
Anand.
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 6 Apr 2021, 01:42 am
It’s probably just preference although my Matrix Element x DAC outputs 4VRMS and the Oticas are 93db. The higher gain just seems to create more realism and more dynamics.
Title: Re: DIY Amps for NX-Oticas
Post by: Bullitt5094 on 6 Apr 2021, 02:55 am
What I'm currently using to power my X-LS Encores. All DIY of course.

Nelson Pass B1 Korg preamp
(https://www.audiocircle.com/image.php?id=222975)

Pass F5 Power Amp
(https://www.audiocircle.com/image.php?id=222976)

I am working on another Pass item. It's an active crossover. Just finished stuffing the resistors today.
(https://www.audiocircle.com/image.php?id=222977)

Next... I have everything to build a second F5. When completed I then intend to use the active crossover in front of the two F5 amps to power the 4 drivers in a NX-Studio build. If the woofers ever come in for them! If not, I'm looking for a similar two-way OB project.




Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 21 May 2021, 01:50 pm
I finally got around to building a Folsom EC7293. I initially used a pair of cheap Kemet film caps for the input cap and it sounded good. I changed those out to VCAP ODAMs and now this amp sings.


(https://www.audiocircle.com/image.php?id=224768)
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 21 May 2021, 02:10 pm
Very nice!
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 21 May 2021, 02:45 pm
Yeah, that is excellent work. I have one of those new, smaller soft start boards from Neurochrome that I plan on using for a preamp project. They are so much easier to fit into a chassis than those huge old ones lol.

My Mod186 monos have been in my system for months, I am going to switch out for my Folsom for a while.
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 21 May 2021, 03:37 pm
Yeah, that is excellent work. I have one of those new, smaller soft start boards from Neurochrome that I plan on using for a preamp project. They are so much easier to fit into a chassis than those huge old ones lol.
Tom's ISS board is worth every penny. I will not build an amp without it. I will probably end up drilling out a hole for a trigger jack and use that feature of the board as well.
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 21 May 2021, 03:51 pm
Tom's ISS board is worth every penny. I will not build an amp without it. I will probably end up drilling out a hole for a trigger jack and use that feature of the board as well.

I agree - nice design. I'm using it in my new preamp build. This one uses a separate power supply chassis.

(https://www.audiocircle.com/image.php?id=224780)

I have four unregulated +/- supplies (two for each channel) that feed different parts of the preamp, plus a regulated digital supply for the input selector and stepped attenuator control/display. The unregulated supplies will feed shunt regulators that are mounted in the main chassis close to to circuit boards they power. I've been building the boards for the main chassis, but haven't started putting everything together yet. A 14 conductor umbilical cord delivers the DC power to the main chassis.
Title: Re: DIY Amps for NX-Oticas
Post by: Early B. on 21 May 2021, 04:04 pm
This thread is awesome!
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 25 May 2021, 11:33 pm
My Mod186 monos have been in my system for months, I am going to switch out for my Folsom for a while.
All I have to say after a week of break in is the Folsom amp is awesome.
Title: Re: DIY Amps for NX-Oticas
Post by: sarora9 on 26 May 2021, 01:07 am
mkrawcz, how does it compare to your other amps? Very curious. (I have a Folsom 7293 too and v. happy with it.)
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 26 May 2021, 01:25 am
mkrawcz, how does it compare to your other amps? Very curious. (I have a Folsom 7293 too and v. happy with it.)
It’s subjective, but I think it beats the Neurochrome and the Elekit. I haven’t tried comparing it to my BHKs yet, but it might be pretty close. The dynamics and soundstage are right up there. I have some Audio Note caps coming tomorrow to try for the feedback cap to see if there is anymore to be gained.
Title: Re: DIY Amps for NX-Oticas
Post by: sarora9 on 26 May 2021, 01:40 am
OK that's pretty high praise. I have not heard neurochrome or Elekit myself but have read the praise for them.

Waiting to hear about your experiment with the capacitor; the one in mine is good but not an expensive one
Title: Re: DIY Amps for NX-Oticas
Post by: sarora9 on 26 May 2021, 01:41 am
(deleted duplicate post)
Title: Re: DIY Amps for NX-Oticas
Post by: tull skull on 27 May 2021, 04:14 am
Guys I know this is a little bit from left field and also a little bit under your skill level but your discussion prompted curiosity to know if you have had any exposure/experience with the Akitika kit? Thanks for your time.:)
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 28 May 2021, 10:16 pm
OK that's pretty high praise. I have not heard neurochrome or Elekit myself but have read the praise for them.

Waiting to hear about your experiment with the capacitor; the one in mine is good but not an expensive one
I changed out the feedback cap at C3 from a Nichicon ES to an Audio Note standard foil and it completely changed the amp. Before, the amp had this lower mid bloom that was not right, the soundstage was smeared, and the sound was slightly veiled. The new cap changed everything and this amp is amazing. My BHKs probably have it beat in dynamics, but the Folsom is at least as good with the soundstage and clarity. The soundstage may even be a little better. Considering what it cost to build this amp, its untouchable.
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 30 May 2021, 01:34 am
I changed out the feedback cap at C3 from a Nichicon ES to an Audio Note standard foil and it completely changed the amp. Before, the amp had this lower mid bloom that was not right, the soundstage was smeared, and the sound was slightly veiled. The new cap changed everything and this amp is amazing. My BHKs probably have it beat in dynamics, but the Folsom is at least as good with the soundstage and clarity. The soundstage may even be a little better. Considering what it cost to build this amp, its untouchable.

I got the impression from Jeremy that the choice of feedback caps wasn't a big deal (I might be misremembering). Those Audionotes are cheap enough to try. Unfortunately I mounted the amp boards on the heatsink instead of on the baseplate like yours. Switching that cap will be a half a days work for me lol.

I don't hear the same issues with the soundstage or with the mid bass as you did though. Even on comparison to my Neurochrome amps. I have a pair of Jantzen Silvers on the input.  I had a pair of Flat stack Jupiters on there first but I found them a bit too smooth, laid back and lacking detail.  I can't remember which Nichicon I used for C3 but I know I didn't use the same green ES version you did. The only thing I remember for sure is that they were 1000uf if that matters at all.
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 30 May 2021, 01:55 am
The Nichicon ES is easy to spot. It’s bright green. If yours is gold it’s probably a KZ and that cap is probably a lot better. Jeremy has been recommending the Rubycon ZL which I think is a similar cap to the Audio Note. I think Rubicon actually designed the Audio Note. The feedback cap definitely makes a big difference. That’s why he left it up to the builder to pick one instead of including it in the BOM.  My regret was not soldiering in a socket header for easy cap swapping.
Title: Re: DIY Amps for NX-Oticas
Post by: RonP on 13 Jun 2021, 09:25 pm
I had some Folsom 7293's built into mono-blocks by pinnocchio over at diyaudio forum's. He did a fantastic job and answered my 9 million dumb emails along the way. A really top notch build.

I only have a few hours of listening on them right now but quite like them.

A few highlights
- XLR in
- Quality Caps and wiring
- Soft Start

He links to the build thread here https://www.diyaudio.com/forums/group-buys/338275-folsom-ec7293-pvi-powered-frontend-60-120w-8-4ohm-post6657513.html (you'll probably want the English translation in the very next post)

He gives a summary of his listening impressions on the bottom of the next page https://www.diyaudio.com/forums/group-buys/338275-folsom-ec7293-pvi-powered-frontend-60-120w-8-4ohm-post6672922.html

Here are a few pics installed here in TX. I had to order another Amp Stand from Butcher Block Acoustics.


(https://imgur.com/Z11vfKT.jpg)

(https://imgur.com/HiJmImD.jpg)

(https://imgur.com/LgfOcgL.jpg)

(https://imgur.com/NmAomdP.jpg)

(https://imgur.com/nqTQBNQ.jpg)

 :popcorn:

(Those are the tape lines on my carpet from LOTS https://www.youtube.com/watch?v=CyTkwkK8ON0
and some cheap yoga blocks https://www.amazon.com/Gaiam-Yoga-Block-Supportive-Latex-Free/dp/B00LY9O83G/ref=pd_bxgy_img_2/134-6843275-0604568?_encoding=UTF8&pd_rd_i=B00LY9O83G&pd_rd_r=3a255a5d-e97a-4c6b-9d74-9c8435b82851&pd_rd_w=jx0GQ&pd_rd_wg=tfnYL&pf_rd_p=fd3ebcd0-c1a2-44cf-aba2-bbf4810b3732&pf_rd_r=YHWNCDB2PJ06AM5ZFYX3&psc=1&refRID=YHWNCDB2PJ06AM5ZFYX3 I'm using to get the speaker cables off the floor)
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 13 Jun 2021, 11:14 pm
Those are solid RonP. I am using those same Neurochrome buffers in my preamp build which is currently mounted to a sheet of mdf. The buffers are extremely transparent.
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 13 Jun 2021, 11:43 pm
@RonP - Very nice build. I bet those sound great. I love the Toroidy transformers. I've used them in my last couple builds.

Did you consider using an input transformer instead of the Neurochrome buffer and input cap?

Title: Re: DIY Amps for NX-Oticas
Post by: RonP on 14 Jun 2021, 12:42 am
thanks guys!



Did you consider using an input transformer instead of the Neurochrome buffer and input cap?

It never dawned on me. We could have used your VTV board and popped a tube on there. oooh la la
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 14 Jun 2021, 03:43 am
I think the advantage of the approach you took is that it is less suspectable to larger DC offset which can saturate a transformer. Downside is higher cost. Of course each approach will also sound a bit different. I'm using Miflex caps as high pass filtering caps between my preamp and amps and they sound great.
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 14 Jun 2021, 03:55 am
We could have used your VTV board and popped a tube on there. oooh la la

I forgot to comment on this. So far, I'm not that happy with the VTV tube buffers. I used these for more than a month so I think they got plenty of break-in.  They just never opened up - just sounded a little too subdued for my taste. I picked up a pair of Pass XA60.8 monoblocks about a month ago and have been listening to them since, so the Purifi amps have been sitting on the sidelines.

I'm planning to design my own input stage for the Purifis as my next experiment with these but I've got a few other projects I want to get done first and have been very busy with work as of late so it's been slow going.
Title: Re: DIY Amps for NX-Oticas
Post by: poseidonsvoice on 14 Jun 2021, 11:04 am
Thanks for the update Jaytor. Good to hear.

RonP...Pinnocchio is a good buddy of mine and his builds are superb, reliable and safe.  :thumb:

I've started (https://www.diyaudio.com/forums/pass-labs/373417-nelson-pass-experimenters-platform-npxp.html) my Pass experiments and we'll see where it goes. Interesting fun so to speak. There are about 1-2 dozen amplifiers I can build into this platform.

I don't want to inundate this thread with my pics and verbage so if interested, link is above.

Best,
Anand.
Title: Re: DIY Amps for NX-Oticas
Post by: RonP on 14 Jun 2021, 01:43 pm
I forgot to comment on this. So far, I'm not that happy with the VTV tube buffers. I used these for more than a month so I think they got plenty of break-in.  They just never opened up -

wow how disappointing. thanks for the update
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 14 Jun 2021, 02:08 pm
I wonder if you can get away with not using an input cap on the Folsom if you put the Neurochrome buffer board before the input. Just short the input cap section.
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 14 Jun 2021, 02:17 pm
wow how disappointing. thanks for the update

Well, it could be that they just weren't a good match to the rest of my system and my listening tastes. But, yes, I was disappointed, particularly since they weren't cheap.  I may try them in a different system to see if they sound any better to me.

I wonder if you can get away with not using an input cap on the Folsom if you put the Neurochrome buffer board before the input. Just short the input cap section.

As far as I know, the Neurochrome buffer is DC coupled so any DC offset will still be passed through (and amplified if you've got any gain in the buffer). Also, I think the Folsom design may require a cap or transformer to prevent adding it's own DC offset from input currents.

Title: Re: DIY Amps for NX-Oticas
Post by: mkane on 14 Jun 2021, 05:32 pm
Aleph J here.
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 14 Jun 2021, 10:03 pm
I picked up a pair of Pass XA60.8 monoblocks about a month ago and have been listening to them since
So how do you like those compared to your JC5?
Title: Re: DIY Amps for NX-Oticas
Post by: AKLegal on 14 Jun 2021, 10:26 pm
I forgot to comment on this. So far, I'm not that happy with the VTV tube buffers. I used these for more than a month so I think they got plenty of break-in.  They just never opened up - just sounded a little too subdued for my taste. I picked up a pair of Pass XA60.8 monoblocks about a month ago and have been listening to them since, so the Purifi amps have been sitting on the sidelines.

That is too bad. I've read alot of mixed reviews on VTV as far as build quality control but not much on sound quality. You have about seven pairs of mono blocks now right?
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 15 Jun 2021, 12:59 am
So how do you like those compared to your JC5?

Both are excellent amps, but the XA60.8s have the edge as they should given the price disparity. The Pass amps have a deeper, more layered sound stage and a gorgeous midrange - particularly vocals. I've sold the JC5 so I didn't get a lot of time to directly compare them. It's possible the JC5 has a bit more bass slam, but since the bottom 2 octaves come from the servo subs in my system, it's a bit difficult to say definitively.

This is definitely a keeper (at least for a while  :D). It gives me a good target to shoot for with my DIY builds. But there are definite downsides. They are big and heavy (each amp is as big and heavy as the stereo JC5), and they use a lot of juice (400 watts each at idle) and therefore generate a lot of heat. But I certainly have no complaints about the sound quality.

I like having monoblocks in my system because I have a set of french doors on the front wall that I like to be able to get to without worrying about tripping over cables, and it's easy to hide the interconnects under cable protectors. Not so easy with speaker cables and power cable.

That is too bad. I've read alot of mixed reviews on VTV as far as build quality control but not much on sound quality. You have about seven pairs of mono blocks now right?


Hah. Only four pairs of monoblocks, plus a couple of older AB stereo amps (Bryston 4B-ST and Krell KAV-250a) :green:. That's not including the 7 channel amp I have in my home theater or the 6 channel amp I have driving my whole-house audio system.

I'm working on another DIY Purifi stereo amp for the bedroom. I want something compact that will drive the NX-Studios I have on order.  :D

The build quality on the VTV tube buffers is excellent. ENIG plated PCB with mostly surface mount components and good quality parts. It's a well designed board that is nicely laid out. I just think it is not a good match for my system and taste. If you were looking for an amp with a mellower, more laid back presentation, or to tame a too-bright system, it would probably work well.

Title: My latest amp build
Post by: Jaytor on 8 Aug 2021, 01:03 am
I wanted a small amp for the bedroom that will be used with a pair of NX-Studios. I built a stereo Purifi amp using the Neurochrome input buffers and a Hypex 3000w SMPS in a Galaxy 2U 230mm x 280mm case. I used the 3KW supply mostly because the 1200W suppliers were out of stock, but it does have the advantage of having multiple power connections.

In order to fit two channels in this case, I had to mount one above the other, and used a 10mm slab of aluminum for the upper case. It's a very tight fit and I have to remove the connectors on the Neurochrome board and hard wire the power connections.

Since the 3KW power supply is not designed for half-bridge amplifiers like the Purifi board, I wired the second channel in reverse phase (both inputs and outputs), to balance the load on the supply so I don't have to worry about large reverse currents at low frequencies (although I'll probably never play the speakers loud enough that this will be an issue anyway).


(https://www.audiocircle.com/image.php?id=227953)

(https://www.audiocircle.com/image.php?id=227954)

(https://www.audiocircle.com/image.php?id=227955)
Title: Re: DIY Amps for NX-Oticas
Post by: DigIndig on 8 Aug 2021, 11:15 pm
Figured I'd share my progress on my own amp builds as I work on my NX-Oticas as well. Last fall, I started a pair of Folsom EC7293 monoblocks, and back in January I bought a Elekit TU-8600S to assemble at some point since I had so much fun building a TU-8800.

Last weekend, I finally had time to start the 8600 build, and I did it over three evenings: the soldering split over two and the transformers and case the third night. It came alive immediately with no issues, and I can already tell it sounds amazing with just the Gold Lion 300Bs in it - I'll try a few other 300B tubes at some point, but for now this will do. The kit came with all the upgrades, and I added VCaps as well.


(https://www.audiocircle.com/image.php?id=227991)

After that experience, I really wanted to finish my EC7293 builds, which had been mostly done minus final assembly and waiting on a few parts which had since come in. Like others, I decided to include the Neurochrome slow start boards, and also have a set of the speaker protection boards that I might integrate in later. For now, each amp will look like this:



(https://www.audiocircle.com/image.php?id=227995)


I saw "will" because it was a bit of a mixed bag. The first one fired up just fine, and I initially tweaked it to have a 8mv DC offset. A little later I went back and was able to get it down to as close to 0 as I could (my meter will flash 1mv every 30 seconds or so).

I was not so lucky with the second unit. First, it had a .4v offset at the output jacks, and the photocells were only reading 2v with the light module. They read a full 8v with my LED flashlight, and the offset remained even if I used the flashlight on the PV cells. I also saw a .3v potential across the input with nothing attached, which seemed odd. As part of an experiment, I plugged a cable (with no signal) into the RCA jack to see what would happen and -poof- I had a smoking 7293 and a blown fuse! (Sorry, no pictures.)  Upon disassembly I discovered that one transistor leg had popped off the solder pad and was hovering less than 1mm above the pad - impossible to see with the board installed against the heatsink. Probably happened somewhere between the drive from my workshop and back, or in the months it's been sitting waiting to be assembled.

I've already fixed both the transistor and replaced the LED module, but of course the EC7293s are on backorder now, so in the meantime I have a really nice sounding monoblock. I still need to drill out a hole on the faceplate for the power switch, which I installed on a long enough wiring harness to fit wherever I finally decide to put it.
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 8 Aug 2021, 11:49 pm
@DigIndig - Sorry to hear about your mishap. I bought the parts to build a pair of Folsom amps last year, but haven't gotten around to building them and have a couple other projects in the works, so these parts won't be used for a while.

I can send you a 7293 if you can replace it once the parts are available. If you are interested, send me a PM with your address.

- Jay
Title: Re: DIY Amps for NX-Oticas
Post by: mkane on 12 Aug 2021, 12:30 am
Pass Aleph J here.
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 12 Aug 2021, 10:01 pm
Just built this Pass ACP+ “naked” preamp. I wanted it for my computer desk to go with a pair of GR desktop minis. Now I have it hooked up to my Folsom and NX Studios and I’m not sure I want to take it out! This thing is really impressive.
 :evil:
(https://www.audiocircle.com/image.php?id=228128)
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 12 Aug 2021, 10:19 pm
Just built this Pass ACP+ “naked” preamp. I wanted it for my computer desk to go with a pair of GR desktop minis. Now I have it hooked up to my Folsom and NX Studios and I’m not sure I want to take it out! This thing is really impressive.

That looks sweet!  I'm tempted to put one together to give it a try but I think I already have too many projects in the works. Maybe next year if the kits are still available.
Title: Re: DIY Amps for NX-Oticas
Post by: Danny Richie on 16 Aug 2021, 03:15 pm
I am about to release an ideal amplifier for the NX-Otica's. Stay tuned.
Title: Re: DIY Amps for NX-Oticas
Post by: poseidonsvoice on 16 Aug 2021, 06:01 pm
That looks sweet!  I'm tempted to put one together to give it a try but I think I already have too many projects in the works. Maybe next year if the kits are still available.

I've thought about building it just for kicks and a plexiglass enclosure.

But too many projects...so nah...

Best,
Anand.
Title: Re: DIY Amps for NX-Oticas
Post by: corndog71 on 16 Aug 2021, 07:00 pm
I am about to release an ideal amplifier for the NX-Otica's. Stay tuned.

I’ve been waiting for this! 

….

still waiting.
Title: Re: DIY Amps for NX-Oticas
Post by: tortoiseman2542 on 16 Aug 2021, 07:22 pm
I am about to release an ideal amplifier for the NX-Otica's. Stay tuned.

Such an amp tease!!  ;)

Robert
Title: Re: DIY Amps for NX-Oticas
Post by: cjsailer on 16 Aug 2021, 10:36 pm
I am about to release an ideal amplifier for the NX-Otica's. Stay tuned.

Oh alright, was going to pull the trigger on one of PS Audio's amps.  But would this be in kit form though?  SS or tube?  Just a few breadcrumbs please.
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 16 Aug 2021, 10:50 pm
I bet I know what it is. :D
Title: Re: DIY Amps for NX-Oticas
Post by: jtwrace on 16 Aug 2021, 10:56 pm
I bet I know what it is. :D
me too
Title: Re: DIY Amps for NX-Oticas
Post by: cjsailer on 18 Aug 2021, 11:10 pm
Well then, how about a little speculation jtwrace or mkrawcz?  If it's a super easy kit, I'd probably give it a shot.  But my eyes are getting old and my hands aren't too steady, wouldn't be able to do any precision soldering.
Title: Re: DIY Amps for NX-Oticas
Post by: Chilkoot on 21 Aug 2021, 05:20 pm
Looking forward to hearing about the amp. Super curious.
Title: Re: DIY Amps for NX-Oticas
Post by: rockdrummer on 13 Sep 2021, 04:35 pm
I have no reason to build more amps right now, but I'm still excited to find out what these amps are....

Ben
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 13 Sep 2021, 05:20 pm
I have no reason to build more amps right now, but I'm still excited to find out what these amps are....

Ben
Check out 26 minutes into the video.
https://youtu.be/_ShoeutZdqQ
Title: Re: DIY Amps for NX-Oticas
Post by: rockdrummer on 13 Sep 2021, 08:09 pm
Thank you.  Looks interesting.

Ben
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 13 Sep 2021, 09:03 pm
I have one of the prototypes coming later this week. The idea of a battery powered amp intrigues me. I may even use a solar powered battery charger so it’s truly “off the grid”.
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 14 Sep 2021, 11:48 pm
Just received my GR-Research battery powered chip amp prototype. Straight away I can tell this amp is really something special. I cannot believe how dynamic this little amp is. It's as transparent as the best amps I've ever heard and its not even broken in yet.
Title: Re: DIY Amps for NX-Oticas
Post by: Hobbsmeerkat on 15 Sep 2021, 01:17 am
I've really been digging mine too.

They really sound incredible and the setup I have currently with a Tube pre-amp is really sweet and sounding, even compared to the 140W tube amps I was using up until then.

I'm really excited to hear it on my X-Statiks, once I get them back..
Not to mention my NX Studios, once they're finished.
Title: Re: DIY Amps for NX-Oticas
Post by: NoahH on 15 Sep 2021, 08:05 am
I am dying for the details. Can you share if they are bridgeable? My NX-tremes are going to be in an area of roughly 750 sqft (open plan house, not monstrous listening room) so while I really want to believe that 10 watts will do it, having a plan b(ridge) would be nice.
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 15 Sep 2021, 09:24 am
I am dying for the details. Can you share if they are bridgeable? My NX-tremes are going to be in an area of roughly 750 sqft (open plan house, not monstrous listening room) so while I really want to believe that 10 watts will do it, having a plan b(ridge) would be nice.
Not bridgeable. The NX-Tremes are 94.5db efficient. 10watts is easily more than you will ever need on those.
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 17 Sep 2021, 11:44 am
(https://www.audiocircle.com/image.php?id=229824)
I figured I would post a pic of the inside of the GR-Research chip amp for the curious. This little amp is quality all the way. It even has what appears to be Cardas Silver plated RCA connectors. There is not much there to get in between you and the music.
Title: Re: DIY Amps for NX-Oticas
Post by: Chilkoot on 18 Sep 2021, 02:31 am
Minimalist!
Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 23 Oct 2021, 10:44 pm
Just built a new one from Neurochrome, the Mod-86 V3. This amp pretty much matches the Benchmark AHB2 in the lowest distortion amplifier in the world category.
(https://www.audiocircle.com/image.php?id=231217)

(https://www.audiocircle.com/image.php?id=231218)
Title: Re: DIY Amps for NX-Oticas
Post by: nlitworld on 24 Oct 2021, 12:37 am
I figured I would post a pic of the inside of the GR-Research chip amp for the curious. This little amp is quality all the way. It even has what appears to be Cardas Silver plated RCA connectors. There is not much there to get in between you and the music.

But does it post a graph of >0.0000001% distortion AND make you breakfast in the morning? These are the important questions that need answered.  :popcorn:
Title: Re: DIY Amps for NX-Oticas
Post by: DJB on 24 Oct 2021, 03:04 am
GR-Research chip amp, when are they available , sounds interesting
Title: Re: DIY Amps for NX-Oticas
Post by: Hobbsmeerkat on 24 Oct 2021, 03:28 am
We currently have approved to make the next batch of 29 chip amps. But the same shortages affecting the world has put a but of a damper on its roll out.

But as soon as we have stock inbound, we'll definitely have more info about them available.  :thumb:
Title: Re: DIY Amps for NX-Oticas
Post by: Jaytor on 24 Oct 2021, 03:57 am
Just built a new one from Neurochrome, the Mod-86 V3. This amp pretty much matches the Benchmark AHB2 in the lowest distortion amplifier in the world category.
(https://www.audiocircle.com/image.php?id=231217)

(https://www.audiocircle.com/image.php?id=231218)

Nice build.
Title: Re: DIY Amps for NX-Oticas
Post by: wgraft5 on 24 Oct 2021, 06:37 am
Just built a new one from Neurochrome, the Mod-86 V3. This amp pretty much matches the Benchmark AHB2 in the lowest distortion amplifier in the world category.
Thats is really nice. :thumb:

I have an upcoming NX Studio build so this is good info.

To bad Neurochrome does not sell turnkey units, I dont have the skill and equipment to assemble one myself. :duh:

I would like one of the GR Chip amps. Parts shortages affecting the world plus I won't be ready to purchase for a few months so not looking good.

Next choice DAC 2-CHerry King version. Its turn key and i can buy it when I'm ready.

I want the tube Doge 8 Preamp at this point, that may change. Definitely want tube pre.

Please excuse my thread jack :icon_twisted:

Title: Re: DIY Amps for NX-Oticas
Post by: mkrawcz on 24 Oct 2021, 09:08 am
We currently have approved to make the next batch of 29 chip amps. But the same shortages affecting the world has put a but of a damper on its roll out.

But as soon as we have stock inbound, we'll definitely have more info about them available.  :thumb:
When I was gathering parts for this latest build, most places where out of stock on the LM3886 chip until September 2022!