[BrandonB]

I've gone on a FET Frenzy... traded with a buddy - my Ayre MX-R Twenty monos (bipolar output) for Pass XA200.5 Class A monos.  That was after I took a chance and bought a Pass XA30.8 Class A amp.  I also sold the KX-R Twenty, because he wanted to give me money and I can get another... or just use the K-5xeMP as I am right now... also FULL of unobtainium Toshiba JFETs. 

The XA30.8 is the best "tube amp" I've ever heard.  It is a revelation.  The XA200.5 is very BIGLY and awesome in a different way.  I will move them along at some point and I will end up with the XA30.8... and some sort of Pass monos... whether XA60.8 or XA100.8 or First Watt for Line Arrays?

If someone wants the XA200.5, they should reach out to me. 

Another pair of speakers I will need to drive are the Mofi Sourcepoint 888.  I like my 8" driver speakers. I wish more options for 8" driver speakers were available, but those appear to be very special anyway.

Now that I have heard what you guys are playing with, "I get it."  Besides, I still have my Ayre VX-5 Twenty for that different, "high resolution" flavor as well.

Perhaps there is an ideal First Watt amp for 96db Line Arrays for someone who REALLY LIKES the XA30.8?   

The First Watt amp that will drive those speakers and "sound like tubes"?  First Watt F5M still "The One"?  I guess if I want SIT, you have to PAY...IT. 

So you have switched most of your equipment for pass labs class A.  So are you liking it better than the Ayre sound?  The SMC Audio amps are compared to the pass labs but I haven't ever compared it would be interesting to be able to compare them.  Have you had a chance to compare your QX-5 twenty to a nice tube DAC?

[Jaytor]

Perhaps there is an ideal First Watt amp for 96db Line Arrays for someone who REALLY LIKES the XA30.8?   

The First Watt amp that will drive those speakers and "sound like tubes"?  First Watt F5M still "The One"?  I guess if I want SIT, you have to PAY...IT. 

I haven't heard any of the SIT amps, but I suspect these will get closest to tube sound in that they have similar distortion characteristics.

The F5M is also a very nice sounding amp. It is probably most similar to the XA25.

I owned a pair of XA60.8s for a while which I think has a very similar sound to the XA30.8. I've listened a few times to the XA25 but not in the same system. I think the XA25 has a bit more control with more natural decay - I think primarily because it has less degenerative local feedback on the outputs. The F5M is similar.  The F5M has less odd-order harmonic distortion compared to either of these, so I expect it will sound a bit more spacious (wider, deeper sound stage). I didn't have the F5M at the same time as the XA60.8, but I think this is the case from my recollection of the XA60.8.

The commercial amps are going to have more protection circuitry, so you are less likely to damage the amp if you short the outputs or drive it too hard, and less likely to damage speakers if something fails in the amp. On the other hand, I think the protection circuits detract slightly from the sound quality.

The XA25 and F5M don't have balanced inputs. If you build an F5M yourself, you can add a line input transformer or some other balanced to single ended circuit if you want balanced inputs. I used the Jensen JT-11P-1 in my builds. But these circuits will have a subtle influence on the sound.

And you'll have to build the F5M yourself (or find a builder or DIY amp for sale). But it can be built for under $500 so it is a real bargain.

[mkrawcz]

The F5M is great. I have a couple of them, including the F5M Redux monoblocks that run on SMPS supplies.  The quality of the power supply and the wiring makes a huge difference with that amp. Currently using a Neurochrome Power 686 supply with mine and the results are great.

[Jaytor]

The F5M is great. I have a couple of them, including the F5M Redux monoblocks that run on SMPS supplies.  The quality of the power supply and the wiring makes a huge difference with that amp. Currently using a Neurochrome Power 686 supply with mine and the results are great.

Nice build. Yes, I agree.

[jmimac351]

So you have switched most of your equipment for pass labs class A.  So are you liking it better than the Ayre sound?  The SMC Audio amps are compared to the pass labs but I haven't ever compared it would be interesting to be able to compare them.  Have you had a chance to compare your QX-5 twenty to a nice tube DAC?

I just traded MX-R Twenty monoblocks.  I still have Ayre VX-5 Twenty and Ayre A-7xe.  The VX-5 Twenty will do things Pass gear won't do. Different flavors.

I have a Joule-Electra LAP-150 point to point wired tube preamp and Joule-Electra VZN-80 OTL 80w tube amp.  No interest in putting tubes into solid state.  I use Ayre Acoustics for front end and will continue to do so.  The transparency of the Ayre gear works very well with the Pass .8 musicality.  It's possible to have too much gravy on mashed potatoes... too lush.

With the way the Pass .8 stuff sounds, you don't need to put tubes anywhere in the system, IMO.  Nelson tuned this stuff by ear and added Negative Phase 2nd Order Harmonic to give it pleasing sound, and to the chagrin of some I'm sure. 

[jmimac351]

The F5M is great. I have a couple of them, including the F5M Redux monoblocks that run on SMPS supplies.  The quality of the power supply and the wiring makes a huge difference with that amp. Currently using a Neurochrome Power 686 supply with mine and the results are great.

I haven't heard any of the SIT amps, but I suspect these will get closest to tube sound in that they have similar distortion characteristics.

The F5M is also a very nice sounding amp. It is probably most similar to the XA25.

I owned a pair of XA60.8s for a while which I think has a very similar sound to the XA30.8. I've listened a few times to the XA25 but not in the same system. I think the XA25 has a bit more control with more natural decay - I think primarily because it has less degenerative local feedback on the outputs. The F5M is similar.  The F5M has less odd-order harmonic distortion compared to either of these, so I expect it will sound a bit more spacious (wider, deeper sound stage). I didn't have the F5M at the same time as the XA60.8, but I think this is the case from my recollection of the XA60.8.

The commercial amps are going to have more protection circuitry, so you are less likely to damage the amp if you short the outputs or drive it too hard, and less likely to damage speakers if something fails in the amp. On the other hand, I think the protection circuits detract slightly from the sound quality.

The XA25 and F5M don't have balanced inputs. If you build an F5M yourself, you can add a line input transformer or some other balanced to single ended circuit if you want balanced inputs. I used the Jensen JT-11P-1 in my builds. But these circuits will have a subtle influence on the sound.

And you'll have to build the F5M yourself (or find a builder or DIY amp for sale). But it can be built for under $500 so it is a real bargain.

Thanks for affirming all of this, guys.

I had a taste of this with the Amp Camp Amps but it just wasn't good enough to make me dig further.

The 30.8 ended up being one of the best flyers I've taken on a piece of gear.

I really understand now what you guys are onto, and you are really onto something.  Nelson Pass is doing quite a service to the hobby with this stuff.  This stuff is The Answer hiding in plain sight.

[BrandonB]

Nice build. Yes, I agree.

These look simple but elegant!

[mkrawcz]

Here is my rebuilt Folsom EC7293. This is probably similar to what Danny’s monoblocks are.

[jmimac351]

If this forum had a "Like" button / indicator it would have a lot more engagement. 

Instead, you have to post a message saying "that's friggin' cool"... which is fine because I have a big mouth... but there are 55 thousand views to this thread, and it's like an empty room sometimes...

Very nice, Mkrawcz. 

""

[Jaytor]

If this forum had a "Like" button / indicator it would have a lot more engagement. 

Instead, you have to post a message saying "that's friggin' cool"... which is fine because I have a big mouth... but there are 55 thousand views to this thread, and it's like an empty room sometimes...

Very nice, Mkrawcz. 

""

Agreed on both counts.

[Jaytor]

I'll add another little bit of eye candy - work in progress.

I'm working on a new DHT line stage. This will be a two chassis build with the power supply in one chassis and the input selection, attenuator and amplifier circuitry in the other. I've still got a ways to go, but I hope to finish in the next couple of months. I've got the power supply chassis mostly done - photos below. I still need to add a couple of connectors, and I think I am going to paint the main power supply caps the same color as the red inner side panels (after removing the blue plastic) and put a nice topper piece on each. I may also lower them a bit further into the chassis.




The main B+ supply is a choke input supply with four stages of filtering LCLCRCRC with the last RC split between the channels in the second chassis. All using ClarityCap polypropylene film caps.

I'm working on an Arduino controlled relay input selector and stepped attenuator. The line stage circuit will use a Emission Labs 20A DHT with a Lundahl choke anode load, filament bias using a Rod Coleman regulator, and parafeed Lundahl step-down output transformer.

DHTs are the most linear amplifying devices available with almost exclusively even harmonic distortion, but they are also fairly susceptible to microphonics. The EML tubes are much better than most, but a lot of care must be taken to reduce vibration. So the tubes will be mounted on their own little subchassis with sorbothane dampeners.

[mkrawcz]

Wow! I bet that will be magic with the 300b amps. A good tube preamp build is probably next for me after I finish building my Honey Badger amp.

[nlitworld]

Jay, your custom work is absolutely stunning. Very well thought out and incredibly meticulous in the details. Drool worthy for sure. You definitely set a high bar for others to measure against, and that's the diy crowd and manufacturers included. 

[Jaytor]

Wow! I bet that will be magic with the 300b amps. A good tube preamp build is probably next for me after I finish building my Honey Badger amp.

Thank you. Yeah, I'm looking forward to hearing how it sounds. I've read a lot about other builder's (both commercial and DIY) DHT line stages which sound very intriguing.

Jay, your custom work is absolutely stunning. Very well thought out and incredibly meticulous in the details. Drool worthy for sure. You definitely set a high bar for others to measure against, and that's the diy crowd and manufacturers included. 

Thank you. That's very kind of you to say.

[Huskerbryce]

This forum never ceases to amaze me at the shear robust audacity of the audiophile spirit.  Agree or not on the absolute ridiculous level of expenditure (myself included), although not always to the sigmoidal curve of others, its insane how a good system can sound on home built $()it.  I have made many systems in my garage.  Not to the level of others but, I am blown away every time I hear a literal million dollar system and think, my $75,000 system destroys that!  Yet, I see people on here spending $250,000 and more on diy systems.  Just awesome!  Wish I could come over and hear this absolute awesome diy wizardry.

[jmimac351]

Holy Cow Jay!  That is awesome!!!

Jay, we need to see how much time you have... you need to start making yourself available to build these for people who don't wanna blow themselves up!  I can ride right seat at 160, but electricity scares me.

Down here, things are still spiraling out of control. 

This afternoon I bought a First Watt SIT-3 amp that appears to be in GREAT shape, and late build. 

Also, I have the XA200.5 hooked back up in place of the XA30.8.  One thing is for sure... I need to live with these XA200.5 for a LONG time before I move them along.  I have a feeling I don't quite appreciate what they are yet. 

The SIT-3... by all accounts it is very special and Nelson essentially making a "tube amp".  Holographic soundstage.  We will hear next week. 

It is 18w/8 - 30w/4.  That will be for the Epiphany 20/21 Line Arrays; however, I suspect it will run anything I need including normal efficiency 2-ways. 

I don't listen loud, but sometimes it has to be about to "Do It".  Need various "tools". 

[Jaytor]

Thanks. Unfortunately I don't have a ton of spare time. I still have a business to run (cycling e-comm retail) and I am the sole software developer. I'm hoping to retire in the not-too-distant future, but that requires finding a good home for my business with my 50+ employees.

I've enjoyed a fair number of track days and a couple race-car driving courses. Lots of fun, but I don't think I've gotten much faster than about 155 at PIR. It's been a few years though. I had a 911 Turbo S for a while, but it was getting too expensive in maintenance to do track days (ceramic brake rotors are ridiculously expensive) and was really too much car for public roads so I traded it in on a Macan GTS.

I'm looking forward to hearing your thoughts on the SIT amp.

[BrandonB]

I'll add another little bit of eye candy - work in progress.

I'm working on a new DHT line stage. This will be a two chassis build with the power supply in one chassis and the input selection, attenuator and amplifier circuitry in the other. I've still got a ways to go, but I hope to finish in the next couple of months. I've got the power supply chassis mostly done - photos below. I still need to add a couple of connectors, and I think I am going to paint the main power supply caps the same color as the red inner side panels (after removing the blue plastic) and put a nice topper piece on each. I may also lower them a bit further into the chassis.


Hey Jaytor I am asking a question from someone who doesn't have much knowledge at all about electronics.  Can you take this choke power supply and connect it to anything that needs an external power supply to make it better such as a DAC or streamer etc.  I am having a preamp built with an external power supply.  The builder said it would cost thousands more to add chokes to the power supply.  Is this because of the chokes or does something have to change inside the preamp. 


The main B+ supply is a choke input supply with four stages of filtering LCLCRCRC with the last RC split between the channels in the second chassis. All using ClarityCap polypropylene film caps.

I'm working on an Arduino controlled relay input selector and stepped attenuator. The line stage circuit will use a Emission Labs 20A DHT with a Lundahl choke anode load, filament bias using a Rod Coleman regulator, and parafeed Lundahl step-down output transformer.

DHTs are the most linear amplifying devices available with almost exclusively even harmonic distortion, but they are also fairly susceptible to microphonics. The EML tubes are much better than most, but a lot of care must be taken to reduce vibration. So the tubes will be mounted on their own little subchassis with sorbothane dampeners.

[Jaytor]

The power supply should be designed with the specific application in mind. It's possible that a given power supply would work with a different circuit, but it really depends.

The specific chokes used need to be determined based on the current requirements. The chokes I used in the power supply are not terribly expensive. They are Hammond 193C which cost about $65 each. They are 20H chokes rated at a maximum of 100mA.

These are decent quality chokes, but you can certainly spend more money. For a power supply choke, I'm not sure there is much benefit though. For the anode chokes in the audio circuit, I am using Lundahl chokes which are considerably more expensive at around $260 each.

A choke input supply means that the rectifier feeds directly into a choke without a filter cap before it. This requires a higher voltage transformer to deliver the same DC output voltage. The DC output after the first cap (following the choke) is approximately 0.9 times the RMS voltage of the transformer. A capacitor input supply (where a cap is used right after the rectifier) has an output voltage of approximately 1.4x the transformer RMS voltage. So a different and potentially more expensive transformer must be used for the same output voltage. Also. the rectifiers will need to handle the higher AC voltage.

The advantage of a choke input supply is that the current spikes are significantly reduced so there is less EMI and less noise to filter out, but it is a bit more complicated to design. Fortunately, there are good simulation tools that can help get you most of the way there.

Chokes can also be used in a capacitor input supply after the first cap. This will still provide improved filtering compared to a resistor, but not quite as good as a choke input supply.

Chokes will take up a lot more physical space than a resistor though, so this may require a different enclosure to fit everything.

[mkrawcz]

Just got this thing up and running yesterday. As it burns in, it’s starting the really open up. This is the Diyaudiostore Honey Badger. It’s 150watts per channel class AB. I don’t think it gets enough attention compared to the Pass amps, this is a really good sounding class AB amp when configured with the right parts.