AudioCircle
Community => Regional Audiophiles => Carolina Audiophiles => Topic started by: xsb7244 on 21 Jan 2015, 06:47 pm
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richidoo,
I want to hear about the Modulus-86 amp you are working on and pictures please. It looks like a terrific amp for the money.
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I am building a pair, with the Power86 PS. The boards are good quality, the design is excellent, support from the designer is excellent. What's not to like? Soon we will know if it sounds good too. Then it will probably get pretty popular. It's not really a kit, but a very thorough plan with PCB. You buy your own parts which is made easy with his Mouser parts list so you can buy all the parts with a couple clicks. The build instructions are very well written, thorough and educational. Theory is explained in layman's terms to assist making project decisions like transformer.
My amps are finished, I just need to wire it up and attach to heatsink. I was working on a DIY box, but my first design isn't right so I'll probably just run the amps on a test board. Some pics at diyaudio.com
He is also designing a LM4780 version to run two 3886s in parallel for double the current.
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I got my Modulus-86 amps running yesterday. They sound really good. I am pretty surprised at how good they sound. I normally don't like the opamp used here, but now after listening I have no desire to change it in this circuit.
They are very detailed and powerful sounding, not your grandfather's tube amp. It is revealing of lesser components upstream, and lesser quality recordings. But the tone is very dense, dead quiet, great transient response (slam) so it is musically involving, easy to ignore flaws. And easy to find flaws to upgrade. :)
Not sure the Mod86 is the best choice for a first electronics project because there is a lot of small parts soldering (though no SMD) but if you can solder pretty well and can get by with solid 30Wpc then I highly recommend this amplifier. The instructions are extremely comprehensive and written for laymen, so you'll not have any questions if you read them thoroughly. If you do have questions the PCB designer Tom Christensen answers emails immediately and he closely monitors his projects' threads on diyaudio. So you shouldn't have a problem if you want it to succeed.
Price per channel all finished is probably about $300/ch? including a box and trannies, connectors etc. Can be done for less, or much more. Imo, nothing can touch this amp's performance for that price, new or used.
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Nice job. How about a picture or two? Look forward to the next GTG.
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Thanks Jason. Me too!
No box yet, always listen to DIY before cosmetics!
(http://www.audiocircle.com/image.php?id=114208)
(http://www.audiocircle.com/image.php?id=114209)
(http://www.audiocircle.com/image.php?id=114210)
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What are the blue caps?
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That's the bipolar PS board, blue caps are storage. ~20kuF, I think? The PS PCB is called Power86, unregulated. It is good for at least 2 Mod86 amps, or more with bigger caps if you have tougher load. My load is 7ohms so the chips don't even get warm to the touch. The amps have onboard 317/337 regulators for the opamps. The 3886/4562 composite amp has extreme ripple rejection, like 120+dB? so unregulated supply is fine.
The tranny is 300VA because I will also be putting a Tiwsted pear Sympatico amplifier on this same heatsink with 2 Mod86 amps. Sympatico is 100W from 4780 chipamp. It has built in power supply on the amp board, all in one, just needs AC.
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Where will you get your enclosure from?
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I don't belong in this region anymore but I will continue anyways.
I plan on starting this project tonight. Have most parts minus some connectors, heat sink and transformer in house.
Will post some pics once progress is made.
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Where will you get your enclosure from?
I'm building 2 three channel boxes from 1/16" aluminum sheet, 1/4" plywood and 3/4" plywood to fit some salvaged heatsinks.
Goskers you are always welcome in Carolina Circle!
Good luck with your build! I think you'll like it.
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I'm building a bridged version right now. Will post when all done, hopefully with measurements and subjective comparisons to NCore 400, LM3875, UCD 400HG HxR, and SKA designs. And if I have enough time this year perhaps an F5 Turbo V2.
I agree with Richidoo...this isn't a 1st timers project as far as the soldering is concerned, the designer has done an impeccable job in shortening traces, and minimizing excessive inductances. And he is eminently knowledgeable in analog design while maintaining very high value.
Best,
Anand.
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poseidonsvoice,
Looking forward to your review.
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Any update from you guys who have been using this amp for a while???
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Any update from you guys who have been using this amp for a while???
Unfortunately, my final build was delayed this summer due to family responsibilities & vacation. I'm currently working on it now and should be done this week. Then I can make subjective and objective comparisons. I know Richidoo had completed his and has been pleased with the design over and above the Twisted Pear Sympatico.
Best,
Anand.
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Thanks for the reply, Anand! I had Peter Daniel build me up one of his integrated amplifiers and it's en route currently. I'm hoping to compare his integrated with a Modulus 86 eventually, though it might be a while until I can save up enough to buy the Modulus parts. From what I'm reading it seems the Modulus might just blow the AudioSector integrated out of the water. Perhaps it's not the best idea to compare them. LOL!
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From what I'm reading it seems the Modulus might just blow the AudioSector integrated out of the water. Perhaps it's not the best idea to compare them. LOL!
Yes. And I have measurements that prove that...however, there are enough in this hobby who WILL NOT make a move on this design until a detailed subjective review is published and that is what I am going to try to do in the Critics Circle.
Stay tuned.
Best,
Anand.
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Ooooh, exciting! Maybe I can shoehorn in the Modulus boards into the AudioSector amp instead. Hahaha! Please link to your review in this thread when you're done. I don't want to miss it.
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Hi Steven
I have 4 channels of Mod86 running for a year or so, all version 1. I like them very much. Very detailed, very alive, very incisive. It has such low distortion because it uses a high feedback opamp to control the chip amp via another external feedback loop. This gives microscopic distortion and an ultra clean dryness to the sound. But there is no trace of the suffocating closed-in sound typical of poorly designed high feedback amps. Mod86 is extremely open sounding. Every detail of tone and space comes through easily. Some might call it sterile, but it doesn't sound actively "sterile" to me, it just sounds like nothing. It is not "aggressively" low distortion like some class D amps that put pressure in the room and attack with their cleanliness, Mod86 has a safe, easy, passive, nothing is there harmlessness. The lack of good or bad distortion allows the most minute and subtle tonal detail and texture to come through. You've never heard a solo violin like this, or classical guitar. Well recorded female vocals are incredible. It's easily the most detailed and well balanced amp I've ever heard. You hear it the instant you first turn it on. Wow! like that. I also have Audio Research tube amps so I go back and forth between clean SS and luscious tubes to maintain context and appreciation of each.
My Mod86 are currently out of service, as I inserted passive line level crossover filters between the input IC and the driver IC in the Mod86s. I adjusted the global feedback resistor for attenuation to match the driver levels. It worked technically OK but not great and dialing it in was too inconvenient so I bailed. I'll be removing the filters, resetting the gain and putting them in chassis to use them with dsp crossover and new multichannel USB and DAC that I just got from diyinhk.com
Mod86 has adequate power for 88dB 4ohm speakers, imo. Mine are 85db 8R with the passive crossover. When I play loud I occasionally hear the "spike" protection sound. But as active amps they are more than adequate power beyond pain threshold driven with professional balanced signal level >5V! Impressive little amps, incredible value. Assembly isn't too hard. The manual is very helpful and detailed. Tom is very helpful, and there is an active build thread to help with the slightest question. If you don't like it, easy to sell since many people won't DIY but would like to hear it.
I think you'll be happy with the AudioSector. Let us know how you like it!
Rich
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Thanks for the informative reply, Rich!
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Thanks for the review. Hard to find in depth reviews of this amp. Might give it a go later next year.
Anand did you sell yours?
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I am currently writing up a review for the HP-1 headphone amp, which is from the same designer as the Modulus-86 (Neurochrome). The man is a technical monster with some very impressive chops, and his headamp is possibly one of the most detailed and resolving that I've heard (and I am one of those nuts who has gone through more than his fair share of headphone gear). While I don't have first hand experience with the Mod86, I have some friends who do and they speak very highly of it.
http://www.neurochrome.com/product/hp-1-ultra-high-end-headphone-amp/
http://www.neurochrome.com/product/modulus-86/
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I am currently writing up a review for the HP-1 headphone amp, which is from the same designer as the Modulus-86 (Neurochrome). The man is a technical monster with some very impressive chops, and his headamp is possibly one of the most detailed and resolving that I've heard (and I am one of those nuts who has gone through more than his fair share of headphone gear). While I don't have first hand experience with the Mod86, I have some friends who do and they speak very highly of it.
http://www.neurochrome.com/product/hp-1-ultra-high-end-headphone-amp/
http://www.neurochrome.com/product/modulus-86/
+1 million.
I use the Modulus 86 as my main amplifier.
Best,
Anand.
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Nice new avatar Anand.
Are those SMPS modules for the power supply, on the headphone amp?
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Are those SMPS modules for the power supply, on the headphone amp?
A quote from Tom from another forum regarding his SMPS...
I use SMPSes in my differential preamplifier (DIFF PRE 8x2), HP-1, and SMPS-86 which I used to power the LM3886DR and Modulus-86. All these circuits provide state of the art performance and have very low noise floors. The switchers perform better than most linear supplies. I do add filtering on the output of the SMPS, but that's mostly a precaution. The switching noise is spread-spectrum, thus, low in amplitude and way outside the audio band (60-70 kHz), so it's not an issue for audio circuits.
On the HP-1, I went one step further and added a set of low-noise regulators to the output of the filtered switching supplies. The main reason was to get the rail voltage I wanted so I could get 3 W into 20 Ω and 3 W into 32 Ω. The post-regulators also provide a nice marketing blurb about super filtered supplies, though, the filtering isn't all that necessary from a technical standpoint.
There are ways to screw up the performance by adding filtering, by the way. If the designer isn't careful, it's possible to cause some severe peaking in the combined output impedance of the filter + SMPS. It should go without saying but I'll say it anyway: I spent considerable time and effort designing the SMPS post-filter to ensure good performance across the audio band.
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His smps is compelling. I love how thorough and accessible his explanations are.
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Good to see that folks are happy with the results - I have the boards for the Mod-86 but haven't started the build yet. I think I'll use the Modushop chassis from the diyaudio store and a PS from a Class-D-Audio amp that I had. the PS voltage is on the upper end of things, but should be ok in my application where I don't really crank it (at least I hope).
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Good to see that folks are happy with the results - I have the boards for the Mod-86 but haven't started the build yet. I think I'll use the Modushop chassis from the diyaudio store and a PS from a Class-D-Audio amp that I had. the PS voltage is on the upper end of things, but should be ok in my application where I don't really crank it (at least I hope).
If you can I'd suggest you use Tom's PS.
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His smps is compelling. I love how thorough and accessible his explanations are.
They always are on paper. And many sound pretty good, you just got to find out who's yankin' the leg. Tom probably chose fairly wisely since he's no fool.
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Tom's amps have extremely high PS noise rejection, so PS efficiency and cost can take priority over noise so a quality prefab unit makes sense. Am I correct to assume the headamp is also a "composite amplifier" topology like Mod86?
In other news: :D I bought one of the last pairs of Parallel-86 PCBs, including the now discontinued amplifier chips. Not even started building them yet, but I was surprised to see that with a lowish 28V PS it can handle 2 ohm load. :thumb:
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Am I correct to assume the headamp is also a "composite amplifier" topology like Mod86?
Again snipped from another forum...
Now about the circuit. As noted a few pages back, the HP-1 uses the OPA1612 for the differential receiver and input buffer. Input selection and gain selection is accomplished by Kemet relays with gold plated switch contacts. The headphone output stage is an LME49600 in a composite loop with an OPA1611. The composite amp has a built-in compensation network which ensures stellar performance even with heavy capacitive loads (long headphone cables). It'll drive up to 22 nF || 300 Ω. That's close to 1 km of headphone cable. That aught to do it... :) I have seen OPA1611+LME49600 amps from other vendors. I wonder if they noticed that it'll oscillate at load capacitances in the 100-500 pF range (common cable capacitance). You need that compensation circuit... To minimize DC on the output of the amp, an OPA2140 provides a third order DC servo for an output DC offset below 100 µV. I chose a 3rd order servo to ensure a fast settling time while not impacting the THD at 20 Hz. The servo settles in about 30 seconds. The HP-1 needs no further warm-up than that.
There are no capacitors in the signal path as the HP-1 is DC coupled. Should any part of the amp or any circuitry upstream of the amp fail resulting in DC on the output, the built-in protection circuit will disable the output. Also, in the event of power supply failure where one rail collapses, the other rail will be shut off. The final feature of the protection circuit is that it provides a turn-on delay, thus, eliminating turn-on and turn-off thumps in your headphones.
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Can any of you share what preamp(s) have worked well with your Modulus 86 amp?
The DIY thread is almost 400 pages and I would really like to hear from some AC folks that built or used this amp and tried out some different preamps with it.
Another question I have is can it drive speakers that tend to like more power and current?
Thanks for your help.
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Nick,
Let’s be more specific. What speakers? What efficiency? What impedance curve?
Thanks,
Anand.
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Anand, thanks for your follow-up.
Intuitive Audio Gamma Summit two way monitors 89db nominal 4 ohms
Wish I could tell you more about the specifications but not much available online about them. I understand they like a little power and current to open up.
I just recently purchased the speakers and haven't had a serious audio system in a few years. Just getting back into the hobby and trying to figure out a great amplifier for these speakers.
Thanks,
Nick
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Anand, thanks for your follow-up.
Intuitive Audio Gamma Summit two way monitors 89db nominal 4 ohms
Wish I could tell you more about the specifications but not much available online about them. I understand they like a little power and current to open up.
I just recently purchased the speakers and haven't had a serious audio system in a few years. Just getting back into the hobby and trying to figure out a great amplifier for these speakers.
Thanks,
Nick
In small/medium sized rooms the 65 watts on the Modulus should do fine. I know of 1 other fella who is quite satisfied with KEF reference series that have an impedance dip to 3.2 ohms in the 100-300 Hz region without issues. In larger rooms, consider the Modulus 686.
Best,
Anand.