I didn’t say anything about a 100VA transformer.
The two that I used were Triad 160VA VPT30-5330, with the secondaries wired in series. One could alternately use an Antek 300VA or 400VA with 30V secondaries, and split the two windings between the channels.
The two that I used were Triad 160VA VPT30-5330, with the secondaries wired in series. One could alternately use an Antek 300VA or 400VA with 30V secondaries, and split the two windings between the channels.
Thanks for the links, are the binding posts non-magnetic? I think I'll go ahead and order the PSU boards as well and these look to be the transformers that Tungsten mentioned https://www.digikey.com/en/products/detail/triad-magnetics/VPT30-5330/2090085
What chassis are you ordering for this?
ZJ27: Yes they are not magnetic. Will check out the transformers, BUT have decided that with the complexity of changing resistors, caps, and such it is not a good idea for me to try the 36 vdc approach -- instead am going to go for 2 24vdc PSUs and make all of the components as high end as possible. Ordered your Mundorf selection noted above. The Chassis will depend upon the transformer and PCB size and won't know those yet. The 2 linear PSUs that I built for the M2xs are huge because they house 500VA Antek transformers and large caps on the universal PCB sold by DIY. Went way over the top here because of what was available and it has worked fine. More than enough amperage to run anything and the M2x has a huge dynamic range.
Are you building a new ACA from scratch with new boards? cool! I was thinking of doing outboard PSU, but with the heat I think it should all go in a big box with big heat sinks!
How does the M2x sound? How does it compare to the modded ACA? besides the obvious headroom difference?
How does the M2x sound? How does it compare to the modded ACA? besides the obvious headroom difference?
Yes, am building from scratch using the DIY boards and chassis. Here's why I decided to try this -- having already built two of the dual-smps ACAs.
I compare any of four installed amps in a process I term "Active Amp Selection." With this design, I can switch between pure class A (ACA), tube 300B SET, Powerful A/B (Emotiva XPA-1) and the M2X (variable with the selected daughterboard) in under 5 seconds. See the attachment for the two boxes necessary to accomplish this -- one for line in and the other for speaker selection. Consequently, have been doing daily tests on which amp sounds best for which source and/or music type/genre and, also, how the amps differ in sound.
To speak to your question of ACA versus M2X, the two sound somewhat similar if you use the M2x MountainView Class A Daughterboard but I prefer the Tucson DB with the Burson OpAmp. This sounds very dynamic and explodes with punch. The ACA, by comparison, sounds very "literal" as if the music is appearing somewhat "tightly" in front of you. The ACA suffered from a one-dimensional soundstage depth before the RKThatcher CRC filter was added -- then it deepened just a little. But the improvement was so marked it suggested to me that there was room to grow for the ACA boards with a much better regulated PSU -- and thus the new build goal of 2 PSUs for a large chassis ACA with the upgraded components.
Specifics:
The M2x has a much greater dynamic range from ppp to fff. It has more punch than, even, the powerful Emotiva XPA-1. It's timbral accuracy is OK but only OK. And it sounds great with all types of sources -- vinyl, cassette and digital (am using the Denafrips Ares II now for a more analog-type digital sound).
The ACA has the cleanest soundstage of any of the 4 amps with lots of room between instruments/voices and each of them tightly defined. It is the best with crescendos showing a micro-control that pictures the instrument/voice perfectly. If your source is a muddled vinyl record from the 1960s (read: poorly miked), the ACA will "clean it up" better than the other 3 amps. Timbral accuracy is OK but only OK.
The 300B Set amp has spectacular timbral accuracy placing the instrument/voice realistically in front of you. Relative poor damping, however, clouds their placement within the soundstage just a little. Dynamics are very good and all, of course, depends on the tubes being used -- the new Western Electric 300Bs are on my upcoming buy list.
So actively selecting amps for individual musical purpose has genuine worth and my investigations have identified a number of preferable matches that I automatically select whenever listening to that musical source. Worth giving a try.
I compare any of four installed amps in a process I term "Active Amp Selection." With this design, I can switch between pure class A (ACA), tube 300B SET, Powerful A/B (Emotiva XPA-1) and the M2X (variable with the selected daughterboard) in under 5 seconds. See the attachment for the two boxes necessary to accomplish this -- one for line in and the other for speaker selection. Consequently, have been doing daily tests on which amp sounds best for which source and/or music type/genre and, also, how the amps differ in sound.
To speak to your question of ACA versus M2X, the two sound somewhat similar if you use the M2x MountainView Class A Daughterboard but I prefer the Tucson DB with the Burson OpAmp. This sounds very dynamic and explodes with punch. The ACA, by comparison, sounds very "literal" as if the music is appearing somewhat "tightly" in front of you. The ACA suffered from a one-dimensional soundstage depth before the RKThatcher CRC filter was added -- then it deepened just a little. But the improvement was so marked it suggested to me that there was room to grow for the ACA boards with a much better regulated PSU -- and thus the new build goal of 2 PSUs for a large chassis ACA with the upgraded components.
Specifics:
The M2x has a much greater dynamic range from ppp to fff. It has more punch than, even, the powerful Emotiva XPA-1. It's timbral accuracy is OK but only OK. And it sounds great with all types of sources -- vinyl, cassette and digital (am using the Denafrips Ares II now for a more analog-type digital sound).
The ACA has the cleanest soundstage of any of the 4 amps with lots of room between instruments/voices and each of them tightly defined. It is the best with crescendos showing a micro-control that pictures the instrument/voice perfectly. If your source is a muddled vinyl record from the 1960s (read: poorly miked), the ACA will "clean it up" better than the other 3 amps. Timbral accuracy is OK but only OK.
The 300B Set amp has spectacular timbral accuracy placing the instrument/voice realistically in front of you. Relative poor damping, however, clouds their placement within the soundstage just a little. Dynamics are very good and all, of course, depends on the tubes being used -- the new Western Electric 300Bs are on my upcoming buy list.
So actively selecting amps for individual musical purpose has genuine worth and my investigations have identified a number of preferable matches that I automatically select whenever listening to that musical source. Worth giving a try.
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Craigl59, Wow that is all really cool, it is so great to read those comparisons of the ACA. It really is sounding good! and I think you really keyed into the strengths of what it can do. I agree that a really good LPS is the final frontier. Don't be too hesitant about running 36v, really a super easy change to add R16.
I also love your switching devices, I do like to swap amps from time to time, I have a very early SAE 60w amp that is really nice, being able to just flick a switch based on music and source choice must be awesome.
Really interesting to hear about the m2X, I wonder once I have the ACA running from a dual mono 36v LPS what there is to be gained from upgrading to an F6 besides power. You really put into words all of the strengths of this ACA, I may work on building a larger pair of more efficient speakers instead.
I am going to order another 36v smps and run dual while I build the power supply (and wait for parts etc)
I also love your switching devices, I do like to swap amps from time to time, I have a very early SAE 60w amp that is really nice, being able to just flick a switch based on music and source choice must be awesome.
Really interesting to hear about the m2X, I wonder once I have the ACA running from a dual mono 36v LPS what there is to be gained from upgrading to an F6 besides power. You really put into words all of the strengths of this ACA, I may work on building a larger pair of more efficient speakers instead.
I am going to order another 36v smps and run dual while I build the power supply (and wait for parts etc)
ZJ27: Am currently having lots of problems with parts -- unavailable and shipping delays. Once I finish the WB2018 and B1 pre combination (with UPS power) am going to turn my attention to other areas for a bit.
Will get back in touch in a week or so and always appreciate your kind posts. The Etsy PSUs have shipped and will be attempting to configure them for a 300va 18vdc transformer once they arrive. But will have to do research on cap size and related board definitions. Always lots to learn.
Will get back in touch in a week or so and always appreciate your kind posts. The Etsy PSUs have shipped and will be attempting to configure them for a 300va 18vdc transformer once they arrive. But will have to do research on cap size and related board definitions. Always lots to learn.
Lot's to learn for sure, I have an engineer brother in law to go to for help, will be looking at the forums too. I think playng with the dual smps and trying out the Mundorf caps will be fun while I slowly figure the rest out...... also thinking about a speaker build!
Hi, I have a 19v version of the amp camp that I built from scratch but using Diyaudio boards about 6 years ago. I subsequently added the resistor to increase power output. I’m thinking of applying the mods described to my amp. The problem I have is that the heat sinks I used when I built the amp aren’t sufficient to move to the 24v power supply - the heat sinks run hot as is! If I fitted the 2 ohm resistors, can anyone advise what bias voltage I should aim for - the stock 19v version has a bias setting of 10.0v. Thanks!
I tried building a Zen V4 using boards from a fairly well known Chinese supplier on Ebay. I was never able to get the boards to operate properly and eventually abandoned that project. The PCB traces were not constructed properly to implement the circuit.
Oh really? I guess I will find out in about a month or so when my power supply caps come in. I have read of others being successful with Jim's Audio boards, and I did some circuit tracing (because I was questioning the extra 10k uF cap in parallel with the power supply) and much of it looks OK. If you want to continue the discussion or keep in touch while I work on it, feel free to PM me so we don't get off topic too much on this thread 😉 Or we can continue on a Zen V4 thread.
Yes, those are the boards in question. Probably best to move discussion to a separate thread. Suffice to say that I had issues with the NPN transistor in the current source, and I think the input FET as well. I re-purposed the chassis and power supply toward a Singing Bush.
I am a bit new too DIY. Could I do just the capacitor upgrades and or the drop in upgrades without the other upgrades
I have built 2 ACA 1.8 running bridged mono, single ended
For reference I also built the Elekit 8500 preamp and have Klipsch RP 5000f towers.
On board, drop-in replacements
C1: 4700 uF, 35V; Nichicon KG series "Gold Tune"
C2: 1000 uF, 16V; Nichicon RNL series Aluminum Organic Polymer
C4: 100 uF, 35V; Nichicon RL8 series Aluminum Organic Polymer
R11: 20 kOhm, 1/4W, 1% metal film
R12: 90.9 kOhm, 1/4W, 1% metal film
thanks for any help and guidance.
I have built 2 ACA 1.8 running bridged mono, single ended
For reference I also built the Elekit 8500 preamp and have Klipsch RP 5000f towers.
On board, drop-in replacements
C1: 4700 uF, 35V; Nichicon KG series "Gold Tune"
C2: 1000 uF, 16V; Nichicon RNL series Aluminum Organic Polymer
C4: 100 uF, 35V; Nichicon RL8 series Aluminum Organic Polymer
R11: 20 kOhm, 1/4W, 1% metal film
R12: 90.9 kOhm, 1/4W, 1% metal film
thanks for any help and guidance.
That will get you most of the way. Check this out as well:
https://www.diyaudio.com/community/threads/aca-amp-with-premium-parts.328357/post-5567843Those recommendations remain valid. Note the addition of a 2.0 power resistor. The more recent updates include substitution of FQH44N10 transistors in place of the IRFP240.
https://www.diyaudio.com/community/threads/aca-amp-with-premium-parts.328357/post-5567843Those recommendations remain valid. Note the addition of a 2.0 power resistor. The more recent updates include substitution of FQH44N10 transistors in place of the IRFP240.