Hi guys I have to share my unscientific experiment.
I got bored in my hotel room so I thought I try something crazy.
I pulled the opamps out of my Chinese R2R DAC and also out of my Accuphase c-3850 preamp clone boards from Ali that normally use NE5534 on the input.
Took some wires that fit nicely into the opamp sockets and connected all in in/out fashion.
Result is very good. Dynamic detailed spacious sound.
All is powered by the Jan Didden silent switcher that runs off a 5v power bank. It puts out positive and negative 15v for the Accu boards and 5V for the Dac itself.
Listened for about 2 hours with only using up 1 bar of four from my 10a/h power bank.
I used my phone with USBplayer pro in bit perfect mode.
Absolutely stunning without any expensive opamps involved.
Gain is very high but for road use I will put the volume pot between the two Accuphase clone boards
If I use my tube amp I can probably get away with using only one Accuphase board.
I got bored in my hotel room so I thought I try something crazy.
I pulled the opamps out of my Chinese R2R DAC and also out of my Accuphase c-3850 preamp clone boards from Ali that normally use NE5534 on the input.
Took some wires that fit nicely into the opamp sockets and connected all in in/out fashion.
Result is very good. Dynamic detailed spacious sound.
All is powered by the Jan Didden silent switcher that runs off a 5v power bank. It puts out positive and negative 15v for the Accu boards and 5V for the Dac itself.
Listened for about 2 hours with only using up 1 bar of four from my 10a/h power bank.
I used my phone with USBplayer pro in bit perfect mode.
Absolutely stunning without any expensive opamps involved.
Gain is very high but for road use I will put the volume pot between the two Accuphase clone boards
If I use my tube amp I can probably get away with using only one Accuphase board.
Can't believe this isn't fueling anybody's interest. This simple solution will benefit many V-out DACs. No crappy opamps just pure sound all for € 17. One of these Accuphase clone boards is enough for people with a preamp or power amp with high gain input. Two in cascade fashion and we get gain to spare.
Here is a better picture of the setup:
Here is a better picture of the setup:
In case you are wondering Jan's Silent Switcher feets + -15v right into the opamp sockets and the 5v out feets the Dac.
Very efficient and clean power for the whole setup running over 10 hours with my power bank. Best sound I've ever heard on my Sennheiser 540 Reference II except for my Cary SLP 90 tube pre clone on this very DAC.
Klaus
Very efficient and clean power for the whole setup running over 10 hours with my power bank. Best sound I've ever heard on my Sennheiser 540 Reference II except for my Cary SLP 90 tube pre clone on this very DAC.
Klaus
Its not clear what you did from that description. Also, there is no link to the boards you used. Is there a schematic for the boards? Is there a ground connection between the boards?
Well I didn't want to go through all the hassle if no interest was shown.
The first picture was so confusing with all the wires of the previous setup that I wanted to show only the signal path without groud.
Cascading the Accuphase boards is self explanatory. Being in the hotel room I have no volume pot so using only one board in bit perfect mode is just right on most tracks on the Sennheiser HD540 Ref2. Little to loud on some tracks and a bit to low on a few older ones.
At first I thought this will sound anemic missing two opamp stages. I was wrong. I never heard more controlled bass on my Sennheisers. The whole presentation is very dynamic and on par with the Sparkos SS2590Pro for a fraction of the price.
This analog stage seems to be a perfect match for the Chinese R2R DAC.
I will certainly try this on all my V-out DACs and maybe on my ESS ones too. It might work in cascaded form.
Dc on the output after about 10 seconds is 0.2 millivolts but for my Horn system I will use coupling caps to be on the safe side.
https://a.aliexpress.com/_EyBLOW0
https://a.aliexpress.com/_EQ4BejE
Klaus
The first picture was so confusing with all the wires of the previous setup that I wanted to show only the signal path without groud.
Cascading the Accuphase boards is self explanatory. Being in the hotel room I have no volume pot so using only one board in bit perfect mode is just right on most tracks on the Sennheiser HD540 Ref2. Little to loud on some tracks and a bit to low on a few older ones.
At first I thought this will sound anemic missing two opamp stages. I was wrong. I never heard more controlled bass on my Sennheisers. The whole presentation is very dynamic and on par with the Sparkos SS2590Pro for a fraction of the price.
This analog stage seems to be a perfect match for the Chinese R2R DAC.
I will certainly try this on all my V-out DACs and maybe on my ESS ones too. It might work in cascaded form.
Dc on the output after about 10 seconds is 0.2 millivolts but for my Horn system I will use coupling caps to be on the safe side.
https://a.aliexpress.com/_EyBLOW0
https://a.aliexpress.com/_EQ4BejE
Klaus
The goal was to remove all opamps and see if I can achieve the sonics of the Burson V7V or even the Sparkos SS2590Pro with only the discreete stage of the Accuphase clone boards and judging from memory I think I did.
Final test will be on my main rig once I get home. After about 40 years in this hobby things like this still get me excited.
Replacing expensive stuff with cheap solutions without sonic penalty has always been my goal.
My next endeavor will be using two boards to go fully balanced into my various digital amps skipping the opamps on those as well.
Klaus
Final test will be on my main rig once I get home. After about 40 years in this hobby things like this still get me excited.
Replacing expensive stuff with cheap solutions without sonic penalty has always been my goal.
My next endeavor will be using two boards to go fully balanced into my various digital amps skipping the opamps on those as well.
Klaus
I was searching hard to find a good active stage for my Behringer DCX without breaking the bank and chances are this will work.
This particular circuit has a well defined nfb path even without the opamp. Distortion is certainly higher and the offset not so well controlled, but i can believe it sounds better this way.
Would have been more appropriate to include a circuit with the first post.
Edit: distortion seems negligible even without the opamp
Would have been more appropriate to include a circuit with the first post.
Edit: distortion seems negligible even without the opamp
Last edited:
Some more info on C-3850 at: https://www.diyaudio.com/community/threads/clon-c-3850.416050/post-7770964
Also there is this schematic:
Also there is this schematic:
Last edited:
Chinese R2R DAC Version 2 has so much drive that its to loud for my ears. No need to cascade the Accuphase clone. Took out those Wima caps like rotten teeth and put in my favorite coupling caps.
I hope I don't forget to put out the "No Room service" sign.
I hope I don't forget to put out the "No Room service" sign.
Welcom to the club, less is more.
15 years ago I removed all opamps from my cdplayer.
And I found that I liked this sound much more as with the opamps.
It has dual PCM1794 dac with Just I/V resistor to tube output stage.
Before there were opa627 and AD742 opamps.
15 years ago I removed all opamps from my cdplayer.
And I found that I liked this sound much more as with the opamps.
It has dual PCM1794 dac with Just I/V resistor to tube output stage.
Before there were opa627 and AD742 opamps.
Bummer I can't use bit perfect mode it's just to loud for me.
No master clock input on this board. Don't know if I like that.
No master clock input on this board. Don't know if I like that.
This Accuphase clone will finally drive my tube stage. There is no getting around a tube stage if you want an expansive sound stage.
The Accuphase clone is dynamic crystal clear and together with these R2R DACs delivers a bass precision and slam I have never heard before. Addictive.
My AKM and ESS DACs can't do this no matter what output stage I put on them.
Thanks Mark
I hope those transistors are cheap enough not to be faked.
Got 4 more boards on the way.
I hope those transistors are cheap enough not to be faked.
Got 4 more boards on the way.
Originally the Accuphase clone board has an opamp preceding the discreete stage. I removed it so naturally it will lack some gain. In order to make up for the opamp I simply connected the discreete stage of a second board to the output of the first. Cascading I guess.
Oddly the big R2R DAC board is able to drive my Sennheisers easily so it should have enough juice to drive my amps.
As I already said the discreete stage of the Accuphase board is on par with my Sparkos SS2590Pro at least on those Chinese R2R DACs and I hope that will also be the case for my other voltage out DACs.
Тhe removal of the opamp has no effect upon the gain.
Btw, is this really a clone of the C3850? Doesn't look very plausible. The C265 and perhaps others have similar discrete topologies but without the largely superfluous opamp.
I am more inclined to think Accuphase used an opamp servo just to sort out the offset.
Btw, is this really a clone of the C3850? Doesn't look very plausible. The C265 and perhaps others have similar discrete topologies but without the largely superfluous opamp.
I am more inclined to think Accuphase used an opamp servo just to sort out the offset.
Last edited:
For me its not relevant what it is. I only care about how it sounds.
What function the opamp has is not clear to me. I assumed it had gain but you seem to suggest it is a buffer? All I know is that I can't stand opamps in the signal path. I could live with the Sparkos SS2590 or the Burson V7V since they transformed every DAC I tried them on.
This cheap Chinese clone board does the trick es well for a fraction of the price.
A smd version would be great.
What function the opamp has is not clear to me. I assumed it had gain but you seem to suggest it is a buffer? All I know is that I can't stand opamps in the signal path. I could live with the Sparkos SS2590 or the Burson V7V since they transformed every DAC I tried them on.
This cheap Chinese clone board does the trick es well for a fraction of the price.
A smd version would be great.
The opamp provides feedback to, among other things, make the preamp more tolerant of different loads, such as different cables of whatever length, and or different power amps' input Z. Otherwise the sound could change more noticeably depending on the load. At least, that should be one goal of using some global feedback in a circuit like this.
