We've done a couple of informal comparisons of perfboard AD1862 vs PCM58 via 'Dark LED', I wouldn't go as far as to call them 'listening tests'. The outcome of those so far favoured PCM58 but we haven't given up on AD1862. I have changed the caps used on the AD1862 board from lytics to tantalums (which are what the DS recommends) and it needs more 'break in' time I reckon.
If price is taken into account then PCM58 offers better bang for the buck based on informal listening. We'll keep going back to AD1862 to verify but until it exceeds PCM58 in SQ (given the price differential) then I'm not planning to develop a board using it. Is that clearer?
If price is taken into account then PCM58 offers better bang for the buck based on informal listening. We'll keep going back to AD1862 to verify but until it exceeds PCM58 in SQ (given the price differential) then I'm not planning to develop a board using it. Is that clearer?
Hi All,The comparison you mention has already been done with DAC chips lashed up on perfboards, just not quad versions, only dual. No plans for a quad AD1862 myself but one of the punters here has already made one, perhaps he'll share that at an appropriate time
I believe I'm the punter refered to here.
Quick pic of quad AD1862 driving the Dark LED IV/filter:
I also ran the Dark LED with a dual AD1862.
Both sounded fantastic and was for sure an upgrade over the previous IV I was using based on AD797 with a 4th order Sallen-Key filter. Can I tell a difference between dual and quad AD1862, I'm not sure. The game changer was upgradinging the IV solution.
I'm interested to do a single blind A/B test with my orginal IV & filter against the Dark Led IV/filter to prove to myself the sonic differences, but it might take me some time to build up a system that let's my wife switch back and forth for me. I think it would be a fun experiment.
I also want to share some REW data and scope screen shots.
Likely I will post this over in Miro's thread as I think Dark LED is a significant upgrade over a the bog standard IV solution and is approachable by more novice DIYers than some of the tube or other IVs frequently discussed there. When I do I'll post a link from this thread over there for people who are not following Miro's thread.
So far the only complaint on the Dark LED IV/filter is from my wife who says I am listening to too much music and didn't talk with her...
G
System used:
Headphones: Macbook Air -> Amanero USB to I2S -> Miro inspired quad AD1862 DAC -> Dark LED IV/filter -> Baxandall low noise volume control (6 OPA per channel) -> Whammy HP Amp -> Hifiman Edition XS
Speaker: Macbook Air -> Amanero USB to I2S -> Miro inspired quad AD1862 DAC -> Dark LED IV/filter -> Baxandall low noise volume control (6 OPA per channel) -> Whammy HP Amp -> Aleph J -> Klipsch RP 600m series I
Hey Vunce,
You are a famous guy in the DAC area for sure! I think you will love the Dark LED IV/filter as you have so much experience with different IV solutions on Miro's design of the AD1862 DAC.
Let me answer you question more holistically in case others want similar information on PS:
DAC's PS is Miro's PS1 for 5V and 12V
Dark LED's PS is VRDN based at +/-18V, I did my own board layout.
VC and Whammy's PS are shared and also VRDN based at +/-18V but this is a totally different supply than the Dark LED supply.
All are of course linear supplies and each leg has a dedicated R-Core transformer.
I will need to do something different in the future as the case doesn't have enough room for all this kit...
G
You are a famous guy in the DAC area for sure! I think you will love the Dark LED IV/filter as you have so much experience with different IV solutions on Miro's design of the AD1862 DAC.
Let me answer you question more holistically in case others want similar information on PS:
DAC's PS is Miro's PS1 for 5V and 12V
Dark LED's PS is VRDN based at +/-18V, I did my own board layout.
VC and Whammy's PS are shared and also VRDN based at +/-18V but this is a totally different supply than the Dark LED supply.
All are of course linear supplies and each leg has a dedicated R-Core transformer.
I will need to do something different in the future as the case doesn't have enough room for all this kit...
G
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With all this iron and other kit in this current enclosure, I think I am in the running for a prize as the heaviest DAC
Hi G
Thank you for the Dark's review.
I would like to ask you when you'll find the time to do a comparative comparison of the I/Vs using a simple passive volume control in place of your 6op amps active one.
My opinion is that op amps can mask fine differences and I always appreciate other's opinions on this.
Regards
George
Thank you for the Dark's review.
I would like to ask you when you'll find the time to do a comparative comparison of the I/Vs using a simple passive volume control in place of your 6op amps active one.
My opinion is that op amps can mask fine differences and I always appreciate other's opinions on this.
Regards
George
Hi George,
I'm not sure that was truly a Dark IV review, more of a first listening impression. I would hope to find the time for a more detailed review as well as some REW measurements even if I can't get the A/B system figured out.
Certainly that would be an interesting but might be a bit harder to achieve in my understanding. In the current system I find using HP is the most revealing which is why in this test system I'm using the Whammy that can drive both HP and and the Aleph J. As you may know the Whammy archtecture has a single OPA driving the MOSFETs in class A, so I assume this is my current noise bottle neck. In this curcuit I'm using a JRC MUSE02 and from the datasheet I did a quick calculation at 22KHz to estimate 0.67uV of voltage noise which likely dominantes the noise in the signal path. This is likely the best to get rid of and replace with a lower noise OPA or better yet a discreet circuit.
I have read a few of D. Self's books as at my level I find them very approachable, and this VC is based on his writings on "low noise" VC, and by paralleling three duals (the circuit needs 2 OPA) and using low noise LM4562 I thought I could get noise well below RBCD. Per D. Self a single OPA in this curcuit is -114 dBu noise, and I believe the three parallel dual OPAs will reduce that a couple more dBu.
On the other hand a passive VC (excluding TVC & AVC) are typically either pots or stepped attenuators with rather high impedence in the range of 20-100K, this seems like a great place to generate noise so is why I moved away from that solution. The above is curcuit using a DIY 2K 23 step attenuator to try to address this passive drawback.
Likely both of these solution have comprises, and would be interesting to compare in the right platform. Abraxalito has hinted at a design of a VC somewhere in the IV curcuit which has the potential to be the least compromised solution. Maybe this will stimulate him for an update on how that is going.
Trying not get off topic for long in this thread, I would be intested in your thoughts on this topic either by pointing me to a DIYA thread or by PM.
G
P.S. My assumption above was that OPA generated noise was the main contributor to mask the fine details. Assuming my ears are not playing tricks on me and that the Dark IV is indeed a significant step up in resolution of these fine details, it is likely that in my system I have moved the bottleneck away from the IV. Which is great for me.
I'm not sure that was truly a Dark IV review, more of a first listening impression. I would hope to find the time for a more detailed review as well as some REW measurements even if I can't get the A/B system figured out.
Certainly that would be an interesting but might be a bit harder to achieve in my understanding. In the current system I find using HP is the most revealing which is why in this test system I'm using the Whammy that can drive both HP and and the Aleph J. As you may know the Whammy archtecture has a single OPA driving the MOSFETs in class A, so I assume this is my current noise bottle neck. In this curcuit I'm using a JRC MUSE02 and from the datasheet I did a quick calculation at 22KHz to estimate 0.67uV of voltage noise which likely dominantes the noise in the signal path. This is likely the best to get rid of and replace with a lower noise OPA or better yet a discreet circuit.
I have read a few of D. Self's books as at my level I find them very approachable, and this VC is based on his writings on "low noise" VC, and by paralleling three duals (the circuit needs 2 OPA) and using low noise LM4562 I thought I could get noise well below RBCD. Per D. Self a single OPA in this curcuit is -114 dBu noise, and I believe the three parallel dual OPAs will reduce that a couple more dBu.
On the other hand a passive VC (excluding TVC & AVC) are typically either pots or stepped attenuators with rather high impedence in the range of 20-100K, this seems like a great place to generate noise so is why I moved away from that solution. The above is curcuit using a DIY 2K 23 step attenuator to try to address this passive drawback.
Likely both of these solution have comprises, and would be interesting to compare in the right platform. Abraxalito has hinted at a design of a VC somewhere in the IV curcuit which has the potential to be the least compromised solution. Maybe this will stimulate him for an update on how that is going.
Trying not get off topic for long in this thread, I would be intested in your thoughts on this topic either by pointing me to a DIYA thread or by PM.
G
P.S. My assumption above was that OPA generated noise was the main contributor to mask the fine details. Assuming my ears are not playing tricks on me and that the Dark IV is indeed a significant step up in resolution of these fine details, it is likely that in my system I have moved the bottleneck away from the IV. Which is great for me.
I've basically got 3 types of PCM58 from China that I have in hand:
1) silver print on typical IC surface - most likely 100% original
2) black-topped with white print on it, original date code
3) black-topped and laser marked, with original date code, obviously pulled as pins had markings on it and visible oxidation on pins near the case
...4) black topped, laser marking, and date code of laser marking (most likely, same as I saw with some TDA154x's) - only saw pictures
All until 3) of them were working, didn't yet compare them in performance
Edit: picture of the first batch I've received from china in 2019
1) silver print on typical IC surface - most likely 100% original
2) black-topped with white print on it, original date code
3) black-topped and laser marked, with original date code, obviously pulled as pins had markings on it and visible oxidation on pins near the case
...4) black topped, laser marking, and date code of laser marking (most likely, same as I saw with some TDA154x's) - only saw pictures
All until 3) of them were working, didn't yet compare them in performance
Edit: picture of the first batch I've received from china in 2019
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@weissi As you're clearly a PCM58 fan, have you seen these papers relating to its design? http://s-audio.systems/blog/pcm58/?setlang=enI'm glad die PCM58 got some attention at least as I was proposing that chip for a long time
yes -sure , thanks to your recent research! That's why I allowed myself to step in again. There's a lot to life out one's tweaking demands with that IC.
What's the thing - the ICs are still a bargain compared to PCM63 and AD1862...
Edit: I'm of German origin, is that correct at all "to life out one's tweaking demands"?
Edit2: Didn't recognise the footnote about the 10k-R in the I/V until you've made it clear - so, 126dB claimed SNR gone... Nevermind, still quantums ahead of TDA1387, ain't it?
What's the thing - the ICs are still a bargain compared to PCM63 and AD1862...
Edit: I'm of German origin, is that correct at all "to life out one's tweaking demands"?
Edit2: Didn't recognise the footnote about the 10k-R in the I/V until you've made it clear - so, 126dB claimed SNR gone... Nevermind, still quantums ahead of TDA1387, ain't it?
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