In this moment the amp is configured with the usual C9 R10 order.
I hope to socket C9/R10 positions tomorrow.
If you're asking if C9 has a different impact if tied to ground instead of the usual position the answer is:
yes but it depends on caps.
With most caps the new position (tied to ground) reduces C9 impact on sound, the worse the cap, bigger the difference.
.."the worse the cap" in terms of certain spec number or listening impression in the original position?
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btw audyn true coppers sound amazing
considering their price, theyre now my reference caps
Congratulations on joining the True Copper Club. I'm glad you and others have taken the plunge. It hurts (your wallet) only for a while.
Peace,
Tom E
Fine, you're welcome
Listening impression
I confirm FPCAPs sounds good but a bit thin, too much 'polite' I would say.
I prefer FGs, Silmic ROS and Cerafines, all much more musical and full.
Choice among those is taste dependent, to those that can't find/afford Black Gates I suggest to buy all three and find the one that best suits your taste.
Silmic ROS are not easy to find on shops, you must use eBay.
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No Low Gain for Me
It's hot here. About 38 deg C. So after a morning and early afternoon of socializing, I've spent the later, hotter part of the day simulating the front end of the FE.
What I've concluded is;
* I don't need all the gain provided by the MyRef design, including FE. Usually, lower gain in an amp is a good thing because it helps with gain-bandwidth, but we don't seem to need that here. The FE is 30 dB gain and I've spent this afternoon listening to a 22 dB gain BrianGT amp using a bare potentiometer and not getting the pot turned up beyond half. I could easily live with 8 dB less gain, even with no gain in the pre-amp (my pot).
* The current gain structure and filtering is the best for the MyRef and the FE. I can manage the filtering at lower gain, but it puts you in the 90 uF range for C9 and that is a big hole for good capacitors. Basically, 90 uF is too large for film caps of good quality and reasonable price and size. It's also too small for good electrolytics. Besides, this approach is proven to sound good.
- I do have a question for Dario. Have you ever tried a 220 pF for C32? Simulation isn't listening, but it seems that C32 mainly controls the linearity of phase at high frequency. I notice that Siva is using 330 pF in his Rev E. My simulation shows that phase at 20k Hz has about 10 degree error with the 150 pF and it continues to increase with frequency to 100 kHz. A 220 pF holds the phase within 1 degree of zero all the way to 100 kHz. I was just curious if it sounded any different.
It's hot here. About 38 deg C. So after a morning and early afternoon of socializing, I've spent the later, hotter part of the day simulating the front end of the FE.
What I've concluded is;
* I don't need all the gain provided by the MyRef design, including FE. Usually, lower gain in an amp is a good thing because it helps with gain-bandwidth, but we don't seem to need that here. The FE is 30 dB gain and I've spent this afternoon listening to a 22 dB gain BrianGT amp using a bare potentiometer and not getting the pot turned up beyond half. I could easily live with 8 dB less gain, even with no gain in the pre-amp (my pot).
* The current gain structure and filtering is the best for the MyRef and the FE. I can manage the filtering at lower gain, but it puts you in the 90 uF range for C9 and that is a big hole for good capacitors. Basically, 90 uF is too large for film caps of good quality and reasonable price and size. It's also too small for good electrolytics. Besides, this approach is proven to sound good.
- I do have a question for Dario. Have you ever tried a 220 pF for C32? Simulation isn't listening, but it seems that C32 mainly controls the linearity of phase at high frequency. I notice that Siva is using 330 pF in his Rev E. My simulation shows that phase at 20k Hz has about 10 degree error with the 150 pF and it continues to increase with frequency to 100 kHz. A 220 pF holds the phase within 1 degree of zero all the way to 100 kHz. I was just curious if it sounded any different.
Fine, you're welcome
I prefer FGs, Silmic ROS and Cerafines, all much more musical and full.
/130349499872?pt=LH_DefaultDomain_0&hash=item1e596f85e0"]eBay[/URL].
Dario,
What is your opinion of the FGs, Slimic ROS, Cerafines in comparison to BG STD?
I was referring to the IsoTek Full System Enhancer CD.
It's a precious tool since it reduce by several order of magnitude the time necessary for burn-in.
If it sounds silly, ask Bob...
I've had them at home since an italian forumer suggested them to me for use in digital decoupling.
According him they're much better than other solid polimer caps for that task, never had the time to try them, though.
Sure.
When I first played the 'guess game' (copyright AndrewT
) with compensation values I've tried all values from 100pF to 330pF.With each step sound changes, paricularly about sound stage.
Curious... give a look at the original My Ref thread, if I remember correctly, according Soongsc and Siva it's the contrary, lower the value higher the phase coherence...
The biggest difference between BG and the rest of electrolithics is the ultimate cleanliness they have, very similar to a film cap.
BG STD is a bit dry compared to higher grade BGs or Cerafine and Silmics.
BTW one of those available elcos bypassed with a 22nF FKP2 it's not too distant from a BG STD.
For What It's Worth
Sorry for the long post.
Capacitor leakage has been discussed here and it's potential effects on sound. So I recently set up a bread board with a lab 4.6 VDC lab source, a 10k resistor, and a test cap in series to ground. Once the cap is charged, the measured voltage across the resistor gives me an indication of leakage current.
I have a few more caps to measure, but I thought I would share what I've seen so far.
Most aluminum electrolytic caps charge quickly and show very low leakage current. In 10 or 15 seconds these 220 uF and 100 uF caps were 95% or more to a stable leakage current of 0 to 0.1 micro amps. None of these showed a 1 minute leakage current of larger than 0.3 ua. "Normal" caps tested;
Nichicon Muse 220 uF, 25 V
Nichicon Muse 220 uF, 50 V
Nichicon Fine Gold, 100 uF, 25 V
Elna Cerefine, 100 uF, 35 V
I also tested the FPCAP R7 series aluminum polymer caps in 220 uF, 6.3 V. KSTR had warned me that aluminum polymer caps had high and possibly unstable leakage. From the specs, the FPCAPs seemed like they were better than most. I have to say that Klaus was very right. The problem is that these caps are neither stable or consistent. Out of 4 caps tested, I had a range of 2 minute leakage from 3.1 to 15.8 ua. Worse than that is that the leakage changes over time. I saw it grow to more than 20 ua on the cap that was 3.1 at 2 minutes, then drop back to 11.
In reverse polarity the leakage was large like a 'lytic' at over 200 ua. I'm not sure I understand completely the affect of leakage current, especially when unstable and asymmetric, but I think it must have a negative impact on phase and, therefore, sound stage. Combined with Dario's comments, aluminum polymer is off my list for audio.
The final leakage test were the Black Gate STD, 220 uF, 16 V. Yet another way that Black Gate caps stand out from the crowd. As with all of these caps, they were new and had been at 0 volts for a long time. At 1 minute, the leakage rate was 190 ua and at 5 minutes, 47 ua. It took about 30 minutes for the leakage rate to stabilize at a respectable 3.5 ua. Very different behavior! As this was the last cap I tested last night, I checked it again 8 hours later and it immediately went to 4.9 ua. A short check of a couple of other BGs show that they are very consistent.
All this confirms for me that BGs really are a different animal and I'm sorry that they are gone. Also, the test supports the idea that BGs need burn in time. Probably more than other aluminum electrolytics.
Sorry for the long post.
Capacitor leakage has been discussed here and it's potential effects on sound. So I recently set up a bread board with a lab 4.6 VDC lab source, a 10k resistor, and a test cap in series to ground. Once the cap is charged, the measured voltage across the resistor gives me an indication of leakage current.
I have a few more caps to measure, but I thought I would share what I've seen so far.
Most aluminum electrolytic caps charge quickly and show very low leakage current. In 10 or 15 seconds these 220 uF and 100 uF caps were 95% or more to a stable leakage current of 0 to 0.1 micro amps. None of these showed a 1 minute leakage current of larger than 0.3 ua. "Normal" caps tested;
Nichicon Muse 220 uF, 25 V
Nichicon Muse 220 uF, 50 V
Nichicon Fine Gold, 100 uF, 25 V
Elna Cerefine, 100 uF, 35 V
I also tested the FPCAP R7 series aluminum polymer caps in 220 uF, 6.3 V. KSTR had warned me that aluminum polymer caps had high and possibly unstable leakage. From the specs, the FPCAPs seemed like they were better than most. I have to say that Klaus was very right. The problem is that these caps are neither stable or consistent. Out of 4 caps tested, I had a range of 2 minute leakage from 3.1 to 15.8 ua. Worse than that is that the leakage changes over time. I saw it grow to more than 20 ua on the cap that was 3.1 at 2 minutes, then drop back to 11.
In reverse polarity the leakage was large like a 'lytic' at over 200 ua. I'm not sure I understand completely the affect of leakage current, especially when unstable and asymmetric, but I think it must have a negative impact on phase and, therefore, sound stage. Combined with Dario's comments, aluminum polymer is off my list for audio.
The final leakage test were the Black Gate STD, 220 uF, 16 V. Yet another way that Black Gate caps stand out from the crowd. As with all of these caps, they were new and had been at 0 volts for a long time. At 1 minute, the leakage rate was 190 ua and at 5 minutes, 47 ua. It took about 30 minutes for the leakage rate to stabilize at a respectable 3.5 ua. Very different behavior! As this was the last cap I tested last night, I checked it again 8 hours later and it immediately went to 4.9 ua. A short check of a couple of other BGs show that they are very consistent.
All this confirms for me that BGs really are a different animal and I'm sorry that they are gone. Also, the test supports the idea that BGs need burn in time. Probably more than other aluminum electrolytics.
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Hi Jac, Great post. One thing that interests me a lot is the 30 minutes in the BG section. I have often asked for confirmation of the need for a tube amp like "warm-up" period before the MyRefs really bloom/stabilize. I would not have expected that being necessary with an amp based on a chip. Are you suggesting this is required for new BGs only, or is it necessary at each power-on? I have noticed the required time has shortened after several passes of the IsoTek process.
Bob,
From what I can tell, the 30 min. stabilization is primarily for the first start up. It needed to recover a little after 8 hours, but not much.
The other interesting question is what happens to a BG without a DC bias as in C9? From what I have read about 'lytics' in general is that they only build/repair the electrode when the current is flowing from + to -. In an AC situation, the current is flowing equally in both directions, so the stabilization process may take longer. Warning.....We have reached the limits of my understanding.........
I think this is one of the reasons that Soongsc is interested in both non-polarized and back to back caps in C9. The trouble is that all of you have found that the BGs are the best sounding cap and they are VERY different from other caps in behavior. Although the alternatives suggested by Dario sound like a close second, we are going to need to be very lucky to find a replacement as good or better than a BG.
By the way, how do find such cool post icons and how do you get them into the text, not just in the title?
Jac
From what I can tell, the 30 min. stabilization is primarily for the first start up. It needed to recover a little after 8 hours, but not much.
The other interesting question is what happens to a BG without a DC bias as in C9? From what I have read about 'lytics' in general is that they only build/repair the electrode when the current is flowing from + to -. In an AC situation, the current is flowing equally in both directions, so the stabilization process may take longer. Warning.....We have reached the limits of my understanding.........
I think this is one of the reasons that Soongsc is interested in both non-polarized and back to back caps in C9. The trouble is that all of you have found that the BGs are the best sounding cap and they are VERY different from other caps in behavior. Although the alternatives suggested by Dario sound like a close second, we are going to need to be very lucky to find a replacement as good or better than a BG.
By the way, how do find such cool post icons and how do you get them into the text, not just in the title?
Jac
Bob,
Have you ever noticed that you can't find specs for Black Gates online? I saw one post where someone contacted Black Gate when they were in business and asked for specs. The reply was, "We don't publish specs. Feel free to use our caps if you want to. If you don't, no problem."
I think they knew that their caps wouldn't look good in a spec comparison, but didn't care because they knew what they were building. Now, if some old Black Gate experts would just set up a little company for audio caps, we would help them get started.
Jac
Have you ever noticed that you can't find specs for Black Gates online? I saw one post where someone contacted Black Gate when they were in business and asked for specs. The reply was, "We don't publish specs. Feel free to use our caps if you want to. If you don't, no problem."
I think they knew that their caps wouldn't look good in a spec comparison, but didn't care because they knew what they were building. Now, if some old Black Gate experts would just set up a little company for audio caps, we would help them get started.
Jac
You have to select the "Go Advanced" tab under the message box. Select the smiley face dropdown at the top of the box and scroll down to "Show All". Be careful the cursor is where you want it in the text entry box. Use "Preview Post" as necessary before you post. If a mistake is made, select "Edit" from the regular listing - then "Go Advanced" again. You have a 30 minute window to make changes in either standard and/or advanced mode..
I actually sent Sonicraft a message several months ago on the subject. I didn't get a reply. I'll try again this week - maybe a phone call. It's hard to believe some company can't manufacture a cap to BG specs - reverse engineering might be a possibility, though probably expensive. Madisonears has connections to the folks at Madisound and they may know a company intrested/capable of supplying that need. I'll also shoot something off to the Trure Copper folks. They advertise a "Custom Service".
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