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Supercapacitor Power Supply tour

Ciunas Audio said:
Sorry, hard to keep it all up-to-date - now modified - that's why I ask members to update the list themselves
suzywong will ship it to you, shortly, I'm sure (or at least bring it around to your place & give you at least an hours audition :)
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Mea culpa.....:oops:

Anyway, posted today to Bruce by Royal Mail. Special Delivery “guaranteed” by 13:00 tomorrow. I have a tracking number that goes active at around 14:00.....er...tomorrow :rolleyes:
 
Received. Looking forward to a listen tomorrow.
I've the following I can compare it to, though perhaps most interested in the DAC:
  • DAC using Four parallel LT3045 regs fed by 18650 batteries, previously on ifi iPower.
  • microRendu using an UA Ultracap LPS-1.2.
  • switch with internal reg replaced with LT3045 and fed by SMPS with DC Neg shunt to Earth pin.
 
Great, thanks for letting me know, bruce
Let me ask you - I presume you found a sonic improvement when you moved from iFi power to battery power on your DAC?
What voltage are parallel LT3045s providing? What DAC is it?
The reason I ask is because I have found all Vregs I tried, stopped at TPS7A4700 (didn't try LT3045), dis-improved the sound compared to direct battery or supercap supply (at the same voltage, obviously).
The supply feeding the Vregs does make a difference - batteries & supercaps being best sound, IMO but the jump in sound when bypassing Vregs is surprising
 
Hmm. Something's not playing well with each other. After a few minutes powering the DAC, I'm getting an electrical pulse at about 1Hz through the speakers.

Everything is fed by a balanced AC transformer with DC blocked, with all sharing the same earth. The Supercap PSU has had 15-20 minutes to charge before use. I don't notice the sound when first turning on the 5V out and connecting to the DAC, but comes on started noticing after a few minutes, in between songs especially.

The 4xLT3045/battery supply is 5VDC.
The DAC is Calyx 24/96 with a PS cap upgrade.

Yes, I noticed an improvement moving from iPower to 4xLT3045/battery and so stuck with it even though the charging is manual and needed every 3 days with average daily listening. Strangely, I made no notes when I switched so can't recall clearly enough to review the specific sonic differences.
 
The pulse disappeared when I lifted the connection to AC-Earth. I previously tried moving it off the Balanced AC transformer to the regular ring main, and also changed out the DC cable, but it was the earth pin which resolved it.

Now I'm trying to get a clear sense of the sound, but enjoying it.
 
brucew268 said:
The pulse disappeared when I lifted the connection to AC-Earth. I previously tried moving it off the Balanced AC transformer to the regular ring main, and also changed out the DC cable, but it was the earth pin which resolved it.

Now I'm trying to get a clear sense of the sound, but enjoying it.
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Yea, glad I PMed you try lifting the mains earth - as I said the original SMPS is not connected to mains earth until I modified it - it's completely safe to lift the mains earth on the SMPS.
This is the second report of some noise with the SMPS - I believe it was zk who reported some ground noise issue.
I suggested using a 3 pin mains cable with ground disconnected or one with plastic earth pin but he didn't manage to do this

All future SMPS will be without this connection to mains earth

Look forward to your impressions now that this pulse noise is sorted
 
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We used a linear PS set to 7.5V (~2.5 Amps) to power the caps instead and this resolved the noise leakage to ground issue that was picked up by both our amps. I'm not sure if our tests were handicapped by using a less powerful power supply. Had it been clear it was safe to disconnect the earth, I'd have done so. Our test results feeding a Squeezebox Touch were inconclusive. In both our systems, the perceived soundstage and instrument separation were reduced when using the Supercap PS when using the Touch as a transport only. In my friends system, and using it to drive the internal DAC, I heard the sort of improvements I was expecting - cleaned up digital hash, deeper bass, more forward/forceful instruments, tight rhythm, but not so on mine. The rhythm on was already tight using a 5V linear PS. However I don't use a mains filter with my equipment. He uses a Tacima block which could be a factor. I have a discrete ladder DAC on the way. Pity the timing of this wasn't better.
 
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Thanks ZK. When is the ladder DAC arriving? Nothing to stop you getting the PS back for audition on your new DAC. I can send a SMPS with no connection to mains earth.
 
Not till August I'm afraid.
It occurs to me that omitting the mod to shunt noise to earth, should work as well as removing the connection to earth all together. There were no issues with noise breakthrough using a linear PS with the same earthed IEC lead as the supplied SMPS.
 
ZK said:
Not till August I'm afraid.
It occurs to me that omitting the mod to shunt noise to earth, should work as well as removing the connection to earth all together. There were no issues with noise breakthrough using a linear PS with the same earthed IEC lead as the supplied SMPS.
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Yes, omitting earth shunt is the same as removing mains earth connection.

Looking back at your impressions & PMs, I still strongly suspect you have ground loop issues.
Ground loop issues can result in audibly noticeable squeals & static as you described with the ungrounded SMPS (& when you power your computer speakers through USB) BUT it can also affect audio in ways that are not noticeable until the loop is removed - such as a lack of real dynamics & soundstage. The fact that your friend has the same setup as you (except for mains filter) but you heard " cleaned up digital hash, deeper bass, more forward/forceful instruments, tight rhythm"

I would try to solve the ground loop if you can?
 
The squalling stopped the moment I disconnected the SMPS from Supercaps, as you suggested. We heard diminished soundstage and separation in both systems when using the Touch as a transport powered by the supercaps. Still there is one thing I'll try tomorrow which did resolve an earthing issue several years ago, though I thought that problem was long gone. How it manifested itself in the audio chain was lack of tonal colour.
 
ZK said:
The squalling stopped the moment I disconnected the SMPS from Supercaps, as you suggested.
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Yep, so earth ground connection through modded SMPS created a ground loop or widened the existing ground loop. If your LPS was also connected to mains earth then you have a ground loop there too. The difference between the two is the spectrum of frequencies in the ground loop noise but as I said one may be noticeably audible as squeals & the other may be only noticeable as compressed soundstage, lack of dynamics - a meh sound?
We heard diminished soundstage and separation in both systems when using the Touch as a transport powered by the supercaps.
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Did you try the SC PS without any connected charger PS either LPS or SMPS - this would ensure no ground loop through the SC PS
Still there is one thing I'll try tomorrow which did resolve an earthing issue several years ago, though I thought that problem was long gone. How it manifested itself in the audio chain was lack of tonal colour.
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Yep, music lacks interest & just isn't listened to much.

I had a customer who recently returned a ISO-DAC for repair - I returned it 3 weeks later. When I returned it he told me he had put back his Meridien DAC but after a short while stopped listening to music, only randomly in those 3 weeks ,whereas he said with my DAC he listens to music every day.
 
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Well my Supercap PSU (dual +5V) arrived today, and I've now got it powering both "clean" and "dirty" sides of the Allo Digi Signature (& RPi obviously).

See post #223 for my thoughts on the SQ with the "Tour Unit". Having sent the demo unit off to Bruce, I reverted to the iFi + Battery pack. The sound definitely "lost something". So I am happy to report that the SQ is restored with the new unit.

A few observations:
1. the new unit is slightly longer (front to back) than the demo unit - an addition cap, I understand
2. if using it on an Allo Digione Signature, then both dirty and clean sides can be switched on at the same time (there are notes on Allo's website to the effect that the clean side should be switched on first followed by the dirty, so that the WM8805 chip initialises itself before the RPi finishes booting- however this has been been clarified on the forums mentioned in Hecky's post #235 above).
3. and RTFM :oops:, it really does take 10 minutes to charge up!

Finally, a shout out is due to John for the speedy delivery.
 
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Thanks Chris - yes 10 mins is charge-up time (actually it's more like 5mins but I'm being conservative) so I recommend to always leave it on charge, just turn off power to whatever device is being powered by using the front push button, illuminated switch on the SC ISO-PS.

Also new case size is the same as the ISO-DAC & ISO-SPDIF

I build devices in batches & the ISO-PS was the last one in stock from a recently built batch - hence the speedy delivery.
 
Well if dynamics are your indicator of earthing issues, there are no issues in that department. They are lightening fast and effortless - far from meh. I use a HackerNap that was developed on this forum.
 
Squashed dynamics & 'meh', uninteresting sound is just one indicator - it probably all depends on the noise spectrum of any ground noise
Lightening fast is good - effortless is the real clincher though - great dynamics with an effortless, relaxed, natural sound would be some of the characteristics I would associate with better PS & removal of any GN issues

But deeper soundstage & layering with more solidity to instruments/voices would be what I would expect followed along with the above so I'm a bit confused why SC PS reduced this aspect in your setup.

Having said that audio system configurations are many & varied which means we are always learning & should be open to uncovering new info - it's one of the reasons I find tours of my devices are worthwhile for the participants & for me

Case in point - I did a tour of a USB cable which has an extra layer of ferrous compound in addition to the screen. I know from measurements that this can screen RFI & stop it entering USB connected audio devices. I put it out on a mini tour to provide a practical demonstration of the audible effects of USB cables - I know this USB cable can change the sound & I was interested in just what others heard & what effect it had. Some found the cable audibly improved the sound, others didn't. I don't jump to conclusions either way i.e that some are biased to hear a change & some are biased NOT to hear a change - I take their reports at face value & wonder if some have RFI in their system coming from USB connection which the USB cable mitigated & some didn't. Hard to know without testing, etc. but interesting exercise nonetheless.
 
Hi,

Can i be on the list for the supercapacitor adjustable voltage? I live in Chicago. Is this possible?

thaNks
 
Hi Ivan
Two problems
- you only just joined PFM so I've no knowledge of who you are
- you live in the US - so far the tour is UK only but I sometimes post on other forums & there might be interest in a tour? See here

What I suggest is that you keep an eye on the tour here & see if you are interested in the higher voltage supercap versions that get introduced?
You can then order one on a sale or return basis (as all my devices are), if it still interest you.
 
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