View Full Version : 7520 with Caiman PSU
This power supply upgrade is bizarre. I've been burning it in 24/7 with white noise and Densen Demagic.
I thought this change would take effect immediately. While there was an immediate effect, it wasn't pleasant, and it is still on-going.
Day 1 - plugged the Caiman PSU in and my 7520 sounds awful. I'm like WHAT? Mid-range came forward strongly and became mushy. Bass and treble took a huge step back.
Day 2 - still pretty bad but signs of something happening.
Day 3- There is most definitely something going on. This PSU upgrade is transforming my 7520 into something else. For a quick test, I plug in my original 7520 PSU to see if the 7520 reverts back to its old, nice self. It doesn't. Whatever is happening I just have to leave the Caiman PSU connected and let it run its course.
Day 4 - OK! The DAC still sounds somewhat tolerable and I notice that imaging has become stronger, more well defined. The imaging is better than my 7520 was ever capable of.
Day 5 - Nice! Treble is coming back and Bass is going deep.
That's it. I'm still at day 5.
It is baffling me how a simply PSU upgrade is changing my 7520, and doing it very slowly.
What I'm experiencing is eerily similar to the threads I've seen here of users breaking in their brand new Caiman DAC.
Why is this happening? My 7520 is over a year old and its just a PSU, right?
CD
Ali Tait
10-05-2010, 19:18
Is the Caiman PSU a higher voltage? If so,the components in the DAC my be burning in at the new voltage.
The electrolytic capacitors in the new psu will require burn in and go through the forming process, times will vary depending on the type of capacitors used.
Some capacitors can sound really horrid when new, things should settle down after a while.
Be it coupling or decoupling caps, they all have an effect
Covenant
10-05-2010, 19:55
Dont try telling that to the powers that be on the squeezebox forum Leo-they will argue that its all in your mind.
Dont try telling that to the powers that be on the squeezebox forum Leo-they will argue that its all in your mind.
I don't give a toss tbh mate ;) I've faffed about with enough diy to know new caps always sound rough compared to ones thats had plenty of run in
BTW I agree a lot of things in audio is BS but always found the burn in process with caps isn't
Ali Tait
10-05-2010, 21:01
Yep,agreed.
Stratmangler
10-05-2010, 21:41
Caiman PSU is 15vdc.
Standard one is 12vdc.
Going off that you've got the caps in the PSU bedding in, plus the reservoir cap in the 7250.
As a 7520 with standard PSU owner myself - my question really is, is it the 7520 burning in or is it actually the PSU itself burning in?
Answers on a post card!
Butuz
Stratmangler
10-05-2010, 22:04
As a 7520 with standard PSU owner myself - my question really is, is it the 7520 burning in or is it actually the PSU itself burning in?
Answers on a post card!
Butuz
Probably a combination of the two.
David,
Do let us know what the final result is. I never got a single reply when I posted this question http://www.theartofsound.net/forum/showthread.php?t=6186
The electrolytic capacitors in the new psu will require burn in and go through the forming process, times will vary depending on the type of capacitors used.
Some capacitors can sound really horrid when new, things should settle down after a while.
Be it coupling or decoupling caps, they all have an effect
Thanks for the clarification, Leo. I wonder, also, with the other observations that leaving their Caiman un-plugged for a whiles causes the device to need a long warm up again, is that also due to the caps re-forming?
CD
David,
Do let us know what the final result is. I never got a single reply when I posted this question http://www.theartofsound.net/forum/showthread.php?t=6186
I'll definitely update as the situation changes.
CD
Probably a combination of the two.
This correlates with my observations as I had temporarily plugged the "old" PSU back in and the system still sounded weird. It didn't revert back to its old self at all.
CD
I wonder, also, with the other observations that leaving their Caiman un-plugged for a whiles causes the device to need a long warm up again, is that also due to the caps re-forming?
CD
Yes, but it shouldn't take as long compared to brand new caps, basically waiting for it to warm up and the circuitry to stabilize from cold when its been switched off a while
Some say the dielectric of a brand new capacitor goes through various changes during use, psu's obviously have a big influence on performance so these things can have an effect on the sound.
dave2010
11-05-2010, 18:53
This correlates with my observations as I had temporarily plugged the "old" PSU back in and the system still sounded weird. It didn't revert back to its old self at all.
CDThat doesn't sound too good. I hope it's bearable though. If it's a real problem, then maybe we need a health warning about powering off.
StanleyB
11-05-2010, 19:31
That doesn't sound too good. I hope it's bearable though. If it's a real problem, then maybe we need a health warning about powering off.
I haven't heard from any other TC-7520 owners who have been using the Caiman PSU instead that they have had any problems. However if the Caiman PSU doesn't appear to like the TC-7520 that much, it is best that I stop offering Caiman parts for the TC-7520. So I have removed the Caiman PSU from sale to TC-7520 owners just now.
I haven't heard from any other TC-7520 owners who have been using the Caiman PSU instead that they have had any problems. However if the Caiman PSU doesn't appear to like the TC-7520 that much, it is best that I stop offering Caiman parts for the TC-7520. So I have removed the Caiman PSU from sale to TC-7520 owners just now.
I never said it was bad. Actually, I did....initially:)
What it comes down to is that it is taking longer than I expected to hear the results. Is it not a good idea to warn potential customers that such and such an upgrade needs some time to bed in?
CD
That doesn't sound too good. I hope it's bearable though. If it's a real problem, then maybe we need a health warning about powering off.
When I plugged in the old PSU, my 7520 was, I gather, still in the midst of adapting to the new PSU. Had I left the old PSU and given it some more time, I'm sure now that it's original character would come back.
The new PSU is starting to sound very promising.
CD
Day 7 Nice. The systems sounds really good again. Maybe a bit forward in mid-range, but very listenable. I listened to music for 4 hours last night and if my body didnt give in to exhaustion, I could have stayed up all night with my 7520.
What this PSU has done is given the DAC more control.
Control that gives it better imaging than before. I don't quite know how to describe it. Before, I could get a good sense of where instruments were. Now, not only do I feel I can localize them, but with my eyes closed I can almost "see" them. Does that make sense?
Control that handles complexity better. Musical passages that have lots going on have revealed other unheard instruments, or mic breathing, that I haven't noticed before. Basically, subtle detail has taken a step up.
Control that makes the music sound less digital. I thought the music seemed not so digital before, but now its uncannily natural sounding. Harmonics, especially in higher frequencies, are more realistic.
Of course this is all subjective and I'm basing my comparisons on memory. But there it is, for what it's worth.
Let the burn in continue:)
CD
Day ??? Weird.....it's like my tweeters are half broken now. Bizarre burn in.
CD
Ali Tait
20-05-2010, 07:41
Have you experienced similar before? You may have poor mains.
Have you experienced similar before? You may have poor mains.
That's possible. Mains, or the system is still settling down.
CD
My system seems to have settled now as it does sound more consistent.
The good news? The PSU does improve the sound. The best way to sum it up is that there is more control. Less a sense of splashy treble. It didn't feel splashy before, but once I heard the new PSU, it did. make sense? Also, bass is more defined.
Hoenstly, it's been quite a while so my comparisons are from memory, so take it for what it's worth.
One thing I do notice with absolute certainty, though, is that this new setup handles complex passages better than before. I play songs from my music library and every so often I would hear something new or different from the same song I had listened to hundreds of times before. Music with loads of activity like many instruments and lots of percussion is more tractable than before.
The bad news? You know that old saying "be careful what you wish for...?" Well, this PSU is an improvement, but it has also made the weakness one of my digital sources more apparent.
I have 3 sources connected to my 7520: a Windows XP digital audio workstation (DAW) thru coax, a sony Blu-ray player thru coax, and an Apple Airport express via optical.
The observation I made of a slight loss of treble are definitely there, and it occurs only with one source: the Airport express. The point really came home when I edited a sound file on my DAW. As I was playing it I noticed a distinct clarity in the output. I saved the file and moved it to iTunes to play through the express. The express version definitely sounded muddier.
To further clarify this issue I burnt a CD from my iTunes library and then played it through the blu ray player. CONFIRMED. The bluray and computer sound far better than my express. Before my PSU upgrade, the computer and blu ray sounded better, but just a bit better.
Now the difference is night and day. The slight congestion and loss of treble is all due to the airport express. I knew that the express was a known, highly jittery digital source, and this new setup really brought the point home.
Now I'm faced with the task of how to improve my airport express:(
Be careful what you wish for:)
CD
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