PSU for Caiman with Pics

[leo]

I mainly just have one fitted for the line/ variable out because I have a few sources I use an external amp for headphone use

I upped the STR output to 15.6v (loaded) it was just over 14v before when loaded It sounds noticeably better now
Its worth trying both LM4562 and AD826 to see which suits you best tbh

[MartinT]

I upped the STR output to 15.6v (loaded) it was just over 14v before when loaded

Aha! I'm running mine at exactly 16V as the dropper diode is still in circuit, bringing it down to about 15.4V at the reservoir cap. I think the STR is doing a fine job, the elimination of noise makes the Caiman initially sound a little smooth but that's to be expected. With the right op-amp the presentation is detailed, dynamic and punchy.

The lag on the STR's voltage adjustment takes some getting used to, doesn't it?

[MartinT]

I was wondering, have you both used a pair of AD826's and a pair of LM4562's, or have you tried combinations of the two?

I swapped them in pairs but I don't use headphones so one of them has had no effect.

[HighFidelityGuy]

I swapped them in pairs but I don't use headphones so one of them has had no effect.

Aparently the opamps do have an effect on each other though. So perhaps you could try an LM4562 in the headphone socket and see if it makes any difference.

[MartinT]

Unless I'm mistaken, the line output op-amp may affect the headphone op-amp but not the other way round? I only use (fixed) line output.

[HighFidelityGuy]

Unless I'm mistaken, the line output op-amp may affect the headphone op-amp but not the other way round? I only use (fixed) line output.

Ah, you're probably right. I knew there was some kind of interaction.

[MartinT]

Its worth trying both LM4562 and AD826 to see which suits you best tbh

I've just gone back to the LM4562 as they are just a touch more detailed and less lush which suits my system better. Both are great op-amps.

[leo]

Yes, these things are cheap to try too.
LM4562 doesn't like capactive loads, shouldn't be much of a concern in most set ups

[Canetoad]

I have built a PSU similar to MartinT to power my Caiman. 80va tx, hexfred rectifier, 2 x 4700 uF smoothing caps and STR. I have set the output voltage to 15.8v under load and now want to replace the large 16v 10000 uF cap in the Caiman with something which has a higher voltage limit. The choices I currently have lying around are:

33 uF 20v Oscon
2 x 2.2 uF 100v metallized polyester (as per MartinT's Caiman)
6800 uF 35v Panasonic

As a novice I haven't a clue which would be the best choice to use. I don't understand what differences the rating of a cap (uF) has on it's performance. I would appreciate some information/advice from those in the know.

[MartinT]

Bernie - since the SuperTeddy is highly regulated and low noise, you don't need a large reservoir cap inside the Caiman so much as power supply decoupling. So let the ST do the regulating work and have the Caiman keep noise down to a minimum. I would therefore recommend the 2 x 2.2uF poly (or whatever you can get to fit) option rather than a large electrolytic as their high frequency response will be a lot better.