[Paul Hynes]

Hi Gustavo,

Provide a link to the documentation and I will have a look.

Regards
Paul

[FullRangeMan]

Sorry Paul I do not have any doc or Link. Aloia is a obscure brand on the web, only now 2010 his site is under construction...
afew month ago there is nothing online.   http://www.aloia.it/
I read in other forum seems there is a inductive powersupply kit or plans for a 6C33 tube amp.
Thanks for your good will, Gustavo

[Paul Hynes]

Hi Gustavo,

When the details of the power supply are posted on the web, get back to me and I will look at it to see if there is anything novel or worthwhile that can offer improvments to power supplies generally.

Regards
Paul

[FullRangeMan]

Hi Gustavo,

When the details of the power supply are posted on the web, get back to me and I will look at it to see if there is anything novel or worthwhile that can offer improvments to power supplies generally.

Regards
Paul

Thankyou Paul. I was think this schematics can be a industrial secret, but I will look the site occasionally.
Regards, Gustavo

[jkeny]

Hi Paul,
You may have seen this post on DIYA from -ecdesigns- http://www.diyaudio.com/forums/digital-source/140538-lossless-sd-card-player-43.html#post2087091 where he has presented a solution for the switching noise usually found on normally rectified power supplies. Have you any comments on the efficacy of this approach? I'm thinking of using it as the PS to feed your regulators. I know they have high PSRR but even so, cleaner supply helps even with high PSRR.

This is what he says:

The stepped rectifiers greatly reduce switching noise as they switch-on and off in stages. Single rectifier goes into full conduction after transformer voltage exceeds reservoir cap voltage plus diode voltage drop, and switches-off immediately (risk of back emf and oscillations) when transformer voltage drops below reservoir cap voltage plus diode voltage drop.

3-stage stepped rectifier starts with low charge current (series resistor #1, one diode conducts, step1), then increases charge current (series resistor #2, two diodes conduct, step 2), finally it provides full charge current (3 diodes conduct, step 3). Switching-off goes in reverse order, reduced charge current (2 diodes conduct, one is switched-off, step #2), lowest charge current (one diode conducts, two diodes are switched off, step #1), then it switches-off completely.

I use diode threshold voltage in combination with bypass resistors to achieve this (resistor already provides charge current when the diode is not yet conducting). One diode is not bypassed with a resistor, making sure current cannot flow in reverse direction.

[Paul Hynes]

Hi John,

This is an interesting idea that may offer a useful and relatively inexpensive reduction of diode switching noise. As I have not tried this I cannot say how effective it would be. Perhaps you could try this out and give some feedback regarding how effective it is. I would have a look at it myself only I am very busy catching up with orders at the moment.

Regards
Paul

[jkeny]

Hi John,

This is an interesting idea that may offer a useful and relatively inexpensive reduction of diode switching noise. As I have not tried this I cannot say how effective it would be. Perhaps you could try this out and give some feedback regarding how effective it is. I would have a look at it myself only I am very busy catching up with orders at the moment.

Regards
Paul

Indeed, I may well give it a try - on that front I have an email order sent to you - did you get it?

[Paul Hynes]

I have been answering e-mail for two hours now and have just delt with yours.

Regards
Paul

[OlesonMD]

We just replaced/upgraded a number of capacitors in my power amp.

The transformer hums like a $10 hooker, and we are looking for a 1kva (or greater) toroidal transformer for replacement. The hum issue is not new, and is what led us to replace the caps.

Do you have a source for these?

[BPT]

Toroidal transformer hum can be caused by poor design for the designated application or DC present on the AC line. The physically quietest I have found are the Plitron LoNo design. http://www.plitron.com/lono.asp

[Paul Hynes]

Toroidal transformers have to be very carefully designed, with high quality materials, to give low noise. Low cost, off the shelf toroidals are often very noisy and you get what you pay for with these. I have not tried Plitron transformers but they have a good reputation. Their LoNo design that Chris recommends looks like a good solution.

Regards
Paul

[satfrat]

Toroidal transformer hum can be caused by poor design for the designated application or DC present on the AC line. The physically quietest I have found are the Plitron LoNo design. http://www.plitron.com/lono.asp

Can the LoNo transformer be ordered directly from Plitron as I'm not seeing any reference to them in their E-catalog? Thanks.
 
Cheers,
Robin

[BobMajor]

Here's the link for buying. About $400 Canadian
http://www.plitron.com/shopping/shopdisplayproducts.asp?id=10&cat=Low+Noise+Power+Transformers+for+Solid+State+Amps