- when you build your amp up on a breadboard (and not yet in the case) how close could you place the trafo near the ampsections before you get audible (or irritating) hum because of the strayfield of the trafo?

- when you cased all sections did you encounter hum problems from the trafo? How did you solve that problems?

- was it in your case needed to place the trafo outside the amp case?

- Did someone looked with a scope to see if there were too much interference between trafo and ampsections? At wich distance did you reach a acceptable hum/noise level?

I am asking this because I personally find it very irritating when hum is interfering with music at low level. I have read that in other headampprojects the advise is given to place a trafo (especially non-toiroids) in a separate little box placed a couple of feet away from the amp.

So what are the expierences with the SOHA on this topic. With that knowledge we can learn how to plan the best lay out when casing up.

Pieter.

That is fully ok with me. I was under the impression that this tread was still open for specific debate on the fully standard ptp SOHA according to your own text in the text by wich you wanted to close SOHA ONE.

My questions were exclusively oriented to collect 'point to point' expierences, so we could make some conclusions for the pcb lay out when one uses closely integrated pcb layouts.

But I am fully content when the same questions are taken care of in the next 'golf' or 'tsunami' of posts on SOHA TWO.

I appreciate when you move my text to the SOHA TWO. Or have I do it myself? Let me know.

Pieter.

SOHA Thread II

Then we can start again.

[Edited by runeight on 05-21-2006 at 02:37 PM.]

I fell in love with sijosae's hybrid amps after seeing his gallery from a post on Make Magazine's blog. Ever since I have wanted to build one. The SOHA looks like a better choice for me than what sijosae's amps are intended to do, instead of running headphones I would like to power a pair of small headphones. However I do not know much about how different components affect the sound quality of an amp. Could any body suggest something like a cmoy that I should build and what could I do to it to figure out what I like and don't like?

great work guys.. see ya on the other thread

[Edited by TOLiS_GR on 11-15-2006 at 03:51 PM.]

Though my version is not point to point, nor breadboard (guess guess), Everything is not cased at the moment, and the small blue plastic toroid transfo is just next to the pcb. Or I'm deaf, or I do not hear any hum. I plan nevertheless to build the case with alodined aluminium plates (surface treatments that help gain RFI/EMI shielding with Alu), some that will be inside the box, between the transfo and the amp itself. I designed this also because signal will commonly come from the rear cinch connectors, to a Tangent Linkwitz, just next the transfo. So in between, there will be a shielding panel to prevent any hum. I must say these AMVECO or equivalent are really quiet transfos.

All the best,

ps, I still admire you guys who build thing without a board, this is man stuff, not solder kit as we do outside Please do not begin a war on my comment, what's most important is music and fun doing/designing things in the end

pps, I'm really happy you're still here Runeight, like a ghost, as TOMO said. I'm currently eagleing a Cavalli-Novell-Futterman board for fun, and maybe if the thing goes well enough, to make it for myself. I would be so much pleased to submit privately the layout to some very skilled person who could help, and you're for sure on my shortlist .

GregVDS

[Edited by GregVDS on 11-15-2006 at 03:15 PM.]