Quote: Originally Posted by regal I doubt the transfo is the source of the buzz, mine is as close and silent. It is dead silent in the second picture. Only when I mount it on top (the transformer goes inside the black enclosure in the first pic) it buzzes.

WIP: Probably should have gone with a bigger case so I can put the toroid way back. Its enclosure is better at shielding EM than the perforated steel, but it does not cover the bottom of the transformer. Now I have to find some mu metal or something to solve the nasty buzz.

Quote: Originally Posted by stringgz301 Hi all. I'm trying to source parts for a SOHAII and everyone seems to be out of the MC7815 and MC7915 regulators. Mouser, Newark, and Digikey are all out. Are you guys hording them? Any suggestions where to find some? Thanks in advance...

It is really easy to have your probes slip and short R6 and Q4 on the left channel. Found out I fried the trimpot when there is no voltage across R6, and the fried trimpot measured in the megaohms.

My SOHA II lives! I accidentally shorted R6 and Q4, smoked the trimpot. Good thing I have a 500R one. +/-18V LV supply, 90V B+, 7mA tail current, using BD137 output transistor.

I will be using perforated sheet metal as the top plate: Amazon.com: Perforated Cold Rolled Steel 12" x 12" Sheet, .060" Thick, 0.078" Round Perfs on 0.125" Centers: Industrial & Scientific $7.68 free shipping. Its not stainless steel though, so I'll have to paint it.

Quote: Originally Posted by tuna320 Having a little problem getting any kind of readout on PB+ test point. I have hooked up everything except the jumpers and am getting a reading of 18.6 volts on the screws holding the yellow and black wires coming into the board. My led on the tubes...

Oh that is what R3P is for. I probably should use 5W 22-33R instead.

Thanks for pointing out holland's post. But with the 2.5x CW multiplier, I should still get a B+ of 98V. I'll get one anyway since its real cheap. Edit: Wait, at 14V the LV supply would fall out of regulation. I could use their 20-0-20 instead, secondaries drop to 19.7V at 0.9A load...

It is mentioned that Antek uses unloaded voltage on its labels. Anyone using Antek transformers? 14.5V (50VA) secondaries at 1.6A load still seems fine.

Home (Audio Society of Minnesota) Nothing much on headphones, but their March 16th meeting is about computer audio.

Quote: Originally Posted by HeyItsBattleKid Well there's one! And just as a note to myself, did you find this thread by looking under the Local/Regional Meet section or via the link in my signature? I'm just thinking that there may be plenty of others interested, they just haven't taken...

I'm on board!

Oh dear I missed this by two weeks... I am a new student at UofM. Came from Malaysia with my HD580 and some nice stuff. Also know a classmate with K702 and headroom amp + dac. Here's hoping for another meet soon

Quote: Originally Posted by fordgtlover What size is that capacitor? It look huge. 25V 1800uF, though supply never exceeds 6V.