OT orientation?

[Tdale]

I placed my OT with the end bells towards the pots and the the preamp tubes.. Can this cause more hum than turning it 90 degrees?

Tommy

[jaysg]

Most advice in this area is about the relationship of PT, OT, and choke. If at all possible, all three should have a different orientation. This is easiest to achieve with a laydown PT. I can't recall any discussion around your question.

It's also considered good to move the PT and OT as far from each other as possible. Soldano does this. Most amps don't though, and the results are usually fine.

[Tdale]

http://www.youtube.com/watch?v=bnfNaOuJy_I

Check it out if you want to...

Tommy

[jaysg]

ah...I hear your problem. That could be better. I haven't built one in that style chassis, so outside of guessing it's a grounding scheme problem or a bad tube, I'm not going to be helpful. I'm not on top of exactly where coax should go, per HAD.

re: OT orientation, ODS pics I have, show the OT bells aimed at either end of the chassis. The Winterland's are aimed front and rear.

If you have a function generator or a synthesizer, start by pulling V1 and V2, then injecting a signal at the PI and work back towards the input. Next, I'd put V1 in and test the clean channel. Then remove V1 and put V2 in and check the OD, and so forth. Use a sine wave if possible.

[CathodeBiased]

It sounds like you have a grounding problem (50/60Hz buzz) and a power supply problem or two (100/120Hz hum). Do you have access to an oscilloscope?

[Tdale]

Yes I have access through a friend who has been a tv-repairman for about 40 years. I don't know how to use a scope to find the error, but I'm sure he does.

Tommy

[drz400]

Most advice in this area is about the relationship of PT, OT, and choke. If at all possible, all three should have a different orientation. This is easiest to achieve with a laydown PT. I can't recall any discussion around your question.

It's also considered good to move the PT and OT as far from each other as possible. Soldano does this. Most amps don't though, and the results are usually fine.

I say a T is fine, laydown exposes the core to the inside of the amp.
The Soldano is interesting... that for an amp made pretty nicely actually it hums more than most and is pretty noisey so I wouldnt copy that layout.

Ground path Ground path Ground path

[Bob-I]

The Soldano is interesting... that for an amp made pretty nicely actually it hums more than most and is pretty noisey so I wouldnt copy that layout.

Funny, the guys at the SLOclone forum swear by the Soldano layout, including theier screwy heater connections. Since I'm starting a SLOclone I'm interested in this.

[drz400]

The Soldano is interesting... that for an amp made pretty nicely actually it hums more than most and is pretty noisey so I wouldnt copy that layout.

Funny, the guys at the SLOclone forum swear by the Soldano layout, including theier screwy heater connections. Since I'm starting a SLOclone I'm interested in this.

Well.... I have worked on a bunch, they all have a high noise floor, healthy hum.
He doesnt even twist the heater wires at all, a few I have done that on and it help big time. Does some things I think are a no no like runs third pin ground to audio ground, uses rivets too much.