[RogueAngel]

Jim,

Since the tube sockets will not be directly mounted to the PCB, should the grid stopper resistors be mounted to the socket pins with the resistor location on the PCB jumpered, or should the resistors be located on the PCB?

TIA
Bobbi

[hagtech]

Best if done at socket, but if you keep leads short you should be ok.  I was.

jh

[RogueAngel]

The casing is not finished yet and I only have a bit over an hour on it, but I can tell already that it beats the Rotel I just took of the shelf.

I decided to keep the grid stoppers at the socket pins and used jumpers on the PCB.  Seems to be working fine that way.

I still have a small hum problem to chase down. I'm thinking it may be associated with the step-up transformers, but overall I'm happy.  

I'm gonna do some trouble shooting after I cook dinner.  I'll let ya'll know how it turns out.

Bobbi

[mgalusha]

Pictures man, we need pictures!

Seriously, it sounds like you've done a good job. What step up transformers did you use? I mounted a pair of the Jensen JT-44K-DX inside the chassis and have been very happy with the results. The cans are shielded and the leads are only about 2" long, so hum hasn't been a problem.

Maybe I need to build an Octal Cornet as well although the 9 pin version sounds pretty damn good. Keep us appraised of how it works out.

Mike G.

[TChung]

Hi Bobbi or Jim,

My Octal Cornet is in the planning stage.  I would like to like which are the grid stopper resistors you were referring to in this thread.

Best,
TChung

[RogueAngel]

TChung,

I connected the following directly to the sockets and jumpered the position on the circuit board: R6, R8, R10, R12, R15 and R17.

Hope this helps.

Bobbi

[TChung]

Bobbi,

I understand the way how these resistors are connected now.  Is the whole idea to shorten the leads from the tubes?

Thanks and wish you the best for the New Year.

Tom

[RogueAngel]

Tom,

Two things:

1. Shorter leads make it easier to control noise.

2. The effectivness of the stopper resistors is reduced with greater distances from the tube socket.

For these reasons, I located those resistors at the tube socket and used shielded cabling for wiring. The shields are all tied back to the PCB ground point.

Sorry for the delayed response, I was out of town during the holidays.

Hope this helps,
Bobbi

[TChung]

Hi Bobbi,

When you said  you used shielded cabling for wiring, I assume you meant wiring the inputs & outputs; not wiring the tube sockets to PCB.

Thanks again,
Tom