[zkool448]

hahaha congrats

If I may I ask, how the heck did you miss soldering them to ground?

 

[Fred_fred2004]

Quote:

Originally Posted by penneydude /img/forum/go_quote.gif Yep, it was my fault - I forgot to connect the other end of the power caps to the ground, haha. Noob mistake, but it's working perfectly now and it sounds GREAT! Thanks for your help guys, and thanks to Pete for the design.

Well done, its usually something simple,
enjoy the amp

 

[J.P.6]

Guys,

I've got 4 19J6 tubes available for people looking for some in the UK.

http://www.head-fi.org/forums/f44/fs...bes-uk-419710/

Thanks.

 

[penneydude]

Quote:

Originally Posted by zkool448 /img/forum/go_quote.gif hahaha congrats If I may I ask, how the heck did you miss soldering them to ground?

I was working away a couple nights ago and decided to take break, so I walked away and when I came back I guess I just forgot where I left off. After that I printed the schematic off and started crossing stuff out with a pencil to keep track, but I crossed the power caps off because they were on the board already, I assumed I had connected everything to them that had to be. Not the case apparently, haha.

It was a real "...OHHHH RIGHT" moment.

 

[zkool448]

haha, i've done similar boo-boos before too and yours reminded me of that "ahhhhh, dang it!" moment I had

 

[Bleuburd]

Well, I finished tonight. But, only one tube is lit. I changed the transistor and checked all the power connections coming to the socket. Could it be a bad joint from one of the other pins? (other than power if that makes sense)

 

[tomb]

Quote:

Originally Posted by Bleuburd /img/forum/go_quote.gif Well, I finished tonight. But, only one tube is lit. I changed the transistor and checked all the power connections coming to the socket. Could it be a bad joint from one of the other pins? (other than power if that makes sense)

Focus on the heater circuit. This is the wiring that connects Pins 3 and 4 of each tube to Pin 3 of the respective MOSFET and to C3 or C5, depending on which tube you're looking at.

 

[Bleuburd]

Ok, I'll check it out tomorrow. I thought those joints were good, but I'll double check. Pics tomorrow!

 

[zkool448]

I'm not quite sure if you've already tried swapping the tubes, nevertheless most likely Tomb's suggestion will help you find the problem (you want ~19V at the points tomb mentioned with respect to ground).

 

[Bleuburd]

Yeah, I switched the tubes. I'll go tomorrow and troubleshoot for a while. I've got school to tend to right now.

 

[penneydude]

Quote:

Originally Posted by zkool448 /img/forum/go_quote.gif haha, i've done similar boo-boos before too and yours reminded me of that "ahhhhh, dang it!" moment I had

Forgetting to put the heat shrink over the wires BEFORE you solder everything together is another good one, which I did quite a few times.

 

[Bleuburd]

Well guys, the connection from the mosfet to the socket is fine. I double checked all the power connections, and still only one tube will light. Any ideas?

 

[tomb]

Quote:

Originally Posted by Bleuburd /img/forum/go_quote.gif Well guys, the connection from the mosfet to the socket is fine. I double checked all the power connections, and still only one tube will light. Any ideas?

Well, I hate to say it, but if the problem is not the tube, then it's a connection somewhere. Look harder.

Have you actually put a meter to the heater pins and can you read voltage there when the amp is plugged-in/turned-on? How does it compare to the voltage for the same pins on the tube socket that lights?

EDIT: It might be a blown MOSFET, too. Can you read voltage across the pins (1 and 3 or 1 and 2) of the MOSFET? How does it compare to the operating channel?

 

[Bleuburd]

I'll check the voltage when I get back from my instructor meeting. It's not the mosfet. I switched that already. I thought it could be the cheap socket I got from the tube center, since I checked all the connections, and then double checked them.

 

[v3nom]

which pins on the pot correspond to what?