aikido heater

[Stixx]

I have finished my breadboarded Aikido headphone amp (6CG7 and 6H30) so far that today I tested the heater part of the psu. It consists of a 9V 50VA toroid and a regulator that delivers 6.15V (thread about the regulator somewhere here on diyaudio).
After checking all connections and inserting the tubes I flipped the switch and happily saw the heaters of one board starting to generate the homely orange....

The other side...nada...nichts...nothing.
I checked all connections again and checked voltages, and I do have 6.15V on pin5 of all four tubes, measured on the soldering joint to the sockets.

Do I have a case of shxxxy sockets on one of my boards? Never had that happen but can't think of another cause...

Btw: I also tried some EL84 in that board, but no heaters coming on...

[Miles Prower]

^^^^

Obvious thing first: did you miswire the heater connections on the sockets that have the dark VTs?

[Stixx]

Obvious thing first: did you miswire the heater connections on the sockets

No, since the sockets can be soldered to the board only in one position and the + lead goes to + on the board.
Also I have 6.15V on all of pins 5...

Thanks Miles!

[jrebman]

Did you solder the heater voltage selection jumpers in place? If they weren't inmstalled, it might explain your problem -- I said might :-).

-- Jim

[Stixx]

Yes I did...
both boards are populated exactly the same...I checked.

Will check the sockets of that board again.

[woodturner-fran]

Check for continuity from the heater pins to PS maybe?

You don't need to do something with pin 9 on some of the tubes?


Fran

[Stixx]

My problem is continuing...

This is my fourth tube amp (all being headphone amps) and I hate to ask silly questions, but after trying a bunch of different things the tube heaters on one board are not working...

Just to rule out the most obvious things:

- heater wires are connected identically
- the psu (regulator) is grounded
- I have switched sides --> all tubes are good, heaters have continuity
- I do have 6.15V on all pins 5 on the boards
- boards are populated identically, jumpers are in
- my regulator has been tested with a load od 2.2 ohm = ~2.9A

This is driving me crazy...

To illustrate things two images of my breadborad attached...





Anybody has an idea what could keep the left side of working properly...??

Thank you!

[Janez]

One board is upside down. If you do this you mess up pinouts for tubes.

[Andy Bartha]

Do continuity check on the wire going to pin 4. You said you have 6v at pin 5. Is this measured to ground or from pin 5 to pin 4. I've seen where the conductor was broken inside the jacket. Maybe you have a bad solder joint on pin 4. Resolder everything at the filament power supply, you never can tell.

[jrebman]

Another thing to check is whether the internal shield is shorted to ground (intentionally, or tied to ground via a .01 - .1 uF cap? Again, just another possibility with the 6cg7/6dj8 -- though don't know that the details of the 6h30 are.

-- Jim