Anybody up ?

[Carlin Mitchell]

I've been working on my champ (first amp) for a month or so now on and off. I plugged it in for the first time a few minutes ago... NO SMOKE !!!!!!!! I get my lamp to light... the heaters glow pretty.... if I touch the end of the guitar cord against the guitar jack I can hear the speaker rustle a bit like a normal amp but I get NO output when I plug the cord into the guitar. I got a tiny peep of sound for a little bit. The volume knob also does not appear to change the sound of the hum or cord noise coming from the amp. I will be working on this for the night.. any thoughts from an old school guy ?? Thanks in advance for the help. Carlin

[bnwitt]

Well first thing you should do is check the wiring on the input jack. Also make sure there aren't any wiskers of wires touching other adjacent contacts. With the amp off pull the speaker plug from its jack and measure the DC resistance to make sure the wiring is good. Should be around 6.3 ohms to 7.2 ohms if the speaker is an 8 ohm unit. Check all ground connections according to the layout. Then maybe do a voltage measurement on the pins of the 3 tubes and share the readings.

Your board layout looks like a typical champ but your tube positions look backwards?? You also appear to be missing some board components??

[Carlin Mitchell]

It's my first and kind of a frankenstein. I have just one input jack and only one 100 ohm input resistor. It's a 4 ohm speaker... the resistance across the speaker is 3.6ohms. There are two lamps on top but only one is hooked up.. mistake. As far as the layout being backwards... that's probably just new guy stupidity. I'm learning. What appears to be missing ? I think I don't have one of the post on the volume pot grounded. The original 5F1 layout does not show the volume pot grounded but the CERIATONE weber version show it grounded.

[austinb]

looks like some of the wires are swapped between output tube and preamp tube.

[Cygnus X1]

Is it possible the placement of the input jack could be a problem?

[Structo]

You don't got no tubes in it!!!!

Just kidding.


You should probably have a 68K grid resistor from the input jack.
And also on that jack do you have a 1M resistor from the tip to ground?

Hard to say what else because a lot is hidden behind the board.

Is this a Champ variant?

[M Fowler]

A different version