Fender Champ 600 talk

[Pacosipulami]

Hey Mark

Make sure the power tube runs at correct bias. Most of these little amps based on legendary models using cathode bias, running much too hot. Biasing correctly also takes out the nasty hum.


If you don't like the raspy nasty tone add a 1nF capacitor parallel to the 220k resistor to ground before the grid stopper of the 6v6. This corrects the raspy, nasty distortion on the little 6" speaker. For using with a bigger external speaker, I often make this cap switchable.

The mains transformer looks smaller than the normal 5F1 champ transformer (which is the same also used in Princeton Amps too). Even the champ 600 transformer has enough power to take another 12AX7 preamp tube if you like to have a improved preamp design.

Have fun, cheers
P

[Mark]

Make sure the power tube runs at correct bias. Most of these little amps based on legendary models using cathode bias, running much too hot. Biasing correctly also takes out the nasty hum.

Agreed they run incredibly hot, my 5F1 clone was running at 16 watts for a 14 watt valve, not good.

That is on my to do list with this amp. I may have to do it sooner than later though. It is chewing through the original Chinese tube at an alarming speed.

[Mark]

I have been slowed down by a buzzing cab. I suspect I have to solution but losing the buzz without losing the bass response it the problem.

https://tubeamparchive.com/viewtopic.ph ... 356#339356

A build isn't a build without some agony.

[Mark]

I ran the speaker in for a hell of a long time and the speaker is good now. I have just fried a 6V6 with the amp cranked to "12".

The problem was the screen grid has 300 ohms between the heaters. Never a good thing, the output tube was a TAD and it was part of a pair, the other still working happily in my modified Kendrick Roughneck.

https://tubeamparchive.com/viewtopic.php?t=28202