[Harp-L] Fender Champ(Steve Webb)



Steve Webb in Minnesota wrote:
> I need some help from one of you amp gurus out there. I have an old Fender
> Champ that a harp-playing friend is interested in buying.  Long story
> short, the tubes have been mucked about and I'm not sure which tubes go
> where.
> Here's what I have: from left to right looking at the amp from the back..
> an old RCA tube that says 5y3 and below that it says GT
> then a 6v6GT (made in Russia)  and then at the far right, a 12ax7.
> The 12ax7 is obviously in the right place, but I'm not sure if the others
> are in the proper place.
> can anyone shed some light on this?
> It has a Weber Speaker that I put in awhile back, but I have'nt played it
> in a long time. It does play with tube sin the order shown above, but it
> doesn't seem to have the bottom that i remember.
> I'd like to sell it, but I don't want to pass it on to this friend if it
> isn't right.
> 
Hi Steve
I'm not a guru but interested in circuits
 Heres a nice illustration for the Models 5E1 (with smoothing choke)
and 5F1:  http://www.studio-eight.com/akavalve/champ_5F1_5E1.gif
Unplug the amp and wait 10 minutes before inspecting the circuitry.
the 5Y3GT is the rectifier, and is wired into the mains transformer
secondary side.
The 12 AX7 is a double triode working as preamp stages, connected to the two
jacks.
That leaves the 6V6GT as the output valve connected to the output
transformer and speaker.
If the tubes are in the wrong order, (6V6GT in 5Y3GT place) the amp won't
work at all (unless you count blue flashes and a burning smell as working :)
The bottom loss may be partly the different speaker? Is the Weber of the
same impedance as the original speaker?

I hope this helps!
Geoff Atkins





This archive was generated by a fusion of Pipermail 0.09 (Mailman edition) and MHonArc 2.6.8.