Cordovox

[matt mincer]

Hey All,

Today I bought a 2 part Cordovox accordion amp and tone generator box. The plan is to convert the amp into a guitar amp and use the 2nd cabinet for an amp I have already built. Anyone know where I can find the schematic for this? 

Thanks
Matt

[Ritchie200]

Matt,

Did you happen to see this project?

http://www.chosenfool.com/?p=146

Jim

[kagliostro]

Matt Mincer do you have an exact model for it ?

Franco

[matt mincer]

Jim,

I did see that posting. He couldn't find a schismatic either. There's a tube chart on the inside but no schematic anywhere. The post will give me a good jumping off point.

Franko,

Take a look at the attached pic. The only model is Cordovox. Weird!

Thanks to both of you.

Peace
Matt

[sluckey]

A google search turned up a site that has service manuals for sale. The link was near the top of my search.

[Tony Bones]

It's probably not a very complicated circuit,(though it might have some features that looks funny if you've mostly only looked at Fender schematics.)

Have you considered trying to trace out a schematic yourself? There's no better way to become familiar with what's in front of you.

[matt mincer]

Yeah, once I got the chassis out of the cabinet, I realized how simple it is. It's only got a 12AX7 phase inverter and 2 power tubes. Most of the circuitry, including the preamp is in the tone box. Should be an easy conversion. Plenty of room to work.

Thanks
Matt

[matt mincer]

Here's a look inside

[PRR]

Historic fluff: "Chicago Musical Instrument Company" was better known as CMI, controlled Gibson for a while, merged into Norlin later.
https://en.wikipedia.org/wiki/Chicago_Musical_Instruments

Can't imagine the power amp circuit is much of a puzzle. The tone-generator needs an organ guru, but is of little interest without the wired accordion.

[sluckey]

I don't see an output transformer. Is it mounted on a speaker?

[matt mincer]

Here's a top view. Check out the size of the power transformer. The sockets on the right (or middle) are plugs that attach to the wire to connect the two halves.

[sluckey]

Ah, it was hiding in plain view.  That PT is so big because it probably powers all those tubes on the generator chassis.

[matt mincer]

Yeah, it does drive them all. It's wild because the power comes into this chassis, goes through the cable to the 2nd box and to a power switch, then back to here to be stepped up and rectified then back to the 2nd box, B+, 6V and all to power 60 plus tubes, then finally the signal comes back to here for the final stage of amplification.

M

[PRR]

It smells like a 40W amp (two 7591).

The OT is small, small enuff to screw to the top, because an accordion has no bass (apparently not even with a tone-organ attached).