ampage
Tube Amps / Music Electronics
For current discussions, please visit Music Electronics Forum. New: view Recent Searches.
New: visit Schematic Hell!
The sunn still shines online!

 
Listen to great tunes streaming live right now!

ampage archive

Vintage threads from the first ten years

Search for:  Mode:  

McGohan M-10 amp. Any info?


 
3/15/2000 10:04 PM
Dan McGohan M-10 amp. Any info?
I just got this old McGohan M-10 PA amp and it has some really cool old features. It has a regular phono/RCA input and a weird ~1/2 inch threaded mic input. All RCA: 2 12AX7, 2 6v6, and a 5y3. There is a multi-tap transformer, and you select the output impedance by a pushing in a pin into a tube socket-looking output marked for 8, 16, 250, 500, and 70V. There are two speaker out jacks, both also use a tube-socket like connector. It only has one of the speaker plugs. The filter caps are bundled up in one big cylinder that sticks up from the chassis next to the transformer. There are separate mic and phono volume knobs, (will this work like an old tweed fender if I bridge the channels somehow?) The bass pot has click-in positions, while the others all have a smooth taper. And there's no circuit board. True point to point!?  
 
As you can tell, I'm pretty excited to get this home and try plugging a guitar into it. Anybody know where I can get new filter caps for this guy?  
The markings outside the cap are:  
20mfd-475W.A  
20mfd-475W.A.  
10mfd-475W.A.  
25mfd-50W.A.  
 
Here's a picture:  
http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=277469642  
 
Anybody have more information or suggestions?  
 
Thanks,  
 
Dan
 
3/15/2000 11:53 PM
Marc
email
McGohan M-10 amp. Any info? a bit....
Dan:  
Looks like a nice platform for your project.  
Try www.triodeel.com for the filter cap. It might not need one, right away. you could try to reform it with series resistance, Pull the 6v6's.  
the screw on connector can be removed and a 1/4" jack put in it's place. If it's got a fiber surround, and not a nut, you can gently twisted it out and have an isolated input jack hole.  
Before you do anything scetch out the schematic so you can reconstruct it back to the original circuit, in case you change your mind or in case you run into a snag that prevents it from working. Sometimes you can use the circuit as is or just modify the preamp and get good to great tone.  
Check out this schematic http://members.aol.com:/fyrebottle/schematics/arkay-deluxe.jpg  
I built this from an old hifi and the guy actually used it with his band, for the tone of it.  
 
Keep us posted on your progress...  
 
Marc
 
3/17/2000 5:44 AM
Marc broken link sorry
Evidently AOL is case senstive, I tried away from home & couldn't get there. Here it is again.  
I put a simple spst switch to brdige ch1 & ch2  
 
http://members.aol.com/fyrebottle/schematics/Arkay-Deluxe.jpg  
or for the folder  
http://members.aol.com/fyrebottle/schematics/  
 
marc
 
3/16/2000 2:25 PM
john
email
Re: McGohan M-10 amp. Any info?
so you're the guy who won that one. I have a little M-102 PA amp I've been slowly working on over the past year. Hope your project works out for you. Let us know.
 
3/16/2000 11:15 PM
Dan
Yeah, I decided to get the amp to play with, and because I work in the same city as the seller. You know, less buyer anxiety. He brought it to my office and everything.  
 
I hooked it up to one of the 8 ohm speakers Celestions from my silverface Twin Reverb last night. Used a 1/4 inch to phono converter and plugged in my strat. Well, its not real loud, and does make some pops and thumps occasionally. The amp has a lot of midrange, but the Celestion may add to this. The separate Phono and Mic volume seem to work like a tweed fender, or at least like the Victoria Deluxe I played last week. Turn the non-plugged in volume up and the amp starts squealing.  
 
Now I have to figure out how to jumper the two channels together like a tweed, but there are only two inputs. Any suggestions? I may take a look at the parts values inside soon to try and adjust the midrange level. If all else fails, I could draw out the insides for future reference, and try a Deluxe kit like from SwampAmp.com to match the 2 6v6 layout.  
 
Dan
 
3/17/2000 6:04 AM
john
email

 
If you're in need of a schematic, I didn't read all the posts here, McGohan is actually still in business. Somewhere in Ohio or Illinois I think.  
Anyway, I called them back in '98 for a schematic and they sent one right out. They were very friendly and didn't charge anything for it.  
I found them through www.bigyellow.com under the McGohan name. I also got a Grommes schem the same way. I don't know if Dan McGohan was still there or not, but you can always ask.  
 
js
 
   Page 1 of 1