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Re: Help with Old Epiphone AMP


 :
5/9/2000 3:49 AM
Carlo
Re: Help with Old Epiphone AMP
Perhaps, like some Gibson amps, it uses a transformer for the phase inverter.  
 
just a thought,  
Carlo
 
5/9/2000 2:59 PM
Steve Jones

Carlo may be right. It could be like a Fender Musicmaster bass that uses a transformer for the phase inverter. That amp has a single 12AX7 and 2 6V6s. Lee, how many transformers are on the chassis, 2 or 3?  
 
Or I suppose it could have a single preamp stage and a cathodyne PI. It just wouldn't have much gain.  
 
Another possiblity is the emply socket is for the PI tube, and the unit uses silicon rectifiers. So far, the assumption has been that the empty socket is octal. Lee, is the empty socket 9 pin or 8 pin?  
 
Steve
 
5/9/2000 3:45 PM
Lee

Hi Steve:  
It has 2 transformers, a large one which I assume is the power supply TX, and a smaller one that two wires come off of to go to the speaker ... (i.e. the output TX?!) The empty socket is an 8 pin. It looks like it is tied to the larger TX. I do not see anything else inside it but hand wired resisters, elecrolitic caps, two large caps (main filter caps?!)... one connected to the lge. TX & what we are assuming is the rectifier socket, the other leading to the power tubes. 2 ea inputs, an on-off switch, power light, fuse, a vol & a tone pot.  
 
I hope this helps some. If someone cannot locate a schematic for me, I'll draw a picture and post it.  
 
I don't remember this amp being very loud & powerful, but it seems to me that it had some really good tone for a small box! I am now 46years old & I first got this when I was in HS in 1970 ....  
 
Thanks y'all for your comments & responses ... & keep 'em comming!  
TX!  
Lee
 
5/9/2000 5:10 PM
Hi

Since Gibson has owned Epiphone since 1957, it's probably pretty much similar to Gibson amps.  
Hi
 
5/10/2000 12:10 AM
Winnie Thomas
I bet this is it!
Howe does this look?  
 
http://www.servtech.com/~piazza/joepage/Amps/gibsonet.gif  
 
Winnie
 
5/10/2000 2:56 PM
Steve Jones

Interesting. Is this what Doc meant by two 6V6s in parallel, single-ended?  
 
When you have two output tubes like this, how does it affect the impedance load on the output transformer vs. one tube single ended?  
 
Steve
 
5/10/2000 3:25 PM
Winnie Thomas

Steve,  
 
the impedence would be doubled. There's two ways to look at it:  
 
One 6V6 into 4,000 Ohms drives an 8 ohm load  
Two 6V6's in parallel into 4,000 Ohms drives a 4 Ohm load or:  
Two 6V6's in parallel into 8,000 Ohms drives an 8 Ohm load.  
 
...I think that's it...  
 
Winnie
 

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