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beatnik

WTB interstage transformer for Gibson guitar amp
« on: February 08, 2017, 11:47:28 AM »
I am looking for a replacement interstage transformer for the Gibson BR-9 amplifier

original Gibson part number T-1011-D . turns ratio is 2.4 : 1

any transformer with similar ratio and a small size would be suitable

Thanks !


hitchhiker

Re: WTB interstage transformer for Gibson guitar amp
« Reply #1 on: February 08, 2017, 06:22:41 PM »
 A-20's have taps for 500:200  = 2.5:1  Would that work well enough?

mjrippe

Re: WTB interstage transformer for Gibson guitar amp
« Reply #2 on: February 08, 2017, 07:04:35 PM »
Is there DC on the primary?

beatnik

Re: WTB interstage transformer for Gibson guitar amp
« Reply #3 on: February 09, 2017, 03:43:11 PM »
A-20's have taps for 500:200  = 2.5:1  Would that work well enough?

I don't think it would fit the chassis. Limited space is available. also the impedance is probably not optimal for this circuit ?

Is there DC on the primary?

Yes, one side of the primary is connected to the second triode plate and the other side is to a +140v tap from the power supply.
I have attached a schematic




mjrippe

Re: WTB interstage transformer for Gibson guitar amp
« Reply #4 on: February 09, 2017, 06:31:00 PM »
Interesting, I was wondering why they used an interstage transformer in a guitar amp.  It is also providing the two phases for the push-pull output stage.  Maybe post this in The Lab instead of Black Market.  I bet CJ will have some input.

beatnik

Re: WTB interstage transformer for Gibson guitar amp
« Reply #5 on: February 13, 2017, 07:00:07 AM »
I have opened a thread on the lab about the amp. I am still looking for these parts