replacing tone stack in tube pa for guitar

blindbrett · 28th June 2008, 12:22 PM

Hi Folks, I have been reading through old threads regarding converting tube pa amps to guitar amps. I have a few of these and have a friend teaching me how to repair them. He is not a guitar guy though, more of a radio guy. My question is this, can I just rewire the tone section to a fender or marshall type tone circuit without worry of causing the amp to be unstable. I have bogen mx-60 and mx-60a that I have repaired and work great but now i want to tweak them to get a nicer tone. I am just worried that if i change to a fender tone circuit, I might create some problems unwittingly. Any help is greatly appreciated. I will include a schematic for the mx-60a but I can't find one for the mx-60 so if anyone has one I would be gratefull for a copy.

thank you all very much

Brett

blindbrett · 28th June 2008, 12:28 PM

can't seem to get the schematic to come up. i will keep trying

Brett

Trout · 29th June 2008, 01:39 AM

Is that the Bogen with a PP 807 output section? Dual rectifiers and weight about 9000 lbs?

I might have the schematic out in my garage with the same unit.
I'll check later.

Trout

blindbrett · 29th June 2008, 11:57 AM

Hi Trout, the bogen mx-60 has 3 rectifiers ( gz34 I believe ) and a pair of 7027's in pp. Mine only weighs 8943 lbs! the mx-60a has a pair of 8417's in pp and a ss rectifier. I find these to be very good amps with heavy iron and very loud. I'm just not sure if I can arbitrarily change the tone stack without having any adverse consequences on the rest of the circuit. If you have any bogen or fanon schematics I would be most grateful for a copy.

Regards

Brett

Gunny · 6th July 2008, 05:26 AM

I would be interested in any info you find out on this as I just picked up a Bogen MX60 as a project head for guitar. My amp has 6l6s in it. Jim

Merlinb · 6th July 2008, 09:13 PM

Provided you don't try and put the tone stack inside the global feedback loop, you should be fine.

28th June 2008, 12:22 PM	#1
blindbrett diyAudio Member Join Date: Sep 2007	replacing tone stack in tube pa for guitar Hi Folks, I have been reading through old threads regarding converting tube pa amps to guitar amps. I have a few of these and have a friend teaching me how to repair them. He is not a guitar guy though, more of a radio guy. My question is this, can I just rewire the tone section to a fender or marshall type tone circuit without worry of causing the amp to be unstable. I have bogen mx-60 and mx-60a that I have repaired and work great but now i want to tweak them to get a nicer tone. I am just worried that if i change to a fender tone circuit, I might create some problems unwittingly. Any help is greatly appreciated. I will include a schematic for the mx-60a but I can't find one for the mx-60 so if anyone has one I would be gratefull for a copy. thank you all very much Brett

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28th June 2008, 12:28 PM	#2
blindbrett diyAudio Member Join Date: Sep 2007	can't seem to get the schematic to come up. i will keep trying Brett

29th June 2008, 01:39 AM	#3
Trout diyAudio Member Join Date: Nov 2004 Location: Midwest Madman	Is that the Bogen with a PP 807 output section? Dual rectifiers and weight about 9000 lbs? I might have the schematic out in my garage with the same unit. I'll check later. Trout

29th June 2008, 11:57 AM	#4
blindbrett diyAudio Member Join Date: Sep 2007	Hi Trout, the bogen mx-60 has 3 rectifiers ( gz34 I believe ) and a pair of 7027's in pp. Mine only weighs 8943 lbs! the mx-60a has a pair of 8417's in pp and a ss rectifier. I find these to be very good amps with heavy iron and very loud. I'm just not sure if I can arbitrarily change the tone stack without having any adverse consequences on the rest of the circuit. If you have any bogen or fanon schematics I would be most grateful for a copy. Regards Brett

6th July 2008, 05:26 AM	#5
Gunny diyAudio Member Join Date: Jan 2006 Location: WI	I would be interested in any info you find out on this as I just picked up a Bogen MX60 as a project head for guitar. My amp has 6l6s in it. Jim

6th July 2008, 09:13 PM	#6
Merlinb diyAudio Member Join Date: May 2006 Location: York	Provided you don't try and put the tone stack inside the global feedback loop, you should be fine.

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