Amp Build Idea

ninjaking67

ninjaking67

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This is really a question for the amp Gurus here on TTR. There are a lot of folks on here that have considerable experience and knowledge regarding all things amplifier related so I am hoping to get their thoughts on my idea.

I am considering designing/building a 18-20W amplifier with 2 separate preamp sections but sharing a phase inverter and power section. I know, not very revolutionary! But wait!

Preamp #1 would be a Fender-style preamp designed for a clean Fender tone. Preamp #2 would be a Marshall-style preamp for Plexi-JCM tones. Each preamp would have its own gain, volume and tone stack. There would be a Master volume (maybe PPIMV) and I would probably add an off-the-self Effects Loop module like what is available from Trinity Amps here in Ontario.

Am I crazy in even considering this? I know there will be suggestions that there are current production amps that do this already.

Any thoughts?
 
ninjaking67 said:
This is really a question for the amp Gurus here on TTR. There are a lot of folks on here that have considerable experience and knowledge regarding all things amplifier related so I am hoping to get their thoughts on my idea.

I am considering designing/building a 18-20W amplifier with 2 separate preamp sections but sharing a phase inverter and power section. I know, not very revolutionary! But wait!

Preamp #1 would be a Fender-style preamp designed for a clean Fender tone. Preamp #2 would be a Marshall-style preamp for Plexi-JCM tones. Each preamp would have its own gain, volume and tone stack. There would be a Master volume (maybe PPIMV) and I would probably add an off-the-self Effects Loop module like what is available from Trinity Amps here in Ontario.

Am I crazy in even considering this? I know there will be suggestions that there are current production amps that do this already.

Any thoughts?
Click to expand...
I have built almost the very same amp before.

I used a bassman chassis, since Marshall and Fender amps are practically the same amp....
I used triode 6L6 / 6CA7 output to reduce the power instead of pentode output.
I used a Metro effects board, which I modified to be series / parallel / bypass...
I used a classic tone power transformer that had various voltage taps to reduce voltage, had a rectifier tube winding, had multi primaries for different countries. Like 100V, 120V, 230V, 240V...

I tried the zener diode method of power reduction and decided it sucked. Abandoned that idea.
But I tried it since so many people were pushing the idea.

I started to make a switch to change between 40 watt and 20 watt...but I was interrupted by a heroin addict.

I settled on a solid state rectifier plug-in tube replacement.
I settled on 6L6 output tubes because I thought the bass was beefier...sounded more hi fi.
I made it switch between plexi / JCM 800 preamp...

I modded it for outrageous sustain, my best sustain circuit ever attempted.
It was the beginning of my original sustain circuit design.
(it could sustain clean notes without distortion) among other things....it was an entirely new idea.

And I left one of the channels stock Fender for cleans, and modded the other channel for Marshall.

All in all it was a fairly fun project, that was heavily criticized by others.
Apparently some people thought that I had committed blasphemy, by combining Marshall and Fender into one amp. It made perfect sense to me.

I think I would like to go at it again, in a small combo cabinet maybe.
But the conclusion is that it's more practical to just mod an existing amp, than to start with all the parts from scratch. Cheaper and easier.
Plus I like Fender cabinet construction, Fender Tolex, fender hardware, etc...
of course the stock speaker is pretty lame, got to use a much better speaker.

I got some more original ideas instead of just copying what everybody else does....can't wait to get going on that new concept.
 
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That's a helluva project. A pair of 6v6's to get you into the 20 watt range... 3x 12AX7's... channel switching technology... DO IT!!!

And... Should you need it: With TTR's AMS, T-Rex, New Religion, Ivan H, & 67plexi, you'll get a lot of good knowledgeable advise and help.
 
syscokid said:
That's a helluva project. A pair of 6v6's to get you into the 20 watt range... 3x 12AX7's... channel switching technology... DO IT!!!

And... Should you need it: With TTR's AMS, T-Rex, New Religion, Ivan H, & 67plexi, you'll get a lot of good knowledgeable advise and help.
Click to expand...

I'm always ripping it apart and trying to improve it...over and over.
So don't use me as an example.
I'm a bad bad boy, who can't make up my mind about anything.

I gotta whole new original idea now; anybody who sees it will reject it as being completely insane.
And for me, that's pretty normal.
I've always been the one who wants to do what nobody else does.
I hate to just be the same as everybody else. ---therefore, very unpopular.
 
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ninjaking67 said:
This is really a question for the amp Gurus here on TTR. There are a lot of folks on here that have considerable experience and knowledge regarding all things amplifier related so I am hoping to get their thoughts on my idea.

I am considering designing/building a 18-20W amplifier with 2 separate preamp sections but sharing a phase inverter and power section. I know, not very revolutionary! But wait!

Preamp #1 would be a Fender-style preamp designed for a clean Fender tone. Preamp #2 would be a Marshall-style preamp for Plexi-JCM tones. Each preamp would have its own gain, volume and tone stack. There would be a Master volume (maybe PPIMV) and I would probably add an off-the-self Effects Loop module like what is available from Trinity Amps here in Ontario.

Am I crazy in even considering this? I know there will be suggestions that there are current production amps that do this already.

Any thoughts?
Click to expand...
Don't give up on it, do it.
 
I was thinking that no channel switching would be necessary. I would just have a separate input for each channel and use an A-B Y pedal to switch between. That would simplify things and reduce the need for a switching relay, etc.
Are there any issues with this idea?
In order to get JCM800 type gain at lower volumes would diode clippers be required or will a PPIMV do the trick?
 
ninjaking67 said:
I was thinking that no channel switching would be necessary. I would just have a separate input for each channel and use an A-B Y pedal to switch between. That would simplify things and reduce the need for a switching relay, etc.
Are there any issues with this idea?
In order to get JCM800 type gain at lower volumes would diode clippers be required or will a PPIMV do the trick?
Click to expand...
ABY has some disadvantages such as loss of signal.
The un-used channel might not be muted to stop the noise (or is it?)
It would be good to have a ground lift switch just in case...

I try to avoid clipping diodes. Although models such as JCM 900 had LEDs for clipping diodes.
I prefer to drive the tubes hard instead, and listen to them scream, (beg) plead, for holy mercy. When it's about to (just before it) explode(s), that's when it sounds the best.
" Almost but not quite out of control."
I really like it when it roars. It's like steering a spaceship to Mars.
I suppose there could be a switch for clip / UN-clipped, diodes / no diodes.
 
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