Difference in tone between JTM50 and JMP50 OT's?

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Big Mike
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Difference in tone between JTM50 and JMP50 OT's?

Post by Big Mike » Thu Jul 14, 2011 5:47 pm

I'm slowly evolving my JTM45 kit into something else. Just not a fan of several thins in that circuit.
Iv'e now got it mostly set to lead specs, split cathode, .0068 V1B, EL34's,. yadda yadda.

So I'm thinking maybe I should swap out the OT for something more in line with what it's morphing to?

So all things being considered, in a Stock metro PT'd amp with the above changes, what's the difference between a 79-128 and a 79-139 OT's going to be?

Also should I be looking at a different choke?

Thanks
Mike
Metroamp kit JMP50 - CM OT
Metroamp JTM45 turned JMP50 w/Classictone OT
Marshall 2550 Jubilee
Powered by Thorn and Kauer guitars
Scumback Speakers

OnTheFritz
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Re: Difference in tone between JTM50 and JMP50 OT's?

Post by OnTheFritz » Thu Jul 14, 2011 8:02 pm

The 784-128 has a 3.5K primary, like the 139', but also has a buried 100V tap which apparently does affect the tone.

Here's Marstran's 128 OT. Two in stock!

http://www.marstran.com/50W%20OT%20128.htm" onclick="window.open(this.href);return false;
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Big Mike
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Re: Difference in tone between JTM50 and JMP50 OT's?

Post by Big Mike » Thu Jul 14, 2011 8:26 pm

Yeah but what's the sound difference?
Metroamp kit JMP50 - CM OT
Metroamp JTM45 turned JMP50 w/Classictone OT
Marshall 2550 Jubilee
Powered by Thorn and Kauer guitars
Scumback Speakers

User avatar
Big Mike
Senior Member
Posts: 796
Joined: Tue Oct 31, 2006 12:42 am
Just the numbers in order: 7
Location: East Bay California - Raider Nation

Re: Difference in tone between JTM50 and JMP50 OT's?

Post by Big Mike » Thu Jul 14, 2011 8:30 pm

Duh of course I meant 784-128 and 784-139

Brain fade...
Metroamp kit JMP50 - CM OT
Metroamp JTM45 turned JMP50 w/Classictone OT
Marshall 2550 Jubilee
Powered by Thorn and Kauer guitars
Scumback Speakers

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