JTM45/100 iron vs. '67 JMP iron

Herec · Post by **Herec** » Fri Dec 14, 2007 3:05 pm

What's the real difference between the 1203-80 used in the '67s and the 1203-43 used in the JTM100's?

Could one use the 1203-80 with a JTM 100 1202-84 OT ?

I was thinking about dropping like a '68 circuit in something that had JTM100 iron...

Flames1950 · Post by **Flames1950** » Fri Dec 14, 2007 6:27 pm

Yes, you can use the 1203-80 power tranny with the JTM100 output tranny and circuit.

Herec · Post by **Herec** » Sat Dec 15, 2007 5:12 pm

So the '67 JMP power tranny would put out 485v approx. on the plates, and then I would use KT66 to go with the JTM100 OT?

Flames1950 · Post by **Flames1950** » Sat Dec 15, 2007 8:24 pm

Sounds like a plan.

Billy Batz · Post by **Billy Batz** » Sat Dec 15, 2007 9:38 pm

Just make sure you use the 80 with the voltage doubler power supply not that 6 diode full wave Fender Style supply in a JTM100. Your voltages would be very low if you did that.

Herec · Post by **Herec** » Sat Dec 15, 2007 10:12 pm

Haha...

I've gone from possibly building a JTM45 to building another hundred watt beast...

I just can't stand putting a PPIMV in a 100 watt amp because I'll probably want to use it with two cabs, and I feel like I'm castrating the amp...

Maybe I can try to get two builds at once, if I have enough parts from some other gutted chassis....

Billy Batz · Post by **Billy Batz** » Sun Dec 16, 2007 10:36 am

Herec wrote:I just can't stand putting a PPIMV in a 100 watt amp because I'll probably want to use it with two cabs, and I feel like I'm castrating the amp...

Hey, if it sounds good it is good. Most of the time Im playing pretty low volumes and you get that real arrogant shit from a lot of people 'ehhh whats the point of playing a Marshall if you play that low, blach, blach blach'.. Well still nothing else Ive played sounds like even a 'low' 100W marshall and it sounds good so whats the problem here?!

Herec · Post by **Herec** » Sun Dec 16, 2007 11:09 am

Dan, do you use the PPIMV?
I don't have a plexi back panel on my current amp, I may just drill a hole to preserve the two cab capacity...

Haha, I think I may have found a winner! This way, I can sell my 50 watt amp so I can get another cab, and still have 100watt capacity!

Can you tell the PPIMV is installed in the amp when it (the PPIMV) is fully dimed? Does the amp react any different than it used to?

Billy Batz · Post by **Billy Batz** » Sun Dec 16, 2007 1:53 pm

No I dont use the PPIVMV. I like how they sound in some ways but I like my UA too. At full volume the circuit is stock basically. I wasnt talking you into anyting just if it sounds good to you or if you think it may work for you do it. FWIW I think they sound much better in your 69 era lead amps then JTM or Bass amps.