Installing a 1959 PTP in my 86' 100 Watt JCM 800

myker · Post by **myker** » Sat Apr 16, 2005 11:03 am

Looks like you are ready to rock, now im thinking that i should have my lego caps out!
mike

Necrovore · Post by **Necrovore** » Sat Apr 16, 2005 12:15 pm

Dax wrote:Is this Correct: JCM 800 2203

C14 - .022
C15 - .1
C16 - .022
C17 - .1

Yeah those are it. I thought you were changing out a 800 1959 to ptp not 2203 to 1959, my bad. Hrmm, how bout trading amps? You get that one to stock and Ill trade you that one for my 800 1959? This way you wont have to mod the chassis on yours. PM me if this interests you.

Dax-The-Ax · Post by **Dax-The-Ax** » Sat Apr 16, 2005 2:33 pm

Necrovore, i will trade you today! But we have to keep Head Boxes, I have the Red Full Stack. I'm not sure you want to do that though. This thing was heavily Modded. It has two extra Preamp Tube sockets-One was the FX Loop, and one was a gain mod. Both have been taken out of the signal, but the sockets remain. On the back, there are two added knobs and two added Input Jacks for the FX loop. The FX Loop is taken out. The DI Jack has beed unwired, i was going to put another MV there. The jack remains, but it's not wired. On the front, it looks like a 4-inputter, someone drilled holes in the faceplate for the gain mod. I put in dummy jacks so it looks like a stock 1959. The input jacks are wired to the board, the traces were damaged. Although, George a while back changed some values for me and it has alot more gain than a standard 2203 if you want more. Let me play it and i'll send you some pics. I'll fricking ship her out monday! Maybe all these mods interest you. You could add another tube gain stage, and maybe another FX Loop, and I think it would be Metal Heaven. It was before i ripped that shit out. I just couldn't stand the mess!!!

Dax

Dax-The-Ax@cox.net

Dax · Post by **Dax** » Sat Apr 16, 2005 3:15 pm

She is really quiet, i re-twisted and wired the Heaters, does this make that big of a difference?

Dax

Flames1950 · Post by **Flames1950** » Sat Apr 16, 2005 5:13 pm

Maybe Necrovore could use the extra preamp sockets for more gain and we can keep him outta the Mesa zone.

Dax · Post by **Dax** » Sat Apr 16, 2005 5:42 pm

That's exactly what i told him!

Dax-The-Ax · Post by **Dax-The-Ax** » Sat Apr 16, 2005 9:17 pm

George, what do you think? Looks alot better huh? Sounds great too. The clean channel is awesome. Although, after about 3 on the Preamp volume it gets into high gain territory. George added some components at one time to increase distortion. I wonder if i removed them when i cleaned her up. Does anyone see anything that looks like the wrong value? George, do you remember what was added. Maybe this distortion is stock, i don't know. I'm trying to chech the schematics to see.
Man, this stuff is fun, i ripped apart my 1987 and rewired the heaters, alot quiter also.

Dax

Flames1950 · Post by **Flames1950** » Sun Apr 17, 2005 12:48 am

Man, this stuff is fun, i ripped apart my 1987 and rewired the heaters, alot quiter also.

FUN? Wiring the heaters? I guess the phrase that came to my mind was "necessary evil."

Dax-The-Ax · Post by **Dax-The-Ax** » Sun Apr 17, 2005 1:31 am

Well boys, i want to say thanks for the help. I found a few values in the VR1 area that were off and returned them to stock. The Cathode bypass cap was 25uf and the VR1 Resistor was 820 ohm. This was giving her Mesa Boogie gain. I put the originals back in, 10K and .68 Sozo (I love Sozo). She's pretty much back to stock 2203 and sounds fucking Badass!!! Clean is beautiful and gain is Captain Crunch!!! I have four option i'm considering. What do you think.

1. Leave the beast alone and be happy with badonka donk crunch!!!

2. Beings i have the jacks, knobs and tube socket, put the FX Loop back in. I love having the versatility of an FX Loop. I love delay and verb with some EQ in the loop. I suck at schematics, so i would probably have to have George put the loop in.

3. Install the PTP 1959 Metro board, Tone controls and new input jacks i have coming and convert it to Superlead specs. I have crossed over and have realized that the greatest amps ever made were the Superleads. I love my 1987 conversion. It Turned my shitty 2204 into a proud tone infested jewel!!!

4. Trade for a bone stock JCM 800 Superlead. It also has board mounted pots and such. Probably built in 87'

I can't decide. I really want the FX. I'm going to post a simple tube FX Loop in another thread and if you all can explain it in laymans terms, i may put it in. My final decision will probably be to convert it to 1959 specs with the PTP and put the loop in.

Thanks.

Flames1950 · Post by **Flames1950** » Sun Apr 17, 2005 8:45 am

You've got the tube sockets so if you go with an FX loop again you might as well do a tube-buffered one, I think your loop will work better for you that way. And there's no point in trading amps if you're going to have to turn around and mod the stock JCM800 for the FX loop you really want anyway.
So to me it sounds like the FX loop is a given, but if you send it to George, it might give him a chance to work up that FX loop card he was considering (admittedly it may have to be a little different than the RI version he had in mind, but it may help get most of the ideas set in principle.) I don't recall if the Marshall RI FX loop was buffered, it may have used an IC to do it, certainly not tube though...... At that point, he could also work the PTP for the later amps so he knows what's involved.
You'd be his guinea pig for the better good of all.

Dax · Post by **Dax** » Sun Apr 17, 2005 4:45 pm

I'm going to keep the amp, play it stock 2203 for a while and then send her to George and let him finish the FX Loop. It sounds pretty good with stock values and Sozo's!!

Dax