BFT Gibson
Ambassador of Originality
Any help with this circuit would be greatly appreciated. Merry Christmas TTR
Need some help Amp friends
- Thread starter BFT Gibson
- Start date
OP
BFT Gibson
Ambassador of Originality
OP
BFT Gibson
Ambassador of Originality
chilipeppermaniac
Ambassador of Decibels
BFT, be more specific what you are asking?
OP
BFT Gibson
Ambassador of Originality
What circuit is it. getting more info later today. Seeing if its the JTm45/100 & has it been gained up a bit.
chilipeppermaniac
Ambassador of Decibels
Good luck BFT, That should give our amp guys a little better idea what you need.
Amp Mad Scientist
Ambassador of Heresy
It looks like a JTM 45 circuit...
You need more close up pictures to tell what values / resistors are installed.
What do you want to do?
It's basically a clean amp until you crank it up really loud. Then it starts to break up from power amp distortion.
But at that point it's extremely loud. Too loud to play in most places.
This is because a basically clean preamp.
You can use hotter preamp tubes which improves the crunchiness.
You can use an attenuator to knock the loudness down.
You can change it to a 2203 to get some preamp distortion, and put a master volume on it.
You can change the output to triode which makes it 40 watts about.
Or you can do a more devious modification which is favored by gain obsessed sustainiac madmen.
Last edited:
OP
BFT Gibson
Ambassador of Originality
The guy is sending me more info. Is there a Super 100 circuit? 100 watt SS Rec. Maybe what am trying to understand. Is it right on the cuff of the 100 watt transition from the jtm 45 to 100 watt 1959 but a hair leaning backwatds. I had jtm50 el34 with SS/Tube rec switch but let it go.
Amp Mad Scientist
Ambassador of Heresy
Can't really see the circuit without more close up photos.
Well actually JTM 45, Super 100, Superlead, is almost the same circuit. There is only small changes and variations.
Are you trying to make it more usable a lower loudness? That's what most people are trying to do.
67plexi
Ambassador of Amps
British Style - Ceriatone
www.ceriatone.com
You can tell by the filter capacitors
Marshall 100W Output Transformer for Plexi, JMP and JCM800 is a copy of a Daglell C1998 OPT Marshall started using in 1968
chilipeppermaniac
Ambassador of Decibels
My question from the pics is does it have 4 power tubes or 2? AND I was gonna ask about the Filter Caps too. Basically in addition to my first post, I wanted to also see Top side views.
OP
BFT Gibson
Ambassador of Originality
I think it is that jtm45/100 Ceriatone. Waiting on more info. Possibly the interest is in the 100 watter circuit. Have had the the 50 watters but never the 100. Don't really need it but moving some non used gear for something interesting is always doable.
syscokid
Ambassador of War & Peace
4 power tubes. Orange colored "Holy Grails" caps are usually seen as part of the Ceriatone products, as 67plexi pointed out.My question from the pics is does it have 4 power tubes or 2? AND I was gonna ask about the Filter Caps too. Basically in addition to my first post, I wanted to also see Top side views.
Clockworkmike
Ambassador of STACKS in WV SHACKS
From what i can see here, its 4 power and 3 preamp tubes from the sockets alone. Like the other wiser folks have said, seems like a JTM 100 circuit which is neat, cause it predates the famous Super Lead variant. Really cool early Pete Townsend inspired amp if its a JTM design ( EVHs plexi was actually one of the famous Black Flag logo JTMs and not the more well known JMP super leads)My question from the pics is does it have 4 power tubes or 2? AND I was gonna ask about the Filter Caps too. Basically in addition to my first post, I wanted to also see Top side views.
OP
BFT Gibson
Ambassador of Originality
Clockworkmike
Ambassador of STACKS in WV SHACKS
Kt66s it looks like, very cool
OP
BFT Gibson
Ambassador of Originality
Was messing with the 45 & 1987/2204 now all morning. What a dif..both are so cool. The 2204 has PPIMV so it gets nastier the lower it goes just a crunch monster. have em both on same cab. What is so cool is how you can lay into a 45 with attack & its juicy & the 2204 its crunch city. With these 2 not sure another one would be needed. The real surpise is how the Jet City 20HV is really what was searching for. it is old school & the controls are so interactive. The treble & presence really function in tandem so well. a recording weapon for sure
OP
BFT Gibson
Ambassador of Originality
In comparison..left the 45 on looper & fired up the Triple rec on clean, tube/spongy..plugged it into my fuzz board..had karma suture & belle epoch on from last time..bam that was it..the best fuzz handling sound i ever heard...sidetracked now to doom land. The Triple into marshall cabs at 16 ohm is very un mesa like but nice bottom for the heavies.. So nice with work volume down on a holiday..life would be calmer maybe.
ivan H
Ambassador of Tubes & Grooves
Mr Plexi67 is onto it, this amp is based on one of the JTM 45/100 variants, though the builder has taken a few liberties with transformers & filtering at least.
If you're interested in learning details/specs of the JTM 45/100 variants, take a look at the Solodallas web page "evolution of the 100 watt circuit: from JTM's to JMP Superleads," it's a very interesting compilation. Cheers
If you're interested in learning details/specs of the JTM 45/100 variants, take a look at the Solodallas web page "evolution of the 100 watt circuit: from JTM's to JMP Superleads," it's a very interesting compilation. Cheers