dstroud
Well-known member
got it dude thanks soooo much for the info!!! I’ll be digging into it
fusedbrain
Well-known member
Agree with what harddriver said.
There's no right or wrong answer to the voltage thing.
If you want bright, harder and stiffer, higher is better. That's why some of those early 80's 2203's will rip yer face off ( in a good way! )
If ya want a chewy, greasy feel with a little more break-up, lower is the way to go. This is kinda what Friedman does with the BE100 preamp, although his power tube plate voltage is still high 400's.
If ya already have a Marshall style amp that does the bright and tight thing, then this new one is a nice complement to that.
Also keep in mind that lower plate voltage on the power tubes will greatly enhance the longevity of current production tubes, so there's that.
There's no right or wrong answer to the voltage thing.
If you want bright, harder and stiffer, higher is better. That's why some of those early 80's 2203's will rip yer face off ( in a good way! )
If ya want a chewy, greasy feel with a little more break-up, lower is the way to go. This is kinda what Friedman does with the BE100 preamp, although his power tube plate voltage is still high 400's.
If ya already have a Marshall style amp that does the bright and tight thing, then this new one is a nice complement to that.
Also keep in mind that lower plate voltage on the power tubes will greatly enhance the longevity of current production tubes, so there's that.
H
harddriver
Well-known member
Here are some actual Marshall issued Voltage charts I have in my shop and in books for 50 watt Marshall amps in the 1977-1980 MKII JMP time frame and you can see they are calling for B+ of 390-395 so around 400 DCV B+ for a MKII 50 watt 2204.
https://www.marshallforum.com/threa....104885/?utm_source=google&utm_medium=organic
https://www.marshallforum.com/threa....104885/?utm_source=google&utm_medium=organic
dstroud
Well-known member
hey man so finally had a sec to crack the amp open - I was at 468v on the power tube B+. I was able to play the amp for several hours over the weekend - feels solid and sounds great, no wierdness lol I’ll prolly secure that long cable with proper clips and call it a day - thanks again so much for the info!!!
D
Deleted member 77333
Guest
H
harddriver
Well-known member
Yep that's what I would do. Look like the B+ to the power tubes is totally stock voltage for a 1987 JCM800 since you are getting 468DCV that's right in line with my 1984 JCM800 2204 with 466DCV. So the tech before you owning the amp only lowered the phase inverter and the preamp B+ voltages more towards JMP values. So now you know exactly what's going on with your amp mod wise.
I bet it sounds pretty darn good, my 1979 2203 was a firebreather back in it's heyday totally stock. Enjoy the amp Darren!
FourT6and2
Well-known member
I don't think Marshall used Philips head screws on the transformers (and no bracket). Unless they switched to this for these '80s amps? My first thought would be transformer swapped.
dstroud
Well-known member
maybe, But they look really old and say Drake so not sure
Mike Oxhuge
Well-known member
Or a tech replaced the fasteners because aome were missing or stripped or fell when going through the amp.
H
harddriver
Well-known member
Both the Drake Power and Output transformers in my 1984 2204 have the very same galvanized Philips buttonhead screws to mount to the chassis. The choke still has a flathead brass machine screws. All the Drake transformer numbers on Darren's 87 2204 check out to be original and the aged patina is correct on the bellhousings to be original to that amp.
FourT6and2
Well-known member
Both the Drake Power and Output transformers in my 1984 2204 have the very same galvanized Philips buttonhead screws to mount to the chassis. The choke still has a flathead brass machine screws. All the Drake transformer numbers on Darren's 87 2204 check out to be original and the aged patina is correct on the bellhousings to be original to that amp.
Fair enough. However RE: bell housings... when people swap iron, it's not hard to swap the bells. They just metal covers. Not saying this is the case for this specific amp. Just something to watch out for. You can't just go by a sticker on the end bell. That's why I always look at the totality of data: end bells, patina, laminations, dimensions, screws, brackets, wiring, soldering, etc.
I've seen many amps with swapped iron where it was clearly a cover up.
R
Racerxrated
Well-known member
Easer to tell on the vintage Marshalls that used varnish on the solder joints; if those were disturbed at the power/ohm selector then you know the transformer's been messed with.
R
Racerxrated
Well-known member
Yep!
In my experience, the 82/83 2203/4s can hit around 500v......beasts!
H
harddriver
Well-known member
I'm pretty sure my 84 2204 didn't have any of that red machinist dye they used into the mid 70's. I bought that amp off of the original owner and I can't remember if my 79 2203 had the dye before Splawn rebuilt it. Come to think of it my 72 SL didn't have it either on any of the solder joints that were never ever touched since it was built as I know all the turrets I've soldered in that amp so there should be some remnants of the red dye elsewhere in the amp and there is none that I can see.
Attachments
Last edited:
FourT6and2
Well-known member
Like everything else Marshall did, the use of dye was incredibly inconsistent. Sometimes they even used it on some connections but not all. And a lot of people try to fake the dye as well...
H
harddriver
Well-known member
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The one thing Marshall was consistent at was being consistently inconsistent..........................
D
Deleted member 77333
Guest
Yep
R
Racerxrated
Well-known member
My 72 SL does. My old 72 50 did not. But, you can usually tell a factory solder joint vs one that's been messed with years later. Even without the dye, I think one could tell if a transformer has been out. Then, when you add in the cloth covered secondaries in the OT/PTs from the early 70s SL models that's another identifier for those years. The earlier C1998 OTs had the thicker plastic on the ends of the wires. Those two things aren't cloned by any modern transformers that I know of.
FourT6and2
Well-known member
Yeah, the Dagnall C1998 OT has cloth (glass reinforced) "self lead" secondaries. Drake transformers have standard plastic/PVC jackets.
fusedbrain
Well-known member
Best 2203 I've ever heard was an '83.
Plate voltage was 495v.
It belonged to the teenage son of a friend of mine, and they asked me to re-tube it and bias it up .
The thing looked like total dog shit cosmetically. It had been dropped hard at least once, cause the tyranny brackets were bent to shit, and the bottom of the headshell was held together with door hinges! The logo was missing, and the front face where the logo would go was recovered with a piece of fabric from grammy's living room couch.
It had 3 power tubes in it when I got it, with the base of the 4th tube and a bit of broken glass still in the 4th socket.
So I retube it, bias it up, and son of a bitch, doesn't it sound fukking incredible.
One of the best sounding amps I've ever heard.
It punched hard, and was bright as hell, but if you swept the gain pot between 6 and 8 o'clock, you could find the sweet spot where the amount of bright cap in the tone was just right, and it was freaking amazeballs!
Total rip yer face off rock machine.
Similar threads
