peterc52
Well-known member
Found two dirt cheap 2204. One from 83 and one from 88. I know the 2203 changed circuits at some point. But not sure about the 2204.
They sound very alike!
They sound very alike!
psychodave
Well-known member
The 2204’s didn’t change filtering. 
Great scores. I dig the small box head shell too!!
Great scores. I dig the small box head shell too!!
peterc52
Well-known member
It was actually a 2104 combo with vented 75’s. But I also recently bought a JTM30 - only for the cab it came with and switched out the headshell and the JTM30 is now a comboThe 2204’s didn’t change filtering.
Great scores. I dig the small box head shell too!!
Love the aesthetics of this JCM800 cab
Now loaded with UK G12H-30 anniversaries
psychodave
Well-known member
Whoever changed the grill cloth did a really good job. Each side look perfectly straight.
I changed 6-7 grill cloths and it’s not easy to get it perfect. I have one more cab I want to change with something different.
I changed 6-7 grill cloths and it’s not easy to get it perfect. I have one more cab I want to change with something different.
LPMojoGL
Well-known member
Headfirst has a video showing the differences in horizontal vs vertical input 2204s. There are some higher voltages in the preamp, I think, with the horizontal inputs. The sound difference isn't enough to make me want to change my 84 horizontal input 4104, but some folks might want to do it.
Congrats on the find! Love my 4104 with 6550s.
Congrats on the find! Love my 4104 with 6550s.
peterc52
Well-known member
Some pointed out in the notes of the video that the amp already had been tinkered with and that’s why the it sounded much better after he worked on it
BesaMoogie
Well-known member
Good video that I was going to suggest as well.
easstudios
Well-known member
Yeah, as Jason's video shows, the horizontal 2204 have the filter cap nodes spread out a bit different, and the transformers are putting out a higher voltage. Both things contribute to higher voltages throughout the preamp.
I just picked up an 89 2204, debating whether to mod it to vertical input specs. In Jason's videos I WAY prefer the vertical input spec sound but there are some pretty good examples of horizontal input 800's sounding just fine.
I just picked up an 89 2204, debating whether to mod it to vertical input specs. In Jason's videos I WAY prefer the vertical input spec sound but there are some pretty good examples of horizontal input 800's sounding just fine.
R
Racerxrated
Well-known member
Nice score! I have read where the quality of the Drake transformers suffered in the late 80s; but I've had a few 87-90 2205s and they all sounded excellent to amazing. My first modded Marshall was a Lee Jackson 2204 from 87, killer amp. The Dagnalls remained the same so the 100w didn't suffer.
I forget where I read this; maybe the Marshall forum? But to my ears they all sounded killer regardless of year. I did have a 1988 2203, which didn't get quite as loud as an 82 2204 I had at the same time. Must've been the filtering.
I forget where I read this; maybe the Marshall forum? But to my ears they all sounded killer regardless of year. I did have a 1988 2203, which didn't get quite as loud as an 82 2204 I had at the same time. Must've been the filtering.
peterc52
Well-known member
B+ of the early 2204 is 468! Always thought the early 2204 has low voltage! Maybe it’s because it’s a European version.
And the 88 has a B+ of 435!
And the 88 has a B+ of 435!
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BesaMoogie
Well-known member
Which year is your early 2204 from? I think from 83 onwards they had the high B+B+ of the early 2204 is 468! Always thought the early 2204 has low voltage! Maybe it’s because it’s a European version.
And the 88 has a B+ of 435!
View attachment 243611View attachment 243614View attachment 243617View attachment 243620
I‘ve also found contrary reports of people saying their 81 and 82 had either high or low plate voltage.
On a side note: your early 2204 has no screen grid resistors (and grid stoppers), so maybe it would be worth, adding them
peterc52
Well-known member
Chubbs
Well-known member
You’ve got screen grids in both.
Very cool to find a jmp with higher than normal plate voltages. I wonder if it’s Canadian spec given the fuse board, do you have a 16ohm out? So much space in that 800 for mods!!
BesaMoogie
Well-known member
yes, didn`t see them. My bad
I
itsme
Well-known member
That top one has to be ‘80 or earlier? They didnt use the JMP logo in ‘81. Never saw an ‘83 that didn’t have the JCM logo.
I
itsme
Well-known member
On my image it looks like the grill cloth goes up a bit left to right?
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lespaul6
Well-known member
the level of filtering in the horizontal 2203's is the same.. they just used less can caps and wired them up differently... the difference is in the preamp voltages as someone already mentioned
burger
Well-known member
if you find the horizontal input amp a little brittle sounding compared to the vertical, the easiest mod is to change the stock 10k dropper between the Screen and PI nodes to 20k.
R
Racerxrated
Well-known member
Every 82-84 2203/4 I've owned has had higher PV. The later 70s 2204s were a bit lower....then 86-on seemed to go back to lower numbers. My 72 has PV at 515....my 86 2210 is around 430.
psychodave
Well-known member
Look at the edges and the white vertical parts of the cloth. Both sides run 99% parallel to the white piping. Whoever did it, did a good job.
Here are two early 70’s (no corner protectors) cabs I did. The first one I did 30+ years ago with original Marshall grill cloth from the 60’s. You can see it faded over time.
The second cab I did with mojo tone cloth and it still looks new after 25 years. I have some Eric Collins pin stripe cloth I’m going to put on…if I ever get around to it. lol
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