2204 clone gut job

fitz said:
Here's a nice 2204 starter kit if anyone is interested...
It even comes with a few extra parts. :yesway:

View attachment 111708

Click to expand...
Seller states has a known volume drop when hot. modded tube fx loop
What are the potential causes of that, addons welcome:
Heater intermittent voltage drop - PT htr winding
Doubt the extra 12ax7 heater current as these had the same drakes for the 2205 which had 5 preamp tubes.​
shorting OT if run hot into an attenuator.
output Tube failing if never replaced and run at mid to lower bias weak output when hot.

These things can be a roll of the dice but you could also be lucky, who knows what other mods were made or if done improperly.

I think it would be cool to get one of these combo chassis and put a mirror faceplate on it in a head cab. So it reads backwards but right side up. :)
 
Rebuild underway.
Tested each part with the gizmo.

gut job (19).jpg

Made a quickie bending jig with some scrap wood.

gut job (20).jpg

Populating the board.

gut job (21).jpg

Went back and trimmed all the long legs after getting everything positioned.
Soldering everything in to keep it place.

gut job (22).jpg

Replaced all the pots, tube sockets, filter caps and fuse holders on the chassis.
Temp mounted the board so I can cut all the leads to length.

gut job (23).jpg

I think that's it for today.
 
I like the gizmo and the home made quickie bendy thingy. (y)

I assume the 470pf treble peaker/470kR will be on the input to pot?

I know it isn't necessary, curious why you don't use the dual diode rectifier?

It all looks good so far, lots of work quickly, great symmetry too:flash:
 
XTRXTR said:
I like the gizmo and the home made quickie bendy thingy. (y)

I assume the 470pf treble peaker/470kR will be on the input to pot?

I know it isn't necessary, curious why you don't use the dual diode rectifier?

It all looks good so far, lots of work quickly, great symmetry too:flash:
Click to expand...
The gizmo is reassuring for my level of incompetence. :rolf:

I'm following the Mojotone wiring diagram for the '78 JMP 2204. (attached)

Yes?, 470k / 500pF parallel on the input.

1783865541417.png

@pdf64 had mentioned the dual diode rectifier in a trouble shooting thread on the forum "that shall not be named".
I have the 2 from the old layout I could add in - now would be the time.
Also have some turrets I can add.
Would I just run them in series?

diode.jpg dual diode.jpg
 

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