Clone 2204 50W Amp Build

[big_teee]

Here's some Pictures of my First Amp build.
I started with a blank undrilled 17 inch Cabinet.
I Made my own Turret board, own faceplates.
It's a combo of JMP- 2204, and JCM800 2204 50 Watt Master Vol.
It has the Pre and Post Master volume.
The PPI-MV makes the amp controllable, and possible to play in the Bedroom.
I don't want an amp without it.
I used USA Classic Tone Transformers.
All the tubes, Chassis and small parts came from my Friends at TubeDepot.
Be gentle, like I said this is my first build.
It has Rear Bias Test points, and bias adjust.
I will probably redo the bias adjust with a non bumpable pot, after I get done trying different tubes, and such.
I left a empty hole for another Gain Stage if I decide to try one later.
It has great tone, and Gain.
Later,
Terry

[Ward]

Hi Terry, so it's up n running and you like/love it? The main thing is it works. The only thing that strikes me as maybe something to look at are the heater wires, they look very thin, what gauge are they, and are they teflon coated. If you read the specs on any power tranny you'll notice that the 6.3 CT 6.3 part of the secondaries are rated at quit a few amps, so your heater wire needs to be able to handle the heat from the demand from the tubes, so they look a bit thin to me. I've used 20 awg teflon but wouldn't go any smaller, a lot of dudes say to use at least 18 but the 20 teflon is plenty IMO.
Oh and as much as the outer bias pot is very convenient, it wouldn't take much to bump it or some punter to move it, I reckon it's better to put it on the top of the chassis and out of reach, anyway, you mentioned that as well but for the sake of trying different power tubes it's a great thing to have at your disposal.
The rest is merely cosmetic if you have a nice quiet amp. Of course there are a lot of ugly solder joints but they look sound and you could get a small wire brush or even a screwdriver and try to remove as much of the flux that is on the board, as I said, cosmetic. I notice you have the NFB on the speaker out, I prefer it on the 8 ohm tap for a 2204, whatever, also I prefer those B+ wires to go under the board out of sight, drill a small hole next to the turret for the wire to come back up and around the turret, I think it just looks better, just me. As for all the other lead dress issues, I'm sure as time goes by you will want to address a lot of them and redo them but as a first time build all we can really hope is that it works and is quiet and safe, plus you made the board yourself which is very rare for a first build so well done mate.

[big_teee]

Hi Terry, so it's up n running and you like/love it? The main thing is it works. The only thing that strikes me as maybe something to look at are the heater wires, they look very thin, what gauge are they, and are they teflon coated. If you read the specs on any power tranny you'll notice that the 6.3 CT 6.3 part of the secondaries are rated at quit a few amps, so your heater wire needs to be able to handle the heat from the demand from the tubes, so they look a bit thin to me. I've used 20 awg teflon but wouldn't go any smaller, a lot of dudes say to use at least 18 but the 20 teflon is plenty IMO.
Oh and as much as the outer bias pot is very convenient, it wouldn't take much to bump it or some punter to move it, I reckon it's better to put it on the top of the chassis and out of reach, anyway, you mentioned that as well but for the sake of trying different power tubes it's a great thing to have at your disposal.
The rest is merely cosmetic if you have a nice quiet amp. I notice you have the NFB on the speaker out, I prefer it on the 16 ohm tap, whatever, also I prefer those B+ wires to go under the board out of sight, drill a small hole next to the turret for the wire to come back up and around the turret, I think it just looks better, just me. As for all the other lead dress issues, I'm sure as time goes by you will address a lot of them and redo them but as a first time build all we can really hope is that it works and is quiet, plus you made the board yourself which is very rare for a first build so well done mate.

Hi Nic:
Your tuff!
Yes the Heater wiring for the most part is teflon.
Its 18 Ga for the EL34s,V4 & V5 (3 Amps Total).
20 ga. teflon for the 3 12AX7s (3*.4A = 1.2 Amps).
I started with the NFB on 4 ohms, I moved it to the Speaker out for Checking liked it on 8 ohms that I was using.
You notice the Yellow wire is not soldered on the bottom of the board now, like it was when I started.
There is no wiring smaller than 20 gauge in the amp.
All of the B+ Can Cap wiring does go through holes drilled in the board.
I put all the B+ Strapping on the top of the board where it can be seen for trouble shooting.
Dress looked better before lifting the board several times for trouble shooting.
I did a little probing at times.
Anyway, what you see is what I got!
All in all I think it looks OK.
I wasn't really shooting pictures for a Instruction Manual.
I like it and that's basically the way it will stay.
As far as flux cleaning.
Rosin Flux hurts nothing, It will get put in a case eventually, and this probably all the pictures I'll take.
I'm proud of it, and I thought others might Like to see it too.
I spent the last month or so beating on it!
Rock Steady,
Later,
Terry

[Ward]

I remember one build I did where I had problems and had to lift the board about 5 times, in the end after I had it all working it just looked terrible. Glad to hear the heater wire is 20, it looks smaller in the pic. Rock on.

[Danelectron]

Terry, Cosmetics as they are, it looks good. My first build was no where as nice. I had no experience with locating components in proper proximity and had an issue with the fuse holder and lamp crowding things. I built it in an eight by eight steel junction box and just had a schematic(5F2). So a couple more holes later I had a good sounding amp that looked like it was the victim of a drive by. It looks like the pots and input jacks are properly located where you could possibly upgrade to a premanufactured faceplate to match the knobs. The graphics on your face plate look good though. Are you going to build a cabinet for it or purchase one? What are you using for speakers? I would probably at least mark where your bias is set so you can tell if some clown has screwed with it. In school I had an instructor that always warned about "knob turners disease". What's this one do? You know. I like the jacks for the test points. I have a couple of those gizmos that you plug between the tube and socket to test current and voltage, but your method looks convenient enough. The circuit board looks fine. My first one was one of those radio shack perf boards. Man, talk about crap. There is no way to make those look good. I discovered this forum about a year after I did my first two or three and have to say I have much improved the looks and functioning of my builds thanks to a bunch here. I have also expanded my knowledge of these circuits though I have a long way to go. I bought Blencoes books and some others and read alot here. I bet you're already planning your next one. A Fender, eh? Have fun with it and SCREW the neighbors! Dan