My 50W Build! (with pics) - COMPLETE!!!
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- mwm523
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- Location: Northern NJ
My 50W Build! (with pics) - COMPLETE!!!
Hey all, I received my 50W kit yesterday, and got started building last night after work. Here are some pics of my progress so far.
Chassis, transformers, choke ready for installation:
Lots of parts!
Transformers, choke, tube sockets, and cap cans mounted:
Whew! Heaters done:
Rectifier bridge and mains fuse mounted, 220V and 240V leads cut and heat shrinked, PT wiring continued:
Switches mounted, PT wiring complete:
OT primary and secondary wires routed, impedance switch installed, 1ohm bias resistors installed:
Screen resistors, indicator, and output jack installed (I will only have one, the other hole will have a PPIMV):
So I'm through step 11 so far. I'll be picking it up at step 12 today.
Chassis, transformers, choke ready for installation:
Lots of parts!
Transformers, choke, tube sockets, and cap cans mounted:
Whew! Heaters done:
Rectifier bridge and mains fuse mounted, 220V and 240V leads cut and heat shrinked, PT wiring continued:
Switches mounted, PT wiring complete:
OT primary and secondary wires routed, impedance switch installed, 1ohm bias resistors installed:
Screen resistors, indicator, and output jack installed (I will only have one, the other hole will have a PPIMV):
So I'm through step 11 so far. I'll be picking it up at step 12 today.
Last edited by mwm523 on Sun Nov 18, 2007 10:52 pm, edited 1 time in total.
-Mike
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Nicely done. If the Gods of shipping are with you, a couple of H75's should be at your door on Tuesday or Wednesday...
Scumback Speakers - Kick Ass Vintage Tone
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Yeah, those don't look like the metal oxide 1 ohm resistors I've used from Metro.rockstah wrote:looking good. what kind of resistors are on the output tubes to ground?
"I don't like country music, but I don't mean to denigrate those who do. And for the people who like country music, denigrate means 'put down' " - Bob Newhart
- mwm523
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- Location: Northern NJ
- mwm523
- Senior Member
- Posts: 521
- Joined: Tue Jul 17, 2007 11:25 am
- Location: Northern NJ
Update... Things are moving along nicely. Here are some more pics.
Pots mounted:
Ground bus installed:
Input jacks mounted:
Close-up of the jacks:
Close-up of the output jack and impedance switch:
Close-up of the output tube sockets w/ 1ohm bias resistors to ground:
V2 plate resistor:
Board mounting bolts installed and board sitting in there:
Board bus wires:
One side of the board wiring:
Both sides of the board wiring (Notice the missing orange/green twisted pair. No need for those since the amp will have a PPIMV):
Close-up of the filter caps:
Board installed. Next step is to cut/route/attach all the wires coming from the board:
I have to replace that white wire at the bottom-right corner of the board, it's too short. Needs to go to the rectifier bridge.
Started to get tired, so I'm taking a break for a while. I'll probably do some more tonight.
Pots mounted:
Ground bus installed:
Input jacks mounted:
Close-up of the jacks:
Close-up of the output jack and impedance switch:
Close-up of the output tube sockets w/ 1ohm bias resistors to ground:
V2 plate resistor:
Board mounting bolts installed and board sitting in there:
Board bus wires:
One side of the board wiring:
Both sides of the board wiring (Notice the missing orange/green twisted pair. No need for those since the amp will have a PPIMV):
Close-up of the filter caps:
Board installed. Next step is to cut/route/attach all the wires coming from the board:
I have to replace that white wire at the bottom-right corner of the board, it's too short. Needs to go to the rectifier bridge.
Started to get tired, so I'm taking a break for a while. I'll probably do some more tonight.
-Mike
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OK, I'm done!!!!
I put in a few more hours Saturday night, until I just couldn't do any more... Then I picked it up Sunday afternoon, and finished up.
More pics...
Working on the pot wires from the bottom of the board:
Preamp tubes wired up:
Board patially populated:
That's where I ran out of steam Saturday night, and went to bed. It was like 2:00am and I was exhausted.
Sunday morning I spent hanging out with the family, and then started up again after lunch.
Ok, here we go, the home stretch!
Finished populating the board:
Bias circuit with bias adjustment pot mounted on the board (Yes, I took care of that unsoldered turret between the 2 .022uf Sozos ):
Power cable and PPIMV installed... HEY! I THINK I'M DONE!!!!!
PPIMV dual 250K pot:
Close-up of PPIMV shielded wiring connected to the board:
PPIMV wiring:
V5 grid stopper resistor on pin 5, connected to PPIMV shielded wire:
V4 grid stopper resistor on pin 5, connected to PPIMV shielded wire:
One last PPIMV shot:
Full chassis shot:
Another full chassis shot:
Rear:
Tubes:
I have Mullard reissue EL34's for power, and the pre's are a NOS Mullard in V1, a NOS Amperex Bugle Boy in V2, and an old Silvertone in V3 (which I think is also an Amperex, it says made in Holland)
Head:
Group shot with its little brother (JTM 45) on the left and my Les Paul:
Testing went very smoothly, all my voltages were right where they should be. I had one head scratching moment on page 26 (Testing Part 1) where it said I should have about 450V DC on the positive terminal of the bridge rectifier, but I was only reading 315V DC. The directions should have said to turn the standby switch on and THEN take that measurement. Once I did that I got 470V DC.
Everything else was right in range, so I installed my tubes and continued on. Installed the pre's first and took measurements, then installed the output tubes, hooked up a speaker cab and measured again. All looking good, and normal light hiss from the speakers when turning up either volume pot.
Then I set the bias. My B+ voltage is 449V, so I biased the amp at 39mA (70% plate dissipation). My tubes are pretty closely matched, only off by about 2mA.
So now it was time to fire it up and plug in the Les Paul!!! I have to say that I IMMEDIATELY fell in love with the tone of this amp. The clarity, the punch, the sustain, the harmonics, the controlled feedback, I am in tone heaven!! I get a nice crunch and singing sustain starting between 6 and 7 on volume 1, and its sweet spot seems to be about 7.5 - 8.
I built a JTM 45 kit a few months ago, and I have grown to love that amp. But the point is, I had to grow to love it over the course of a couple of months, making modifications, finding ways to tame the fizz, etc.
This 50W kit just floored me right out of the gate. I'm getting sounds I have been wishing I could get from the JTM, but the JTM is just a different animal. It definitely has its place though, especially for playing bluesy stuff. The 50W is a ROCK amp.
With the Les Paul, I'm getting Cream, Free, Allmans, Zeppelin, all the classic plexi tones. I plugged in the Strat, and while I still have some tweaking to do, I was definitely getting into Hendrix territory.
The only thing I'm considering changing so far on the 50W is the value of the bright cap on the channel 1 volume pot. I've got a 250pf there right now and it has a slight case of ice pick-y-ness at lower volumes (stock value is 500pf, I think that would make my ears bleed ). I think I'll try a 100pf there, that's what I have in the JTM.
Hope you all enjoyed my build, I know I did! (I am enjoying playing it too!!!!!!)
George, this kit is a HOME RUN.
I put in a few more hours Saturday night, until I just couldn't do any more... Then I picked it up Sunday afternoon, and finished up.
More pics...
Working on the pot wires from the bottom of the board:
Preamp tubes wired up:
Board patially populated:
That's where I ran out of steam Saturday night, and went to bed. It was like 2:00am and I was exhausted.
Sunday morning I spent hanging out with the family, and then started up again after lunch.
Ok, here we go, the home stretch!
Finished populating the board:
Bias circuit with bias adjustment pot mounted on the board (Yes, I took care of that unsoldered turret between the 2 .022uf Sozos ):
Power cable and PPIMV installed... HEY! I THINK I'M DONE!!!!!
PPIMV dual 250K pot:
Close-up of PPIMV shielded wiring connected to the board:
PPIMV wiring:
V5 grid stopper resistor on pin 5, connected to PPIMV shielded wire:
V4 grid stopper resistor on pin 5, connected to PPIMV shielded wire:
One last PPIMV shot:
Full chassis shot:
Another full chassis shot:
Rear:
Tubes:
I have Mullard reissue EL34's for power, and the pre's are a NOS Mullard in V1, a NOS Amperex Bugle Boy in V2, and an old Silvertone in V3 (which I think is also an Amperex, it says made in Holland)
Head:
Group shot with its little brother (JTM 45) on the left and my Les Paul:
Testing went very smoothly, all my voltages were right where they should be. I had one head scratching moment on page 26 (Testing Part 1) where it said I should have about 450V DC on the positive terminal of the bridge rectifier, but I was only reading 315V DC. The directions should have said to turn the standby switch on and THEN take that measurement. Once I did that I got 470V DC.
Everything else was right in range, so I installed my tubes and continued on. Installed the pre's first and took measurements, then installed the output tubes, hooked up a speaker cab and measured again. All looking good, and normal light hiss from the speakers when turning up either volume pot.
Then I set the bias. My B+ voltage is 449V, so I biased the amp at 39mA (70% plate dissipation). My tubes are pretty closely matched, only off by about 2mA.
So now it was time to fire it up and plug in the Les Paul!!! I have to say that I IMMEDIATELY fell in love with the tone of this amp. The clarity, the punch, the sustain, the harmonics, the controlled feedback, I am in tone heaven!! I get a nice crunch and singing sustain starting between 6 and 7 on volume 1, and its sweet spot seems to be about 7.5 - 8.
I built a JTM 45 kit a few months ago, and I have grown to love that amp. But the point is, I had to grow to love it over the course of a couple of months, making modifications, finding ways to tame the fizz, etc.
This 50W kit just floored me right out of the gate. I'm getting sounds I have been wishing I could get from the JTM, but the JTM is just a different animal. It definitely has its place though, especially for playing bluesy stuff. The 50W is a ROCK amp.
With the Les Paul, I'm getting Cream, Free, Allmans, Zeppelin, all the classic plexi tones. I plugged in the Strat, and while I still have some tweaking to do, I was definitely getting into Hendrix territory.
The only thing I'm considering changing so far on the 50W is the value of the bright cap on the channel 1 volume pot. I've got a 250pf there right now and it has a slight case of ice pick-y-ness at lower volumes (stock value is 500pf, I think that would make my ears bleed ). I think I'll try a 100pf there, that's what I have in the JTM.
Hope you all enjoyed my build, I know I did! (I am enjoying playing it too!!!!!!)
George, this kit is a HOME RUN.
Last edited by mwm523 on Mon Nov 19, 2007 5:38 pm, edited 1 time in total.
-Mike