Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: martinman on January 09, 2023, 04:55:01 pm
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Need some help on my 6v6 plexi build. I've built up a few amps so far - mainly paint by numbers kids from Mojo & Mission. This my first challenging build where I'm trying to go off of schematic / layout. I'm still learning, so go easy :)
1) In the layout "C" connects to the board from the large filter cap. The layout and build pic differ in which terminal "C" is connected. because the terminals are tied together, does it matter?
Layout:
https://el34world.com/Hoffman/files/Hoffman_Plexi_6V6-V2.pdf
Pic:
https://el34world.com/projects/images/Img_9081.jpg
2) Not sure about the "E" designation on the board. I see in the schematic it looks to be an additional filter stage that I don't have on the larger cap? I have OUXY plus a ground. The build pics don't seem to show any lead connecting to this area.
3) Choke terminal area. There are 2 black, 1 red for the choke, plus a red for A (large cap), one red for B (large cap) going to this area (so a total of 2 black, 3 red wires). In the build pic, i'm guessing that 2 black are choke & 2 red wires are from filter cap leads. Then the red wire for choke connects to the diode lead (opposite the PT leads)?
4) D area -- I see in the layout, it's coming from V2 pin 6, but the build pic looks like it has a second red wire? https://el34world.com/projects/images/Img_9090.jpg Where is this coming from?
5) What's the best way to wire in the pilot light?
Thanks!
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READ THE FIRST SENTENCE ON THIS PAGE...
https://el34world.com/projects/Plexi6V6.htm
1. Does not matter.
2. The filter cap for node "E" is on the board. No need for a wire.
3. Don't look at the build pic. Use only the schematic and layout to sort this out.
4. DON'T LOOK AT THE BUILD PICS! The other red wire goes to the cap can.
5. Follow the schematic. Pilot connects parallel to the PT primary leads.
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Ok sluckey, I think I have it. Thanks for the push - schematics are difficult for me to read, but I have it a shot:
For question #3:
A lug:
1. black choke wire
2. Cap can A
3. Red OT wire
B lug:
1. Black choke wire
2. Cap can B
3. V5 pin 6
Do I have that right?
(I know, don’t look at the pics, but…) looks like the OT red wire connecting to the diode area. Is this acceptable as it’s all on the same bus (?) wire?
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Do I have that right?
yes
(I know, don’t look at the pics, but…) looks like the OT red wire connecting to the diode area. Is this acceptable as it’s all on the same bus (?) wire?
Yes. The "A" turret is laced together with the two diode turrets. It's all the same electrical point. You can call all three of those turrets "A" if you want.
"Don't look at the pics" only means don't compare the documents to the build pics because there will likely be some changes in the documents. Don't get hung up on small differences. Use the documents for your build. Of course you should look at the pics. Doug does beautiful work. Admire the workmanship and strive to make your amp look just as good as his. There's a lot to be learned/gain from looking at his pics.
I have a slightly different building style than Doug. Not better, just different. You may pick up some building techniques looking at my stuff too. Here's my Plexi 6V6...
http://sluckeyamps.com/6v6plexi/6v6plexi.htm