Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: KimboDb on January 31, 2022, 11:15:03 am
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Hello, I was wondering if someone could help with a wiring question. I have an amp that has 3 output options. Its currently wired 8 ohm 8 ohm 16ohm. The OT has the 8 ohm outputs married by a jumper wire. I want to hook up the 4ohm wire so i have all 3 options 4, 8, 16. I know i have to cut the jumper to the married jacks and add the 4ohm outout wire. Do i have to add a 2nd wire to the 4ohm output. The16ohm has 2 wires from the OT and the 8ohm output minus the jumper wire has what i think is the negative feedback wire and 8 ohm wire.
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Perhaps you didn’t explain the OT secondaries correctly. Your wording doesn’t make sense, at least to me. What color wires are on the secondary side..? Better yet, have a spec sheet on the OT..?
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heres another pic. these are 3 of the 4 secondary wires from the OT. im sorry i though they were called the taps
The pic doesnt show the 4ohm seconday wire, i have to add some new wire to the 4ohm secondary. it was cut short by the amp builder.
The 16ohm seconday output jack has the com+16ohn seconday wire
The 8ohn secondary has the Feedback+8ohm secondary+Jumper to the 3rd output jack
If i cut the jumper wire for 2nd 8ohm output jack and add the 4ohm secondary, does the jack require an added ground wire? wil it require a wire from anything on the ground lug?
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If you could post the schematic that would help a lot.
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If i cut the jumper wire for 2nd 8ohm output jack and add the 4ohm secondary, does the jack require an added ground wire? wil it require a wire from anything on the ground lug?
A ground wire is not really needed, but not using one means you are relying on the jack mounting nut to give a good electrical connection to the chassis. I recommend that you connect a jumper wire between the ground lugs of all three jacks. Then if a jack becomes loose there's no worry because they are all hardwired to the OT ground.
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Thanks Sluckey, you always save the day. The jacks are grounded by the chassis so i just hooked up the wire and now i got 3 output choices. tested and working just fine.