Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jukelemon on October 03, 2024, 11:04:20 am
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Hi all.
So..working on this Kalamazoo 12 Reverb and it is the only amp I have ever come across that has a reverb tranny with terminals as opposed to RCA jacks/color coded secondaries.
My question is...does it matter which terminal is used for ground? I found a pic of one that had a certain orientation on the terminals BUT I then asked a fellow collector about his 2 Reverb 12s and they are both wired the complete opposite :(
So..does it matter? I have never had to think about it in the past and given how most other amps use RCA jacks as opposed to terminal connections.
Thanks!
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verify 1st that neither lead in "internally" grounded to the transformer, if not then , no, shouldn't matter since you'll be shifting phases all over the room once the signal hits the tank
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verify 1st that neither lead in "internally" grounded to the transformer, if not then , no, shouldn't matter since you'll be shifting phases all over the room once the signal hits the tank
Understood and thanks.
If it was grounded internally AND I chose the wrong ground terminal (I have it wired opposite to my friend's amps now), the tranny would not work at all right?
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https://el34world.com/charts/Schematics/files/Kalamazoo/Kalamazoo_reverb12_original.pdf
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https://el34world.com/charts/Schematics/files/Kalamazoo/Kalamazoo_reverb12_original.pdf (https://el34world.com/charts/Schematics/files/Kalamazoo/Kalamazoo_reverb12_original.pdf)
Thank you.
I have the schem already unless you are thinking this answers my question. If so, I am not following. Please explain.
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https://el34world.com/charts/Schematics/files/Kalamazoo/Kalamazoo_reverb12_original.pdf (https://el34world.com/charts/Schematics/files/Kalamazoo/Kalamazoo_reverb12_original.pdf)
Thank you.
I have the schem already unless you are thinking this answers my question. If so, I am not following. Please explain.
Why not include it in the opening post?
Details matter, a schematic is kinda essential for any thread.
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verify 1st that neither lead in "internally" grounded to the transformer ...
If it was grounded internally AND I chose the wrong ground terminal (I have it wired opposite to my friend's amps now), the tranny would not work at all right?
Right.
The scenario we're considering is that one of the leads is already connected to the housing of the transformer, which would then be grounded by virtue of its connection to the chassis.
If you then choose the other lead as "ground" then the secondary of the transformer is shorted. The tank gets no signal, and the driver tube will see a load of nearly-zero (maybe 10's of ohms). The driver tube would likely overheat while you attempted to use it, and overheating increases the risk of poisoning the cathode (thus killing the tube).
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https://el34world.com/charts/Schematics/files/Kalamazoo/Kalamazoo_reverb12_original.pdf (https://el34world.com/charts/Schematics/files/Kalamazoo/Kalamazoo_reverb12_original.pdf)
Thank you.
I have the schem already unless you are thinking this answers my question. If so, I am not following. Please explain.
Why not include it in the opening post?
Details matter, a schematic is kinda essential for any thread.
I would agree to your statement unless the schematic has nothing to do with the question which is the case with mine :)
The schematic is not going to answer if the tranny is grounded to itself and/or if the phase matters. Unless I am missing something.
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verify 1st that neither lead in "internally" grounded to the transformer ...
If it was grounded internally AND I chose the wrong ground terminal (I have it wired opposite to my friend's amps now), the tranny would not work at all right?
Right.
The scenario we're considering is that one of the leads is already connected to the housing of the transformer, which would then be grounded by virtue of its connection to the chassis.
If you then choose the other lead as "ground" then the secondary of the transformer is shorted. The tank gets no signal, and the driver tube will see a load of nearly-zero (maybe 10's of ohms). The driver tube would likely overheat while you attempted to use it, and overheating increases the risk of poisoning the cathode (thus killing the tube).
Yep..thought so.
I tested the terminals on the secondary and neither are internally grounded so it seems all is well and it doesn't matter which terminal orientation is used. Right?
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... it seems all is well and it doesn't matter which terminal orientation is used. Right?
Yes.
Just hook the sucker up. :icon_biggrin:
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... it seems all is well and it doesn't matter which terminal orientation is used. Right?
Yes.
Just hook the sucker up. :icon_biggrin:
Cool and much thanks!