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Hoffman Amps Forum image Author Topic: AB763 deluxe reverb pentode/triode  (Read 3974 times)

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Offline Rockranger

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AB763 deluxe reverb pentode/triode
« on: November 30, 2018, 04:44:18 pm »
Just wondering if anyone could tell me how to install a pentode/triode switch in this amp?
https://el34world.com/Hoffman/files/Hoffman_AB763_2.pdf

I am aware this may not be a desirable addition to this amp just wanted to try it out, any help would be appreciated!

Offline sluckey

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Re: AB763 deluxe reverb pentode/triode
« Reply #1 on: November 30, 2018, 04:54:26 pm »
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline Rockranger

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Re: AB763 deluxe reverb pentode/triode
« Reply #2 on: December 01, 2018, 03:12:57 am »
Perfect, Thanks

Offline tubenit

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Re: AB763 deluxe reverb pentode/triode
« Reply #3 on: December 01, 2018, 05:26:49 am »
I have found the pentode/triode switch to be a useful mod with 6V6's giving two distinct tone/vol changes.  Not so much with 6L6's where I couldn't hear that much of a difference.  Just an FYI, IMO.

With respect, Tubenit

Offline davidwpack

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Re: AB763 deluxe reverb pentode/triode
« Reply #4 on: December 01, 2018, 01:33:07 pm »
I tried it with KT66 and thought it sounded completely awful... muddy. I removed it.

Offline Rockranger

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Re: AB763 deluxe reverb pentode/triode
« Reply #5 on: December 02, 2018, 10:28:38 am »
What would be the appropriate voltage rating for the dpdt switch? I have a mini switch here but I believe the DC rating on it is quite low.

Offline sluckey

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Re: AB763 deluxe reverb pentode/triode
« Reply #6 on: December 02, 2018, 10:36:05 am »
Use the same rating you would use for a typical standby switch. I definitely would not use a mini switch of any rating. That DPDT Long bat switch that Hoffman sells looks good to me.

     https://hoffmanamps.com/MyStore/catalog/parts7.htm
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline Rockranger

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Re: AB763 deluxe reverb pentode/triode
« Reply #7 on: December 02, 2018, 10:58:08 am »
Yeah thanks sluckey, I will order some!

 


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