Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: noac on July 03, 2019, 07:30:05 am
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Hello there!,
I love the Sluckey's 1960 Vox AC-15. I'd like to modify it to fit a single 6V6 power tube (I don't need 15W). What do I have to modify o transform the amp from PP to SE?
I attach the Sluckey's 1960 Vox AC-15 pdf.
Cheers!
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I love the Sluckey's 1960 Vox AC-15.
You have one n want to modify? or you like the schematic n want to build?
The trem channel is probably gonna be a problem, it's pretty hard to get that circuit to operate "the same" in a SE
look up an AC4? believe it's an SE, I'm not where I can surf easy
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I am building a new one. I am familiar with the ac4, but it's an EF86 preamp with a a single output tube. I want to add the 12ax7 to increase headroom.
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a single output tube
that's the part you want/ask for - copy it :icon_biggrin:
as to the VERY complex AC15 trem/vib channel - it's a bias vary n MORE circuit that will probably sound/act completely different than ANYTHING the original 15 was "known" for. Headroom will be WAY down on the list of "issues" that crop up trying to wiggle a preamp with the 15's circuit
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If the desire is for less watts/volume, but keeping the PP character, I would consider lower output power tubes with lower voltage PT. ECL 82/84/86 have all been used successfully by Forum members, and there are schematics here. I'd think about that route, borrowing as much of the AC-15 circuit ideas as practical.
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This is what I'd do. This is uncharted territory so plan to experiment once it's built.
Build the board exactly as if you were gonna do the original. Keep the same chassis layout even with the P/P output tubes. Make the couple changes shown in purple. Use the Hammond 1760C OT or get your favorite Fender Champ OT. I would not expect the "Top Cut" to sound the same on a SE amp but it may still be useful.
If for some reason this does not work out satisfactorily, just undo the purple stuff and you will have a working AC-15. If it's too powerful for you just turn the volume down.
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turn the volume down
Now why didn't I think of that?
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This is what I'd do. This is uncharted territory so plan to experiment once it's built.
Build the board exactly as if you were gonna do the original. Keep the same chassis layout even with the P/P output tubes. Make the couple changes shown in purple. Use the Hammond 1760C OT or get your favorite Fender Champ OT. I would not expect the "Top Cut" to sound the same on a SE amp but it may still be useful.
If for some reason this does not work out satisfactorily, just undo the purple stuff and you will have a working AC-15. If it's too powerful for you just turn the volume down.
Thanks!!! We are getting closer!!!
But I did not mention from he beginning that I want to remove the vibrato channel (solely my bad), nor Cut control. The amp would remain as one channel only: The EF86.
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In that case you need to look at my AC15 Lite...
http://sluckeyamps.com/hammond/hammond.htm
...or my Dual Lite...
http://sluckeyamps.com/dual_lite/dual_lite.htm
Apply the same purple changes to that.
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Perfect!!!!!!!
I've got the main picture now. Gotta try soon!!!
Thank you!!!!!!!
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Since you will only have one channel you need to connect the left side of C28 to ground.
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I did not mention from he beginning
that makes it way easier :icon_biggrin:
Sluckey, I like that a lot, nice n clean, easy :thumbsup:
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Sluckey, I like that a lot, nice n clean, easy :thumbsup:
Maybe we'll get to find out if it works! :icon_biggrin: