I will check with some guys who also have used these switches to see if I have drawn it correctly and get back with a corrected drawing or confirmation.
I am trying to draw the one on the top right to be the same as the one on the bottom which does work.
EDIT: OK, the guy that I originally got the idea from confirmed that my attempt at the 1/4 switch was incorrect as Larry pointed out. However, he was kind enough to confirm what would work also.
The attachment shows the incorrect on the top left and the correct in the middle frame of the top.
With respect, 10thtx
EL84 Blues Amp
Moderators: pompeiisneaks, Colossal
Re: EL84 Blues Amp
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Last edited by 10thTx on Mon Oct 13, 2008 10:49 am, edited 1 time in total.
Re: EL84 Blues Amp
In the right schem and the one on bottom the caps always are in series w/ the resistors, no matter, where the switch is switched to. And the switch then simply is switching both/none/one R/C-conjunction to ground.
In the left schem (yours) the switch either doesn't connect the caps anywhere, or it's switching it in series through the 100K's to ground, what doesn't affect anything, since these R's are about 400 times bigger than the cathode R's itself
Larry
In the left schem (yours) the switch either doesn't connect the caps anywhere, or it's switching it in series through the 100K's to ground, what doesn't affect anything, since these R's are about 400 times bigger than the cathode R's itself
Larry
Larry's Website now with included Pix's Gallery
Thanks
Larry,
I appreciate your patience and repeated efforts to help it make sense to me. Thanks!
I have edited the schematic and layout per your critique to reflect the full, half, &1/4 power attentuation switch.
With respect, 10thtx
I appreciate your patience and repeated efforts to help it make sense to me. Thanks!
I have edited the schematic and layout per your critique to reflect the full, half, &1/4 power attentuation switch.
With respect, 10thtx
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Quad el84 cathode cap bypass switching
Hey
I am new to posting and amp building, but am familiar with concepts and all cautions and warnings of tube amps and voltages. I work on power mains all the time.
That being said, I am planning a quad el84 trainwreck sort of liverpress, and would like to hear more about using this cathode cap bypass switch modified for the quad.
Would it make sense to cut 2 out completely and use the switch on the remaining pair, or use the same concept on both pairs for more versatility.
I will be modifying a mid 60's claricon 35w pa, and dont have it yet and cant find schems, so I dont know anything about its P.I or anything.
If I can use the stock output stage with modifications, that would be pref. but not mandatory. I'll rebuild the whole damn thing to get the sound right.
I know its early on to get accurate answers, but any incite would help.
Rick
I am new to posting and amp building, but am familiar with concepts and all cautions and warnings of tube amps and voltages. I work on power mains all the time.
That being said, I am planning a quad el84 trainwreck sort of liverpress, and would like to hear more about using this cathode cap bypass switch modified for the quad.
Would it make sense to cut 2 out completely and use the switch on the remaining pair, or use the same concept on both pairs for more versatility.
I will be modifying a mid 60's claricon 35w pa, and dont have it yet and cant find schems, so I dont know anything about its P.I or anything.
If I can use the stock output stage with modifications, that would be pref. but not mandatory. I'll rebuild the whole damn thing to get the sound right.
I know its early on to get accurate answers, but any incite would help.
Rick
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Last edited by javahead on Mon Jan 14, 2013 4:25 pm, edited 1 time in total.
Re: EL84 Blues Amp
I have used the cathode attenuation switch on several amps. It works.
Having said that, I prefer the Lar-Mar PPIMV to control the volume.
Given what you've stated, I'd probably just shut off two power tubes and use the LarMar PPIMV with the design you're considering.
With respect, 10thtx
Having said that, I prefer the Lar-Mar PPIMV to control the volume.
Given what you've stated, I'd probably just shut off two power tubes and use the LarMar PPIMV with the design you're considering.
With respect, 10thtx