6SJ7 Pentode Operating Conditions

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Andy Le Blanc
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Re: 6SJ7 Pentode Operating Conditions

Post by Andy Le Blanc »

there is a difference as to whether you go to cathode or to ground with the divider and or bypass cap...

you can mix that up to taste as well.
lazymaryamps
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Kagliostro
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Re: 6SJ7 Pentode Operating Conditions

Post by Kagliostro »

During your experiments did you used a common pot or a 2-3W pot ?

Franco
Andy Le Blanc
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Re: 6SJ7 Pentode Operating Conditions

Post by Andy Le Blanc »

I used a common pot. I believe I double checked the current on the screens of most sharp cut off pentodes was less than .75 w... ... And with a divider the screens dont run into the same conditions as they would dangling at the end of a series resistance.
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Kagliostro
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Re: 6SJ7 Pentode Operating Conditions

Post by Kagliostro »

Thanks

Franco
brewdude
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Re: 6SJ7 Pentode Operating Conditions

Post by brewdude »

Is the pot noisy when rotated?
Is this arrangement suitable for mounting on the front (or back) panel?
How would you characterize the tonal difference of connecting the screen cap to ground vs. to cathode?
Andy Le Blanc
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Joined: Sat Dec 22, 2007 1:16 am
Location: central Maine

Re: 6SJ7 Pentode Operating Conditions

Post by Andy Le Blanc »

I've rigged it inside on a PCB. I didn't want it as a tone control.
I wanted a flexible rig to run a variety of pentode types.

Could be useful as a tweak but once you find the devices optimal
operating point all your doing is emphasizing the less than
optimal tone ... I know theres a lot room here... And finding "The" tone
Doesnt mean perfection. Worth a try
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Kagliostro
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Re: 6SJ7 Pentode Operating Conditions

Post by Kagliostro »

I'm wondering if such a pot will be interesting (I think it can be) in an arrangement similar to the schematic I've posted previously

http://ampgarage.com/forum/viewtopic.ph ... 30#p370157

I think the regulation of the gain can be very interesting as there are two different condition of work of the pentode there

Franco
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