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6j6 paralleled
http://www.diyaudioprojects.com/Forum/viewtopic.php?f=9&t=6482
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Author:  pmccx [ 13 Mar 2019, 12:55 ]
Post subject:  6j6 paralleled

Hello everyone i am looking for schematic to start a 6j6 paralleled preamp,any help will be appreciated.
Thank you.

Author:  Suncalc [ 15 Mar 2019, 20:55 ]
Post subject:  Re: 6j6 paralleled

Do you mean like this?
Attachment:
6J6 Preamp Schematic.jpg

Author:  ILoveHiFi [ 15 Mar 2019, 21:18 ]
Post subject:  Re: 6j6 paralleled

Suncalc wrote:
Do you mean like this?
Attachment:
6J6 Preamp Schematic.jpg

Not sure why you want to draw the schematic with a inverted output signal.
As can be non inverting by swapping output cap to other 50k resistor

Author:  Suncalc [ 16 Mar 2019, 11:20 ]
Post subject:  Re: 6j6 paralleled

ILoveHiFi wrote:
Not sure why you want to draw the schematic with a inverted output signal.
As can be non inverting by swapping output cap to other 50k resistor
Very true.

I normally just draw most single stages like this as inverting. Unless you're including it inside a feedback loop, it really doesn't matter. The neat feature of this one is if you match the 50KΩ load resistors, you can get two outputs 180º out of phase. This is a handy feature for some circuits.

Author:  ILoveHiFi [ 16 Mar 2019, 15:19 ]
Post subject:  Re: 6j6 paralleled

I always like to have the piece of mind that my audio signal isn't inverted.

I also noticed that the second triod is grounded by a 50k on the grid.
This means if we were to take the output of from the other triode so is non inverting then the voltage gain would become small or very small.

If we were to take the output as inverting as current schematic, then I think the second triod won't be acting much in the schematic.
As the grounded grid configuration with large 50k resistor on grid removes any voltage gain or effect in schematic to beocme small or very small.

But if the design is intended to be like this, just adding a small touch of extra sound from second triod then I don't have much to say.

Author:  pmccx [ 16 Mar 2019, 16:02 ]
Post subject:  Re: 6j6 paralleled

Hello thank you for your responses :) looking like that plates together with 6j6.
Image

Author:  Suncalc [ 17 Mar 2019, 12:29 ]
Post subject:  Re: 6j6 paralleled

Here is a load line design for a fully parallel (i.e. plates and grids tied together) 6J6 preamp.
Attachment:
6J6 Full Parallel Load Line.jpg
Watch the high frequency rolloff. This tube tends to oscillate at RF with the cathodes above ground. Choose a grid stopper that limits the upper rolloff to somewhere not too far above 20kHz.

Author:  pmccx [ 18 Mar 2019, 05:30 ]
Post subject:  Re: 6j6 paralleled

Thank you for your help!

Author:  mwhouston [ 30 Mar 2019, 18:32 ]
Post subject:  Re: 6j6 paralleled

Has anyone built a preamp yet? Grid stopper? 5K?

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