Tube Depot 18W build question

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rphilyaw1
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Tube Depot 18W build question

Post by rphilyaw1 »

I have a question related to the Tube Depot 18W kit I'm building. Note that this is a head, not a combo. I'm doing the EF86 mod. The parts inventory lists a 22uf 50V cap as part of the EF86 mod. According to the schematic and wiring layout this is the EF86 cathode bypass cap. The 12AX7 circuit uses a 47uf cap, and unfortunately the instructions and the wiring layouts show the 47uf for the EF86 circuit. My question is, what would be the effect of the larger cap with the EF86?

Thanks!
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Bieworm
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Re: Tube Depot 18W build question

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rphilyaw1 wrote:
Thu 10/06/22 10:19 am
I have a question related to the Tube Depot 18W kit I'm building. Note that this is a head, not a combo. I'm doing the EF86 mod. The parts inventory lists a 22uf 50V cap as part of the EF86 mod. According to the schematic and wiring layout this is the EF86 cathode bypass cap. The 12AX7 circuit uses a 47uf cap, and unfortunately the instructions and the wiring layouts show the 47uf for the EF86 circuit. My question is, what would be the effect of the larger cap with the EF86?

Thanks!
Keep the 50uf cap. In the 18W EF86 design it calls for that value too. More gain and fatter is a question for debate.. maybe better for stability against oscillation perhaps?
I don't know what size of coupling cap is on the Tube Depot schematic , but make sure you use a small value such as the .0047uf on the EF86 in the downloads section.. for flubbiness' sake
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rphilyaw1
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Re: Tube Depot 18W build question

Post by rphilyaw1 »

Thanks for the quick response. Coupling cap is .0047uf as you mention. For the cathode bypass did you mean keep the 22uf or the 47uf?

Thanks,
Richard
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Bieworm
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Re: Tube Depot 18W build question

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rphilyaw1 wrote:
Thu 10/06/22 2:18 pm
Thanks for the quick response. Coupling cap is .0047uf as you mention. For the cathode bypass did you mean keep the 22uf or the 47uf?

Thanks,
Richard
Put the 47uf in, I meant.
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rphilyaw1
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Re: Tube Depot 18W build question

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Thanks!
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