Schematic..... 6K6 like the standalone reverb?

[Bob-I]

I drew up this schematic. Please look it over and give me some feedback. I plan to start work on this for one of my amps after I get the 5G15 I'm working on for a friend done.

[Luthierwnc]

Looks good. You might consider some sort of a treble bleed cap/trimmer after the recovery stage coupler to control the tone. Skip

[FUCHSAUDIO]

Do not forget a .002 in parallel with the reverb return resistor. Without it, the reverb return may be a little bright.

Also, a capacitor (small, say 470 pf) may be required from plate to cathode on the driver tube to avoid oscillation on transients.

It might be nice to just make the 6V6 a triode (470 ohm 1-W from plate to screen, instead of sourcing screen from raw B+. If you do source it from the B+ rail a screen resistor cannot hurt. The reverb input can only take a certain amount of input before saturation, so you won't need all the wattage a pentode 6V6 can deliver.

The 100-K drop resistor you have the reverb circuit across might be too small to allow enough reverb, and may introduce too much backfeed from output to input, making your reverb too close to feedback....

Just putting in my two cents.

[Bob-I]

Do not forget a .002 in parallel with the reverb return resistor. Without it, the reverb return may be a little bright.

Do you mean the return grid load resistor, the 220k? Bleed some of the treble to ground?

Interesting that Fender doesn't use any grid load, the reverb pan loads the grid.

Also, a capacitor (small, say 470 pf) may be required from plate to cathode on the driver tube to avoid oscillation on transients.

Gotcha

It might be nice to just make the 6V6 a triode (470 ohm 1-W from plate to screen, instead of sourcing screen from raw B+. If you do source it from the B+ rail a screen resistor cannot hurt. The reverb input can only take a certain amount of input before saturation, so you won't need all the wattage a pentode 6V6 can deliver.

I took this directly from the Fender 5G15 reverb. I questioned that too. Also, they use a 6K6 but I have 6V6's around so I thought I'd try that first.

The 100-K drop resistor you have the reverb circuit across might be too small to allow enough reverb, and may introduce too much backfeed from output to input, making your reverb too close to feedback....

That's what I have in there now with the parallel 12AT7 driver. I agree that with the higher drive of this tube I may need to up that resistor.

Just putting in my two cents.

Thx

[FUCHSAUDIO]

Do not forget a .002 in parallel with the reverb return resistor. Without it, the reverb return may be a little bright.

Do you mean the return grid load resistor, the 220k? Bleed some of the treble to ground?

Yup. If you look at most amplifiers with reverb, this cap exists. I think sometimes it may be to minimize the possible oscillation from the actual amplifier output itself.

Interesting that Fender doesn't use any grid load, the reverb pan loads the grid.

Again, in the amps a 220-K and .002 is the norm. Not to say this won't work, but keep it in mind.

Also, a capacitor (small, say 470 pf) may be required from plate to cathode on the driver tube to avoid oscillation on transients.

Gotcha

It might be nice to just make the 6V6 a triode (470 ohm 1-W from plate to screen, instead of sourcing screen from raw B+. If you do source it from the B+ rail a screen resistor cannot hurt. The reverb input can only take a certain amount of input before saturation, so you won't need all the wattage a pentode 6V6 can deliver.

I took this directly from the Fender 5G15 reverb. I questioned that too. Also, they use a 6K6 but I have 6V6's around so I thought I'd try that first.

A 6V6 is a higher wattage tube than a 6K6, so keep that in mind.

The 100-K drop resistor you have the reverb circuit across might be too small to allow enough reverb, and may introduce too much backfeed from output to input, making your reverb too close to feedback....

That's what I have in there now with the parallel 12AT7 driver. I agree that with the higher drive of this tube I may need to up that resistor.

Yup.

Just putting in my two cents.

Thx

No problemo...have fun.