Where would be the best place to insert a reverb circuit into a tweed tremolux 5G9?

[Dandrix]

i finally got time to piece a little recording of the 5g9 modded with the reverb. i think it came out good and i slowed down the tremolo.


https://youtu.be/6WznYmpz2cs

Thanks to all for the help especially Chuck

[Enzo]

Agree, any pot you pick will work, absolutely no strain on it. You could mount a real control on a panel if you like. Or a tiny screwdriver turned trimmer right on an eyelet board.

[Chuck H]

Those would be fine. If you have a fairly stiff pot on hand that would be fine too. It's just a small signal there at relatively low voltage and no real current. Anything you buy will be up to the task. Same applies to the 220k resistance off the reverb pot. You could install a trimmer there too so that both adjustments could be made at your whimsy. Because any time you change the drive into the reverb system you'll probably want to adjust the output level to balance.

[Dandrix]

The trimmer pot that Enzo was speaking of? Is there a certain brand i should be looking for. the trimmer pots have a power rating? I have been looking at a few not sure they will handle the application?
https://www.goldmine-elec-products.c...?number=G21832

https://www.goldmine-elec-products.c...?number=G23477

[Chuck H]

Here ya go. Changes in green

[Dandrix]

There's a 1M resistor as the grid load for the reverb driver tube input. Imagine that is a volume pot. You can create a voltage division with a series resistor and a dropping resistor to the ground with the total sum being near the 1M value. Incidentally, you could even wire a 1M pot there temporarily. Wire it JUST LIKE A VOLUME CONTROL. Signal from the 500p goes to the right lug, left lug grounded and the center lug feeds the grid of the driver tube. Now you can alter the drive to that tube. If you find a level that sounds better to you, remove the pot and measure the values at each end. Replace the pot with fixed resistors. Easy peezy. THEN...

Is there any chance you could show me in a layout? I am the type that needs to see it.
Sorry for any inconvenience

[Chuck H]

Why make it temporary? Wire a small 1 meg trimmer pot right on the part board in place or the 1 meg resistor. Dial it all the way up and the circuit is stock. Want less drive, dial it down to suit. And if you ever change your taste in reverb, there is nothing to un-modify. Just adjust the trimmer.


If you lose some reverb volume, I should hope there would be plenty of room left on the panel control. I don't know anyone who plays it on 10. Or 11...

This is entirely do-able too. But you may be signing me up for more drawing to make sure the layout is stable Which I can do I suppose.

[Enzo]

Why make it temporary? Wire a small 1 meg trimmer pot right on the part board in place or the 1 meg resistor. Dial it all the way up and the circuit is stock. Want less drive, dial it down to suit. And if you ever change your taste in reverb, there is nothing to un-modify. Just adjust the trimmer.


If you lose some reverb volume, I should hope there would be plenty of room left on the panel control. I don't know anyone who plays it on 10. Or 11...

[Chuck H]

Ok. I'm going to describe it and I hope that will be sufficient. It's actually a pretty good effort to arrange the drawings and such that I've put together so far. And I'll do it if needs be, but lets try this first...

There's a 1M resistor as the grid load for the reverb driver tube input. Imagine that is a volume pot. You can create a voltage division with a series resistor and a dropping resistor to the ground with the total sum being near the 1M value. Incidentally, you could even wire a 1M pot there temporarily. Wire it JUST LIKE A VOLUME CONTROL. Signal from the 500p goes to the right lug, left lug grounded and the center lug feeds the grid of the driver tube. Now you can alter the drive to that tube. If you find a level that sounds better to you, remove the pot and measure the values at each end. Replace the pot with fixed resistors. Easy peezy. THEN...

If you limit drive to the reverb you may/will lose some reverb volume. You can regain any lost volume by reducing the value of the 220k resistor that feeds the mix stage triode. A smaller value will increase the wet to dry level.

[Dandrix]

It might be possible to reduce the decay time a little. To reduce it a lot would require a different tank. The old Fender stand alone reverbs had a control knob labeled "dwell". It reduced the signal to the driver tube. By driving the springs less they didn't sustain as long. It could also be used to make the reverb less "boingy". So you could try reducing drive to the tank. If you want to maintain the same reverb level you have now you would have to balance the lower drive by reducing the value of the 220k resistor you just put in to increase volume.

Hey chuck, I am interested in reducing the decay. Could you walk me through what could be done? Hopefully a component or two change? Lol
Everything else is working great.

[Chuck H]

Simply reducing the load at the driver tube grid isn't the way to do it.

There's that 1M load resistor at the driver tube grid now. You would need to create a "voltage divider" as if that were a 1M pot. Exact resistances aren't critical though. So if, say, you wanted to cut the drive in half you could use a pair of 470k resistors. One to the grid after the 500p capacitor and the other as the load resistor from the grid to ground.

If your reverb volume drops too much you can restore it by decreasing the value of the 220k resistor from the reverb pot to the mixing stage grid.

[Dandrix]

lower drive by reducing the value of the 220k resistor you just put in to increase volume.

i will try a 150K or 100K res.
there's probably a give and take with this?

[Dandrix]

I'm not sure I'm understanding this. Is the reverb doing what a reverb should? That is, no more non reverb noises are happening?

Any trouble with acoustic feedback from the tank springs themselves?

yes, the reverb is good! hence the thumbs up ion guy. no more noises exactly. not even feeding back at full dial "12"

[Chuck H]

I'm not sure I'm understanding this. Is the reverb doing what a reverb should? That is, no more non reverb noises are happening?

Any trouble with acoustic feedback from the tank springs themselves?

Over 10 get's messy is good. Any knob on the amp should be able to give you 'too much' if only so you know you have enough

Hows the hum level with the reverb up? A little is normal. But if it's objectionable it can almost always be reduced.

It might be possible to reduce the decay time a little. To reduce it a lot would require a different tank. The old Fender stand alone reverbs had a control knob labeled "dwell". It reduced the signal to the driver tube. By driving the springs less they didn't sustain as long. It could also be used to make the reverb less "boingy". So you could try reducing drive to the tank. If you want to maintain the same reverb level you have now you would have to balance the lower drive by reducing the value of the 220k resistor you just put in to increase volume.

As to the tone of the reverb, we can only control the EQ. And even then only a little. I don't think we could make it much brighter, but we could probably make it a little fuller if it sounds too thin.

[Dandrix]

You had me on the blue circle! all good. BORROWED 100pf cap from a treble bleed cap from one of me guitars. i will buy a new one for the guitar. lol
the reverb is dead quiet. 1-4 not very noticeable. 5 is my happy spot for now. over 10 is about it. anything over that gets messy. the trailing end of a chordwhen you strum it once, sounds like it roaring still, Dwell is to long?
I also tried that with the amp volume dimed. which the amp is naturally distorted and would make the reverb nasty. not complaining, just trying to give feedback
Is there any tweaks that could be made to change the characteristics of the reverb (components) that would change? trailing end dwell, more reverb less reverb etc...
and good job!
thanks for sticking with me.
I have enjoyed tinkering and experimenting again.