Twin Reverb Wet Signal Tone Shaping

[portersage]

Has anyone ever added a tone control to the reverb circuit in a silverface fender? I have a 74' 100 watt model that Ive been experimenting with, and I'm curious to see how that could be done.

And, if not, what would be things to look at / change if I wanted to just increase the brightness of the reverb signal? The reverb signal in my particular amp is far darker than other twin's I've heard, and despite having a tech give it a check up, and numerous tank swaps, I cant get much of a change in tone.

Thnaks!

 

[Matador]

Some silverface twin's have a 2nF cap hung off the grid of the reverb recovery stage (to ground). I would look at removing that first if present. Some also place a cap from the plate of the reverb driver stage to ground and you can remove that as well. You can also lower the cathode bypass cap from 25uF down to 1uF on the recovery stage to cut the bass gain down which tilts the tone towards the highs. Lastly, look into adjusting the 3nF coupling cap leading tot he reverb pot - reducing this down to 1nF will HPF the recovered signal to emphasize more of the highs.

 

[rock soderstrom]

And, if not, what would be things to look at / change if I wanted to just increase the brightness of the reverb signal? The reverb signal in my particular amp is far darker than other twin's I've heard, and despite having a tech give it a check up, and numerous tank swaps, I cant get much of a change in tone.

What Matador says, or you can also reduce the 500pF capacitor in front of the reverb driver to filter out deeper frequencies ---> brighter reverb signal.

 

[portersage]

Some silverface twin's have a 2nF cap hung off the grid of the reverb recovery stage (to ground). I would look at removing that first if present. Some also place a cap from the plate of the reverb driver stage to ground and you can remove that as well. You can also lower the cathode bypass cap from 25uF down to 1uF on the recovery stage to cut the bass gain down which tilts the tone towards the highs. Lastly, look into adjusting the 3nF coupling cap leading tot he reverb pot - reducing this down to 1nF will HPF the recovered signal to emphasize more of the highs.

Awesome, thanks! I'll try a couple of those and see what happens

 

[Electrobumps]

Some good mods on this site.

https://robrobinette.com/Silverface_Amp_Mods.htm

Also the AB763 mods will work on the reverb.

 

[CJ]

I notice a lot more reverb tone controls on modern amps that come in, but these are mostly the DSP daughter board types where high end noise is less of a problem,

 

[Electrobumps]

I notice a lot more reverb tone controls on modern amps that come in, but these are mostly the DSP daughter board types where high end noise is less of a problem,

I did a AB763 twin build, I really like the tone on the reverb. The noise is an issue, but also part of the character, I have the tank loose in the cab so I can move around if I need less noise.

 

[xazrules]

Make the tone as bright as possible driving the reverb and add a tone pot (high cut) at the recovery stage. The best solution I’ve found is to drive it with a mosfet in source follower config, clean and plenty of level.

 

[Electrobumps]

Make the tone as bright as possible driving the reverb and add a tone pot (high cut) at the recovery stage. The best solution I’ve found is to drive it with a mosfet in source follower config, clean and plenty of lev

I respectfully disagree with a bright reverb in regards to a twin reverb this will create a lot of additional noise. Springs generally start rolling off at 3khz.

 

[xazrules]

I was thinking in a preemphasis and deemphasis manner like in tape or riaa eqs. Usually I’m more concerned about hum than noise in spring reverb circuits.