SuperReverb Head

[jimsz]

Not quite sure what you're asking...

The 6A14's I've built ahd a hole in the chassis for a ground switch, just to keep up the vintage appearance, I guess. Nobody uses ground switches anymore now that we have 3-prong power plugs, so the 6A14 winds up with an extra hole in the chassis where you can mount a pot or a switch.

Okay, I see what you mean. No, it doesn't appear to have a ground switch hole. Would I really need access to this pot once it was installed and I found a relatively safe spot to put and found a decent setting for it?

So I was saying: remove the 1M resistor, tie the "top" lug of a 1M pot to the 500pf cap where it used to hit the 1MR, tie the bottom lug of the pot to where that 1M used to connect to ground, and connect the wiper of the pot to pins 7&2 of the 12AT7 (the grid, aka the input of the tube). Now you have a volume control for the signal going into the reverb tank, this is what they called a "dwell" control on the standalone Fender Reverb boxes.

Thanks for the detailed explanation. I understand that completely.

The dwell does a couple of things - it llets you tone down the verb to a much more usable range, and I find that the reverb has a less boingy, more ambient sound when the dwell is turned down and you're not hitting the reverb tank so hard.

If you turn the dwell all the way up, you're back to the stock circuit.

You may or may not have a convenient spot to mount the pot, and it may or may not be worth the effort. You could alternatively just hardwire a voltage divider - replace the 1MR with say... an 820K in series with a 150K r and feed the pins 7&2 from the junction of the two resistors, simulating a rolled down dwell control.

..or you could just leave 'er as is.

That's not a bad alternative either, changing out those resistors. That's what another amp tech told me to do and mentioned that it would actually improve the overall tone as well.

I could also leave it as is, but I'm just not satisfied with it. The settings are way too tight and overbearing. Even putting a slip cover over the amp when in transit winds up moving the dial slightly, but changing the setting drastically. I have to tweak the thing constantly. What a pain.