6G15 Input Question (FX loop operation)

[Dave]

Does anybody know how to wire up an input on a 6G15 Standalone Reverb that will play well in an effects loop?
The Kendrick unit has one, but I have know idea how its done.

Dave

[sluckey]

I'd start with this...

[Dave]

Nice.....

I suppose what you are trying to say is that it will work fine in the loop as is.

Whoops, I missed a lot the first time I looked at that picture.
At first glance I thought you just took the stock schematic and made the input line red.
I see that that is not the case.

Thank you very much.

Dave

[Dave]

Hmm.... I wonder if it wouldn't be effective to inject the input right before the dwell pot instead of at the driver tube?

BTW, I think I have the jack figured out...... one switching jack wired with the switch to ground for guitar and one switching jack with the switch wired to whereever the insertion point is.

Dave

[sluckey]

I wonder if it wouldn't be effective to inject the input right before the dwell pot instead of at the driver tube?

That could work. It still leaves a gain stage before the driver that may put you with too much gain. Another idea would be to replace the 220K driver grid resistor with the dwell pot.

What are you trying to do specifically? Do you have a 6G15 that you want to mod to work in an FX loop? Or maybe be able to work in an FX loop AND work as designed? Or are you just kicking around ideas for a possible build?

[Dave]

I am slowly working on a 6G15 / warbler matrimony. I have eliminated the Warbler's input stage because the 6G15 already has one.
I would like to include the ability to use it in or out of an fx loop just to give it more versatility.

Dave

[Dave]

After looking at it more carfully, this is what I have come up with.
If I do it as Sluckey suggested then, when in fx loop mode, the Dwell pot is bypassed and there is no control over how much signal gets verbed. This is starting to look like the only option. Because .........

If I do it right before the dwell pot, then the dwell pot attenuates the signal before it continues on either the wet or dry path.

There must be a better way, but I can't figure one out.

Dave

[sluckey]

The dwell pot will not affect the dry signal if you wire it like this...

[Dave]

OK, that's worth a try. I would have never even thought of doing it that way because I wouldn't have known that a cap between the injected signal and the pot would save the signal from attenuation.

It must be sort of a "path of least resistance" kind of thing because at a glance it looks, to me, like it still would attenuate the dry signal.

I'll give that a try and see what happens. If it works like you say, then it will be the answer I have been looking for.

Dave

[sluckey]

that a cap between the injected signal and the pot would save the signal from attenuation.

The cap has nothing to do with it. The dwell pot is wired such that it only affects the amount of signal you send to the reverb driver. It has no effect on the signal that goes down to the dry path. Think about it. The dry signal is picked off directly from the input jack. Now if you picked off the dry signal from the wiper of the dwell pot, yes, the pot would affect the level of the dry signal too. But that ain't the case.

That cap really isn't even needed, IF you guarantee that no dc voltage will be put on the input jack.

[Dave]

I looked at it. You are right as rain. There will always be 250K between the injected signal and ground regardless of the setting on the dwell pot.
That's what I get for studying the circuit to brain fatigue instead of just building it.

Dave