Extra knob on the back of Deluxe reverb RI

[WayneReed]

EDITED . . . Thank you, Guy. That was the exact info I needed!

Also, I played with it today. And there absolutely is a difference
with the knob at zero vs. 10. The highs are much cleared using the
knob. Thanks!!!

I got a mint Fender amp as part of a trade recently. Love the amp!
I was told it is a DRRI.

There is a knob on the back, right next to the standby and on toggle switches.
It barely fits!

Looks just like the knobs on the front. Under the knob is has SPKR. The knob
actually covers a bit of the top of the letters.

I've looked in the manual. No pix of a knob on the back.

Also I played a guitar through it. I can't hear any difference between 1 and 10.
It seems like the knob does nothing.

Any ideas? TIA Wayne Reed

 

[Lonn]

Have you turned it to see what it does?

 

[Guy Incognito]

Sounds like a previous owner did the "Bright Cap Mod".

There was a thread on this a few days ago and if I find it I'll add it. Basically, it's removing a capacitor. Some people don't remove it outright but rather re-route it so it can be added at will vs always active (factory) or never active (clipped). The knob is likely in the External Speaker location so the mod can be reversed.

Edit. If it's right beside the power/standby switches then the knob is likely in the Internal Speaker location and they're using the External Speaker jack for the Internal Speaker.

Thread 'Clipping bright cap on a deluxe reverb mod' https://www.strat-talk.com/threads/clipping-bright-cap-on-a-deluxe-reverb-mod.538273/

 

[WayneReed]

Thanks for the replies!

Lonn, I know how you feel. I'm now the same age as 73 year old people! LOL
RE Have you turned it to see what it does?
In my post it says . . . Also I played a guitar through it. I can't hear any difference between 1 and 10. It seems like the knob does nothing.

Guy, Thanks! That's gotta be it. Sure sounds likely. I'll check out the article. Not hearing any noticeable change 0 to 10. Personally, if you
can't hear any difference, I want to set it so it has no effect. Do you know if that would be the obvious setting, ZERO? Or 10?

 

[Triple Jim]

Personally, if you
can't hear any difference, I want to set it so it has no effect.

Hmmm... if you can't hear any difference, then it has no effect at any setting!

 

[StratUp]

Just to be clear... we're not talking about the factory Line-Out control, right? This is down by the toggles at the other end? Photo perhaps?

 

[WayneReed]

Just to be clear... we're not talking about the factory Line-Out control, right? This is down by the toggles at the other end? Photo perhaps?

No, the knob is right next to, almost touching the power on toggle. Obviously after market because, as it says in my
post, the knob slightly covers the letters SPKR. Guy answered the question earlier.

 

[Guy Incognito]

Thanks for the replies!

Lonn, I know how you feel. I'm now the same age as 73 year old people! LOL
RE Have you turned it to see what it does?
In my post it says . . . Also I played a guitar through it. I can't hear any difference between 1 and 10. It seems like the knob does nothing.

Guy, Thanks! That's gotta be it. Sure sounds likely. I'll check out the article. Not hearing any noticeable change 0 to 10. Personally, if you
can't hear any difference, I want to set it so it has no effect. Do you know if that would be the obvious setting, ZERO? Or 10?

It's been said that the capacitor in question has less noticeable effect at louder volumes. Perhaps you were running at the volume where it really didn't matter.

That link I sent earlier is to a page here on ST from another member talking about the bright Cap Mod.

In that link is the OP's video on the mod and then later on is this video where they talk about why people do the mod (around 14 minutes in). At 16 minutes in he talks about adding a Mid Range knob by putting the pot in the speaker jack hole. Since the knob effect on your amp has a very subtle change I think they incorporated the midrange knob idea to the original bright cap.

 

[WayneReed]

Thanks again, Guy! Perfect info.