# DRRI Bright Cap and mods



## Stratin2traynor (Sep 27, 2006)

Had this question posted in another thread but decided to move it to aa thread all of it's own.

Can anyone somehow tell me what difference it will make to cut the bright cap on the Vibrato channel of my DRRI. The thing sounds amazing straight up with my Strat but once an OD is kicked on it just goes for shit - all fizzy with excessive treble. Hurts my ears, ya know.

The pedals sound better on the Normal Channel but the "magic" just isn't there like it is on the Vibrato Channel. I've read that the mod will make the Vib Ch sound more like the Norm Ch - but with the extra Db's gain on Vib 1 the magic is still there.

True or not. Do tell.

Also, is it possible to through an extra switch in there as a "Bright Switch" when needed????


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## bagpipe (Sep 19, 2006)

I did this mod on the DRRI I used to own. Its a bit of a pain as you have to take the amp apart (remove amp from cabinet, remove all knobs on front panel etc) to get access to the circuit board. I didn't find it made all much difference to be honest. While I loved the clean sound of the DRRI, I was never really happy with any dirty sounds other than a really light overdrive - it always sounded too buzzy and "bees in a can" sounding to me. This was with the mod done or not. But, if you like the sound of an overdrive pedal into channel one (which doesnt have the bright cap), then it might be worth your while removing the bright cap on channel two.

If you know what you're doing it would be fairly easy to install a little switch (maybe on the back panel?) to insert or remove the bright cap into the circuit.


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## Stratin2traynor (Sep 27, 2006)

So it didn't make that much of a difference? I may or may not try it. Maybe I have to tweak my OD's a bit. Like I said, the clean is second to none - just love it with my strat. 

As for the bright switch mod, I've built and modded a few pedals and have modded an amp so, I think I can do it without screwing it up (I hope - lol!).


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## Wild Bill (May 3, 2006)

Stratin2traynor said:


> So it didn't make that much of a difference? I may or may not try it. Maybe I have to tweak my OD's a bit. Like I said, the clean is second to none - just love it with my strat.
> 
> As for the bright switch mod, I've built and modded a few pedals and have modded an amp so, I think I can do it without screwing it up (I hope - lol!).


Before you did too much work I thought I'd give you the dope on how the bright cap works. Even if you already knew it might help someone else.

There's a funny thing about the human ear. It isn't as sensitive to treble frequencies at low volumes. So in the early years players would complain that when they turned the volume down they had to crank up the treble control. So someone had to invent the bright cap!

A bright cap is simply a cap wired across the hot and wiper terminals of the volume control. What happens is that when the control is turned down extra amounts of high frequencies flow through the cap. When you turn up the volume the cap is at the same time gradually shorted out so when you get the volume up to 6 or more the bright cap isn't doing anything but at that volume your ears are hearing the treble just fine without it.

The value of the cap is chosen to control just how much extra highs are added at low volumes. Guys like Leo Fender also would put a switch for the bright cap so if you found it too much you could switch it out.

So you if you understand all this you can decide if the bright effect is ok for different volume levels. If you put in a switch and take it out of the circuit it might lose too much treble at lower practice volumes. If that happens you can try a smaller value cap! Some amps use a rather big value like 500 pf. Try cutting it to 250 pf or less. Fender used 120 pf in the Bassmans. You could try 47 pf instead.

More unsolicited FYI from Wild Bill!:smile:

:food-smiley-004:


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## Adicted to Tubes (Mar 5, 2006)

The DRRI uses a 47pf cap already and it does not add a whole lot of treble.Clipping it is subtle at best.I find that the stock Eminence speakers are the real problem.Change it out to an Eminence Govnor and Holy Hanna! Not only does the whole amp sound better,the overdrive characteristics are vastly improved.Put a pedal in front and prepare for a very nice overdrive.
A 120pf cap like in other fenders,is too trebly for a Deluxe and adds a little boost.A 250pf and 500pf add tons of boost.

www.claramps.com


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## Wild Bill (May 3, 2006)

Adicted to Tubes said:


> The DRRI uses a 47pf cap already and it does not add a whole lot of treble.Clipping it is subtle at best.I find that the stock Eminence speakers are the real problem.Change it out to an Eminence Govnor and Holy Hanna! Not only does the whole amp sound better,the overdrive characteristics are vastly improved.Put a pedal in front and prepare for a very nice overdrive.
> A 120pf cap like in other fenders,is too trebly for a Deluxe and adds a little boost.A 250pf and 500pf add tons of boost.


Thank you, A2T! Great timing! I have a SF 1977 DR in for service, one of the ones with a pull-boost. It is indeed awful bright and kinda over enthusiastic with gain.

I've done some things to improve it but I've been looking long at the speaker. I had thought about a Cannabis Rex but a Governor could be a good choice!

I never argue with experience!:smile:

:food-smiley-004:


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## Stratin2traynor (Sep 27, 2006)

Thanks WildBill and Addicted to Tubes. Very interesting. I actually did swap out the stock Jensen and replaced it with a Tone Tubby Ceramic. That got rid of the annoying highs and made that amp sound ultra sweet with my strat. Natural OD is great with both strats and LP's. 

After reading the last couple of posts, I figured out that the problem arises when I play with the volume around 2 and use an OD pedal for dirt/distortion. 

With that in mind, I messed around and tried out my Tonebone Classic in front of the DRRI at low volume. It's a pretty good match. I can dial out some of the high and smooth things out. So I think I'll hold off on the surgery for now. 

Thanks!!!!!!!:bow:


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## Stratin2traynor (Sep 27, 2006)

Wild Bill said:


> Thank you, A2T! Great timing! I have a SF 1977 DR in for service, one of the ones with a pull-boost. It is indeed awful bright and kinda over enthusiastic with gain.
> 
> I've done some things to improve it but I've been looking long at the speaker. I had thought about a Cannabis Rex but a Governor could be a good choice!
> 
> ...


Another option may be a Tone Tubby Ceramic.


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## Adicted to Tubes (Mar 5, 2006)

Tone tubby's are nice but way too much money for what they are.I find the Eminence Redcoat and Patriot series is way more bang-for-the-buck.
I recently tried the Ceramic tone tubby in a chicago bluesbox amp and it was not impressive at all.The Govnor kills it IMHO.We tried the Tone Tubby with another amp and it didn't have the highs in the right spectrum.Not nice!
If you want to spend the money for a speaker,you might as well get one that delivers what you pay for.The extra cost for a hemp-cone is not worth it.Again,this is my opinion.

www.claramps.com


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## Stratin2traynor (Sep 27, 2006)

I think I figured out a less invasive option to the bright cap problem. I threw a Boss EQ into the chain and dialed out the highs. Now when I play around with OD at low volume I kick the EQ on and it sounds great. 

Interesting comment about the Tone Tubby. I use to have a Governor but I had it in a combo that I sold recently. The only other speakers I have left are a Weber Blue Dog, a Vintage 30, Eminence Red White and Blues and of course the Tone Tubby (that's in the DRRI).


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## Jeff Flowerday (Jan 23, 2006)

I vote Cannabis Rex. Best Deluxe Reverb speaker IMO. The Celestion voiced Emminence speakers always exhibit weird high end crying symptoms for me.


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## Adicted to Tubes (Mar 5, 2006)

So you see,there are many opinions about speakers!I find the cannabis rex is better suited to clean jazz styles.
I like the high end detail but not the shrillness.I found that Tone Tubby's are dark sounding.The Cannabis Rex is better in my opinion than the Tone Tubby.


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