Why it's good that we do what we do

[Ed G.]

A friend of mine plays music pretty much for a living. He said he wanted me to try to mod his Fender Hard Rock Deville to make it more 'dynamic'

I never fooled around with the pcb fenders before, but I gave it a stab with some of the mods from Paul Marossy's great site. Thanks Paul!
He liked the results.

My friend was impressed. Not only am I going to the N.O. Saints game tomorrow (yeah, they suck, but it's a free game) but he gave me a crybaby that he said didn't work! I've been looking for a wah shell!

[Mike Burgundy]

Very true,  and very cool. We all have these minor but VERY important little responses, that make it just a little more worth while than the basic "building yer own sound" satisfaction. Mine happened this week. A friend called after a radio-concert to report that several people wanted to know "what the f&*$ that is, it's cool!"
Getting free wah-shells is a cool bonus. Hey Puretube, did you ever get one from ... (insert maniacal grin here)

[Paul Marossy]

Cool Ed. I'm glad that page was of some use to you.  

Those Fender PCBs seem kind of delicate, but my PCBs withstood three or more changeouts of some caps/resistors without any major problems. Of course, I desoldered things very carefully - it wouldn't take too much to mess up those small traces. Anyhow, glad that your friend liked the results of your mods.

[RDV]

Not only am I going to the N.O. Saints game tomorrow (yeah, they suck, but it's a free game)....

Don't worry, they'll win, they're playing the "Sucks"(Bucs)~

RDV

[Steben]

I twiggled with some pedals of a guitarist I've met via Ebay (he bought a DIY pedal from me). This guy seems now to be playing in "Novastar", one of the most recognised groups with origin in Belgium. Now I went for free to a very outstanding small venue concert on the guest list! We could almost touch the artist's hands! These things are what we are all happy about in life...

[Ed G.]

Cool Ed. I'm glad that page was of some use to you.  

Those Fender PCBs seem kind of delicate, but my PCBs withstood three or more changeouts of some caps/resistors without any major problems. Of course, I desoldered things very carefully - it wouldn't take too much to mess up those small traces. Anyhow, glad that your friend liked the results of your mods.

Paul, I found another mod, and it might get my friend's amp to sound even closer to what he wants. He wants it to sound closer to his Twin Reverb.
He says "to wire a jumper between the center tap of the midrange control and the ungrounded side of that same control. This changes the configuration of the tone controls to be the same as a twin reverb. One will now be able to completely cut the voloume of the amp by turning the bass, mid and treble all the way down, something that certainly doesn't happen with the stock amp."
Check this out:
http://groups.google.com/groups?hl=en&lr=&frame=right&th=12ce7fbce05c0289&seekm=87019e5d.0408022102.aa8be70%40posting.google.com#link1

However, looking at the layout for my super reverb ab763, the midrange pot's center tap is not connected to the ungrounded tap. I'm going to have to research this a bit more.

[Elektrojänis]

However, looking at the layout for my super reverb ab763, the midrange pot's center tap is not connected to the ungrounded tap. I'm going to have to research this a bit more.

Um... Not familliar with that specific tonestack but is that ungrounded tap connected to anything on that super reverb of yours?

[Paul Marossy]

Actually, I have a '74 Twin Reverb, not a Super Reverb...   :wink:

I haven't looked at the schematic for a while, I'm not sure how the tone stack is wired in regards to your question. I would like it if my tone controls worked the same way on my Blues DeVille as it does on my Twin Reverb, though (I think).

Let us know what you find Ed.  

[Ed G.]

Top is the HRD tone stack, bottom is the AB763 tone stack.
You can't tell by the schem here, but the HRD puts the tone stack after the second gain stage, like bassman/marshall. AB763 is after the first gain stage.

It's slightly confusing to me. The AB763 schem's pots make it look like the center tap is connected to nothing, or maybe I'm not looking at it right. I would imagine that means it's wired up as a variable resistor, and the center tap would be wired up to one of the legs. That's how it appears in duncan's tone stack calculate, but that's not the way it appears on the layout, however.
Maybe someone familiar with fenders can help out here.

[Paul Marossy]

The AB763 schem's pots make it look like the center tap is connected to nothing, or maybe I'm not looking at it right.

Yes, that is correct. The AB763 schematic indicates that the bass and mid controls are wired as variable resistors. Looking at those two schematics, it appears that on the HRD, one could take the connection from the wiper of the mid pot and connect it instead to the junction of the mid and bass pots. You would also have to remove the connection to the wiper of the  bass pot and that 220K resistor that is connected to the bass and mid pots. This would make the tone stack behave much more like the old Twin Reverbs.

[Ed G.]

Yes, that is correct. The AB763 schematic indicates that the bass and mid controls are wired as variable resistors. Looking at those two schematics, it appears that on the HRD, one could take the connection from the wiper of the mid pot and connect it instead to the junction of the mid and bass pots. You would also have to remove the connection to the wiper of the  bass pot and that 220K resistor that is connected to the bass and mid pots. This would make the tone stack behave much more like the old Twin Reverbs.

The mod I posted seems to ignore the 220k resistor. I'm not sure what it does, it seems to isolate the pots? Either way, it would seem that the simple jumper wire mod could get the tone stack 'close enough' to act like the standard AB763 tone stack.
Either way, it's a simple enough mod. If and when my friend brings his amp back to do the mod, I'll report on its effectiveness.
BTW, my friend likes the HRD distortion, but I find it muddy and flubby in the bottom end. Are there any good mods to tighten up the distortion?

[Paul Marossy]

Don't have an definitive answer on how to make the bottom end more tight. I pretty much only use the clean channel on mine with my dist/OD pedals, but I do like the amp dist for certain tones.

I think messing with the values of C26/C27 may clean up the bass a little bit more - make them a little smaller. (C26/C27 are the caps on the grids of the power tubes)

You could probably post at the ampage forum at www.firebottle.com , I'm sure someone here must have done a mod to do exactly what you want to do.

[Doug_H]

[q;lkj

[Ed G.]

Well, leave it to the Saints to give other teams a rebound.
Anyhow, it was fun just to be in the 'dome and having fun. Even if the 'Aints suck.
My next door neighbor is an ex-NFL coach. He summed it up, and I quote:
"You can't make a racehorse out of a *&^*&^."

[RDV]

That was actually a better game than I thought it would, and not just cause the Bucs won. That's the 1st game where they've actually made some plays this year. I love football.

RDV