Quencho092
New member
I'm curious about the mods cesar diaz did on SRV's vibroverb and if any of them are DIY-able
Cesar Diaz's mods on SRV's Vibroverb
- Thread starter Quencho092
- Start date
Curly
Moe's Bluesman
Re: Cesar Diaz's mods on SRV's Vibroverb
my gut feeling is, "if you have to ask" ... then the answer is likely NO
what are the mods, and what amp are you using?
I think one mod is a rectifier switch? maybe the other is a triode/ pentode switch, but I don't really know
I'd think the Fender Forum would know though
and, it would probably take a decent tech to do the mods
my gut feeling is, "if you have to ask" ... then the answer is likely NO
what are the mods, and what amp are you using?
I think one mod is a rectifier switch? maybe the other is a triode/ pentode switch, but I don't really know
I'd think the Fender Forum would know though
and, it would probably take a decent tech to do the mods
L
Lewguitar
Guest
Re: Cesar Diaz's mods on SRV's Vibroverb
I believe he changed the value of the 68K input resistors to 100K or so. I guess SRV liked it CLEAN.
I believe he changed the value of the 68K input resistors to 100K or so. I guess SRV liked it CLEAN.
Quencho092
New member
Re: Cesar Diaz's mods on SRV's Vibroverb
i have 63 AA763 bandmaster...and im pretty sure he used the 63 or 64 AA763 vibroverb, unless its the less valuable AB version. Its essentially the same circuit minus tube rectifier and reverb unit.
I presume the 100k resistor on the input is easy to do. I use 11's on a strat with extra heavy picks so i figure my playing style is similar to SRV's 13's i think it was. This would clean up the sound a bit and soften the attack?
i have 63 AA763 bandmaster...and im pretty sure he used the 63 or 64 AA763 vibroverb, unless its the less valuable AB version. Its essentially the same circuit minus tube rectifier and reverb unit.
I presume the 100k resistor on the input is easy to do. I use 11's on a strat with extra heavy picks so i figure my playing style is similar to SRV's 13's i think it was. This would clean up the sound a bit and soften the attack?
Quencho092
New member
Re: Cesar Diaz's mods on SRV's Vibroverb
well im pretty handy with an iron, i fixed my peavey classic when i got it with a toasted transformer and a couple of melted caps, so i guess replacing one resistor or two wouldnt be such a problem.
Curly said:
well im pretty handy with an iron, i fixed my peavey classic when i got it with a toasted transformer and a couple of melted caps, so i guess replacing one resistor or two wouldnt be such a problem.
Re: Cesar Diaz's mods on SRV's Vibroverb
If you want what Diaz did to SRV's VV, go pick up a new Fender Custom Shop Vibroverb. Great amp, with the option for which rectifier you want to use and a special "hot" circuit mod that Diaz did for SRV.
It's a really nice amp. I had one for about a week or so. The one I had rattled like crazy and I couldn't track it down. If I didn't think the Two Rock was superior in every way, I'd have gotten another one. Beautiful cleans, but to overdrive it, you had to crank it.
as far as the AA circuit being more valuable than the AB circuit, someone might be filling your head full of crap. then again, I might be the one full of crap.
Old bassman heads used to be a dime a dozen. The lack of a tube rectifier and reverb on them just about automatically makes them a bit less valuable to 85% of the vintage amp guys. That's why you can pick one up for 300 bucks or so, depending on condition and where you live.
They do have a lot of potential for mods for sure. The price of them makes that a little easier to manange. No one wants to mod a $1200 vintage Blackface Reverb amp. Kills the value.
You can fairly easily play with one channel's tone stack to give it more of a Plexi feel and tone. Lew can probably talk you through that. Not too difficult. The main thing is to learn how to properly discharge capacitors inside an amp you're working on or you're sure to fry yourself, maybe forever!
If you want what Diaz did to SRV's VV, go pick up a new Fender Custom Shop Vibroverb. Great amp, with the option for which rectifier you want to use and a special "hot" circuit mod that Diaz did for SRV.
It's a really nice amp. I had one for about a week or so. The one I had rattled like crazy and I couldn't track it down. If I didn't think the Two Rock was superior in every way, I'd have gotten another one. Beautiful cleans, but to overdrive it, you had to crank it.
as far as the AA circuit being more valuable than the AB circuit, someone might be filling your head full of crap. then again, I might be the one full of crap.
Old bassman heads used to be a dime a dozen. The lack of a tube rectifier and reverb on them just about automatically makes them a bit less valuable to 85% of the vintage amp guys. That's why you can pick one up for 300 bucks or so, depending on condition and where you live.
They do have a lot of potential for mods for sure. The price of them makes that a little easier to manange. No one wants to mod a $1200 vintage Blackface Reverb amp. Kills the value.
You can fairly easily play with one channel's tone stack to give it more of a Plexi feel and tone. Lew can probably talk you through that. Not too difficult. The main thing is to learn how to properly discharge capacitors inside an amp you're working on or you're sure to fry yourself, maybe forever!
Quencho092
New member
Re: Cesar Diaz's mods on SRV's Vibroverb
i dont mind missing the 'verb, but how much does a tube rectifier affect tone?
Would it be a good idea to throw a 100kohm resistor instead of the 68k on the input jack?
Anything to make the sound really really smooth.
And by the way...how often should one re-cap an amp and how does an old capped amp sound in comparison to a freshly capped one?
i dont mind missing the 'verb, but how much does a tube rectifier affect tone?
Would it be a good idea to throw a 100kohm resistor instead of the 68k on the input jack?
Anything to make the sound really really smooth.
And by the way...how often should one re-cap an amp and how does an old capped amp sound in comparison to a freshly capped one?
Quencho092
New member
Re: Cesar Diaz's mods on SRV's Vibroverb
hmm...excellent...thanks. Know 'bout cap jobs and how often they should be done?
And as the for the AA, AB, the AA's are adjustable, AB's are balanceable so i figure AB's are harder to bias?
hmm...excellent...thanks. Know 'bout cap jobs and how often they should be done?
And as the for the AA, AB, the AA's are adjustable, AB's are balanceable so i figure AB's are harder to bias?
Quencho092
New member
Re: Cesar Diaz's mods on SRV's Vibroverb
i have the schematic for the fender inputs. There's 3 68kohm resistors on the input jacks.
One coming from each jack's positive end splicing together to a wire that goes to the preamp circuit, and one that goes from input 2 to the side of input one. Do i replace all of them with 3 100k ohn resistors?
i have the schematic for the fender inputs. There's 3 68kohm resistors on the input jacks.
One coming from each jack's positive end splicing together to a wire that goes to the preamp circuit, and one that goes from input 2 to the side of input one. Do i replace all of them with 3 100k ohn resistors?
Quencho092
New member
Re: Cesar Diaz's mods on SRV's Vibroverb
i figured it out, i just put it on the input i wish to change, what's a good quality resistor i can get from mouser?
i figured it out, i just put it on the input i wish to change, what's a good quality resistor i can get from mouser?
Re: Cesar Diaz's mods on SRV's Vibroverb
Inspect the cap ends. If you see a bubbling, it's time. If they look like they haven't been changed in a really long time, it's time to change them. The rule of thumb is every 10 years.
When I pulled the cover off the large caps on the underside of my Pro Reverb's chassis, they were just about to disintegrate. Several of the resistors crumbled when I poked them a bit with my hemostats. So, some of them had to change as well.
Gerald Weber used a good analogy. If you had an old car, wouldn't you change the oil and tires on a periodic basis to keep it running in tip top condition? Same with your amp. Something to think about.
As far as the AA AB thing goes, I'm not sure that is very accurate.
Go to the Fender Amp Field Guide and look up the Deluxe Reverb Blackface AB763 layout. That's an adjustable bias. Still in the Deluxe Reverb, look at the AA763. Same adjustable bias.
Then go look at the Pro Reverb blackface (AA165) layout, then the silverface layout. (AA1069). The AA165 is adjustable, the AA1069 is a balance.
I'd say that might poke a hole in the theory.
http://www.ampwares.com/ffg/
The guide just shows the AB763 as the Bandmaster's only layout. But Fender was all over the place sometimes. My Pro Reverb's sticker had AA165 on it, but I have a first year silverface (68). The guy selling it didn't have a clue. I was pretty stoked. Then I opened it up and saw the balance pot. They had already started to monkey with the circuit, but didn't get around to changing the sticker inside.
The Field Guide is a pretty good resource. Lots of folks use it all the time.
Is yours the blonde one with the gold sparkle grille?
Quencho092 said:
Inspect the cap ends. If you see a bubbling, it's time. If they look like they haven't been changed in a really long time, it's time to change them. The rule of thumb is every 10 years.
When I pulled the cover off the large caps on the underside of my Pro Reverb's chassis, they were just about to disintegrate. Several of the resistors crumbled when I poked them a bit with my hemostats. So, some of them had to change as well.
Gerald Weber used a good analogy. If you had an old car, wouldn't you change the oil and tires on a periodic basis to keep it running in tip top condition? Same with your amp. Something to think about.
As far as the AA AB thing goes, I'm not sure that is very accurate.
Go to the Fender Amp Field Guide and look up the Deluxe Reverb Blackface AB763 layout. That's an adjustable bias. Still in the Deluxe Reverb, look at the AA763. Same adjustable bias.
Then go look at the Pro Reverb blackface (AA165) layout, then the silverface layout. (AA1069). The AA165 is adjustable, the AA1069 is a balance.
I'd say that might poke a hole in the theory.
http://www.ampwares.com/ffg/
The guide just shows the AB763 as the Bandmaster's only layout. But Fender was all over the place sometimes. My Pro Reverb's sticker had AA165 on it, but I have a first year silverface (68). The guy selling it didn't have a clue. I was pretty stoked. Then I opened it up and saw the balance pot. They had already started to monkey with the circuit, but didn't get around to changing the sticker inside.
The Field Guide is a pretty good resource. Lots of folks use it all the time.
Is yours the blonde one with the gold sparkle grille?
Quencho092
New member
Re: Cesar Diaz's mods on SRV's Vibroverb
yea mine is a the 63 transitional model that's a blackface in disguise. Gold sparkle grill, light blue bulb on the little LED, circuit AA763. 4 preamp tubes, 2 power. i checked the insides and the serial, it was built october 11, 1963 right before they went blackface. I guess this is a rare model if it was only made in late 63, early 64...
yea mine is a the 63 transitional model that's a blackface in disguise. Gold sparkle grill, light blue bulb on the little LED, circuit AA763. 4 preamp tubes, 2 power. i checked the insides and the serial, it was built october 11, 1963 right before they went blackface. I guess this is a rare model if it was only made in late 63, early 64...
Quencho092
New member
Re: Cesar Diaz's mods on SRV's Vibroverb
and one more thing, are there higher quality resistors i can get for the input from mouser or is a resistor a resistor?
and one more thing, are there higher quality resistors i can get for the input from mouser or is a resistor a resistor?
L
Lewguitar
Guest
Re: Cesar Diaz's mods on SRV's Vibroverb
I looked up the schematic for the 6G16 model Vibroverb from '63 and also the AA763 and AB763. They all use the normal Fender configuration of two 68K reistors and a 1 Meg resistor. There should be a two 68K reisitors on the normal input and two on the bright input. The other resistor is the 1M grid load resistor. I'd leave that alone. Change the 68K's to 100K and you'll do at least one of the mods I know Cesar did to SRV's Vibroverb.
Alternately, if a player has a blackface or silverface Fender and wants to push the input harder, you could change the two 68K reisitors to 33K and double the 1 Meg grid load resistor to 2.2M.
The normal and reverb channel on my Deluxe Reverb and Super Reverb are both wired for reverb and vibrato.
That's what I did on the inputs to the normal channel on my Deluxe Reverb and Super Reverb. Great for getting a little ballsier tone with Strat or Tele pickups.
Lew
I looked up the schematic for the 6G16 model Vibroverb from '63 and also the AA763 and AB763. They all use the normal Fender configuration of two 68K reistors and a 1 Meg resistor. There should be a two 68K reisitors on the normal input and two on the bright input. The other resistor is the 1M grid load resistor. I'd leave that alone. Change the 68K's to 100K and you'll do at least one of the mods I know Cesar did to SRV's Vibroverb.
Alternately, if a player has a blackface or silverface Fender and wants to push the input harder, you could change the two 68K reisitors to 33K and double the 1 Meg grid load resistor to 2.2M.
The normal and reverb channel on my Deluxe Reverb and Super Reverb are both wired for reverb and vibrato.
That's what I did on the inputs to the normal channel on my Deluxe Reverb and Super Reverb. Great for getting a little ballsier tone with Strat or Tele pickups.
Lew
Quencho092
New member
Re: Cesar Diaz's mods on SRV's Vibroverb
how do you wire normal for reverb and vibrato? splice the input line after the 68k resistors with the input line of the vibrato channel? I dont got reverb tho so its no biggie.
Tone wise, how does the vibrato channel affect sound in comparison to the normal?
how do you wire normal for reverb and vibrato? splice the input line after the 68k resistors with the input line of the vibrato channel? I dont got reverb tho so its no biggie.
Tone wise, how does the vibrato channel affect sound in comparison to the normal?
