Can we revisit the blackface/ silverface again ?????

hmx1 · February 14th, 2006, 11:02 PM

Hi Guy's,
I got my vibrolux today that I won on ebay, pretty cool amp, pure Fender all the way.
Here's one of my questions, what did the original blackface vibrolux sound like compared to this 1979?
Why do people make the change, what sound are they looking for?
Does anybody know where I could get a schemadic ( or directions on how to)that might show the parts and how to blackface one?
You may remember that I have a retired friend who loves to repair tv's and amps but he is not a techno wizard or anything, he pretty much needs to see a pic of how it works and he he can get into it.
I have spoken with Dave Allen and he has been real helpful about what he can do to it, but it would be neat if my old friend could do it to.
Many of the old posts said how bad the push pull volume pot is and I have to agree, that thing sucks, it goes from the coolest blues amp I have ever played to this solid state sounding dog.
Thanks to all who send answers, I look forward to hearing from ya.
DR

milocj · February 14th, 2006, 11:21 PM

First off, Vibrolux Reverbs are great and as long as you don't pull that boost pot it's not taking anything away from the amp (like some master volume circuits do). You should be able to find the schematics and chassis layouts for the BF and SFVR at
http://www.ampwares.com/ffg
The blackface schematic that you want is the AA964 and you can have your friend compare that to the latest silverface which I believe is the AA270.

My friends 1973 SFVR doesn't sound terribly different from my first year 1964. His is a little bit brighter and has a bit more headroom so I guess if you blackface your amp you could expect a little bit earlier, and probably a touch smoother breakup. You may not want this. I'm not an amp tech but the main differences are that the SF model uses a 5U4GB rectifier tube instead of a 5AR4, the bias circuit is a balance pot instead of an adjustment pot, and I believe the phase inverter has a couple of different resistor values. Your friend can probably pick most of these differences out.

Does your amp have original speakers? A simple speaker change can make a big difference in older Fenders. I've got Reverend Alltone 1030s in mine, but the Weber 10F150 and the Eminence Ragin' Cajun or Copperhead also come highly recommended. The stock Fender speakers are usually a little flabby on the low end once you start turning the amp up.

BrianF · February 14th, 2006, 11:23 PM

http://acruhl.freeshell.org/mga/main/bf_vs_sf.html

Actually there's enough technical differences that it becomes a 'slippery slope' of where to stop vs. reward and payback for the work and effort.

Taken to the limit...one could conceive of dumping everything in the amp except for the chassis and rebuild it from scratch including Mercury Magnetics transformers and a custom made solid finger-jointed pine cabinet.

My guess is that you'd get 90% of the way to tonal happiness just upgrading the speakers, tubes, and give it a good cap job.

Scott S · February 15th, 2006, 01:44 AM

Quote:

Originally Posted by BrianF

http://acruhl.freeshell.org/mga/main/bf_vs_sf.html

Some neat info, but the editorializing gets really old after a couple paragraphs. I'd prefer more details instead of "seemed to get worse..." He also doesn't seem to realize that Fender had been using 5U4 rectifier tubes since the early 1950s.

Paul G. · February 15th, 2006, 07:02 AM

SF/BF differences vary by model. In general the bigger, more expensive amps changed more.

Your Vibrolux has a bigger transformer than a BF. There are differences in the circuit and cabinet.

Generally speaking the BF will sound "softer", especially when the volume knob is raised. The SF will sound "harder", have more headroom and clarity and a somewhat harsher distortion.

If you play clean, stock SF amps are well suited. If you go into the drive territory, minor changes, known as "Blackfacing" can be worth it.

P.

5965 · February 15th, 2006, 04:16 PM

Congratulations. The pull boost amps are way underrated and way underpriced. The boost is useful.

About the only thing I'd add is the sf's tend to sound a little cooler than the bf's, but much of that can be altered with different tubes or speakers.

Before changing anything in the circuitry, I'd suggest getting some new, or newer, tubes and switching them around a bit- preamp for sure, and possibly power tubes later on. Speakers might or might not be helpful, depending upon what's installed. In short, you may not need much, if anything else.

Good luck.

jpkusa · February 16th, 2006, 11:58 AM

I recently got a late 70's SFVR like yours, with the pull-boost, and had it re-capped and blackfaced. Smoother, better, earlier breakup; more warmth. Definitely worth it, but probably not best for straight country players (not clean enough).

CancerLeoCam · February 16th, 2006, 01:05 PM

"..I have spoken with Dave Allen and he has been real helpful about what he can do to it, but it would be neat if my old friend could do it to. "

Well, what are you waiting for? According to the world of amplifiers Dave is THE BEST when it comes to pricing, service, reliability, products, nice guy, etc. Why are you gonna monkey around with it instead of having the Midas touch? Take it to a pro man!

mad dog · February 17th, 2006, 11:34 AM

Gary Croteau (hope that's the spelling), the guy who builds Juke amps, told me that there's more to the BF/SF deal than circuit. Cabinet build -- especially baffle construction and attachment -- changed over time with these amps. How the baffle attaches (he says) is one reason for that harder SF sound.

I like both the SF and BF VRs. Best one I've heard yet is a blackfaced SF. The smaller OT probably suits me best, as I play mostly blues and appreciate drive at medium volume. I'd own either one in a minute. You can't go wrong.

February 14th, 2006, 11:02 PM	#1 (permalink)
hmx1 TDPRI Member Join Date: Apr 2005 Posts: 43	Can we revisit the blackface/ silverface again ????? Hi Guy's, I got my vibrolux today that I won on ebay, pretty cool amp, pure Fender all the way. Here's one of my questions, what did the original blackface vibrolux sound like compared to this 1979? Why do people make the change, what sound are they looking for? Does anybody know where I could get a schemadic ( or directions on how to)that might show the parts and how to blackface one? You may remember that I have a retired friend who loves to repair tv's and amps but he is not a techno wizard or anything, he pretty much needs to see a pic of how it works and he he can get into it. I have spoken with Dave Allen and he has been real helpful about what he can do to it, but it would be neat if my old friend could do it to. Many of the old posts said how bad the push pull volume pot is and I have to agree, that thing sucks, it goes from the coolest blues amp I have ever played to this solid state sounding dog. Thanks to all who send answers, I look forward to hearing from ya. DR __________________ Blues Power, Can you dig it

February 14th, 2006, 11:23 PM	#3 (permalink)
BrianF Friend of Leo's Join Date: Apr 2003 Location: Carlsbad, Ca Posts: 2,179 7 Photos	Read this link http://acruhl.freeshell.org/mga/main/bf_vs_sf.html Actually there's enough technical differences that it becomes a 'slippery slope' of where to stop vs. reward and payback for the work and effort. Taken to the limit...one could conceive of dumping everything in the amp except for the chassis and rebuild it from scratch including Mercury Magnetics transformers and a custom made solid finger-jointed pine cabinet. My guess is that you'd get 90% of the way to tonal happiness just upgrading the speakers, tubes, and give it a good cap job.

February 15th, 2006, 07:02 AM	#5 (permalink)
Paul G. Tele-Holic Join Date: Mar 2003 Location: Rhode Island Posts: 885	Some differences. SF/BF differences vary by model. In general the bigger, more expensive amps changed more. Your Vibrolux has a bigger transformer than a BF. There are differences in the circuit and cabinet. Generally speaking the BF will sound "softer", especially when the volume knob is raised. The SF will sound "harder", have more headroom and clarity and a somewhat harsher distortion. If you play clean, stock SF amps are well suited. If you go into the drive territory, minor changes, known as "Blackfacing" can be worth it. P. __________________ Listen to your mother

February 16th, 2006, 01:05 PM	#8 (permalink)
CancerLeoCam Tele-Afflicted Join Date: Jul 2005 Location: Mule Deer-Mt. Lion Safari, CA Posts: 1,692 5 Photos	Hey, "..I have spoken with Dave Allen and he has been real helpful about what he can do to it, but it would be neat if my old friend could do it to. " Well, what are you waiting for? According to the world of amplifiers Dave is THE BEST when it comes to pricing, service, reliability, products, nice guy, etc. Why are you gonna monkey around with it instead of having the Midas touch? Take it to a pro man! __________________ Everyone's your "buddy" or "friend" when they want you or something from you. If you're not willing to work for free why should somebody else?

February 14th, 2006, 11:21 PM	#2 (permalink)
milocj Tele-Meister Join Date: Aug 2005 Location: Michigan Posts: 453 3 Photos	First off, Vibrolux Reverbs are great and as long as you don't pull that boost pot it's not taking anything away from the amp (like some master volume circuits do). You should be able to find the schematics and chassis layouts for the BF and SFVR at http://www.ampwares.com/ffg The blackface schematic that you want is the AA964 and you can have your friend compare that to the latest silverface which I believe is the AA270. My friends 1973 SFVR doesn't sound terribly different from my first year 1964. His is a little bit brighter and has a bit more headroom so I guess if you blackface your amp you could expect a little bit earlier, and probably a touch smoother breakup. You may not want this. I'm not an amp tech but the main differences are that the SF model uses a 5U4GB rectifier tube instead of a 5AR4, the bias circuit is a balance pot instead of an adjustment pot, and I believe the phase inverter has a couple of different resistor values. Your friend can probably pick most of these differences out. Does your amp have original speakers? A simple speaker change can make a big difference in older Fenders. I've got Reverend Alltone 1030s in mine, but the Weber 10F150 and the Eminence Ragin' Cajun or Copperhead also come highly recommended. The stock Fender speakers are usually a little flabby on the low end once you start turning the amp up.

February 15th, 2006, 04:16 PM	#6 (permalink)
5965 Tele-Holic Join Date: Apr 2003 Posts: 738	Congratulations. The pull boost amps are way underrated and way underpriced. The boost is useful. About the only thing I'd add is the sf's tend to sound a little cooler than the bf's, but much of that can be altered with different tubes or speakers. Before changing anything in the circuitry, I'd suggest getting some new, or newer, tubes and switching them around a bit- preamp for sure, and possibly power tubes later on. Speakers might or might not be helpful, depending upon what's installed. In short, you may not need much, if anything else. Good luck.

February 16th, 2006, 11:58 AM	#7 (permalink)
jpkusa Tele-Holic Join Date: Dec 2004 Location: Nowhereseville Posts: 585	I recently got a late 70's SFVR like yours, with the pull-boost, and had it re-capped and blackfaced. Smoother, better, earlier breakup; more warmth. Definitely worth it, but probably not best for straight country players (not clean enough).

February 17th, 2006, 11:34 AM	#9 (permalink)
mad dog Tele-Holic Join Date: Jun 2005 Posts: 849	Gary Croteau (hope that's the spelling), the guy who builds Juke amps, told me that there's more to the BF/SF deal than circuit. Cabinet build -- especially baffle construction and attachment -- changed over time with these amps. How the baffle attaches (he says) is one reason for that harder SF sound. I like both the SF and BF VRs. Best one I've heard yet is a blackfaced SF. The smaller OT probably suits me best, as I play mostly blues and appreciate drive at medium volume. I'd own either one in a minute. You can't go wrong.