Fender Vibrosonic with master volume

Dave Zirbel · From: Sebastopol, CA USA

I just picked up a 1972 Vibrosonic chassis (8 ohm) to drop into an empty Twin cab I had laying around. It has a master volume but it has been bypassed. One of the wires is from the master volume has been disconnected, one remains soldered to the board. Should they both be disconnected?

Do most Fender users prefer the master volume or not? It seems that the more desired Twins and Vibrosonics are the non master volume models.

The amp sounds good the way it is. I have a 1-15" baffle and plenty of 8 ohm 15" speakers to use. Most likely I'll use the K130 JBL. One thing I noticed is that I was playing it around the house with the volume around 4-5 and thought it could be louder. Could the bias be set a little on the cold side? Does that make a difference in volume?

Thanks, Dave

Mike Vallandigham · From: Martinez, CA

Hi DAve,
I ahve a master volume Vibrosonic, love it.
I leave the master at 10, never lowered it for playing steel. Just makes the sound muddy.

I dont know how to disconect the master properly, but I'm sure someone here does.

As far as volume, I CANNOT play either chanel at 4-5. vol at 2.5-3 is about as loud as I get it around the house. frikin loud amp.

enjoy it~

David Doggett · Posted 5 Sep 2008 10:35 am

My impression is that the prejudice against master-volume Fenders comes from guitar players because of several reasons:

A) The preamp distortion you get from turning the master down and channel volume up is not considered as good as the distortion you get from driving both the preamp and power amp tubes into distortion - of course the latter achieves distortion at much higher volume.

B) The non-master-volume Fenders are earlier models that have more in common with black-face Fenders and/or are easier to mod to black-face.

C) The later master-volume Fenders are ultra-linear transformer amps that would require even louder volumes to get distortion, don't give much distortion at any volume, and can't be modded to black-face.

Unless you are after blues/rock distortion, none of those reasons seem relevant to pedal steel. For the clean steel sound with lots of headroom, the master-volume models are as good or better than the earlier ones. Maybe they aren't quite as warm, but they have more clean headroom. And they are all-tube amps that have way more warmth and character than the sterile solid-state amps most steelers use. In other words, they are a very nice middle ground between black-face Fenders and solid-state Peaveys.

That preamp distortion guitar players disdain can actually have some use for steelers. I have a master-volume Pro Reverb that has some black-face mods (I don't know what they are - they were done without my asking by a well meaning guitar player/tech). If I open the master all the way, I get the maximum headroom, which is clean almost all the way to the top, as long as I don't turn the channel volume all the way up. If I want a little grit in small venues or for home practice, I can turn the master down to any desired level, and turn the channel volume up near or past the same spot on the dial. This can give me anything from a little grit to more distortion than works for steel. While that preamp distortion might not be ideal for guitar, it is actually not bad for steel. It is certainly as good or better than many commonly used distortion and fuzz boxes used by many steelers in front of clean steel amps.

So for my money, the anti-master volume prejudices of guitar players aren't necessarily relevant for pedal steel. It is a very different animal. For steel, because of the greater sustain of the instrument and volume pedal, and the thick chords, a little distortion, even preamp distortion, goes a long way. Basically, the master volume gives some versatility to the amp for steel. And as far as I can tell, if you open it all the way, it's as if it isn't there.

An advantage for steelers is that guitar player prejudice against master-volumes keeps the prices out of the stratosphere.

Mike Vallandigham · From: Martinez, CA

and, yes, I believe the bias setting does effect volume.

Dave Zirbel · From: Sebastopol, CA USA

Thanks guys. Might be in my best interest to hook the master vol back up. I was hoping for a good double duty amp for Tele as well but even my Deluxe Reverb is too loud for some bands! 85 watts and a JBL would be too much for most situations for me as far as Tele playing.

I recently did some gigs on steel with a Super Reverb. It was fine for a small club situation but on the big stages it didn't cut it. I think I'll be OK with this Vibrosonic. Classic tube sound!

Thanks again. I'd like more opinions and ideas from other Fender users. Very Happy

Dave

Steve Waltz · From: USA

Dave,

I had the reverb wired to both channels for about $25 when other work was being done. It's nice to have that option if you play guitar and steel through it.

I use one of the 72 vibrosonics as my bass head with John. You hear how loud it gets with bass, you should have an idea about whether your power output sounds like it's in the right range. Both of mine had previously been black faced, which I had partially reversed in order to have it sound better (to me) for steel. You played it in Richmond.

It's still strange that for being almost identical in every way, these two amps sound pretty different.

I forgot to speculate that if someone pulled the master off, I would assume that they went to town on the blackface mods and such in order to get it to break up. (on yours)

Dave Zirbel · From: Sebastopol, CA USA

Steve, did you have the master volume bypassed when I played your amp or after? I haven't seen you in awhile. I remember your amp sounded good and thinking it wasn't as loud as it should be.

Dave

Steve Waltz · From: USA

Dave,

Did you say that my amp wasn't as loud as it should be? I was always told to turn down in Richmond so I wouldn't have had my amp turned up that night. I don't always "10" the master so if you were just looking at what number the volume was at it might have looked a bit odd since it might have been higher to make up for a lower master.

I don't play with really loud bands so I can't say if this amp isn't powerfull enough.

I didn't have the master removed on either amp. It is and has been in place. One is wired a bit differently.

They were both black faced in the Phase inverter area and I had that changed before you played it. So when you played it is had all new tubes and caps and I think Eric had biased it and not me. I put in some oil and foil caps, changed a few resistors, added a dwell to the reverb, changed the reverb tube a less gain version and changed the reverb pan. That also has an Altec 421 in it.

I have a 67 showman at the house. It's been gone through and it doesn't have a master volume. The one vibrosonic still sounds better to me.

Dave Zirbel · From: Sebastopol, CA USA

Hope it wasn't me that told you to turn down! Smile

I say turn up the steel! Very Happy

I'm going to play the amp tomorrow at an outdoor gig and see how she does.

Dave

Danny Naccarato · From: Burleson, Texas

I had a Non-master Vibrosonic a few years back. However, Ken fox can weigh in here. As far as I understand, you want the master full on at 10. I also had a Dual Showman Reverb, pretty much the same as a Vibro, Twin, Quad..... and had Ken do his thing to it. It sounded great. He rewired, put new caps, etc in it, and adjusted the midrange "honk" out, by changing a component which slips my mind at the moment. He also wired the first channel with reverb. So, the first channel was the "stock" sound, the second had the component for getting rid of the "honk", for steel. That would take care of being able to use the same amp for both guitars, I would think...... Great sounding amps either way !!!!

Danny

Joe Shelby · From: Walnut Creek, California, USA

Dave,

When I took my twin to Skip Simmons' to diagnose/fix a buzzing reverb, he had a heck of a time isolating
the buzz. The amp is a ultralinear (135w). He removed
the pull boost/master volume cicuit and that fixed it. It doesn't bother me to not have it, on any master volume Fender I just dime that knob anyway.
I did have a mod-ed Super Reverb a long time ago that
sounded pretty decent using the channel/master volume
circuit for distortion with a S-10 Sho-Bud.
The twin I now have, I bought from Marty Muse, who, besides being a great steel player, also does tech work, and put the early '70's reverb circuit in it.
Sounds very nice and is worth having done for those
who have the later SF amps.

Joe.

Donny Hinson · From: Glen Burnie, Md. U.S.A.

Dave Zirbel · From: Sebastopol, CA USA

My Vibrosonic and my Super are on the way to Skip Simmons at this very moment for a checkup. Glad to have a great tech like Skip within reasonable distance. Thanks Henry Nagle for dropping them off! Very Happy

Dave

James Morehead · From: Prague, Oklahoma, USA - R.I.P.

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