Help on Pedal Steel/guitar amp build ideas

[Benteleman]

Hi this is my first post on this great forum!

I am planning on a build based on the  Custom VibrAsonic amp from the 90's designed by Bruce Zinky. I owned one of these and found it to be one of the best sounding double duty amps i've played, great steel tone and great tele tone. I've owned many twin reverbs, mostly silverface or blackfaced silverface amps and currently own a Vibrosonic Reverb with the master volume.

Maybe this is a bit ambitious but ive built a few 5E3's and a deluxe reverb and done all kinds of mods on mostly twin reverb amps.

I am really trying to answer the age old quest for all steel/guit players who dont want to carry two amps! My thoughts are to do away with the tremolo circuit entirely because I never use it for steel and very rarely for guitar. I feel like this amp was a real sleeper- maybe because it was marketed to steel players but I found it to be a fantastic amp for tele as well.

So from what I can tell, it is pretty close to a AB763 twin and no NFB

Is this a dumb idea? I mean I have a Vibrosonic reverb and I guess I could mod but I feel like giving it a shot. Also, any and all suggestions for this idea are greatly encouraged

This is only in the idea stage but I tend to jump into action pretty quickly so I would love your input.

[HotBluePlates]

... I am planning on a build based on the  Custom VibrAsonic amp from the 90's designed by Bruce Zinky. ...

So from what I can tell, it is pretty close to a AB763 twin and no NFB

Is this a dumb idea? I mean I have a Vibrosonic reverb and I guess I could mod but I feel like giving it a shot. ...

I haven't looked carefully enough to spot all the differences, but it sure does look like a Twin Reverb (or a silverface Vibrasonic Reverb) with a different approach to mixing the two channels, reverb on both channels, tone-stack caps changes in the Guitar channel, and always-on Bright caps (my preference would be to have those on a switch, as I rarely like bright caps).  And of course, no negative feedback, as you pointed out.

If I'm thinking of the correct amp, the silverface Vibrasonic Reverb is essentially a Twin with a 15" speaker, right (I had one briefly, maybe 20 years ago)?  If so, I'd be looking at ways to modify that amp to match the Custom Vibrasonic schematic.

I don't recall if the silverface amp had bright switches, but if yes (for both channels) you will have solved the issue of how to have the Fat switch & Sweet switch (really just a bright cap you're taking out) on the front panel.

[super&plexi]

Funny I referenced that very amp tonight on other Forum... this was a black faced amp right? Said something like Vibra-Sonic? But the words  custom and Reverb were definitely there. If so the one I played had two 10s, don't remember make, but far as I rembr amp was stock.... Yesss! Killer tone. Got complements from guy I played with james garrison who is blackface cork sniffer/lover of 50s/to66 Fender tweed b/face originals... the amp was definitely fender I didn't mean to throw that off when I said don't remember make;  ( just in regards to the speakers)   I had the 60 two or three Brown original with four 5881s & $$ rect. More for resale, as was 100% stock.  Didn't like too much, but not really fair to say because it was just gone through for originality and not for anything else and then just sold. I also played the brown VibroVerb RI, hey older reissue with a cheesy circuit board and some smaller resistors oh my God I'm starting to go off again like I just said I wouldn't another post.......          I think they were killer amps if we're talking about the same thing the time period is about correct actually mine was used from the store and well-kept..... My Lord!  The equip. You have access to when your friend owns something like "THE GEAR TRADER"  IN H.B. CA.NOW DEFUNCT! SO NO COMMERCIAL!.... JUST MEMORIES!

[HotBluePlates]

... this was a black faced amp right? Said something like Vibra-Sonic? But the words  custom and Reverb were definitely there. If so the one I played had two 10s, don't remember make, but far as I rembr amp was stock....

The "Custom Vibrolux Reverb" is a reissue Fender with 2x 6L6's and 2x10" speakers.  Black panel with "Custom" in quotes above the otherwise vintage-looking Vibrolux logo.

But the "Custom Vibrasonic" is a reissue-style Fender amp with 4x6L6's and 1x15" speaker.  It's also an amp that never was, because while there was a brownface Vibrasonic, and a silverface Vibrosonic Reverb, there was never a blackface version with that name.

You could make a case that the blackface Vibroverb was the link between those amps, but you know...

... I also played the brown VibroVerb RI, hey older reissue with a cheesy circuit board and some smaller resistors ...

I recall playing through a RI brown Vibroverb when it first came out and was surprised to hear it sound just as good as a '67 Princeton Reverb I owned at the time.  Very few new amps had a tone where you played one chord and knew it was right.  That one did (regardless of any claims tonal impact due to "cheesy circuit board").

[super&plexi]

And yes the weight thing is huge because usually played my super Reverb on that gig... it was really hard to get to on Balboa Island on like Sunday the most popular gay. It was so nice to only have to carry half of the amp.

 You might have to get there early enough to ferry boat over drop off your equipment try to find a parking spot or park so far away you need to have a bike or skateboard in the car to get back if you didn't get lucky...

OR ferry boat back your car to where there was more parking and then ferry boat back just your body so you could play and then have to do the whole crap over again when you're done.   

All in favor of lighter/less load in

 and on that note you just drove me towards my silverface question which I will start posting now on another...

[super&plexi]

Funny... I think I said I was referencing the same amps earlier in another post on another place and the funny part is I posted in another part of this poem about my long-winded responses. Nutshell, 

   I had referred to the cheesy circuit board because it was nothing to work on at least with my talents or lack thereof. I've got zero against circuit boards especially Marshall old 72/3 six whatever the hell basically anything with a good heavy trace and a good layout. Although unless you want to take the whole damn thing out you've usually got to clip parts and then solder to them on the top...

That brown reissue along with my 72 super lead some of my best recorded clips probably 25 or 7 years ago at the Sundance Club at the Colorado River but the brownie had Oxford reissue speakers also that I had to glue nylon and fabric all around the outside surround because they had ripped from the frames.

I don't think I've ever argued with anyone online and I'm done sure not starting now on this site.

I'm just bringing up the point for discussion if weight has something to do in this equation would it not be more advantageous for aPrinceton ( a small Princeton with a 200 watt Electro voice speaker and Ratbox & red and Chrome rotovibe the one with the Vactrols was one of my best sounding rigs that I still get compliments on to this day)

 to sound as good as an almost twice as large and twice the wattage amp with two speakers then for the larger amp to sound as good as a small one.

If I sound combative at all I do not mean to... I will post on the appropriate forum subtitle any possible related thoughts plus I entered into this discussion also because I am thinking of downsizing a silver face UL pro rev. That  I actually think sounds great but I just can't deal with the weight.

[super&plexi]

Crap HBP. ... I thought I was responding to the first poster . nothing changes any of my response, but like the old guy I'm getting to,  it's harder for me to remember who the hell I'm talking to and I sometimes get off course but it's always important to know the Who at least.😁

[terminalgs]

deleting vibe should be easy.  remove R35 and C19 and oscillator below it. Are you also deleting reverb?


Note that V1B and V2B mix the two channels at the plate. they share cathode resistor as well as plate resistors.  If you build as-is you can combine R11 and R22 into a single 50K (47K) R.  I think this type of mixer has about a 50% signal attenuation hit.  If you are omitting reverb (including V4B), you can make V1B and V2B be their own independent triode gain stages and mix post coupling cap with some 220K resistors before heading to the PI (like a BF Bandmaster...)  I don't think doing this would steal the Zinky magic, that's probably all in the tonestack and the 86ing of NFB.

[Willabe]

Note that V1B and V2B mix the two channels at the plate. they share cathode resistor as well as plate resistors.   

I think this type of mixer has about a 50% signal attenuation hit.

Some call that a 'tweed' mixer, it has it's own sound as far as losses and distortion.

He used that for a reason, probably part of the sound/tone he wanted for the amp.

[terminalgs]

Some call that a 'tweed' mixer, it has it's own sound as far as losses and distortion.

I wonder which Tweed?  All the Tweeds I'm familiar with use mix resistors.  Unless it's based on one of those super early Tweeds like a '53 Bassman that mixed two inputs at V1.


The schematic posted above has single voltages at various stages in the amp (see ovals).  Very interesting.

[Willabe]

I wonder which Tweed?  All the Tweeds I'm familiar with use mix resistors.  Unless it's based on one of those super early Tweeds like a '53 Bassman that mixed two inputs at V1.

Yes, I believe it's from very early amps and not just Fenders? 

[HotBluePlates]

Some call that a 'tweed' mixer, ...

I wonder which Tweed?  All the Tweeds I'm familiar with use mix resistors.  ...

It's Kevin O'Connor terminology; not to be confused with Fender amps.