Buescher Varitone Octamatic

[DrGonz78]

Here is a really cool solid state amp from 1967. This amp was used by Sax players back in the day and is similar to the Selmer Varitone brands. I am in the process of trying to figure out what to do with it and have two options. I can find someone that will have all the missing parts to use it as it was intended or mod it to use with any instrument. Problem is that I have no schematic and really don't think I am gonna find one either. It is a really rare collectors piece and would love to see go to someone who can use it the way it was intended. If I can't find a buyer then it will be time to figure out how it wires up. Basically there was a mic in the top part of the saxophone and then a box that had volume/octaves/tone etc that attached to the sax. There is a cinch jones 8-pin jack that connects the instrument to the amp. I am wondering if anyone has come across these amps or any working knowledge to offer. Really would have to figure out what the control box does in relation to the amp. Without a schematic this seems impossible, but I think the effects were in the control box. If something is wrong with the amp or goes wrong it might be nearly impossible to fix without a schematic. I have attached some pictures and information to get an idea about this amp. Thanks for reading take care.

Some Pics of the parts involved...
http://caffeinatedrecordings.com/ebay/

Here is a youtube of a player on a Selmer Varitone Octamatic type amp, that is very similar to this one.

Lots of info here on another version of the Buescher type varitones.
http://bassic-sax.info/blog/?p=32591

[Mark Hammer]

I wonder what the relation is between the Buescher unit, the Selmer unit and the Conn Multivider?

[sgelectric]

This unit looks identical to a Selmer Varitone I encountered some while back that a sax player friend brought in.
The speaker was also a black EV SRO Alnico as pictured.
The controls for the effects were in the instrument mounted control box. The actually effects were built into the preamp mounted at the top of the case. The amp at the bottom is a basic SS power amp.
His unit included the controller but he did not have the required Selmer tenor neck which contained the microphone necessary for him to use it.
Apparently the people at Selmer did a lot of research to optimize the mic position in the horn although the mic itself was nothing revolutionary. These necks for Selmer altos and tenors show up on Ebay occasionally and can cost around $500 IIRC.
I was unable to find any schematic after an extensive search.

Good luck with your project.

SG

[DrGonz78]

I would say the Selmer and Buescher are nearly identical. I think the Conn Multivider was obviously another breed of the same species of course. I think it was all price for competition, who could make it for the lowest cost. Now how closely related are the controller circuits in relation to effects and amp components? Perhaps very similar and pretty much the same exact pots/switches. So the Conn Multivider might be a way to have some schematic information that is very similar to the Varitone? We'll see...

I have to say looking at the components in this thing it is in great condition. I will post pictures as I get an inside chassis view of the circuit. I first need to get it up and running. Got to find an AC cable or just rig one up via light bulb limiter and variac. Going to bring it up to line voltage real slow since god knows the last time it was turned on. I am going to add a grounded 3-prong AC plug on the amp. I have been looking around for something that is round that might work. Found this web page that has some old style round AC plug jacks. They are older styles but I have found some on Ebay that might work. Anyone have an idea where to look for a round AC plug that might fit nicely in this amp? BTW thanks for the feedback thus far. I will definitely be back for help as I try to figure out how this thing works.

AC Plugs that might fit... Perhaps the Heart lock special might work if the middle pin is actually ground??
Obsolete AC Power Connectors

[sgelectric]

The Selmer unit had a divider between preamp top and the power amp/speaker bottom.
As shown in the picture you've attached, the back panel on the top section was removable (magnetic latches). The black box on the backside housed a small reverb pan (isolated with foam).
There was also space to store the controller and cables.

These units were made at a time when every instrument wanted to be able to "plug in" like the keyboard and guitar players. This amp allowed the tenor and alto players to do so.
While these amps have a certain historical and novelty appeal, I would imagine the effects would be considered rather "ho-hum" by contemporary standards.
Later examples of electronics for woodwind players included the EWI (electronic wind instrument).

The Electrifying Eddie Harris album has recorded examples of the Selmer Varitone amp in action.

SG

[Mark Hammer]

I would say the Selmer and Buescher are nearly identical. I think the Conn Multivider was obviously another breed of the same species of course. I think it was all price for competition, who could make it for the lowest cost. Now how closely related are the controller circuits in relation to effects and amp components? Perhaps very similar and pretty much the same exact pots/switches. So the Conn Multivider might be a way to have some schematic information that is very similar to the Varitone? We'll see...

In some ways, these dividers are about as alike as most chorus circuits are. That is, there are subcircuits you have to have for it to do its thing, and every brand is going to have them, albeit with little tweaks.

Pretty much all of these are going to have a 4013 flip-flop in there for octave division, a preamp stage with some filtering to bring the input signal up to the level required to trigger the 4013, some filtering of the flip-flop output to tame the square wave into something tolerable, and a mixer stage to combine the at-pitch, octave-down and sub-octave, or whatever divisions or multiplatons of pitch the device has.

The question is, where those subcircuits are situated: in the remote controller, or in the amp chassis.

In a way, this reminds me of the old Epiphone Professional guitar/amp combination, where the amp itself had a fairly sparse control panel, and the "real" amp controls were mounted on the guitar and connected through a multi-conductor cable.

[sgelectric]

Stumbled on this press release this morning:

Akai offers EWI players a taste of wireless freedom

SG

[DrGonz78]

Well this is an old thread!! Anyway I got thing running and it needs some work. I was able to get the control box and even the schematic for the control box. Quick question is the schematic calls for 6.4uf caps. So I could get 6.8uf caps. However if looking at this schematic can anyone advise if putting in 10uf would be okay? Perhaps not enough information to know? Any thoughts?

[DrGonz78]

These old caps are measuring near to 10uf anyhow. So I am just going to put in the 10uf

[g1]

These old caps are measuring near to 10uf anyhow. So I am just going to put in the 10uf

Depending on your cap meter, leaky caps can measure high. Typically the cap function on a DMM.

[DrGonz78]

Depending on your cap meter, leaky caps can measure high. Typically the cap function on a DMM.

Yup and the control box was functioning with the old caps. I put in the 10uf caps and still functioning.

I have two of these units now. I have the Selmer version too but the speaker is missing and I am pretty sure someone screwed up the power amp. Good thing they are both exactly the same circuits so I can hopefully fix the other one. Sounds pretty cool with a bass guitar plugged in. Of course I got the clicking tremolo problem so gonna be replacing a few caps. No schematic of anything else but the control box.

[DrGonz78]

The only other thing I found on this unit was a block diagram. Someone on another site posted that they got the schematic from Electrovoice, so I may try to inquire with them.

[DrGonz78]

Also to note is the wonderful speaker in this amp. It says 76574. Which I take to mean 765 = EV 7 = 1967 4th week. It has EV on the cone so I know that but manufacturer code for EV is 649. Either way this speaker sounds fantastic! I am sure Juan Fahey will appreciate a picture or two.