The following is a comment/post from Jedistar.com:

I was living in the San Fernando Valley in the late 60’s and my college employment office got me a job at Audio Guild. The company was very small; the boss Donald Bonham, an outside sales rep (we never saw), three women wiring the amps and me. I put together a couple of sub assemblies, assembled the final product and with a wave generator I tested the amps. I also used my guitar in the possess, in effect getting paid to practice! The cabinets were ‘farmed’ out to a cabinet shop.

Bonham was an engineer with the Hammond Organ Co before he started building amps, so it was only natural he would be interested in the vibrato effect. In appearance he was very distinguished. He had terrible head aches and took large doses of aspirin chased with lots of coffee. Bonham believed in the highest quality sound and innovation. The Audio Guild amps he produced in the late 60’s were used by pros in the studio where the highest fidelity was much more important than brute power. Carol Kay, the most popular studio bass player in Hollywood, used his amp.

I remember working on an amp The Jefferson Airplane used in the studio. Nothing wrong with the amp, they were just worried all the candle wax that melted into the cabinet might be a fire hazard (it was the sixties, you had to be there). The amp was very popular with accordion players. You might say that’s not much of endorsement, but at the time the accordion was being electrified for the first time. And they sounded like crap. Only the highest quality amp made the sound bearable. And with the built in FM vibrato the pro accordion player could walk into a gig with the accordion in one hand and the amp in the other, and have the equivalent of a B3 with Leslie speaker. Well, the poor mans equivalent.

One of my jobs was assembling the components of the vibrato. A light dependent resistor was placed next to light bulb under a light proof cap. The intensity of the light was controlled by a circuit that produced an oscillating current. The change in the resistance in the audio circuit produced a change in the audio frequency.

Bonham was a big fan of Acoustic Suspension speakers. Unheard of in instrument amps, A.S. speakers could not mounted in open cabinets, the large, unrestrained cone travel would destroy the speaker. But Bonham didn’t want to use the usual cabinet design of a box filled with foam to dampen the box’s resonate frequency, the foam also lowered efficiency.

So Bonham designed a cabinet with a small chamber next to the speaker chamber, with a small hole between the chambers that acted as a valve. It allowed the speaker to function at max efficiency while eliminating any resonating frequencies.

A technology Bonham borrowed from the HiFi world was bi-amping. The input was split into high and low frequencies and amplified separately, for a cleaner sound.

Donnald Bonham didn’t make the loudest or the most, he just made the best.

David De Gomez October 3, 2019 at 9:39 pm

While doing some research on Versatone amps, I ran across your website. That Versatone you picture there is the model that Carol Kaye used in the late 60s/early 70s. This was verified directly with her by both myself and another individual who owns one. She indicated to me that she had 4 of these which were used exclusively by her for about 3-4 years in her studio sessions. She says they were just excellent recording amps...clear tone, lively. Jack Cassady did use a different model of Versatone...not the Pan-o-Flex amp you have pictured there. These Versatones were first made by the Electronic Music Co. of Sherman Oakes California, which alter became Audio Guild Corp. of Van Nuyes. Don Bonham, who invented the Magnatone vibrato, is said to have been involved. Carol Kaye says the principles were Bob Hall, another electronics guru, and Jack Cookerly, who was from the music side, but also had an electronics background. Mr. Cookerly is still alive living somewhere in Oregon as I am told. Mr. Hall passed away. The Magnatone connection seems to have some validity, as the amps carried various named which included Lyric and Panaramic, for whom Magnatone-Estey produced models as well. Audio Guild Corp. is listed in the California State Archives as defunct at this time, but when it was made inactive in not listed. Obviously there's a lot more information unknown about the company and their amps, which are really great in my opinion.

Hope this provides some information you have not yet seen.

- Packardman1351 -at- aol.com (11/13/08)

"According to Carol Kaye the Versatone amp started life as a design by the Bonham amp company, I guess sometime in the early-to-mid sixties. I don't know if the Bonham amp was manufactured or not, but Jack Cookerly - best known as a composer and musician for TV shows (has an imdb page, worked on 77 Sunset Strip and The Untouchables I think) - and Bob Hall - a keyboard player - acquired their design and supposedly reworked it into the Versatone. Jack and Bob's most successful invention seems to have been creating a method for playing chords on the Lowrey organ by hitting a single note; there's some info on this & their adapting it for guitar here, roughly halfway down the page: http://www.utstat.utoronto.ca/mikevans/hroberts/references/nelson.html

That's pretty much the only solid info I have on the amp, and even with that I'm not sure about the Bonham amp company info. I also don't know when they started manufacture, or where they were sold. Cookerly and Hall seem to be remembered more for tinkering than producing, and apart from the Lowrey invention I don't know of what else they designed that was successful, but evidently there were some other inventions. Carol Kaye indicated in a 2001 message (not to me, but one that was forwarded) that she had about four of them in rotation for studio work and started using them around 1968 (no indication as to whether these were all the same model amp). The only pic I've seen of her with the Versatone is from '73, and she's partially obscuring the amp in the photo. I was told, I think by Chris at Vintage Gear, that Versatone amps were intially planned for accordians and synthesizers, as Cookerly and Hall got into working on synthesizers and Hall's wife was an accordian player, but again I'm not quite sure on that one."

- John Gwatney (04/08/08)

I've never responded to a blog before, so hopefully I'm doing this right. I have a versatone 133 just like yours. I bought it about a year ago at a swap meet. I've been trying to do research on it ever since, but there's very little info out there. Yours is the first 133 I've seen. The rest I've seen are a couple of other models. There's a tag in mine that says it was made by Audio Guild in Van Nuys California. The guy who used them was Jack Casady, bass guitarist for the Jefferson Airplane (before they were Jefferson Starship). He later left to form Hot Tuna. I have looked at hundreds of pictures on the internet of those groups, but have found no pictures with a Versatone amp visible. Carol Kaye was a session guitarist who I never heard of until I started doing my research. She worked on a lot of stuff in the 1960's, including the Beach Boys Good Vibrations.

Can I ask where you found out about the number made and how much you were asking for yours on Craigslist? Also, have your received any other responses with info. If you could share any of that with me, I'd appreciate it. I don't play guitar, but have a CD player hooked up to mine. I love to play 60's music through it with the reverb. I've included a picture of mine. It's in pretty good shape and sounds great.

-Steve Mishne (04/05/08)