This was here in Seattle. Sold for $318.00

Me thinks maybe a nice value. Was Tempted to go look at it, prolly best not to push things, my lady is due back in town tomorrow .

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... :IT&ih=001

A very interesting Magnatone site: Here for all things Magnatone In addition to making and selling amps under its own name, Magnatone licensed its designs and vibrato circuits to other manufacturers. Several members here including default and mad dog have magnatone amps. There are several U-TWOB Magnatone demo vids.

The Magnatone vibrato works using varistors; a rare, and getting rarer, electronic cousin of a resistor. Unlike tremolo which manipulates volume by increasing / decreasing / increasing volume at a user defined speed, vibrato actually changes the pitch of the notes; bends them electronically and, though subject to a control, at a considerably faster rate providing a unique effect unmatched by any amp of the period. This model uses the 7591 which is back in distribution; many, like the M10A use the 7189, an expensive, hard-to-find output tube. cj

This site is run by a Portland-based guy, and supposedly there is a shop farther east of the city. Must check it out some day. I've heard that he's got some amp building supplies too.

BTW capn, I am now the proud owner of a rather sorry-looking GA-17RVT, successfully secured by trading a bunch of collectible toys given to me by a friend who was moving. I, having no interest in such lovelies as a "new-in-box Speed Racer Captain Terror" or "mint condition The Rock bobble head," opted to gladly swap the bundle for the Gibson Scout.

Interesting little amp--three knobs for volume, reverb, and tremelo--no eq. Stripped of tolex, robbed of the reverb unit, original CTS speaker, missing a few tubes, and some unknown mods to the inputs, including an added toggle switch. Fortunately the footswitch was present. Tube lineup is a 12AX7, two 6EU7s, two 6AQ5s, and a 6CA4. It'll proabably be on the back burner, yet it's the one I would feel most comfortable messing with. Perhaps it'll be so. I'll try to snap some pics.

Hi JP; not sure I would have been so quick letting the Speed Racer Captain Terror go .... This would be the 'Crest' model, no? Toggle swith / input mods? I can forgive any tinkerer who leaves behind a lttle note or diagram explaining what he did... Is the FS hard-wired or connected plug/jack? If you get going, I have a Gibson reverb can; connections intact but possibly a little tired. I can clean and coat w/ phosphoric acid to replenish the light galvanized coating. Looking forward to the pics! cj

Hello gentleman, first post here.
It was this short thread, that amplifier that drew me to this board.

I own one of these amps. I do believe it to be quite rare.
It only took me about 5 years to find it, and I was on a specific mission to find THIS amp.

I have only seen two others, one with the Panoramic name, the other with a Magnatone name, all of which I believe to be identical. The Audio Guild version, I do believe preceeds all other models.

I realize there is virtually no information anywhere about these amps, there isnt even a mention of Audio Guild in Aspen Pittmann's "Tube Amp Book".

My amp, 100% original (tubes replaced in 2006), has two Utah Speakers (12" in the sealed enclosure, 10" in the open portion)
with Speaker codes dating in 1962.
I know nothing about the company Audio Guild, as they seem to have vanished off the face of the earth.
I have emailed 100's vintage amp collectors and dealers, never have I found someone who knows a thing about Audio Guild or these amps.

Here are a few pics of my amp:




Its in some rough shape as it is. The sound, though, It is truley unique and remarkable. Its no wonder why I searched for one of these for 5 years. If I ever stumble across another one for sale, no doubt, I would not hesitate to buy it.

Hi Dood and welcome: nice-looking amp ... IIRC another member owns (owned?) one; rare indeed. Have you been able to find a schematic for it? Yes, Pittman's book sticks pretty much w/ the better known brands; Guild amps didn't rate an honorable mention either. Ya like this amp? What does it do good? cj

Hiya Dood! Audio Guild amps were a California company as you well know. They licensed the vibrato circuit from Magna Electronics, which was owned by Estey at the time. The circuit design was Maggie's but the construction was Audio Guild's own. As far as I know, Magnatone didn't use 7591's at all, which makes you fortunate- as cj said 7189's are scarce. What's worse 7189A's were most frequently used and there is no substitute available. The "A"s were typically run with 400 volts and there's nothing in production that will drop in.

7591's OTOH, can have the sockets rewired to take 6L6s. That's not neccessary, because, like cj said,EH and JJ tubes have them back in production.

Go over to Yahoo Groups for Magnatone-Valco and you'll find just as rabid a bunch of Maggie fanatics as Guild fans here.

Link!

http://launch.groups.yahoo.com/group/Magnatone-Valco/

I owned a Audio Guild Grand Prix like the one in the pictures a few years back. It had a stereo input, vibrato and reverb. My particular amp did not have the tone of a Guild guitar amp with the 7591A finals. The upper end was pretty flat (i.e., no brightness) sounding. I tried to improve the tone with speaker changes but to no avail. I don't know if it was designed to have a flat tone or if it was just my amp.

Also, I don't recommend modifying an amp with 7591A's to 6L6's. Amps with 6L6's are everywhere. Amps with 7591A are more rare. The 7591A are not as loud but have a totally different sound than a 6L6 tube. They breakup much more agressively than a 6L6 when pushed hard and sound great. I think one of the issues with the Audio Guild amp was that the preamp stage of the Grand Prix did not push the 7591A's finals hard enough to get the best tone.

M

Hey M: is the front end of the Audio Guild on a pcb or point to point?

Hey Dood: what does the 6GH8 do? built like a 6BM8 / 6GW8; triode and pentode in one bottle; does that amp have a stand-alone reverb board in it like the Guild T1 RVTs and Thunderbirds?

Neat amp! cj

capn,

I am having a hard time remembering the internal design on this amp. I thought is was point-to-point but can't be sure. I am sure that the amp has a standard reverb pan. The amp is laid out such that the power tubes lay horizontal (i.e., parallel to the floor). The amp cabinet is laid out with an upper compartment for the amp chassis. The reverb pan is mounted to the "floor" of this upper compartment and runs parallel to the chassis. Below is a speaker compartment. It is divided into two cavities. The largest cavity seals in a 12 inch speaker. Adjacent to it is second "tuning" cavity that is coupled to the 12 inch speaker cavity through a hole of about 1 inch in diameter. The entire back of the cabinet is sealed with a single board.

The other amp shown is similar except it has 4- 7591As and a third cavity that is located above the sealed 12 inch section and holds a single 10 inch speaker in a open back configuration.

The Audio Guild amps are cool and thoughtful designs. The cabinets are pine construction. My first and only experiance didn't make me crazy about the tone of the amp. I would love to know if mine was not a representative sample of the tone. There was a lot I wanted to like about the amp.

M

Whoa! Missed the 4 X 7591s; what do you think, 50 watts or so? These are not as well-documented as some of the others; Magnatone, Univox, and comparables...like 'Sound' amps; 2 or 3 every year on eBay but vanished into history....

The Audio Guild amp I owned needed some cosmetic repairs. I replace the grill, made some cosmetic updates and a few other items and removed the Grand Prix plate. The series of pictures will show the features I described in the earlier description.

M








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Interesting; sub-divided similar to the Thunderstar to get the closed back / 'British' sound. Too bad all the mfrs didn't spend a little more on output transformers; better-sounding amps might have had better survivability statistics; Thanks. John

Those Audio Guild amps as I understand it were designed by Don Bonham, post Magnatone, and exist under a few different brand names. I believe they are closely related to the Versatone amps as well. According to Carol Kaye, the Versatone she used as a bass amp for some classic 60s records had two output transformers and two speakers, so you could crunch out one speaker while keeping the other clean (such as the long version of Good Vibrations with the crunchy bass break).

Thats just how mine is, except mine has the 10" in the cab, but outside the sealed portion.



matsickma, looks like you did a fine job cleaning that one up.

I wouldnt ever dare modifying my amp.
It's tempting, but Im afraid that changing the grill, or even the Tolex covering, would make the amp lose some of it's value.
The amp is noisy. It is in need of a ground wire, somewhere. Ive considered modifying the power cable for that purpose.

7591's arent difficult to find, now that GrooveTube's in manufacturing them.
I replaced all the tubes back in 2006. All the tubes previously installed, were original.

As far as whether is it PCP or Point to Point, I dont remember. It's been nearly a decade since I've had it opened up.