"GUild Slave"?? What's this?

dklsplace

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There is an old line of Guild Audio stuff along the lines of HiFi gear rather than instrument amplification. I don't know anything about the history or affiliation of the company, but I'm guessing this may be from that batch of stuff.
 

matsickma

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Hi Guy's,

The Guild Slave amp is indeed an origional Guild "slave" amplifier. This amp concept was introduced by Guild around 1966 during the "beige tolex" era of tube amplifiers. It appeared in the "Hi-5" catalog that presented the new beige style Guild amplifier line along with the Thunderbird S-200 and other accessories.

The Guild slave amp was mounted to a 2-15 cabinet. The amp housing was mounted through the back of the amp in what looked like a standard 2-15 Quantum Thunderbass Amp cabinet. The amp was designed to accomidate the Auxiliary output of the Thunderbass and Thunderbird amp of that era. (Note: Most people assume the Aux output of these amps is for an extra speaker cabinet. They will drive a extra speaker but it wasn't the initial intent.) Basically the slave amp has an input that accepts a speaker level signal. The amp then acts like another set of power amp finals and drives a seperate cabinet.

The Slave idea was Guilds concept on how to prevent feedback and distortion from your amp and allow you "unlimited power-to infinity" by daisy chaining the Slave Amp/Cab around the auditorium. Guild advertised the Slave approach to achieve P.A. system power for your guitar. (Note: P.A. system is another geezer term!) The Slave amp used a pair of 8417 finals that I suspect was ran at a pretty high voltage comparable to the early model Quatum Thunderbass amps. Guild stated these amps ware capable of 160 Watts peak so these were capable of about 80 Watts RMS- pretty loud.

I intended to bid on this amp the other night but I got back too late from a school event for my son. I was curious to try one of these out. The amp listed in the auction described the amp as using a pair of EL34 tubes. The EL34 bottles are about the same diameter albeit longer than the 8417's so I assumed the auction description was incorrect. I contacted the seller and he confirmed the power tubes were EL34's. Assuming that is true then the amp had some modifications made to work with the EL34's- not necessairly a bad thing.

I came across a complete Guild Slave Amp & Cab on ebay back in 2001. It was an oddball amp that I later found info on. I didn't buy it at the time and it would have been expensive to ship.

This was an interesting period for Guild amps. Guild was starting to favor rock-n-roll bands in their advertisements but they retained their clean sounding Jazz background in regards to amplifier tone. The operating manual for the Guild Thunderbird and Thunderbass amp describes proper operation as one where you keep the volume lower to prevent unnecessary and unwanted clipping of the output. The literature questions why you would ever want to push an amp to levels of distortion-Guild figured it out a little later but it was too late to save the tube amp line.

Guild eventually abandoned the stand alone slave amp concept for guitar players but later in the 1960's replaced it with an equivalent and more flexibility power concept for bass player. Guild introduced the Thunderstar Bass amp and cabinet series. These heads had a Preamp-Out and Poweramp-In connection on the back of the amp to allow you to use multiple heads to drive other heads and power other cabinets in an "unlimited" manner.

The Preamp-Out/Poweramp-In configuration of the Thunderstar Bass amp sounds similar to modern effects loops on amps today. However there is a difference-the Preamp-Out splits the signal and not re-route it like a modern effects loop. The end result is the Master head always has a power output. This feature, although perfect for Guilds concept means you cannot use this feature as a clean effects loop. (However, I think it could be modified to function as a standard effects loop.)

By the late 1960's, Guild issued a revised version of the Thunderbass - the Thunderbass 1A. This amp included the Preamp-Out/Poweramp-In configuration of the Thunderstar Bass amp. As another point...the Thunderstar Bass amp used 6L6 power tubes and the Thunderbass and early model Thunderbass Quantum used the 8417 finals. I find the 6L6 amps better sounding for guitar applications.

Hope my amp ranting wasn't to long...

M
 

john_kidder

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Damn, Matsickma, I wish I'd known all that when the auction was open. I run two old Roland speakers from the SPEAKER and the AUX output on my Thunderbass. Could have been fun to have a separate amp in-line to one channel. Just getting a Guild-Harte 2x10 cabinet (doesn't have the original aluminum speakers), looking forward to hearing the combination. Also bought a T1-12 a couple of months ago - sounds wonderful at volume, a little ambient hiss, but a malfunction in the tremolo - the tremolo works, but there's a loud "thump" repeating at maybe 2 Hz.

Thanks - you have a great wealth of useful information, and your writing is clear, concise and complete. It's always a pleasure to see your name against a new posting.

Cheers,
 

john_kidder

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And whaddya mean

matsickma said:
(P.A. system is another geezer term!)

Hold on a minute there, young fella. "Another geezer term" - wow. How's that for the old self-esteem? We need to learn, as we get older, to be more compassionate and accepting of each other. Then, as we approach the end, we can mutter terms like "great PA" without worrying about whether or not we'll be taken for "geezers".

Oh, it's a burden, it is, being so old-fashioned. But someone has to keep speaking up for the old ways, or they'll just be lost, won't they? What then of our proud history and our culture?
 

matsickma

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Hi John,

Well I didn't want to comment a lot about the slave amp during the auction for my own self interest. With regards to P.A., well I guess P.A. are still around at raceways, HS and Youth footbal games, etc. The term of P.A. as applied to music venues is past-sound systems and sound-reinforcement now apply.

In regards to the AUX output of the Guild amps...to my ears I notice a difference in amp tone (harmonic distortion) when using a pair of speakers driven from the Speaker Out (i.e., 2-8 Ohm speakers in parallel) verses 1-8 Ohm speaker driven from the Speaker Out and 1-8 Ohm driven from the AUX. This is especially noticable at loud volume.

Now I know their are a variety of reasons like how the amp drives 8 Ohms verses a pair at 4 Ohms speakers. However I have been suspecting the tone differences was due the AUX output expecting to see a higher impedance circuit like that of athe Slave amp instead of a 8 Ohm speaker. The AUX output is not wired in parallel with the speaker Output. It is a different transforment tap.

Do you or anyone else notice the difference in tone between driving speakers from the Speaker Out or from both? I have done experiments , albeit basement tinkering, using a pair of JBL E130's. To my ears there seems to be a difference.

M
 

john_kidder

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Very interesting - helps to explain why it's labelled AUX rather that 'SPEAKER 2" or some such.

My ears are not much good for this sort of thing (lost all my >4K hearing working in mines in the '70s) but I'll play around a little this afternoon with SPEAKER/AUX outputs and try to report back.

Just got the Guild/Hartke 2x10 cab yesterday - that gives the Thunderbass something worthwhile to work with - great big fat sound, presence galore. I'll pop the back of the cab to find out what the speakers are.
 
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