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Solid State Amplifiers => Amplifier Discussion => Topic started by: Jack1962 on October 27, 2008, 04:58:22 AM

Title: A bit of Amp HIstory
Post by: Jack1962 on October 27, 2008, 04:58:22 AM
I found this while cruising the web this morning.

History of the Guitar Amp:

As with the Electric Guitar the origins of the guitar amp aren’t really known. The first guitar amp was probably a hi-fi or pa amplifier. The transistor hadn’t yet been invented. Rickenbacker and Gibson started making guitar amps in the late 30’s. Gibson had a model that was meant to be sold with the ES-150 which was their first hollowbody electric. This was in 1937 where it appeared in the Gibson catalogue. Rickenbacker is known to have manufactured their first electric guitar in 1932 but there is no mention of an amplifier to go with it. When they and Gibson started manufacturing amps they were based on the current amps used in radio and hi-fi amps.

Fender got in to the act in the mid 40’s (1945) with the company was still called K&F Manufacturing. They were also very simple amps and didn’t have any controls (volume or tone). You used the guitar’s volume and tone controls. It wasn’t until after the aliens landed at Roswell J (1947) that Fender introduced their first amp. It still didn’t have any volume, and tone controls. It was the Model 26 which used a 6V6 and Jensen speakers. The transformer was actually mounted onto the speaker rather than inside the amp housing. The first guitar amp with a volume control was the Fender Champion 600. These amps where beginner’s amps (similar to the Champ Amp of today) and used a single 6V6 output tube. Also in 1947 Fender introduced the Dual Pro which had two channels and two volume controls (one for each channel) and a single tone control. These amps where used for the pedal and lap steel guitars as well as hollow and solid body electrics.

In the early 50’s Gibson introduced the Les Paul Amp which used the 6L6 output tubes. It was also of a similar designed to that of the Fender which was based upon the RCA tube application manual. The demand for louder amps came around this time as well. Fender responded with the Tweed Series of amps and most notably the Fender Bassman. These amps had more tone controls (treble, middle, and bass) as well as a Presence control and found the use of the now very popular 12AX7 and 12AY7 preamp tubes. These tubes allowed the amps to have more tone variation than any amp. With the Tweed amps you found one of the first uses of ‘Vibrato’ (modulating pitch changes) and ‘Tremolo’ (modulating volume changes). Each of these functions further advanced the sound of guitar amps.

Vox introduced the AC15 in 1956 which was the first amp to use a class ‘A’ design. The Fender and Gibson amps all where class ‘B’. The Vox amps even though only had 15 watts or so where loud and sounded great when turned up (distortion). They became the amp of choice for England guitarist mainly because Fender amps cost too much. The Beatles for instance used Vox Amps quite extensively. Some of the more important Vox amps are the AC30, AC50, as well as the AC100. The number was the amount of watts the amps put out. There was one great Vox amp called the Vox AC30TB. The TB meant Top Boost which it had because of the addition of an extra tube.

The 1960’s found the guitar amp in even more demand with the start of Rock-n-Roll. Fender introduced there famous BlackFaced amps. These amps were known for their great tone and reliability. These amps are the first Fenders where the controls of the amp are on the front panel instead of the top panel. The Fender Tweeds, Gibsons, and Vox amps all had their controls mounted on the top of the amps so the guitarist could clearly see the amp settings. This change to move the control knobs to the front of panel probably came from the amps being louder. With the amp being louder caused the guitarist to be located further away from the amp. This meant that they couldn’t see the controls if they were on top of the amp. So they got moved to the front. From what I can find out is the Fender VibroVerb was the first amp to have a spring reverb. Gibson had around the same time as this something called a Maestro EchoPlex. The EchoPlex was the first tape delay system that used a ¼ inch tape to record the guitar and then delay it and then play it back. This could be used to create a not so convincing reverb effect.
Title: Re: A bit of Amp HIstory
Post by: teemuk on October 27, 2008, 10:52:36 AM
Few points…

G.D. Beauchamp, one of the leading figures in early steps of Rickenbacker, actually held a patent that featured the circuit diagram of the first amplifier dedicated solely to guitar amplification. It was filed in 1934. I’ve even seen photos of such an amp that was built in 1932.

Also, pretty much every amplifier from the early days (whether it was in a radio,PA or guitar amp) was based on datasheets and application notes of manufacturers. Like today, such examples boosted the sales of products and for the same reason it was also common that manufacturers even allowed to use their patented designs. (Pretty much every  circuit in a generic vintage guitar amp was patented by some major company). Papers from companies such as Mullard or RCA have been the base for thousands of amplifiers. Just check out every vintage Fender, for example: To early 60´s these amplifiers included prints that told what patented circuits they used.

This type of engineering still continues today. New products come up, engineers study their datasheets and often replicate the presented circuit with minor modifications. Most of those are made due to fact that datasheet circuits are often sketches that omit some stuff just for simplicity’s sake.

Vibrato and tremolo date back to early organ designs, in which they appeared way before guitar amps. First tremolos actually were electromechanical devices.

I believe that tweed Fenders didn’t really have very complex tone controls. You don’t see such in Fender amps before the late 50’s, whereas you can find examples of Gibson amps dating back to times before WW II that have rather complex tone controls. The generic treble-mid-bass tonestack circuit appeared in (I think) the late fifties or early 60's – about the same time in both Fender and Gibson amps. It is highly questionable who invented it in the first place. I’m inclined to believe that the circuit actually was not invented by the guitar amp companies at all.

The claim of Vox AC15 being the first class-A amp is totally incorrect. Even Fender champ was introduced before it (actually, something like ten years before it) – and I’m quite sure there are many guitar amplifiers we just are unfamiliar with that were class-A even before the Champ.

Standel claims to be the first company to use front-mounted controls. I’m more inclined that they were the pioneer of this configuration, rather than Fender – which usually just copied the designs of other amps after they were proven successful. You can study history of Fender (both amps and guitars) and you’ll find that it becomes quite questionable to whether they actually were as innovative as they first seem to be. Sure, they made fine amps and guitars and popularised a lot of features – but they didn’t really invent most of them.

Controls didn’t really move their place due to loudness. It had to do with stage setup: Big bands and jazz artists traditionally placed the guitar amps in front, pointed to the audience. The guitarists then sat behind them. When the style of playing guitar evolved to that of rock-n-roll (the band was standing and more “in front”) guitarists began to place the amps behind them. Getting loud wasn’t really an issue before the 60’s.

Vibroverb also wasn’t the fist amp with spring reverb. I believe Ampeg introduced Reverbercoket before it. Fender might have had a spring reverb unit before Ampeg’s product. Nevertheless, spring reverb where used in organs and they date back to phone technology. Guitar amps were about the last devices to use that innovation.

I don’t know where you found this text but its author really should have done more background study.
Title: Re: A bit of Amp HIstory
Post by: Jack1962 on October 27, 2008, 04:35:01 PM
It was a GENERAL history , in the first place , and for your info teemuk ALL TUBE AMP CIRCUITS are designed around the western electric design considering the fact the built the first tube usable for audio amplification(and every other circuit that has followed since is based on it as well. If you want to get down to it  with  electronic history son I can go there , I have my degree and time in as well. that was just something I found online we all know about how accurate the facts you find online are.

                                    Rock On
Title: Re: A bit of Amp HIstory
Post by: teemuk on October 27, 2008, 04:56:53 PM
I don’t know why you took so personally the few points I wrote about the obvious errors in the article. I know the article was about generic history but if I, say, wrote an article about World War II and told that it took place in 1955 – 1978, and made a lot of other errors as well, I bet people would jump in and correct them. History, after all, has a lot to do with accurateness of the information.

I realize that it’s not you making the error, though – you just quoted the article here and I have to admit it’s pretty entertaining and enlightening in its own right.

And if you want to get down to electronic history I’m all ears. From what I figured, you have a lot of years under the belt working with amps and other electronic stuff. If you have stories to share – please do so.
Title: Re: A bit of Amp HIstory
Post by: gbono on October 27, 2008, 09:33:45 PM
If you want to get down to it  with  electronic history son I can go there , I have my degree and time in as well.

Okay, I'm waiting for the history lesson...............
Title: Re: A bit of Amp HIstory
Post by: Jack1962 on October 29, 2008, 03:17:32 PM
If you want to get down to it  with  electronic history son I can go there , I have my degree and time in as well.

Okay, I'm waiting for the history lesson...............

What amp do your want to know about , lmao-if I can remeber anything about it I'm more that willing to share the info.
Title: Re: A bit of Amp HIstory
Post by: teemuk on October 29, 2008, 05:50:15 PM
If you allow me to make a request (for you, as well as for anyone possessing some info), I’d like to know about...

Risson amplifiers by Robert “Bob” A. Rissi. More particularly, the Risson amps from the early 70’s that supposedly were solid-state. E.g.

And maybe the one at the top in:

I know the man’s history with Rickenbacker and Fender but his website isn’t too informative about the amps he began to make when he established his business. The later ones seem to be run-off-the mill tube boutique amps and I can’t say that they would interest me too much. The early ones on the other hand… they don’t look as ordinary.


At present, the history of modelling / “computer amp” designs interest me a lot. For example…

Delta Products. I’ve seen the brochures of the Concept model – which sort of was a forerunner of amp modelling - and if I remember right Harvey Gerst from Acoustic Control was a member of its design group. But surely this company must have existed before that as well – especially considering that the Concept model wasn’t a commercial success.

ADA. Man, this company had some great and innovative products, yet all information about them seems like vanished from the face of the earth. ADA Depot has some pics and schematics but there are no historics whatsoever.

Hughes & Kettner. The Stamer brothers and Bernd Schneider made a notable debut with AS 64 in 1985. We all know the present state of the company too. What happened in between?

TUSC. Supposedly Qualtrol Electronics, the same company that worked as a subcontractor for Earth Audio Research, made these. Their Prestige series were hybrids with digitally controlled- interface and supposedly they were the first amps that featured presets that could be stored to memory. How is it that so little is known about these today?

And just to make it clear: I don’t really care about opinions how these amps sounded like. That’s pretty subjective. Essential is that quite a many of their products seemed to be rather innovative and therefore they have historical importance.

I guess the history of DSP and signal processing goes hand in hand with this stuff. So basically, the research about this subject should be extended to makers of rack processors and effects units, as well as floor pedals and early guitar synths… There isn’t much written about these. For example, it’s quite hard to find some info about the early days of companies like Rocktron or Alesis. I appreciate if someone could point me to some reasonably extensive reference about this subject.

Other companies of interest….

KMD. They endorsed Bon Jovi and had some design with overdriven CMOS logics. But what’s the story of the company?

Ovation. Any solid state amp from 1969 that looks like this has got to be interesting:
I know Ovation guitars but what’s the story with their amps?

H||H. All that people seem to know about this is that one of its founders was Mike Harrison and that the company made amps and other equipment (locations of factories are quite well-known). There is even a dedicated website for these, yet the information on it is very shallow (few pics and scans of brochures and almost nothing about the history). Their equipment was super popular in 80’s. How is this complete lack of knowledge possible again?

SG Systems from CMI-owned Standel. What's the story behind them?

Sonax: The collaboration of Baldwin and Yorkville Sound (Traynor). What happened?
Title: Re: A bit of Amp HIstory
Post by: Jack1962 on October 30, 2008, 05:17:19 AM
lol-ok I'll see wht I can dig up, The Risson, I have worked on 1 but it was the tube unit nothing unusual really. I"ll let you know what I find in my dusty old file cabnets , and what I can remeber about these units.

                                       Rock On
Title: Re: A bit of Amp HIstory
Post by: Jack1962 on November 02, 2008, 01:21:57 PM
Bob Rissi (Risson Amps) and Kaufman work at fender around the same time , if my memormy is correct. This makes it real hard to say who designed what. I have heard that the Solid State Champ was Rissi's , but to be honest the only thing of his I know much about are the tube amps he has done and the  Rickenbacker Transonic(I still have 1 of these). Rissi possible  designed  most of the Rick solid state amps the design is very simular in all of them. The tube amps he has done the guitar amps sound like Marshall clones and the Bass Amps sound like Ampeg clone IMHO.
     The modelling question I really can't give you any insight on , I just don't work on them , if you wanyt it to sound like a Fender, Marshall, Mesa , buy those amps.

      The Hughs & Kettner , what happened was they started selling trash, I have made thousands for dollars repairing there design errors(keep'em coming H & K).

   out of time I have to get back to work for now , I will continue when I can.

                                          Rock On
Title: Re: A bit of Amp HIstory
Post by: Enzo on November 03, 2008, 10:06:10 PM
KMD - unless there was more than one KMD, we are talking about a division of Kaman - as in Kaman Music Division or something like that.  Kaman is mainly a distributor, so I have no idea who made their KMD line.  COntact them and ask.

We were a service center for them back when they distributed TraceElliot, Dean Markley, and KMD amps.
Title: Re: A bit of Amp HIstory
Post by: Jack1962 on November 07, 2008, 03:44:18 PM
lol- I think Kaman sold it's music division to Fender 10 or 11 years ago.
lmao-Fender or Gibson owns just about all of the smaller compamies these days.

                                      Rock On
Title: Re: A bit of Amp HIstory
Post by: Enzo on November 08, 2008, 12:00:47 PM
I guess it has been awhile, April 1995 according to my warranty listings file..  At the time they sent us this schematic set:

MC Mixers
Title: Re: A bit of Amp HIstory
Post by: thekon on November 12, 2008, 10:18:00 PM
jack1962,  i've been lurkin here awhile,  what are some of your favorite ss amps?
Title: Re: A bit of Amp HIstory
Post by: Jack1962 on November 14, 2008, 12:35:38 PM
I would have to say the Valvestat, and just about all of the Peavey equipment, there are tons of great SS amps. The one I still have and use the most(mostly in my shop to mess with the guy's) is my old Peavey Stereo Chorus 400.

                                   Rock On