- The original Don Lancaster "Lil Tiger" amplifier (Popular Electronics, Dec 1967 - see < http://www.swtpc.com/mholley/PopularElectronics/Dec1967/PE_Dec1967.htm >) used "recently developed" (at that time) complementary silicon power transistors, so it seems fair to say that the shift to silicon was well under way by mid 1967.
- The "Brute 70" amplifier, published in Feb '67 (see < http://www.swtpc.com/mholley/PopularElectronics/Feb1967/PE_Feb1967.htm >) used all silicon transistors, but the output stage was quasi-complementary so you might assume that silicon PNP power devices weren't yet available to hobbyists in late '66.
- The reverb amplifier featured in Feb 1966 (see < http://www.swtpc.com/mholley/PopularElectronics/Feb1966/PE_Feb1966.htm >) featured germanium PNP's in the output stage, but silicon transistors in the small-signal section.
- The "Bargain Page Amplifier" (Oct 1964 - see < http://www.swtpc.com/mholley/PopularElectronics/Oct1964/PE_Oct1964.htm >) featured an all-Germanium semiconductor complement.
Dale
I suppose you guys are on the wrong side of the pond to remember the OC71
Mister Transistor's Historic Semiconductors
Mister Transistor's Historic Semiconductors
Wow. Thank you very much.
This is consistent with the guitar effects unit circuits I've been looking at from the early 1960s. The hobbyists who recreate these circuits all insist on germanium transistors and I wasn't sure if this practice was just dogma or for authenticity's stake.
The unit I'm looking to recreate has appeared on a couple popular recordings but there are no known surviving units or known schematics ever produced. It was a homebrew device cobbled together by Red Rhodes (a famous tech and pedal steel player) in 1961. He let recently deceased session guitarist Billy Strange use it on an Ann Margret track and even built a unit for Nokie Edwards of The Ventures in 1962.
The only lead in my research of this device came when I discovered that it is rumored to have been copied for use as a built-in fuzz effect for an unsuccessful line of solid state guitar amplifiers designed in 1966. The source for this rumor is Nokie Edwards himself, who also had a hand in the production of these amps.
I found the schematic for these guitar amplifiers and the two transistors used in this effect are two germanium 2N2926 NPN transistors running off a 35V power supply. Trying to reverse-engineer back to the original stand-alone device, I am curious what sorts of transistors may have been used five years prior, running off a 9V battery.
There must be hundreds - perhaps thousands - of web pages featuring DIY pedals and effects boxes for guitars and similar instruments. Many of them claim to provide schematics and background notes of circuits manufactured many years or decades ago, so I'm surprised you couldn't find at least a tangential reference to your unit (e.g., comments such as "this circuit is similar to . . . " or "my project is based on . . . ", etc ).
When I got to looking at some of those old references I was surprised at the sheer number of germanium transistor types that were actually registered. I might have guessed somewhere between 1000 and 2000 types, max, but it looks like there were at least that many in the 2Nxxx series alone - and many long-departed vendors had their own type numbering systems.
If you're convinced that Mr Rhodes created his design using hobbyist parts, then scanning the ads and projects in Popular Electronics, Radio-TV Experimenter, QST etc from that era should give a good idea of what was available to casual hobbyists. On the other hand, in my experience many distributors of that era - though officially "wholesale only" - conducted over-the-counter sales of small lots to anybody who had a sales-tax resellers registration, and sometimes under-the-counter sales to anybody who walked in with money-in-fist. If Mr Rhodes worked for a recognized dealer or repair shop, or simply "knew somebody" in the equipment design business, he may have had access to components that were then state-of-the-art - which would have included early silicon transistors.
But unless he had some training in circuit design I'd make my bet that he used a common type of Germanium PNP, because they had a much more extensive history of successful applications at that time, than the silicon devices did.
Dale
When I got to looking at some of those old references I was surprised at the sheer number of germanium transistor types that were actually registered. I might have guessed somewhere between 1000 and 2000 types, max, but it looks like there were at least that many in the 2Nxxx series alone - and many long-departed vendors had their own type numbering systems.
If you're convinced that Mr Rhodes created his design using hobbyist parts, then scanning the ads and projects in Popular Electronics, Radio-TV Experimenter, QST etc from that era should give a good idea of what was available to casual hobbyists. On the other hand, in my experience many distributors of that era - though officially "wholesale only" - conducted over-the-counter sales of small lots to anybody who had a sales-tax resellers registration, and sometimes under-the-counter sales to anybody who walked in with money-in-fist. If Mr Rhodes worked for a recognized dealer or repair shop, or simply "knew somebody" in the equipment design business, he may have had access to components that were then state-of-the-art - which would have included early silicon transistors.
But unless he had some training in circuit design I'd make my bet that he used a common type of Germanium PNP, because they had a much more extensive history of successful applications at that time, than the silicon devices did.
Dale
Red Rhodes was a very successful session musician, but is most famous for playing in Michael Nesmith's band. Like Bo Diddley and Danny Gatton, I'm not aware of any training in circuit design. It seems likely that germanium was used, though there are "but if's" that won't go away.
Credit for the Lil Tiger should be given Daniel Meyer. Audio's never been Don Lancaster's gig.
Wow. "Si or Ge?" may be the easier part of this task.
Credit for the Lil Tiger should be given Daniel Meyer. Audio's never been Don Lancaster's gig.
Dale, thanks again for such an insightful reply.
My initial thoughts are that I ought to research Mr. Rhodes to try and find out how high a profile he kept at the time (tech, businessman, session guy, etc) to best guess his pool of resources.
Other than that, I'm absolutely certain that's all is known about the circuit I'm trying to reverse-engineer. Despite it's way to insinuate itself into popular recordings of it's time, very few were made and it was never copyrighted. So no surprise as to how it got lost. This is no Maestro FZ-1.
My initial thoughts are that I ought to research Mr. Rhodes to try and find out how high a profile he kept at the time (tech, businessman, session guy, etc) to best guess his pool of resources.
Other than that, I'm absolutely certain that's all is known about the circuit I'm trying to reverse-engineer. Despite it's way to insinuate itself into popular recordings of it's time, very few were made and it was never copyrighted. So no surprise as to how it got lost. This is no Maestro FZ-1.
You are correct - I would correct the attribution in my post, but there's no way to go back and edit it. Both of those men were prolific developers and authors of articles published in the hobby electronics magazines of the 1960's and 70's.
Dale
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