Fundamental extractor

[StephenGiles]

I've been saying it for years now, and found this extract from an interview with Howard Davis, chief engineer with EH in the late 70s.

HD:  I’d say the most popular is the Memory Man. I didn’t design the first delay stompbox with this name, but in 1977 I re-engineered it with such a substantial improvement in performance that it just took off - it was hard for the company to keep up with the demand. I’m also proud of my Deluxe Octave Multiplexer. The hardest part of that design was the fundamental extractor - the circuitry that locks in on the fundamental, or basic pitch, of the note being played. Before my work the existing products of this type had a tendency to “yodel,” to jump up an octave and then back again. I came up with what may still be the best analog fundamental extractor circuitry ever used in a stompbox. Once you have a good fundamental extractor, synthesizing the suboctaves is easy. I also like my Ambitron, but that was designed for the audiophile market, not really in EH’s primary area of interest.

What did I tell you!
Stephen

[puretube]

gotta love fundamental extractors...
soon to be posted here: nice tube-versions...

[David]

gotta love fundamental extractors...
soon to be posted here: nice tube-versions...

...which can then be emulated with JFETs?  Oh, cool!

ROG, are you listening? :mrgreen:  :mrgreen:  :mrgreen:

[puretube]

bet they`re busy (like others, too),
emulating pentodes behaviour
with 3-legged bugs  :wink:

[ExpAnonColin]

(Scrambles for Octave Multiplexer schematic, but comes up with nothing)

...help?

-Colin

[StephenGiles]

I'll post it later - I'm sure I've posted it before.

[StephenGiles]

Here is my drawing of the fundamental extractor which appeared in both the EH Guitar synth and the deluxe Octave Multiplexer, for which I can't lay my hands on the circuit right now.


The PNP transistor with incomplete value is 2N5087
Stephen

[StephenGiles]

Found it!
http://img.photobucket.com/albums/v317/StephenGiles/EHdeluxeOctave2.gif

Of course the EH1048 are CA3094. The power supply seems to be slighly chopped off at the bottom

Stephen

[puretube]

lotta nice stuff comes from Cincinnati/Ohio:
http://www.pat2pdf.org/patents/pat3538806.pdf

[gez]

I can't keep up Ton!  No sooner do I print off one patent when you link to another!! 

I haven't even got round to reading any of them yet.  Slow down!! 

[puretube]

C`mon! that one has been out there for 35 years...

(can make a nice gateing-free fuzzbox out of it...)

btw: can you imagine how much time people ( ...) spent @ the P.O.
before "wwww", just searching according to classification numbers??


and: anybody ever wondered that I never post patents younger than 20 years?
(it`s not that "they don`t make`em anymore"...)