Jimi Hendrix' Gear and Mods at West Coast Organ and Amp

[daveweyer]

About the tube modulator:
This is the device I was working on during 1969 for the new world of tonal effects which were popping up in inventors' garages everywhere around Los Angeles at the time. I was trying to add a new dimension to the guitar player tonal pallet. It is one of the sounds you probably would have heard had Jimi lived and West Coast Organ and Amplifier Service survived. You might even be building clones of it today.

The original concept was patented I believe in 1959 by the Baldwin Organ company, and its purpose was to provide an electronic simulation of something known as the string celeste stops on a pipe organ. I came across it when I was a traveling service rep for the company and became infatuated with its possibilities.
Basically what it does is add and subtract multiple frequencies from a waveform which is input from an electronic source. Specifically, it has four phase shift oscillators, running at 1, 2, 4 and 8 cycles per second. These frequencies are added and subtracted from divided frequency bands of the originating signal, raising and lowering the pitch by that amount.

What I discovered about the unit was that Baldwin had neglected the possibility of dividing the signal into two, a modulated signal and an unmodulated signal, and then acoustically mixing them together in a room through two amplifiers, also slowing down the phase shift oscillators to widen the pulses as required for the spacial effect.
I had also built in a special preamp for guitar to bring the signal up to levels sufficient to drive the circuitry.
You can see that stage by the Allen Bradley pot. The capacitor banks are on the sides of the unit lined up on perf boards--it takes a lot of capacitance to make a phase shift oscillator run at 1 HZ or 1/2 HZ, and you need three caps for the three poles in each oscillator.

Anyway, the spacial effect is just out of this world psychedelic, and the feedback from a guitar moves constantly from one harmonic to another--it will actually play itself.

It is one of many projects which were on the bench at West Coast Organ And Amp Service, and would have entered into the world of the rock guitar gods had things gone the way we planned. These are the things that time cheated you out of hearing, and you never even knew.

I hope I'll get time to post a clip of Jimi playing through this thing, I can only imagine you would like that.

[shakti]

I hope I'll get time to post a clip of Jimi playing through this thing, I can only imagine you would like that.

!!!! You mean you have a recording of Hendrix playing through it???!!

[peter25]

I hope I'll get time to post a clip of Jimi playing through this thing, I can only imagine you would like that.

!!!! You mean you have a recording of Hendrix playing through it???!!

All I can say is YES please! Awesome thread btw. Been lurking here forever, but now I get up and first thing I do is check this thread for new info. It would be a shame if all this knowledge would get lost over time. Please keep the info coming.

[mathd]

I hope I'll get time to post a clip of Jimi playing through this thing, I can only imagine you would like that.

!!!! You mean you have a recording of Hendrix playing through it???!!

All I can say is YES please! Awesome thread btw. Been lurking here forever, but now I get up and first thing I do is check this thread for new info. It would be a shame if all this knowledge would get lost over time. Please keep the info coming.

Haha, yep, every morning i get directly to this topic .
The davophone?(if that is the real name) and hendrix playing it? omg. can't wait to see how it sounds like(especially with hendrix playing it).

[mathd]

I hope I'll get time to post a clip of Jimi playing through this thing, I can only imagine you would like that.

!!!! You mean you have a recording of Hendrix playing through it???!!

All I can say is YES please! Awesome thread btw. Been lurking here forever, but now I get up and first thing I do is check this thread for new info. It would be a shame if all this knowledge would get lost over time. Please keep the info coming.

Haha, yep, every morning i get directly to this topic .
The davophone?(if that is the real name) and hendrix playing it? omg. can't wait to see how it sounds like(especially with hendrix playing it).

[daveweyer]

Yeah I have a recording of Jimi playing through it, SOMEWHERE................
There are thousands of tapes here so this may take a while, and no most of the tapes are not Hendrix.

[Tone seaker]

I was just looking at the Woodstock DVD the second one that is video bootleg and it shows the cabs Bill Cox is playing thru with 50 watt heads behind Mitch are Bass Cabs

[yladrd61]

You guys are talking about tone and the Univibe affect on it. I use a Deja Vibe that is supposed to be just like the Univibe. What do you guys think about it? Have any of you tried it or compared it to others?

I have the KR Mega Vibe, Sweet Sounds Mojo Vibe, and Fulltone Mini Deja Vibe, they all sound good but the KR works the best with my rig

[yladrd61]

Very honored to display this amazing invention from Dave, for him. The Davophone ! Tube modulator.
it sounds like a terrific project that unfortunately we didn't hear in the hands of Jimi Hendrix.

Dave ? please, can you tell us the story of this amazing machine ?

My 1970 Super Lead had 1500 Ohm 10 Watt Screen Resistors that looked exactly like those long green ones on your device... It also had 7027A power tubes in it when I got it...

PS: Do you still have that device and does it still work ?

[mmp31]

Yeah I have a recording of Jimi playing through it, SOMEWHERE................
There are thousands of tapes here so this may take a while, and no most of the tapes are not Hendrix.

Yeah, that needs to happen. Do you have schematics of the Tube Modulator you'd be willing to share? Eh? Eh?

[frenchie]

Ok ... Now i think we can call it a day on the 6550 debate ...
Complete analysis here ;
big link;
http://www.partage-facile.com/PEJYGV06C ... s.pdf.html
short link;
http://paf.im/Objl4

if you cannot download it ( shit happens ! ) , just pm me i'll mail it to you ....

[daveweyer]

Yeah I've still got the tube modulator and it works well. I just took the pictures the other night.
I'm working on getting you a chance to hear it.

Interesting about the long green resistors, I often used those in amp mods or repairs. I never used 7027s in Marshalls, but I did in Fenders. Sweet sounding tube. Better look for a West Coast sticker on your amp!

Haven't seen Frenchie's video, is it positive evidence or negative evidence?

Second try on this post.

[frenchie]

Haven't seen Frenchie's video, is it positive evidence or negative evidence?

It's not a video dave , it's a pdf i made ... After calculations shown in this pdf i came up with the width of the tube in front of the shiny transformer cover of the first of the daisy chained plexis , i confirmed mathematically at 99.99% that the tube is a big bulb 6550 ....

i uploaded the pdf to show the method i used , so that anyone with any remnant of doubt can do the calculuses by themselves ...

[Xplorer]

Frenchie, that's cool !

i wish i could see your pdf but the website you choosed doesn't let me download it, and it opens commercials.
please, can you post it on something like wetransfer or Google drive ? thanks !

[Xplorer]

oh ! i finaly managed to get the pdf. wow !!!! Thales certainly never imagined he would help our quest

i see that you managed to calculate, chapeau ! bravo !
if it can help, i improved the visibility of the tubes :

http://i.imgur.com/2A29Xh6.jpg