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Devin, Ya, after I told you to Google "Klangumwandler", I tried it myself. I guess I have way too much faith in the Internet. :) It seems as if the Klangumwandler that Wendy Carlos mentions and Moog built and was designed by Harald Bode, may have been an entirely electronic device. Nowhere on the Internet was I able to find any mention of a "rotating tape head pitch shifting device". Yet I have a very clear memory of reading about it back in the late 70's. I thought that I read about it in "Source" magazine, though I could be mistaken. Even though I've never seen one, the discription that I read was so clear in my mind, I feel that I could build one myself just from the memory of how it was described. Basically, it is a rotating disk about 3" diameter with the four tape heads located in an X pattern, 90 degrees from one another. This disk is set in motion by a reversable motor, allowing variable speeds and directions. You are correct in assuming that you'd have to have carbon brushes on the rotating disk to transfer the electronics up into the wiring harness, I don't see any way around that. My thoughts are that this device was used in the 50's and 60's back in the days of the classic electronic music studios. Dr. Zvonar are you there? As far as keyboard control of tape speed, I have seen two track studio decks with a digital readout of the percentage of pitch shift with increase or decrease of motor speed. This one went up to an octave in either direction. I believe it was an Ampeg, though don't quote me on that one. Stephen <<<Thanks Stephen for the post about the "klangumwandler." I appreciate you chiming in, particularly because I had seen a picture of one of these in a book ("How Things Work," a sort of multi-volume scientific encyclopedia published in the 60's some time), where it was described (though not named) as a device used to alter the pitch of a sound without altering its playback speed. I had a bit of trouble understanding how that might work. And since they didn't really give any more information than that, I figured it a dead relic of the tape music days, something that maybe never worked quite right anyway, or was way to expensive/hard to build. <<<I would really appreciate some more info anybody out there has any. The only stuff I seem to turn up on google is lots of Wendy Carlos stuff and a few very casual mentionings of the work klangumwandler. Do you think this would be tricky to build? The one I saw in "How Things Work" looked like a detachable or retrofit unit. It seems that one would have to come up with some kind of a circular "railroad track" kind of brush that the contacts for head could ride in, otherwise, your wires would be twisting around with the 4 tape heads, and would snap pretty quickly. This is the same problem I ran into when I was trying to build my own leslie speaker years back. Everything was simple enough but the contacts for the speaker that actually spins. I wound up just pirating a cheapy foam-baffle leslie out of a Thomas organ and building a box for it. It does sound good, but not quite the real thing. <<<Anyway, back to tape music stuff, any info out there would be much appreciated. In particular, I would like to know sort of what it sounds like. Any recordings to check out with obvious klangumwandler usage. If this thing is as cool as it sounds, though, I would love to build such a device. I am hoping not to simply build a cut and dry delay machine, but something a bit different, drawing from different sources and musical posibilities. It would be great to have a combination tape delay/looper/klangumwandler/reverb box. <<<Another idea I had, (more along the lines of pipe dreams) would be to build a small keyboard controller for the motor speed of the unit. I remember reading about one design that used kind of a derralieur system or maybe belt drive with ramped tensioning sprockets (ala continuously variable transmission) to change pitch/speed of a tape machine at music intervals. I thought motor speed would be easier to manipulate, but alas, there is probably not enough workable voltage range to be able to get much more than an octave or so. Of course, it would be monophonic too, unless you looped it! -Devin __________________________________ Do you Yahoo!? Yahoo! Mail - Helps protect you from nasty viruses. http://promotions.yahoo.com/new_mail