Westrex 3DII cutting head on ebay for a measly...
all the best!
- tommie 'plan 9' emmi
poly-cut lathe cuts / cymbalism recordings
- tommie 'plan 9' emmi
poly-cut lathe cuts / cymbalism recordings
- dietrich10
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- Aussie0zborn
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I think perhaps this Westrex cutter head has been modified for use with helium to cool the drive coils. The later Westrex cutter head, the 3-D 2AH was sold to use with helium in cutting. Thus the letter H, for helium after the model number of the cutter head. I believe this is to be correct after reading this from my Westrex product brochures.
- Aussie0zborn
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From what I've read here and elsewhere, the reason for helium is that it is a better heat conductor than air. Considering that the Westrex 3DII head with the 1700 amplifier was originally designed to run without any sort of forced gas cooling (and the gas line is an upgrade to an already successful design), my guess is that use with any gas (or none) would be fine. But we'll find out. How much is a coil replacement again?
- petermontg
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could you not put a fuse in the link from rack to head to minimise blowing a coil. Am sure with both cooling and fuse your chance's of blowing a coil are very slim.audadvnc wrote:From what I've read here and elsewhere, the reason for helium is that it is a better heat conductor than air. Considering that the Westrex 3DII head with the 1700 amplifier was originally designed to run without any sort of forced gas cooling (and the gas line is an upgrade to an already successful design), my guess is that use with any gas (or none) would be fine. But we'll find out. How much is a coil replacement again?
Peter Montgomery
+353(0)894926271
peter(at)petermontgomerymastering.com
Stereo cutter head wanted. Send email or smoke signals.
+353(0)894926271
peter(at)petermontgomerymastering.com
Stereo cutter head wanted. Send email or smoke signals.
Perhaps you're right, but due to the feedback network in the 1700 electronics, an open circuit to the record head can cause other problems. Today, while doing machine setup, I smoked both the Westrex 1703 record coil power amps by inadvertently applying high amplitude sweep waveforms from my generator ( of course the manual warned us about how touchy the amps are, but did I listen?)
"What's that smell - and why is the ammeter reading negative current?" SNAP - Pooffffff..........ssssssssssssssssssssssssssss!
"Ooh, no, I didn't... Criminy."
Ah well, chalk up one to experience - at least the record head coils weren't damaged. I can fix electronic gear, if I can find the parts, but ...
Do you know how hard it is to find modern replacements for 1970's era transistors? I'm looking all over the Internet for MPSU04 driver transistors, and so far my only leads are to a couple NOS pieces here and there. I hadn't counted on parts shortages.
"What's that smell - and why is the ammeter reading negative current?" SNAP - Pooffffff..........ssssssssssssssssssssssssssss!
"Ooh, no, I didn't... Criminy."
Ah well, chalk up one to experience - at least the record head coils weren't damaged. I can fix electronic gear, if I can find the parts, but ...
Do you know how hard it is to find modern replacements for 1970's era transistors? I'm looking all over the Internet for MPSU04 driver transistors, and so far my only leads are to a couple NOS pieces here and there. I hadn't counted on parts shortages.
Last edited by audadvnc on Tue Feb 07, 2012 8:15 pm, edited 15 times in total.
I think compressed air would have a good bit of moisture in it too. You would need a special compressor that removes moisture. Don't think I would want damp cutterhead.
Cutting, Inventing & Innovating
Groove Graphics, VMS Halfnuts, MIDI Automation, Professional Stereo Feedback Cutterheads, and Pesto 1-D Cutterhead Clones
Cutterhead Repair: Recoiling, Cleaning, Cloning of Screws, Dampers & More
http://mantra.audio
Groove Graphics, VMS Halfnuts, MIDI Automation, Professional Stereo Feedback Cutterheads, and Pesto 1-D Cutterhead Clones
Cutterhead Repair: Recoiling, Cleaning, Cloning of Screws, Dampers & More
http://mantra.audio
- petermontg
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Fuse will leave your loop open/closed. It won't change you loop. If you just place it on one of the wire into the cutter head after all racks, will act as circuit breaker. Give Len/Dan a shout about Westrex gear and where to find what http://www.hrsrecords.com/audadvnc wrote:Perhaps you're right, but due to the feedback network in the 1700 electronics, an open circuit to the record head can cause other problems. Today, while doing machine setup, I smoked both the Westrex 1703 record coil power amps by inadvertently applying high amplitude sweep waveforms from my generator ( of course the manual warned us about how touchy the amps are, but did I listen?)
"What's that smell - and why is the ammeter reading negative current?" SNAP - Pooffffff..........ssssssssssssssssssssssssssss!
"Ooh, no, I didn't... Criminy."
Ah well, chalk up one to experience - at least the record head coils weren't damaged. I can fix electronic gear, if I can find the parts, but ...
Do you know how hard it is to find modern replacements for 1970's era transistors? I'm looking all over the Internet for MPSU04 driver transistors, and so far my only leads are to a couple NOS pieces here and there. I hadn't counted on parts shortages.
Peter Montgomery
+353(0)894926271
peter(at)petermontgomerymastering.com
Stereo cutter head wanted. Send email or smoke signals.
+353(0)894926271
peter(at)petermontgomerymastering.com
Stereo cutter head wanted. Send email or smoke signals.
- Kiss the Groove
- Posts: 24
- Joined: Tue Jan 31, 2012 11:42 am
audadvnc,
The NTE replacement for the MPSU04 is their NTE190. Here's the data sheet. It reads identically to the MPSU04. $16.60 at Mouser.
I wasn't so lucky -- back in the 70's when my boss and I were calibrating a brand-new SC-2 at A&M records, I stupidly turned the test oscillator frequency decade switch the wrong way. A full-power 10 kHz screech filled the room for a few seconds before I figured out what I'd done. Too late. The varnish on both coils was bubbled, and they had to be rewound.
After that, I didn't try to do that stuff at the end of a 10-hour workday anymore.
The NTE replacement for the MPSU04 is their NTE190. Here's the data sheet. It reads identically to the MPSU04. $16.60 at Mouser.
I wasn't so lucky -- back in the 70's when my boss and I were calibrating a brand-new SC-2 at A&M records, I stupidly turned the test oscillator frequency decade switch the wrong way. A full-power 10 kHz screech filled the room for a few seconds before I figured out what I'd done. Too late. The varnish on both coils was bubbled, and they had to be rewound.
After that, I didn't try to do that stuff at the end of a 10-hour workday anymore.
Peter and KTG, thanks for the leads. I did find the needed parts around the WWW, but will keep the NTE190 in mind if ever I blow up the Motorola parts I'm getting in. As you recommend, I will be fusing the drive coil leads, at least until I'm done getting the machine back up and aligned. A cooked $15 transistor is a minor annoyance - a blown cutter head is a big deal.