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Looking for a copy of the California-made Thomas-Vox Pacemaker combo amp, version V-1022.
Thanks!
Thanks!
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Vox Pacemaker V1022 is similar to the schematics Vox Berkley II V1081, only that Vox Pacemaker V1022 does not have reverb.
Schematics for Vox Pacemaker V1022 (download to be able to enlarge) is a small sorry, but these will be helpful when comparing with the Vox Berkley II V1081.Attached FilesIt's All Over Now -
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Additional schmematics?
Any chance you have schematics for a SS Cambridge Reverb?
Many thanks,
Paul
Originally posted by vintagekiki View PostComment
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It's All Over NowComment
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CR schematic
Vintagekiki-thanks so much for the prompt reply and schematic! This info is greatly appreciated, I need to study it more carefully to determine the similarities and differences...I am not familiar with this version-something the Korg made? it does appear to have the mid range boost circuit which could be very helpful. Mine is a mid-late 60s Thomas Vox Cambridge Reverb-all solid state, 1x10 speaker, with the 3 button footswitch with MRB. It is in great shape but has a few age/disuse related issues that i am trying to work my way through. If anyone has any additional documents or specific experience with this amp i would be very grateful for any guidance.
Best regards,
paul
Originally posted by vintagekiki View PostComment
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With a little luck may be helpful schematics for Vox Berkley II V1081 (3 button footswitch for MRB, tremolo, reverberation, perhaps poweramp).Originally posted by ihscout2 View Post
Preamp schematics with MRB is similar to the schematics brilliant channel VOX Beatle series.
http://music-electronics-forum.com/attachments/2509d1211666621-vox-super-beatle-v1141.pdf
For schematics from VOX Beatle series as Buckingham, Royal Guardsman see
http://www.el34world.com/charts/Schematics1.php find VOX
Best regards,
vkIt's All Over NowComment
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Definitely not. Thomas Organ. I owned a Cambridge back when I was in my teens and dinosaurs ruled the earth.Originally posted by ihscout2 View Post
Great amps. I regretted selling it for about 25 years, til I found another one. I now have two.
Thomas Organ Vox amps are a kind of mania of mine. I have some advice.It is in great shape but has a few age/disuse related issues that i am trying to work my way through. If anyone has any additional documents or specific experience with this amp i would be very grateful for any guidance.
1. Count on it being difficult to work on without breaking off the interconnecting wires inside. They used solid core hookup wire, stripped with mechanical strippers that nicked the wires. The wires break at the ends of the insulation very easily. Take many digital pictures as you go so you can go back. And be very careful not to bend those wires in raising the PCB any more than you have to, either in the total mechanical bend or number of times you bend them. Raise the PCB *once* and prop it up with cardboard or something and never put it back down to raise it again until you get finished, if you can. Raise it only enough to get to the solder joints on the back of the PCB. Breaking off wires is the single biggest reason service people refuse to work on these.
2. The black wires doing grounding were actually very carefully thought out, and produce a relatively hum-free amplifier if they go back where they came from. Repairs that get some of these wrong is the reason for most hum issues in Thomas Organ Vox repairs.
3. Replace 100% of the electrolytic capacitors. Just do it. The caps are - what, 45 years old now? Even if they work, the are due to fail, and will do so just about a week after you get it working. Replace them all while you're in there.
4. For low hiss, replace the input transistors with modern low noise transistors. I have a list of replacement types on my web site (Geofex.com).
5. If you have to replace the output transistors, don't go buy matched germanium PNPs. You can replace them with silicon PNPs if you rebias by a bit by increasing the values of the 3.3 ohm biasing resistors on the output transistors.Amazing!! Who would ever have guessed that someone who villified the evil rich people would begin happily accepting their millions in speaking fees!
Oh, wait! That sounds familiar, somehow.Comment
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Many thanks for the feedback and advice. I am just digging into this amp now...I think it has great potential and I am looking forward to getting it running again soon. Upon visual inspection none of the caps look bad, just old and dry at this point I guess. I'll let you know how it goes-and I may have a few more questions as well.
Paul
Originally posted by R.G. View PostDefinitely not. Thomas Organ. I owned a Cambridge back when I was in my teens and dinosaurs ruled the earth. Great amps. I regretted selling it for about 25 years, til I found another one. I now have two.
Thomas Organ Vox amps are a kind of mania of mine. I have some advice.
1. Count on it being difficult to work on without breaking off the interconnecting wires inside. They used solid core hookup wire, stripped with mechanical strippers that nicked the wires. The wires break at the ends of the insulation very easily. Take many digital pictures as you go so you can go back. And be very careful not to bend those wires in raising the PCB any more than you have to, either in the total mechanical bend or number of times you bend them. Raise the PCB *once* and prop it up with cardboard or something and never put it back down to raise it again until you get finished, if you can. Raise it only enough to get to the solder joints on the back of the PCB. Breaking off wires is the single biggest reason service people refuse to work on these.
2. The black wires doing grounding were actually very carefully thought out, and produce a relatively hum-free amplifier if they go back where they came from. Repairs that get some of these wrong is the reason for most hum issues in Thomas Organ Vox repairs.
3. Replace 100% of the electrolytic capacitors. Just do it. The caps are - what, 45 years old now? Even if they work, the are due to fail, and will do so just about a week after you get it working. Replace them all while you're in there.
4. For low hiss, replace the input transistors with modern low noise transistors. I have a list of replacement types on my web site (Geofex.com).
5. If you have to replace the output transistors, don't go buy matched germanium PNPs. You can replace them with silicon PNPs if you rebias by a bit by increasing the values of the 3.3 ohm biasing resistors on the output transistors.Comment
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RG, I greatly appreciated your response and advice to my post about CR questions and I am sorry to bother you again, but I have finally found some time to start working in this amp and have run into an unanticipated problem already...I ordered a full set of electrolytic caps from Mouser to replace the old ones and was going to work my way through one by one to understand better which components were causing problems and to minimize problems troubleshooting if something should go wrong...unfortunately I got stuck at number one. My amp was somewhat functional when I acquired it (all controls and functions worked except for the mid boost/shift as far as i could tell) but sound was distorted and crackly with bad hum. I removed and hollowed out the main filter cap 5000MFD/35V and replaced it by putting an axial lead 5000MFD/50V cap inside the old can. Unfortunately, when i fired up the amp again to test this repair I got no sound and perhaps a smell/ hint of something over heating but don't see anything "wrong". Voltage across the cap after the swap was ~32V. I was very careful druing this swap and did not break or disturb any wires or connections-this was a minimally invasive effort. Any thoughts or suggestions would be greatly appreciated.
Best regards,
PaulComment
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