Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tdvt on March 18, 2023, 01:55:56 pm
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I have only recently been drawn into the Magnatone pitch-shift vibrato quest after watching a few videos with the new Twilighter stereo, then working backwards to the originals.
I can totally understand the attraction to that sound as compared to other types, though each has it's place. I have 2 Fender-types covered already (Showman harmonic & Princeton bias-vary) and also have a Gibson GA8-T.
Basically, I would like to build one of the pitch-shift circuits into a future project.
After all the information overload (unobtanium varistors, LFO variations, voltages, etc.) I am wondering where things sit with replicating the circuit with available components, as the new Magnatone is doing?
I looked over the new Twighlighter vibrato schematic included in one of the Magnatone mega-threads which looks somewhat stripped down compared to the old ones.
(https://el34world.com/Forum/index.php?action=dlattach;topic=27260.0;attach=90518 (https://el34world.com/Forum/index.php?action=dlattach;topic=27260.0;attach=90518))
Besides buying $$$ old stock, it was said somewhere in my internet travels that the new Magnatone had the old style varistor being remanufactured, somewhere else stated that someone was using modern metal oxide varistos with success & somewhere else stated that those are ill-suited/bad sounding. HBP even had a post somewhere about the possibility of adapting a Vactrol to the application.
Lots of conflicting information (can you imagine..?) & much of the stuff I read was 6-7 years old, so I am wondering if there is anything newer happening that people have had good results with?
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There was good thread on TAG a few years ago about making varistor substitutes that would work in Maggies. Can't remember who started it. Mr Manning perhaps.
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There was good thread on TAG a few years ago about how making varistor substitutes that would work in Maggies. Can't remember who started it. Mr Manning perhaps.
Thanks, I know I skimmed that & have it bookmarked.
I'll go back & dig deeper.
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... HBP even had a post somewhere about the possibility of adapting a Vactrol to the application. ...
Beware that was an idea I never tested out. I don't know how well it would actually work.
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There was good thread on TAG a few years ago about how making varistor substitutes that would work in Maggies. Can't remember who started it. Mr Manning perhaps.
What is TAG?
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There was good thread on TAG a few years ago about how making varistor substitutes that would work in Maggies. Can't remember who started it. Mr Manning perhaps.
What is TAG?
The Amp Garage
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Thanks
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... HBP even had a post somewhere about the possibility of adapting a Vactrol to the application. ...
Beware that was an idea I never tested out. I don't know how well it would actually work.
Yeah, I realize that.
But I had wondered about that possibility myself, just prior to reading your post & was pleased that it wasn't a completely crack-pot notion.
Unfortunately, don't have the depth of knowledge to facilitate working that out. At this point anyway.
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This seller on ebay has some of the Magnatone vintage varistors for sale. I think he may have both types that were used. He used to run the vibroworld website and company, looks like the site is still around. I've got some of these for myself and they work well. Anyway, get 'em while you can.
Greg
https://www.ebay.com/itm/373618229142?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=373618229142&targetid=1264870805264&device=c&mktype=&googleloc=1024479&poi=&campaignid=14859008593&mkgroupid=130497710760&rlsatarget=pla-1264870805264&abcId=9300678&merchantid=6296724&gclid=CjwKCAjwzuqgBhAcEiwAdj5dRk0RSXH-c4KeTGuidFhih77EAuNWMoaE2eU9EeQvBA7cbjiLR7srcRoC8bkQAvD_BwE (https://www.ebay.com/itm/373618229142?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=373618229142&targetid=1264870805264&device=c&mktype=&googleloc=1024479&poi=&campaignid=14859008593&mkgroupid=130497710760&rlsatarget=pla-1264870805264&abcId=9300678&merchantid=6296724&gclid=CjwKCAjwzuqgBhAcEiwAdj5dRk0RSXH-c4KeTGuidFhih77EAuNWMoaE2eU9EeQvBA7cbjiLR7srcRoC8bkQAvD_BwE)
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Thanks for the link, those are nearly reasonable by comparison to many.
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The FR1039 that he is selling is one of the silicon carbine varistor types that were used in vintage Magnatones. Another type was the FS308. He may sell those also.
Here are some of the specs of the varistors of the time, with those two highlighted in yellow. I recall seeing both types in various models of Magnatones that I have worked on.
Greg
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The FR1039 that he is selling is one of the silicon carbine varistor types that were used in vintage Magnatones. Another type was the FS308. He may sell those also.
Here are some of the specs of the varistors of the time, with those two highlighted in yellow. I recall seeing both types in various models of Magnatones that I have worked on.
Greg
Thanks, much appreciated!
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This seller on ebay has some of the Magnatone vintage varistors for sale. I think he may have both types that were used. He used to run the vibroworld website and company, looks like the site is still around. I've got some of these for myself and they work well. Anyway, get 'em while you can.
I also bought some of these varistors (https://www.amazon.com/gp/product/B08TGV86P3/). The amp turned out great!