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Topic: 7199 to 6U8 Adapter |
Randy Owens
From:
West Central Indiana, USA
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Posted 23 Apr 2017 2:22 am |
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I know this is a stretch but I know that a lot of us like to use vintage gear. My Ampeg G-15 uses a 7199 tube which is no longer in production. They're out there but most that I have seen are $50+. There is an adapter that plugs into the socket that changes the pinout of the tube so that you can use a 6U8 tube which is supposed to be electrically identical and about $10. The tube and adapter can be purchased together for about $25. According to my tube tester, my 7199 is still good for now but all tubes are perishable!
The other option would be to rewire the tube socket as a more permanent modification. The mod is simple but I haven't verified it with another source. (proceed at your own risk):
Step 1. Remove wire from pin 2 and relocate it to pin 6
Step 2. Remove wire from pin 6 and relocate it to pin 7
Step 3. Remove wire from pin 7 and relocate it to pin 2
I guess I'd like to know if any of you have tried the socket adapter and a 6U8 tube. Would you do the socket rewire and call it good...noting the change on the tube chart? Obviously a NOS 7199 would be the correct way to do it but the supply is finite. A NOS tube could outlive me though. I believe the one that is in it is the original tube from 1965.
This amp is a great old survivor that sounds outstanding. I'd like to keep it around a good long time. I replaced the filter caps and and have installed a 3 wire power cord in the name of safety.
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2003 Mullen Royal Precision, Walker Stereo Steel, Ampeg G-15, Telonics FP-100 |
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Cartwright Thompson
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Posted 23 Apr 2017 3:11 am
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| If I were you, I'd just avoid the hassle of modifying the amp and bite the bullet and shell out for a n.o.s tube. Like you said, it will most likely outlast you. |
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Michael Butler
From:
California, USA
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Randy Owens
From:
West Central Indiana, USA
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Posted 23 Apr 2017 10:32 am
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Yes indeed. I've been to various links pertaining to the conversion and adapters. Some do prefer the 6GH8A and some prefer the 6U8A. The interesting thing is that people seem to prefer either of those tubes to the original 7199! I'm going to see what I can dig up on the 6GH8A conversion. If it's the same as the 6U8, I'd have an additional option using an adapter. If it's not, it's no big deal. Both tubes and their adapters are cheap enough to experiment with.
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2003 Mullen Royal Precision, Walker Stereo Steel, Ampeg G-15, Telonics FP-100 |
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