Matt C
Well-known member
I'm working on rehabilitating an Ampeg VT-40 for a friend and I have a couple questions. Any advice would be appreciated. Schematic is attached below. Also keep in mind that I'm trying to stay away from doing any serious modifications to the amp, just looking to get it healthy again.
1. Replacing PSU filter caps - I'm having trouble deciding between using new multi-cap cans (to keep it as original as possible), or just throwing up a few turret strips and using single caps. I realize either way would work, just wondering if there are other pros and cons I'm not thinking of. Individual caps will probably be cheaper, but probably a bit more work to install, and they'll clutter up the inside of the chassis. Cap cans are pricey and some people seem to think the quality is inferior to single caps. I'd most likely use the 100uf+100uf multicaps that Weber Speakers sells. Those CE cap cans are nice and shiny but I can't imagine they're worth $40 each. Any opinions here?
2. Output tubes. Schematic calls for 7027A, and it seems like the modern version of these are more or less the same as the 6L6GC. The B+ in this amp (almost +600V) is above what both of these tubes are rated for, but the general consensus in internet world is that they both work just fine, so I'm leaning towards getting some 7027As as called for and calling it good. Other people seem to like 6550, but that seems to come with it's own set of concerns. Any recommendations one way or the other on this?
3. I'm having trouble figuring out what type of diodes are used in the power supply section (D1-D6). The schematic says F10 and F8, but internet searching hasn't given me much usable information about these. Anyone know the scoop? I have tons of 1n4007s sitting around so I'm hoping that's a reasonable substitute.
Thanks!
1. Replacing PSU filter caps - I'm having trouble deciding between using new multi-cap cans (to keep it as original as possible), or just throwing up a few turret strips and using single caps. I realize either way would work, just wondering if there are other pros and cons I'm not thinking of. Individual caps will probably be cheaper, but probably a bit more work to install, and they'll clutter up the inside of the chassis. Cap cans are pricey and some people seem to think the quality is inferior to single caps. I'd most likely use the 100uf+100uf multicaps that Weber Speakers sells. Those CE cap cans are nice and shiny but I can't imagine they're worth $40 each. Any opinions here?
2. Output tubes. Schematic calls for 7027A, and it seems like the modern version of these are more or less the same as the 6L6GC. The B+ in this amp (almost +600V) is above what both of these tubes are rated for, but the general consensus in internet world is that they both work just fine, so I'm leaning towards getting some 7027As as called for and calling it good. Other people seem to like 6550, but that seems to come with it's own set of concerns. Any recommendations one way or the other on this?
3. I'm having trouble figuring out what type of diodes are used in the power supply section (D1-D6). The schematic says F10 and F8, but internet searching hasn't given me much usable information about these. Anyone know the scoop? I have tons of 1n4007s sitting around so I'm hoping that's a reasonable substitute.
Thanks!