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PrimaLuna ProLogue Two - mixing tubes?

I have a newer quad set of SED 6550Cs that I've been using as a replacement for the stock KT88 tubes. I decided to take advantage of the auto biasing feature of this amp and run one 6550 and one KT88 per channel, only because one of the stock KT88s is bad. I'd like to use up the other two good KT88s. I've read that this is acceptable with this amp, but I'm not sure if this will have negative impact on the 6550s. I plan to rotate the 6550s so that I still have a somewhat matched quad set of them. Has anyone done this before, and are there any pitfalls I should take note of?

Thanks
jwglista

Showing 1 response by martykl

martykl
3,578 posts
 
The PL amps are designed to safely accomodate this. However, Kevin at Upscale can probably give you the upside/downside of operating the amp in this fashion. I think that I've used every outpube tube out there in my PL 7s and there's a fair bit of character shift when you change the output tubes. I've pretty much settled on KT 66s for most apps.

Good Luck

Marty
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