Parafeed
100+ Head-Fier
- Joined
- Jun 6, 2005
- Posts
- 432
- Likes
- 10
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Thanks. If it had a name, it'd be a pun on "pain"! Something to do with pain anyway, on account of the fact it took a year and the expiry of one of my last stashed pair of 3A/167M's to come up with a 6C45 design that was at least as good as, or better than the amp it replaced - basically the Gary Dahl Espressivo design on steroids - series and shunt regulated (each channel) after the choke input power supply, and using a choke load rather than the hybrid Pimm pentode CCS load.
I could waffle on about how the Miller capacitance seems to affect the 6C45 SQ (bandwidth) more so than with the WE437A and STC 3A/167M, even using a low value input pot. (So drive it from the cathode and ground the grid.) Or how they love to oscillate given half a chance. (Never believe anyone who tells you that the 6C45 sounds solid-state or has "glare" unless you've 'scoped it in the circuit! Stopper resistors are not a luxury, they are a necessity!
)
Anyway, it's a very good sounding amp and I've built two more based on the design for other people. One, same as pictured, no expense spared with the BG WKz, (every other cap is poly), MQ (Peerless) TL-404 autoformers and the other, a budget version (relatively speaking), using Sowter 8665's at the output transformers, dropping the shunt regulators and skimping on the parts quality a little. But to be honest, SQ wise it didn't make a lot of difference.
Originally Posted by swedishhatfaction /img/forum/go_quote.gif That is most excellent! Does she have a name? |
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Originally Posted by apatN /img/forum/go_quote.gif Wow, that's a beauty Parafeed! |
Thanks. If it had a name, it'd be a pun on "pain"! Something to do with pain anyway, on account of the fact it took a year and the expiry of one of my last stashed pair of 3A/167M's to come up with a 6C45 design that was at least as good as, or better than the amp it replaced - basically the Gary Dahl Espressivo design on steroids - series and shunt regulated (each channel) after the choke input power supply, and using a choke load rather than the hybrid Pimm pentode CCS load.
I could waffle on about how the Miller capacitance seems to affect the 6C45 SQ (bandwidth) more so than with the WE437A and STC 3A/167M, even using a low value input pot. (So drive it from the cathode and ground the grid.) Or how they love to oscillate given half a chance. (Never believe anyone who tells you that the 6C45 sounds solid-state or has "glare" unless you've 'scoped it in the circuit! Stopper resistors are not a luxury, they are a necessity!
Anyway, it's a very good sounding amp and I've built two more based on the design for other people. One, same as pictured, no expense spared with the BG WKz, (every other cap is poly), MQ (Peerless) TL-404 autoformers and the other, a budget version (relatively speaking), using Sowter 8665's at the output transformers, dropping the shunt regulators and skimping on the parts quality a little. But to be honest, SQ wise it didn't make a lot of difference.