@charles1dad Well, my best audiophile friend, Mike, already owned the autoformers and some Atmosphere OTL amplifiers and he runs with just 1 pair of tubes due to heat issues. He suggested I ask the designer, Kang Su, if I could run with 1 or 2 tubes safely since my amps are a parallel design similiar to the Atmospheres sans an output transformer. I contacted Albert Porter and he graciously and expeditiously reached out to Kang Su and he was able to get me my an affirmative answer a couple of short hours later.
The only downside to running the single tube is the 4ohm output transformer tap of the amp effectively becomes 16ohms and that's a terrible mismatch with a 4 ohm load such as the Encores are by default. This would likley stress the tube more.
Paul at zeroimpedance.com created the autoformers for this purpose. Apparently, any amplifier below 100wpc can benefit by using them and he even has people with push pull solid-state amps using them too and enjoying them. Seems making your amplifier loaf and not forcing it to push extra current into lower loads seems to have audibly pleasant effects for those users.
For me personally I'm enjoying using them in their 4x load mode or 4x4ohm=16ohm making it match perfectly with my amps 16ohm output impedance. (Autoformers can be set to 2x,3x,4x so there's versatility) It sounds like peanut butter and jelly or rather a match made in heaven.
The sound flows effortlessly at any volume. I can play very loud and I have still have complete composure regardless of the scale or amount of bass of the music. It also fully restores the 10db of damping the amps have because you lose 3/4th the damping only running one tube. There's something very intimate and even more set-like about the presentation running one tube since now the power, interstate, and output transformers are all loafing running just one 300bxls power tube and the autoformers are like the icing on the cake. The Allnic A6000 is like buying a versatile 15,30,45,60wpc SET amp.
Personally, if you don't need the extra wattage I think there's something to say for the sonic purity of driving a single triode, but if you need the power do to inefficient speakers you would benefit by adding tubes and power as needed to lower overall distortion that creeps up rather quickly as you drive a single tube up to its15wpc maximum output.
For me I get no audible softclipping or compression at all with just 15wpc at very high volume levels. Just complete composure. It's well nigh perfect. My system has never sounded this good.
The only downside to running the single tube is the 4ohm output transformer tap of the amp effectively becomes 16ohms and that's a terrible mismatch with a 4 ohm load such as the Encores are by default. This would likley stress the tube more.
Paul at zeroimpedance.com created the autoformers for this purpose. Apparently, any amplifier below 100wpc can benefit by using them and he even has people with push pull solid-state amps using them too and enjoying them. Seems making your amplifier loaf and not forcing it to push extra current into lower loads seems to have audibly pleasant effects for those users.
For me personally I'm enjoying using them in their 4x load mode or 4x4ohm=16ohm making it match perfectly with my amps 16ohm output impedance. (Autoformers can be set to 2x,3x,4x so there's versatility) It sounds like peanut butter and jelly or rather a match made in heaven.
The sound flows effortlessly at any volume. I can play very loud and I have still have complete composure regardless of the scale or amount of bass of the music. It also fully restores the 10db of damping the amps have because you lose 3/4th the damping only running one tube. There's something very intimate and even more set-like about the presentation running one tube since now the power, interstate, and output transformers are all loafing running just one 300bxls power tube and the autoformers are like the icing on the cake. The Allnic A6000 is like buying a versatile 15,30,45,60wpc SET amp.
Personally, if you don't need the extra wattage I think there's something to say for the sonic purity of driving a single triode, but if you need the power do to inefficient speakers you would benefit by adding tubes and power as needed to lower overall distortion that creeps up rather quickly as you drive a single tube up to its15wpc maximum output.
For me I get no audible softclipping or compression at all with just 15wpc at very high volume levels. Just complete composure. It's well nigh perfect. My system has never sounded this good.
