45 Type Push/Pull

Agree,implementation of a product is crucial to the actual performance
level. I'd also prefer a well design and built PP amp over an average SET
amp . However if both are done at a high quality level then give me The
SET.I find the level of involvement and emotional connection with music is
for me unmatched.I react to them in a very spontaneous way, head
nodding, foot tapping, humming, imaginary playing along with the
musicians etc.They provoke a lot of goose bump moments and completely
satisfying immersion into the soul of music. These are attributes that can't
be measured yet are so powerful when present.Other amplifier
types can do this(to various degrees) ,but in my experience not nearly as
often nor as deeply
felt.SET amplifiers won't be the answer for everyone but they are ideal for
me.I haven't any experience with the DHT push pull amps, just the pentode
tube types (I like them wired triode rather than ultra linear).I wonder how
much I like is actually due to the DHT tube genre itself.They seem more
musically natural and present more realism then IDHT tubes (well to me
anyway). 
Regards,

Just remembered that I have heard the VAC Renaissance amplifiers which are DHT push pull.It's been quite a while but I really liked what I heard from them.
Regards,

subtle push-pull crossover notch grunge

This is something that should not happen with a DHT p-p design. Crossover or notch distortion are artifacts of transistors and designs that are not class A, unless there is a serious design defect.

I have a pair of type-45 amps that I have been playing at home for several years. They started as 45 SETs, but on examination of the internal circuit it was obvious they were candidates for improvement in the wiring, parts and input circuitry.

With each update the amps sounded better- more detailed, smoother sound, etc. Ultimately I pushed them to a P-P design and the improvement over the SET version was dramatic! I think they can be improved further, but its been convincing enough that I just play them for the most part.

Phil (213cobra)
You raise an interesting point, the quality of the output transformer and power supply are so critical to what you'll hear with a SET.Get those done to a high standard and sit back and enjoy. Compromise with those aspects and you will never know the full potential of this type of amplifier. It's true for all topologies but seems more so for the SET.

>>This is something that should not happen with a DHT p-p design.<<

Yup. Assuming push-pull class A. But what about Class AB p-p designs using triode power tubes, or for that matter p-p voltage amplification sections using small signal triodes. A push pull design *can* forego notch grunge but not every designer elects to.

DeHavilland made a 75w triode push-pull amp built around a pair of 572 tubes. It was confusingly described as "100% pure Class A A/B." We see today an increasing number of push-pull triode amps with power ratings well above what could be expected from Class A push-pull and one of the effects is that they sound like Class AB amps and sometimes like Class AB amps that use tetrodes or pentodes. What's good for guitar amps (biasing AB toward B for sparkle) doesn't always benefit hifi.

Phil