SET Shootout China VS The USA

Charles1dad,

Thank you for pointing out the Manley PSET-PP amp that can operate both topologies,.  I do wonder, however, if it can really deliver optimal performance for both types, particularly because of the specific demands for a good SET transformer.  Because the full DC current drawn by the output tube must flow through the primary of the output transformer, the transformer must be designed to handle this current without core saturation.  This requirement is usually met by an air gap in the magnetic circuit, which results in reduced inductance which can be compensated for with more iron and more turns in the primary.  These compensatory measures would not be as desirable for PP operation.  

I do wonder if this type of convertible amp is somewhat like an amphibious car--it can be both a car and a boat, but it does neither very well.

@larryi 

You make salient points.  The amphibious vehicle is a good analogy.  However as I noted above, that amplifier was a good sounding unit. So I must give Manley Labs credit for this unique  achievement. 

Charles 

I had a pair of Cary PP 2A3 monos back in the mid 90’s that were great sounding and fairly energetic..  Too bad the reliability/quality wasn’t a priority with them. 
I found Cary had some real gems in their product lineup..  but I had problems with almost everything I owned by them.. They rushed one design out the door and started on another.. Just the opposite of what a fine company like Pass would do..  

I went through 3 Cary 306 SACD players before I found one that was half way reliable.. even that one skipped and stopped loading properly a year later..  They’re just up the street from me, but I got tired of their lack of quality control and never looked back.. 

With the Manley, which sounded better in the setup you heard--the pushpull or single-ended setting?  

I am pretty much agnostic when it comes to best topology.  I've heard quite a number of very good amps employing all sorts of approaches.  Between my pushpull 45, pushpull 349 and parallel single-ended 2a3 amps, my favorite is the pushpull 349.  There are things I do like about the parallel SET amp, but the fullness of the 349 amp carries the day.  

Among all the amps I've listened to in a familiar system, my favorite is a custom-built output transformerless amp--the sound was extremely vivid and lively, without having an unnatural edginess to it.  My next favorite is a pushpull 252 amp (a real Western Electric 59A amp) that was also extremely lively and full sounding.  I heard the 252 amp side by side with the Audio Note Kageki (the parallel SET amp that I own), and by comparison, the Kageki sounded thin and drab.  The best SET amp I heard was an Audio Note Gaku-On.  The Gaku-On sounds good with just about any speaker I heard it playing; .