Clayton Audio Class A


Just curious: are there many amplifiers out there that use a balanced bridged class A design like Clayton Audio?
For both the M300’s and the single box version S2000, Wilson uses two class A 75 watt amplifiers in bridged design per channel. Just haven’t seen that topology spoken of much. They do sound quite good. Would love to learn more about this topology. I know it allows larger class A wattage outputs but still surprised that bridged designs double down. (300 into 8/600 into 4). Thanks for your thoughts about balanced bridged class A topology.
audiobrian
My vintage Adcom GFA-1 uses that design (two bridged amps per channel). 200wpc and a cooling fan at the back because of current draw making it run hot!
Thanks roberjerman. Good to know that about the earliest Adcom design. I wonder if there are any other balanced bridged class A designs on the market?
Accuphase Class A amps do as well. 8ohm 60w, 4ohm 120w, 2ohm 240w, 1 ohm 480w. Bridged mode, 8ohm 240w, 4ohm 480w, 2ohm 960w.

Accuphase has serious power.


Thanks technik; Accuphase is serious power class A!  I guess what was confusing me about the Clayton S-2000 is that it is a single chassis dual mono class A design with each channel already bridged. (2 x 75 watt class A amplifiers per side)for output of 300 wpc class A into 8/600 into 4.  Essentially two monophonic bridged amps in one chassis.
I doubt that the Accuphase amps are of the dual-bridged design. This particular design does have a problem with low impedances. Too much current draw - too much heat from the output stages! That's why Adcom abandoned it after the GFA-1 and went back to conventional class AB output stages.Without that cooling fan it would overheat and shut down!
Check out the Accuphase website roberjerman, I could be wrong but those are the number posted and I have the A65, granted in stereo mode only due to available funds to get a second one but stereo mode for 60 watts of class a has serious power.

     I've got one of those class A Accuphase amps. 
     Had to install 2 bridged coal furnaces in the basement to generate enough electricity to run it then 2 more bridged out by the pool to run the ac to cool down my room.
     I can't tell when it's sunny out anymore and I think the wife and kids all might have lung cancer. 
     It's pretty cool how it glows that bright orangish-red and pulsates like a lava pool to let me know it's all warmed up and ready for some tunes.
     But it sounds terrific! So, definitely worth it.  Oh yeah, worth it, worth it, no doubt about it.

Tim

Post removed 
Take two stereo amps, bridge each and you have what the Adcom GFA-1 did with one chassis.
Post removed 
No doubt there are some great high bias class AB amplifiers out there, many of which I’ve owned over 30 years. However, the class A Clayton and Accuphase amplifiers (and others, Pass etc, that I’ve not had the pleasure of ownership) add the ‘organic texture’ most characteristic of tube amplifiers, without dynamic limitations or bloat.  As I’m now recently in a smaller retirement home, with a daughter moving back home, there is no dedicated listening room available.  I’ll be moving to an excellent integrated amplifier and monitor speakers. I will miss the Clayton S-2000 as my wife will not have that large amplifier in our family room.....oh well, I’ll find it a good home.😊. The Clayton M300s, and then the S-2000, have served me wonderfully for 12 years. Thank you Clayton!
 
I have the M300s and I believe your S2000 is for the most part two of those in one chassis.
There are many bridged differential designs such as McCormack's DNA-500 and all of his SMc modded amplifiers that are converted to monoblocks, Cary's 500 series amplifiers, Bryston's big amps, I believe the PS Audio BHK Signature 300 monos, and many more.  Most of these are specified to double power from 8 to 4 ohms but most are not as comfortable driving loads below about 4 ohms.  As a side question, are you sure Wilson is not using two of his S100 amplifiers in each monoblock?
Hi Mitch2

Yes, you are correct. The S-2000 is 2 x M300’s in one chassis, or 2x M100’s bridged per channel.  I had the M300s for 7 years, and then decided to go with the single channel S2000 for my small listening room with upgraded power supply.....absolutely fabulous Amplifiers, both M300s or S-2000.  Thanks for referencing all the designs that use bridging in their high power monoblocks.