SET amp owners thread

[bonzo75]

Wavac.

Yes true. I don't have experience with it, General does.

 

[microstrip]

Thomas, true, I very rarely go past 12o/c on my volume dial, that's plenty loud for me. Knowing my Nats are not breaking sweat.

Although the time measured on your volume dial is meaningless, can I ask if you have or have seen measurements of distortion versus power and impedance of your amplifiers?

 

[morricab]

I am aware, question is if he compared them to jadis or KR

I compared KR VA350 and Kronzilla to a lot of amps. VA350 was better on Focal Mezzo utopia Be than Jadis Defy 7 mkiii. On my Odeons the Aries Cerat Genus is better than other SETs I have tried on that speaker, including: KR VA350, Ayon Crossfire III, Wall Audio Opus M50 monos + NAT Plasma, JJ-322 + NAT Plasma or Aries Cerat Incito, Ayon Vulcan Evo + Ayon Auris or NAT Plasma or KR P135, NAT Symbiosis SE, MasterSound Dueundici, Puresound A30(great sounding budget amp) and VAC 30/30 + NAT Plasma. Never tried it with Kronzilla but I know the move up from VA350 since I was a KR dealer in the past.

 

[morricab]

Kedar, I think it is great that you like the KRs (I am sure I would like them too), but isn’t that largely another way of saying that you like a transistor input stage and a tube output stage?

Of course KR uses their selected components and circuit topologies but I wonder if you could achieve largely the same sonic result by combining a hybrid line stage or an all-transistor line stage with an all-tube amp.

Putting it differently I guess I feel less black and white about what is good and what is bad, and what works with what and what doesn’t work with what, than it seems you do. I feel there are only so many ways to slice and dice amplification chains and circuit topologies to achieve a desired level of total gain and desired sound, and, while many things sound slightly different or materially different, I wonder if our subjective preferences and component matching combinations often account for greater variability than the differences in similar circuit topologies themselves.

No, Ron it’s definitely not the same.

 

[Sablon Audio]

How about a 250wpc GU81 design?

www.iconaudio.com/main-products/mb81-mono-blocks/

 

[bonzo75]

How about a 250wpc GU81 design?

www.iconaudio.com/main-products/mb81-mono-blocks/

Whoa with el34 too

 

[morricab]

At a certain point you need to try yourself to find what fits your choice of compromises the best. Also try to look behind the numbers. There is no standard for example how to specify the sensitivity of a speaker. There is a lot of room to wiggle the numbers. I have seen speakers with claimed 98dB sensitivity which dropped way below 90 db in the upper bass region. Also the impedance curve of the speaker is important if you want to use SET amps. SET amps prefer a load which does not vary excessively over frequency and which does not drop to low.

The same with power output. There is no standard how to measure the max power of an amp. An amp can produce 20W at 1kHz but does drop to 5 at 30Hz.

Also SET amps typically have low damping factors. Going even as low as 2 is not uncommon. I try to stay at 5 or more. Some speakers need a good damping factor and others actually sound better with a low damping factor.

And so on and on...

I have found my backloaded Horns don’t like a high damping factor as this overdamps the bass. Otherwise , they play friendly with most SETs or PP from 10 watts to 50 watts.

 

[bonzo75]

I have found my backloaded Horns don’t like a high damping factor as this overdamps the bass. Otherwise , they play friendly with most SETs or PP from 10 watts to 50 watts.

Tannoys too. Don't over damp

 

[morricab]

Interesting - as I will be hearing the Wagner 2 with Tron 300b presumably in mid-April. That's all the distributor here demos (imports)

Tron also makes a 211 amp as well

 

[morricab]

Hi Thomas, how does your 845 tube sound compared with a transmitter tube?

845 is also a transmitter tube...just not a huge one.

 

[morricab]

What else do you have over 100 watts/

For me, a higher powered SET is 45-50 watts and up. Some would say 20 and up qualifies. I think WAVAC, Traffomatic and maybe TubeGuru make amps rated at 100+. ACs most powerful is 65 watts but to be honest the 25 Watters are very powerful sounding and all you need for mid-90s and up in a normal size room.

 

[morricab]

Although the time measured on your volume dial is meaningless, can I ask if you have or have seen measurements of distortion versus power and impedance of your amplifiers?

I have for the SE2SE and it was prodigious, over 100 watts with still acceptable distortion level (<3% if I remember correctly). Was really surprising to me from 2x211 not in PP. for sure deep Class A2 but distortion didn’t look so bad.

 

[morricab]

Whoa with el34 too

Popular driver tube when wired in triode for driving big transmitter tubes

 

[bonzo75]

For me, a higher powered SET is 45-50 watts and up. Some would say 20 and up qualifies. I think WAVAC, Traffomatic and maybe TubeGuru make amps rated at 100+. ACs most powerful is 65 watts but to be honest the 25 Watters are very powerful sounding and all you need for mid-90s and up in a normal size room.

In my past posts I was referring to various levels - one is the low power sets (300b, 2a3, etc), then are the 20 - 30w, which as you say are high power for SET applications (211 types). 45 - 50w gets pretty high for SETs and starts going into the territory of other designs (PP, SS). However, by higher power I was referring to those if at all that can compete with a PP or an SS for a speaker that is normally designed for such amps. That is what people will use NAT Magma or KR VA 200 for. Wavac too, and I guess the Trafomatic in Munich that was 120w but was a one-off.

 

[morricab]

In my past posts I was referring to various levels - one is the low power sets (300b, 2a3, etc), then are the 20 - 30w, which as you say are high power for SET applications (211 types). 45 - 50w gets pretty high for SETs and starts going into the territory of other designs (PP, SS). However, by higher power I was referring to those if at all that can compete with a PP or an SS for a speaker that is normally designed for such amps. That is what people will use NAT Magma or KR VA 200 for. Wavac too, and I guess the Trafomatic in Munich that was 120w but was a one-off.

Again, the KR VA200 is not a SET.

 

[bonzo75]

Again, the KR VA200 is not a SET.

What would you call it?

 

[morricab]

In my past posts I was referring to various levels - one is the low power sets (300b, 2a3, etc), then are the 20 - 30w, which as you say are high power for SET applications (211 types). 45 - 50w gets pretty high for SETs and starts going into the territory of other designs (PP, SS). However, by higher power I was referring to those if at all that can compete with a PP or an SS for a speaker that is normally designed for such amps. That is what people will use NAT Magma or KR VA 200 for. Wavac too, and I guess the Trafomatic in Munich that was 120w but was a one-off.

It is very similar to a BAT VK75 or REX amp using an OTL circlitron design with output transformers.

 

[morricab]

What would you call it?

Circlotrons are still PP.

 

[joaovieira]

My SET Audiopax M100 are 100W class A1 amps.

 

[spiritofmusic]

Also, reading 6 moons on Zus, as well as what 213cobra, Keith, recommend, Marc will be better off with sub 30s amp. 211s or silvercore 833c 20w.

Ked, you'll have to take my word for it that 70W 211s worked better in my old space, and in my new, than 30W 845s.

Other than some marginal lack of transparency in my 70W Nats, I would not switch back to Audion. The heft I hear from a grippier control on my Zus is hard to live without.