Is there a Solid State amp that can satisfy a SET guy?

Yes there is only one : Robert Koda.
Better than Dartzeel.

@rh67 

Have used SET amps for the last four decades. A SET amp produces a 3d sound to each instrument and the stage which contributes to music sounding real. The SS amps that for me capture much of this is the Pass XA25 and FW SIT3, i was so impressed with the XA25 that i purchased one 2 months ago".

Very interested if you could ellaborate on diferences between XA25 and SIT3. How are they different between them and how do they differ from your SET experience? BTW, what kind of music do you listen to?

I'm designing an active system around SETs for midrange and treble, but SIT3 and XA25 often make it to the "what if". But haven't heard them.

@lewinskih01, I can’t comment on the sonic differences between the XA25 and SIT3 (I’m a very happy owner of an XA25, but I haven’t heard the SIT3). However a non-sonic difference that may be important in many applications is that the gain of the SIT3 is **very** low for a power amp (spec’d as 11.5 db; measured by Stereophile as 11.3 db). That would make it a non-starter for use in my system, for example, since the DEQX HDP-5 I use as my preamp provides little gain. In fact the 20 db gain of the XA25 (which is about 6 or 7 db less than typical for a power amp) approaches (but does not quite reach) the point of being marginal in my system when I'm playing LPs.

Best regards,
-- Al

The posts caught my attention as I am in the middle of choosing a 211 or 845 amp. You’ve allayed the concerns the posts raised.

@atmasphere Can you comment as well? Thanks.

@david_ten   The bigger the SET, the more issues you have with bandwidth. Some of this depends on design, for example the type of amp known as a 'parafeed' can have more bandwidth since DC is kept out of the core of the output transformer. This is why the 300b for the most part has described the upper limit of 'hifi' since getting more than about 7 or 8 watts means that the audio passband is compromised. If you really want to get the soundstage right, the amp needs to have minimal phase shift in the audio regions so it will need bandwidth past 80KHz. Most larger SETs simply can't do that!


Also if you want to get the bass right, you need bandwidth on the bottom end to prevent phase shift from robbing the amp of that impact. The general rule of thumb is 10x the cutoff frequency so to do 20Hz correctly you have to go to 2Hz. Again, most SETs can do that, many struggle to get down to 20Hz without rolling off!

IOW the larger SETs can be regarded as a tradeoff between bandwidth and power. Now as I've mentioned a fair amount, with SETs that do not run feedback (which is the vast majority of them) you really don't want to run them past about 20-25% of their full power rating in order to really be hearing what they do. This means that you really need an efficient speaker. Higher power SETs try to get around this limitation somehow, but IME this is a forlorn hope. So if you need more power, you are far better off getting a moderately powered push-pull amp. The distortion is lower overall, so you get a greater amount of 'usable' power. I put that in quotes because of course you can run an SET past that power limit I mentioned, what happens is you get more distortion and it starts to sound loud. But that is an interaction with the kind of distortion its making (higher ordered harmonics) and the way our ears perceive sound pressure (it uses higher ordered harmonics to gauge sound pressure). A push-pull amp is less likely to do this.

If you've ever read a comment about how 'dynamic' a certain SET is, that comment derived directly from running the amp on a speaker that was not efficient enough to prevent the user from running above that 20-25% power region. Dynamics are supposed to come from the recording, not the amp!! The word 'dynamics' as used by audiophiles usually means 'distortion' and the latter can replace the former in most audiophile conversation without changing the meaning of the sentence in which the change occurred.


Bottom line: I would think twice about a buying a higher powered SET, if getting the music to sound more real is your goal. OTOH no worries if you just want a nice sounding stereo that sounds loud.

Thanks for the more easily understood, non technical explanation Ralph. One comment that pertains to my exact situation is that when I do crank the volume on my 300B SET it does start to sound loud! I have put in a First Watt M2 amp into my system. Through what I have come to understand and accept is that SS may be more intellectual and SET more visceral. But the detail, bass and overall impact are things to be appreciate and enjoy. However, it is also clear that I am an emotional man, especially when it comes to my hi fi and even the two channel home theater that it doubles. I am forcing myself to continue to listen to the M2 but I don’t know if I will be able to sacrifice the visceral. I believe I could get that with say one of your amps but 38, I think, tubes and very low WAF. Could I get this with a push pull tube amp? Then a BIG SS plus is getting an amp with a lot of power and a lot of head room. I imagine the effortless sound of tons of headroom my be very attractive. Intellectual? Now listening to a great recording of a Telemann chamber orchestra and hearing the inner detail makes it quite enjoyable. I can imagine how additional headroom would add a lot! However, it still does not grab my subjective and emotional senses. Could SS be a more objective and intellectual exercise?