So, this past weekend I had Christoph, Acousticsguru and another friend who is not on WBF over to my place to hear my Horning Eufrodite Ellipse PM65 loudspeakers with a variety of SET amplifiers.
The Eufrodites have now been placed where the Odeon La Bohemes once sat and seem to work well in the room once I got the degree of toe-in correct. They need quite a bit of toe-in to get good image focus and I think this is due to the fact that the 5 inch Lowther driver goes all the way up to 12Khz and that the cone tweeter is about 50mm in diameter, so there is significant beaming at high frequencies. Not an issue but it does make for a narrow sweet spot.
The amplifiers on test included the following:
Amplifon SET42se integrated amp
Silvercore "Silberglut" 2A3 integrated amp
Decware 25th anniversary EL84 SET (wired in triode)
Horning SATI 520b integrated amp
All amps were being driven by the Aries Cerat Incito preamp (despite them all being "integrated" it made it easier to regulate volume and gives a nice low output impedance platform to drive the various amps) and my Ayon Skylla 2 DAC.
We could have added the following SET amps but it would have taken too many hours of amp swapping:
Lady Day LD+ 300b monos (based on WE91 circuit modified by Thorsten Loesch)
Ayon Spark MKI (6C33C based amp)
Various KR Audio amps (from Christoph)
Ayon Crossfire III integrated (with Ayon 62B output tube)
Line Magnetic AS-125, 211 based integrated (from Acousticsguru)
Maybe for another day
We started the demo with the Horning SATI 520b with Sylvania VT-231 6SN7 input tubes and NOS "winged C" Svetlana rectifier tubes.
Initial impressions were that the sound was transparent, spacious and with powerful tight bass. However, it was noted that image focus was a little big vague. Tone is very good and image layering in depth is excellent. The sound was considered to be very good and both Christoph and David were impressed with the overall sound from the speakers.
Next up was the Decware 25th anniversary amplifier.
This little has thus far been a bit of an enigma. It is in it's own way quite extreme with voltage rectification AND regulation for both the input and output stage...only the LAMM ML2 has output stage tube regulation ASFAIK besides the little Decware. Since this is an EL84 wired in triode, it makes a whopping 2.3 watts. Trying it previously on my Odeons kind of worked but you could hear it struggling already at not so loud levels.
With the Horning speakers the amp worked MUCH better than I have heard it with other speakers. We did some rolling of rectifiers to get a sound that sharpened up a bit (it was a little soft with the initial rectifier choice) and we were rewarded with a VERY transparent amplifier with sparkling highs, good image focus, nice tone and very articulate but somewhat lighter weight bass. With non-super demanding music it performed admirably and didn't give away it's low watt nature at all. It was dynamic and punchy and demonstrated that the Hornings truly are a sensitive and easy to drive load.
Only when we tried some big classical music did we start to hear the amp strain. It didn't break up completely or clip harshly but it did harden up and sound less relaxed than it did with other music...well afterall it is only 2.3 watts! Short of that the sound was uniformly excellent and given the new price (but a 2 year wait for a new one!!!) it is a steal if you have speakers like the Hornings that can really work with a low watt amplifier.
After a nice lunch (our favorite Kebab place) we then hooked up the mighty Amplifon SET42se, which more at the higher end of the power scale with 42 watts of SET power on tap (35 of which is < 1% THD).
After about a 10 minute warmup (it continues to improve over about 30-40 mintues) we started listening and started with the big classical piece where the Decware was getting a bit strained (It is fair to note that the 18 watt SATI also had no issues with this classical piece and rendered it quite well indeed). The Amplifon made it sound utterly effortless with the Horning speakers, the power in the bass was evident and the depth of soundstage, evenness of tone and ability to handle the music swells was impressive. Layer and transparency were very good but I would say the Decware was superior with micro dynamics and detail. That's not to say it's not there with the Amplifon it's more the focus is more macro than micro and the Decware is more micro than macro. The Amplifon had better image focus than either of the other two amps although the Decware was closer.
I did feel that on some tracks used for demo, the Amplifon, while having powerful controlled bass didn't have the last word in articulation of the bass...here the SATI 520b and the Silberglut resolved bass, kick drum etc. micro detail and texture better.
The SATI kind of straddles the two, not as micro as the Decware and not as powerful sounding as the Amplifon. Transparency is similar feeling with all amps but the focus of each is slightly different.
The final amp we tried was my Silvercore "Silberglut" integrated amp. This is a 2A3 based amp that uses a 6C45P input tube that is transformer coupled to 2A3 output tubes. Recification is with a 5U4G. This is a very solidly built amp with a LOT of iron on the deck.
Firing this amp up showed the same sort of WOW micro resolution of the Decware but with more powerful and very articulate bass (probably the best bass of the bunch if not the most power). Space was not quite as deep as the Amplifon or SATI 520b but it was by no means flat or stuck to the speakers. imaging was good but a shade behind the Amplifon. However, there is a verve and energy in the amp that makes it a joy to listen to...and the transparency! Decware was equal in that category but lighter weight in balance where the Silberglut gives an amazing amount of umph for a 3.5 watt amp. The big classical piece also didn't phase it and it refused to sound strained. The only slight down side was that at times the amp could sound a bit "raw" but never to the point of being coarse or grainy sounding. Given that the amp came to me with one of the cheapest 2A3s (Sovtek), it is entirely possible that an output tube roll would eliminate that minor caveat.
So, at the end of the day, all amps were very good and worked very well with the Horning Eufrodite Ellipse PM65 and I would classify this as a VERY friendly SET speaker. My Odeons seem to work best with 10 watts+ range but these work great down to 2-3 watts.
I think Christoph would rate the Amplifon first because of its big powerful sound, even tone, good transparency and nice relatively precise soundstage. But perhaps he will comment further on my post.
I think David would rate the Amplifon first for the same reasons but with the caveat that both the small amps did some things around low level resolution and micro dynamic/detail that the two bigger amps didn't do.
My other friend, who was quite fond of the SATI 520b at his place, found the imaging a bit vague with it here (his coax speakers have quite tight focus that the Horning speaker doesn't quite have) and so I think he overall preferred the Amplifon (he didn't hear the Silberglut, having to leave before we hooked it up) although he quite liked the openness of the Decware.
As for myself, I cannot decide. I like the relatively good transparency, bass articulation, sense of space and tonal balance of the SATI 520b. That said, the Amplifon is its equal in all but bass articulation but superior in power on the low end and better image precision. The one that right now tugs at my mind the most is the Silberglut. It combines the utter transparency and micro dynamic/detail of the Decware but with a powerful sound that seems at least equal to the SATI 520b. I think that slight 'raw' sound is tuneable with a good output tube swap. It is also good in imaging and soundstage and sounds more balanced from top to bottom than the Decware. Bass articulation is particularly of note, which suggests very good output transformers (as would be expected from Silvercore).
Would other amps do better? Perhaps and given the speakers openness to very low power amps, this opens up a new territory to explore.
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