Demo'ing Class A amps, Appreciation Suggestions from those who recently been there

@decooney - I am very impressed by the sound, very good soundstage with beautiful decaying of instruments, I did not expect so much right away as I am using the pre out of my old intergraded amp, but I can live with this sound happily until I get a tube pre.

I think it sounds neutral, the bass is very good, very live, the treble sounds extended too me, but the midrange is just wow, very good tonally and at the same time very clear.

My hybrid amp gave some more atmosphere, like being in a small nightclub listening to Grant Green, but when I get my tube pre I expect that to come back, the SA-30 has much better resolution than my hybrid, that’s for sure.
    
The amp design looks real quality, very thick front, back and top plate, nothing ringing when you knock them, only tender knuckles ;-)

A very faint hum can be heard if one puts the ear close to the amp, but the speakers are dead quiet with full output on the pre.

It does get very warm though, so good ventilation is important. 

If tube amplification is an option, my suggestion would be Linear Tube Audio. I am using a ZOTL 10 amp with the MZ3 preamp on Spatial Audio M4 Triode Master speakers. The speakers are rated at 93db and average 12 ohms. These are open baffle speakers and are probably getting around 8 watts from the ZOTL 10 amp. This amp can drive me out of the room if I cranked it up, so it has plenty of power for normal listening levels. I believe the amp puts out 12 watts at 4 ohms.

These amps are very different from a normal tube amp with normal transformers. They have a frequency response that goes down to 6 hz at -0.5 db which gives you the bass response of a ss amp. They have no massive transformers and the tubes run at much lower amperage than a normal tube amp. The tubes are supposed to last between 10-20 years and the heat generated is less than a normal tube amp or a Class A ss amp in my experience. LTA amps and preamps are dead quiet with no hiss at all. I went from using a Cary Rocket 88 tube amp to a CODA 10.5R ss amp (100 watt, 25 watt Class A) to my current LTA system. LTA describes their sound as tube tone with solid state detail which I think is very accurate.

They have a two week trial period and will take back the amp for any reason and will cover the return shipping. The ZOTL 10 power amp is $3,200 and they have a Z 10 Integrated amp for $4,900.  

@aldoallen
..LTA describes their sound as tube tone with solid state detail which I think is very accurate...
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aldoallen,
A friend who’s owned the same tube and SS amps I’ve run described his ZOTL amp the same way as you have, and LTA does on their site. And, we’ve both owned solid state amps which have "tube tone. Friend indicated his ZOTL can be "less tubey" sounding, and therefore kept a few of his tube amps to rotate in/out periodically. Been asking him to roll some different tubes in it to compare again.

The other comment on the LTA site about tube amps is... "but their “warmth masks details and can sound thick.". Yes, true for some tube amps, not all. Particularly not with more modern amps with modern power tubes like KT150s. Seems LTA/ZOTL was looking for a hybrid sound and approach. It’s great to see different approaches.

I would’n’t mind demo-testing the ZOTL40 Reference amp with my custom speakers, to see what it can do, and how different it is versus some of the more capable Class A>A/B solid state amplifiers we all know. Grew up past 40 years transitioning through very "tubey" sounding solid state Mosfet designs with dual mono torroids and really enjoyed those too. Then, on to tubes. Have great appreciation for those blending both together.

Noting you’ve owned CODA and the Rocket88, both with their own signature sounds, do you feel your ZOTL leans more to SS than tube amp sound then? If you could change the sound a bit more with your ZOTL, what would it be - if anything?

Dennis Had 'Inspire Fire Bottle' SET tube amp is an option.

Based on online measurements, the Luxman 550 seems misleadingly underrated when it comes to wattage. I suspect this has to do with meeting test standards requiring pre-conditioning.

I'd treat it as a much larger amp when considering it's application.