Cool running, low powered power amp

My regular amp is a Class A, all tube (KT 88’s) affair that runs very warm. For most of the year, it doesn’t matter. But in the dog days of summer, it can become unpleasant in my smallish listening room, where the AC doesn’t reach as well.

My speakers are Volti Razz, which are something like 97 db efficient. My big tube amp is out in California getting repaired, and at the moment, the Volti are enjoying time spent with a Scott 299A. Those 17 wpc are plenty (and sound way better than a 65 year-old amp with original tubes (or at least, tubes marked "H.H. Scott") should. Volti says it only needs to be 8 watts to do the job.

I was thinking of First Watt, or maybe Pass Labs XA 25. But both of those are also Class A. But maybe all Class A are not alike in terms of generating heat. I am not anti-class D, and have had two Class D amps that sounded good, but I’d be more interested in A/B, or cooler running Class A. I'd like to bring it in under $3000, and I am a big fan of used equipment.





I would strongly recommend hearing any amp first before buying.  In particular, putting money down for something you have to wait three years for seems very risky.  I've heard three Decware amps and all of them were whimpy sounding things that sounded pleasant, but, very limp and unable to deliver punch.  The speakers they were used with were high efficiency speakers (about as easy or easier to drive than the Volti Razz).  

With low heat a big priority, Class D solid state makes sense.  Find a high quality lower powered Class D amp.  

If you are sticking with tubes, the advice above about Audio Note Oto or Soro is good, if you can find something used in your price range.  I would not be looking at hot running tube amps such a those employing KT88, KT120, KT150 or KT170.  If you have someone to service your amp, you might be able to find something vintage that runs EL84, 6L6 or KT66, and even EL34 (not one of my favorite tube types, but some amps running those tubes sound good).  These tube types I've mentioned tend, to my taste, to sound better than the KT88s you run (not as hard or brittle sounding).  

Good luck in your search.

+1 @fthompson251 I would talk to Aric of Aric Audio about his tube amps. He makes a couple SET amplifiers. 

@dtorc FWIW, we make a 5-Watt/channel class A tube amplifier that can sit on a sheet of notebook paper with room left over. I designed it for my bedroom system.

BTW, something to keep in mind about SETs: if they have no feedback (and most don't), their actual usable power is about 20-25% of their rated power. This is because at power levels above that, the higher ordered harmonics start to show up on musical transients. This causes the amp to sound dynamic (since the ear uses higher ordered harmonics to sense sound pressure) but its really distortion masquerading as 'dynamics' and is the source of why so many people say SETs are a lot more dynamic than their power suggests.

Consider the Schiit Aegir. No, really.

I just swapped a pair of Aegirs for an ARC VT100MkIII and they are no joke. You'd probably only need one. And the resale on Schiit is so good... I mean, why not?

It's less than you spent on your cartridge, isn't it?

It really only fails on the sexy quotient.

Have fun!

@lanx0003 The KRELL Duo 175XD was used on my Thiel CS3.7 and also my RAAL SR1a earphone using the older amp interface box. Interestingly, the SR1a drew more power out of the amp. I knew this because when I used the CODA #8 in place of the KRELL I could see the meters on the amp flying for the SR1a but not move for the Thiel CS3.7. I had both KRELL and the CODA on hand.

When I used the KRELL as a earphone amp I had the amp about 1 foot from my seating position. I never heard the fans.

Here is something on both the KRELL and Westminster Labs amps that I posted about earlier. Class A amps that stay cool.

WestminsterLab, LampizatOr, VSA and Hear This | AXPONA 2024 - Part-Time Audiophile (

I now use the Schitt Aegir amp in place of the CODA and the KRELL using a new RAAL amp interface box. It is rather good, not as good as the CODA or KRELL, but I only need 20-watts Class A with the new RAAL amp interface box.

The Aegir is mechanically nosier than the KRELL with fans. The new Aegir 2 is supposed to remedy that mechanical noise.

The CODA #16 does get warm generating the first 100 watts in Class A, but it is not very hot.