SST Son of Ampzilla ii power amp

Hey guys,

I need your opinions, advise, insights & thoughts on the SST (Spread Spectrum Technology) Son of Ampzilla ii (series ii) stereo power amp. The amp receives many glowing reviews from the likes of TAS, Hifi Plus, 6moons, EnjoytheMusic, etc. I know this amp was barely discussed anywhere and isn’t a popular mainstream amps. It is a class AB design with biased into class A for the first 10 to 12 watts. I know it looks ugly as hell but I would care less for the look and only care for the audio performance sound quality, musicality and reliability. Many reviewers claimed that this amp punches way above its price and competes well with many amps costing much more. Well, some reviewers always said that, don’t they?

I’m thinking to buy this amp to replace my Classe Sigma Amp2 class D amp to drive the Monitor Audio Gold 200 5g (latest generation) speakers. The rest of my gears are : Classe SSP 800 preamp processor, Cary Audio CD 306 SACD player/DAC served as my CD/SACD player and DAC. I also have the Oppo 105 universal bluray player used as a bluray & occasional DVD-Audio transport which is connected via HDMI to my Classe SSP 800.

What do you guys think of the SST Son of Ampzilla ii (series ii) amp and how would it compare with my existing Classe Sigma Amp2 class D amp? I know they would probably sound different. Any other options out there I should consider? Any input, insights & thoughts are welcomed. Thanks in advance.
My new Monitor Audio Gold 200 5g speakers (latest generation) use MPD (micro pleated diaphragm) high frequency transducer, kinda similar to the ribbon tweeter but not a ribbon tweeter. The same kind of MPD tweeter used in the MA Platinum series ll (latest gen). The previous generations of the MA Gold series 4g use ribbon tweeters. The latest gen of Gold series 5g shares the same DNA & technology (trickle down technology) with the latest gen of Platinum series ll.

So my MA Gold 200 5g (latest generation) are warmish sounding speakers, very smooth very refined, and definitely sounding much more laid back, much smoother and warmer sounding than the previous Gold series 4g, which I found to be bright. The current latest version of Gold series 5g sound very different from their prodecessors. They are complete opposite as far as tonality.

That said, I’ve heard from some that the SST Son of Ampzilla ii is slightly warm sounding amp. I’ve never heard the Parasound Halo A21 before.
@dilatante +1 It is, and it is a good choice. I own one.

I’ve heard from some that the SST Son of Ampzilla ii is slightly warm sounding amp

@ david_ten 

Do you own the SST Son of Ampzilla ii (series ii) amp? What are your speakers? 
James Bongiorno designed fine SS gear (SAE, Dynaco, GAS, Sumo, SST). Right now I am using the Sumo Andromeda amp with DCM Time Windows. This combination sounds quite impressive! I also have on hand two of the old GAS Sons and a Thoebe preamp. I expect that the SST Son will sound excellent!
@jasonbourne52 +1 re.:

James Bongiorno designed fine SS gear (SAE, Dynaco, GAS, Sumo, SST).


I have the series 2 (the one under W4S leadership/direction).

I have driven Gemme Tanto V2s, Charyo Academy Sonnets, and Tekton Design DIs and DI-SEs with the SoA 2.

Didn't we have this same post in November? It's a fine AB amp, inexpensive, owners like it (I do), the reviewers like it. Unlikely anyone will be able to comment on it vs the Sigma or with your particular speakers, that's a needle in a haystack. Talk to Walter at Underwood, he will have the most info, not sure if he has anything to demo, that's the challenge with smaller brands with limited distribution.
I have listened to and sold many of the great brands of hi-fi gear out there, and I have owned tube, hybrid, and solid state amps. So my comments below are informed by this experience.

After much research and consideration, I opted for a Son of Ampzilla II amp as the final amp for my system. The amp sits between my Wyred for Sound DAC 2 and my Living Sounds Audio LSA-20 Statement speakers. It proved to be a 'sound' decision.  ;-) (My virtual system post is at

The amp offers the best aspects of tubes and solid state amps and it has no sonic weaknesses. It presents a very low distortion and cohesive sound across the audio spectrum, and sounds equally good at low, moderate, and high volumes. The best characterization of its sound is that it sounds like a great class A solid state amp. I think its lack of distortion coupled with a high level of cohesive detail is what makes many people think of it as a 'warm' sounding amp. 

I am unabashedly biased towards this amp I recommend it without reservation.  

Happy listening everyone!
Their amps are great, not heard a word of negativity about them.

    Few warranty things, some electronics have a half soldering, loose connection during shipping.

years ago I bought the Crown studio ref II, 780W a8 Ohm, and so on.
  Came with a 30 amp plug, which I could not use.
sold my grail amp at a slight loss to a nice guy, he emailed me one channel had some issues, I said, I just received it 2-3 weeks prior, it still had plastic on everything.    Mailed me back in a couple weeks, thanking me, it was some loose wire, or a solder joint, a very minor fix. I hope he still uses it, I wish I had the 30 amp outlet for it, would not have sold it.

damn, I always ramble, the Ampzilla Is a serious piece of iron!!    Use it, enjoy!  I looked at them years ago, but, could not $ a new one, plus they don’t come up for sale used often, .....this tells you something.

 The good stuff comes for sale on a blue moon,....
I happened to find my monoblocs’ for a very nice price, so I think it’s a great price.     Only bought a few new pieces, Onkyo m-504, b&k pro-10mc newer model)
cerwin Vega D-9s’. Altec Lansing m508 or the m510 pair, they were only here for 2 weeks, amps used were my mistake, why they are not still here, they were a great speaker, and that dome midrange had nice subtle sound when needed, and a wicked crunchy vicious guitar when called for.
   I miss those, big time.

 They had the carbon woven woofers, some tweet and some mid, 2 8” or 2 10”.  I think I had the m510s’.......damn now I’m kicking myself, they would have sounded so good with a good amp.

   I’ve kicked my own arse over the years for dumb mistakes in audio.

   Yet again,....sorry

Ampzilla is amazing, if you can afford one, get one, let her break in and please report back....
I have gone through many amps over the years. I was using BC REF500M’s, which are awesome Class D amps. Then, I found a great deal on a SOA II and since I had wanted one for some time I jumped on it. It has transformed my system. From going through numerous amps in the same system my past experience told me that there will be some differences between amps., but they tend to be incremental and subtle. After having the chance to listen to many of my go to albums I can honesty say that the experience with the SOA II has been transformative. First you will notice that the sound stage and imaging are insane. You feel like you are stepping into the music and the artists are right there in the room with you. From there you will just have that sensation of there being more of everything from the decay of the cymbals to the heart stopping bass. The vocals are so life like you just want to reach out and touch the artist. If you have the speakers and DAC to do this marvel justice I would recommend the SOA II without hesitation.

My setup: Auralic Aries - BC DAC 2.7 - Wyred4Sound ST Preamp- SOA II - Acoustic Zen Adagio Speakers + Martin Logan Sub

I find this thread interesting, since I’m in the market for a new amp. Any sense of how this amp would compare with an AVA Set 500?