Impressions: SMSL PA200 GAN FET Power Amps


I got (back) into hi-fi listening a couple of years ago, after quite a long hiatus, and started playing catch-up, and one of the hardest games of catch-up was my power amp game. Long story short I started with Fosi ZA3s, then V3 Monos, then Topping B100s, and finally auditioned a Hypex nCore-based amp, and there was just something lacking with each of them. The V3 Monos had plenty of power, but the sound wasn’t as good as the amazing B100s. The B100s unfortunately just didn’t make enough power to really make my LS50 Metas sing, even when high-pass filtered and supplemented by my mighty SVS SB-3000 subwoofer handling the bottom-end. The B100s cut-out in my numerous times because of safety mechanisms. I loved their sound (could be that they’re class-B as opposed to class-D? Or could just be their insane measurements), but the power limits weren’t practical. I had been researching higher-end class-D amps so I tried an IOM Ultra (NC252MP) which sounded good and was plenty powerful, but still not as good sounding as the B100s. Plus the power-on/-off pop was annoying me, so I gave that amp to my dad, who happily replaced the pair of V3 Monos I had given him with it. Finally I read that people say GAN FET class-D amps wouldn’t be truly beneficial until they took advantage of the technology and came out with a design that utilized a much higher switching frequency (say, 1MHz) than MOSFET designs (400-600KHz). 

Then came along SMSL’s new PA200 power amp. Based on Infineon’s latest GAN FET technology, these amps truly use a 1MHz switching rate. They have an integrated, bypassable Texas Instruments chip-based volume control if you run the amp stereo via single-ended input. The amp also allows bridging via balanced, differential input (which bypasses the volume control by default). Power figures are astonishing in bridged mono mode. Could these finally be the holy grail of amps with class-D efficiency and power but class-A/B sound signature combined with near-SOTA measurements? I decided it was time to find out, so I ordered up a pair.

Got them for about $700 shipped for the pair after combining store coupon from SMSL’s AliExpress store plus various seasonal AliExpress app coupons. The came in, I hooked them up, and listened…and hallelujah!!! These sound as good as the B100s at low to mid volumes, but with absolutely vast power on tap, so really outshines them once cranked up. I had heard that LS50 Metas need big power to truly sing, but I never really believed or understood that until now.  They really blew the B100s away at high volumes. I literally didn’t even know my speakers could sound so good. I haven’t heard B200s, but in my mind they may be the only thing that comes close in this price range, but actually they cost almost 50% more MSRP. In fact, with the massive power on hand, I actually ended up removing the subwoofer from my chain entirely as the KEF LS50 Metas are able to now extend down to below 35Hz in-room at reference level thanks to the driving ability of the  dual PA200s in bridged mono.

Negatives? Just a few:
1) no 12V trigger. You can, however, get around this by using a Panamax M8 AV Pro 12V trigger-activated power strip, as I am now doing
2) only comes in silver, and the rest of my gear is black—first world problems. I bought a D400 Pro DAC in silver to match them off better
3) no signal-sense auto-on/-off
4) also a faint pop when powering on (though none at all when powering off), but not as loud as NC252MP

Summary: SMSL PA200 sounds amazing, has ridiculous power, especially in bridged mono mode, and build quality is excellent. You just need to get over the lack of black color way and added cost to get 12V trigger function with the Panamax power strip.

-Ed

PS This is an update/repost of a prior thread I posted to the Amps/Preamps section not realizing that this Member Reviews section existed

eddnog

I use Class D Audio (US based) stereo GanFet with Ls 50 metas. Outstanding pairing similar to what you describe so not surprised. Also have a Hypex Ncore based Cambridge Audio integrated. Very different sound, both enjoyable but the GanFET clearly took things to a higher level of absolute performance resulting in sound improvements across the board specifically more laid back, neutral, dynamic in all regards and revealing. Fatigue is not an issue with either. A bargain priced home run!

Congratulations on the new find! I'm curious how the sound from a single P200 stereo compares to a bridged dual for the LS50. Are you still getting the LS50 to sing down to 35Hz in your room?  Thx.

@lanx0003 I decided to test this idea out, swapped to RCA connections and hooked up both speakers to one unit, and then put on some highly dynamic orchestral pieces and cranked it way up.

And it still sounds great! Extension is fairly deep, highs are still airy. Looks like I can just use one and be perfectly happy with it! However, I do feel there is less weight to the deepest bass notes.

-Ed

Thank you for the confirmation, Ed. On its way... I’d like to try it with my 4-ohm speakers, which dip down to 1.5 ohms and are demanding in EPDR. Getting the LS50, which is rated at 45 Hz (-3dB), down to 35 Hz kind of amazes me.

@lanx0003 I think part of that was also careful speaker placement/use of room reinforcement, because I could never achieve this in the past even with NC252MP. Of course, all that being said, the speakers need to be driven well enough down that low for anything to be reinforced in the first place!

-Ed

I tried placing the Buchardt S400 MKII closer to the front wall, but the soundstage depth suffered. I pulled it at least three feet away to restore some of it but the bass becomes thiner. Right now, I’m using EQ to extend the bass into the mid-30Hz range, but at times, the bass texture isn’t quite what I desire. I was considering a Hypex- or Purifi-based amp like the ones you’ve tried, but none of them are rated as stable at a 2-ohm load... Hope this one works.

If you know of a small-form-factor amp that is 2-ohm stable and/or has a power efficiency of at least 60-70% at that load, let me know. I know so far only Benchmark AHB2 could achieve that spec but it is over my budget... Thx.

I recommend the AHB2 be used in stereo for a 2-Ohm load.  Benchmark says mono is OK for 2-Ohms, but I found that the stereo was preferred when I had Thiel CS3.7 speakers.

@lanx0003 I have bought and sold the AHB2 about 6x over the last 10 years (cash positive). The AHB2 is not that hard to find, maybe a little harder today. If you check on UASM you should see one pop up.

The price of the AHB2 went up about 2 years ago. Check the date on any AHB2 you are interested in because an older unit (which is fine) sold for $3k. Some of these older units are listing MSRP at $3500.