Audiophilepure

https://www.hifichoice.com/content/longdog-audio-p6100m

This is helped along somewhat by the naturally gutsy, barrel-chested sound, but it’s not thuggish or brutish in any way. There is enough slam to really tickle the big 12in bass drivers of my loudspeakers. This power is swiftly deployed; the opening drums on Roxy Music’s More Than This for example, are wonderfully powerful and dramatic when the wick is turned up. Yet still there’s no obvious sense of strain, despite the amplifiers not having a ‘muscle amp’ look about them.

Extended listening ends up with me thoroughly enjoying these Longdog Audio monoblocks. They’re really good at pretty much everything; for example, soundstaging is excellent, with a really ‘out of the box’ presentation that is never less than expansive and three dimensional. Ultimately, perhaps, they don’t have the true grit and insight of some really high-end designs – yet they deliver massive amounts of sound per pound.

https://www.enjoythemusic.com/superioraudio/equipment/1023/Margules_Audio_U280SC_30th_Anniversary_Limited_Edition_Vacuum_Tube_Amplifier_Review.htm

I learned that even in ultra-linear mode, this amplifier could easily drive the Scansonic speakers to a volume that I considered “realistic.” Not only was the volume more than satisfactory but so was their sound, due to the sound quality prowess of the Margules U-280SC 30th Anniversary tube amplifier. Even though the Scansonic MB5 B speakers cost less than half the price of the speakers that were used for the majority of the audition period, their midrange transparency made it so I felt as if I could hear not only details from the musical signal being sent to the speakers but the details from the musical signal that was sent to the Margules amplifier.

The above description might seem a bit obtuse. Yet, it was the relative amount of transparency of these speakers that led to a feeling that I could imagine hearing through to the Margules amp, and therefore could sense that I could clearly hear the intentions of the musicians, engineers, and producers that were responsible for the recording I was listening to at the time. The Margules amp’s level of transparency was often frighteningly lifelike sounding on some recordings.

https://www.enjoythemusic.com/superioraudio/equipment/1023/Art_Audio_Opus4_Carissa_Vacuum_Tube_Amplifier_Review.htm

Art Audio’s Opus 4 monoblocks managed to convey an impression to me of nearly as much depth of overall musicality as the 275 Watts of ultra-linear power of my other reference system amp, the CJ Premier 8A. I ultimately decided to keep the Carissa amplifier as part of my system to use with the Quad 57s and as an alternative for the 63s when they are not connected to the big CJ amps. The power, control, and sound along with the lavish and lovely looks of this latest revised Art Audio 18 Watt SET amp as designed by Tom Willis is highly recommended to be seen and heard.

Art Audio’s Carissa vacuum tube stereo amplifier has character, a distinctive beauty, and elegance that it continues to be part of my reference system. If you are looking for an elegant-looking design and musically refined, and lovely sounding amp in a more powerful rating range, then seek out an audition of the Art Audio Opus 4 monoblocks that have a diminutive look and weight yet produce a prodigious, powerful, and excellent quality output. Bravo to both Tom and Scott for their excellence in design, musical listening, and customer support throughout this evaluation period.

The Parasound Halo A21+ amplifier impressed me with its powerful, musical, and accurate reproduction of music and movie soundtracks. This amplifier had wayyyy more power than I could ever need as well. The performance I heard was beyond reproach and I didn’t hear any untoward sounds the whole time it was in my system.

In terms of implementation, the Halo A21+ was well-made in most respects. My only quibbles are the stamped metal cover and the two-piece heat sinks. These parts fell short of a high-end build in my view. However, they did not take away from the very flexible hook-up options and apparent protection circuitry. These features render the amplifier very useful in a wide range of settings.

My final conclusion is to buy this amplifier for its flexibility and performance qualities over the build decisions. The price of this amplifier has been raised recently but it is still well worth every penny you spend on it. Recommended for sure!

https://www.soundstagehifi.com/index.php/equipment-reviews/1833-nuprime-audio-evolution-two-mono-power-amplifier

To my ears, the Purifi Eigentakt based NAD Masters M23 stereo/mono power amplifier, which I reviewed in March, sets the standard for a truly high-performance amplifier at a reasonable price—by a wide margin. With a retail price of only $3749, it sounds superb, measures spectacularly well, and has a healthy power rating of 200Wpc into 8 ohms. As I said in my review, it is a “screaming bargain.” Bryston’s spectacular 4B³ ($7495), which I reviewed in June 2017, is also a stellar performer on the test bench, albeit at twice the price. Rated at 300Wpc into 8 ohms, it delivers significantly more power than the NAD, and has a beefier but very neutral sound. There is nothing like a brawny class-AB amplifier to instill a sense of confidence and pride in ownership. These are my two favorite power amplifiers among those I have reviewed in the past few years. I’ll be interested to see Diego Estan’s measurements of the Evolution Two. It may not be quite as neutral as the NAD and Bryston, but I found that its overall high level of performance and marginally warmer sound was just as pleasing and, in fact, may be preferable to some listeners.

Conclusion

NuPrime Audio had fallen off my radar in recent years. The last NuPrime product I reviewed was the IDA-8 integrated amplifier-DAC, which I loved. It was an absolute steal, providing fantastic sound and a healthy amount of power for under $1,000. But that was almost eight years ago. The Evolution Two has reintroduced me to this innovative brand. The market for power amplifiers at the Evolution Two’s price level is now very competitive. But NuPrime has more than kept pace with their reference mono amp, and by keeping its price relatively constant, the Evolution Two rivals the very best in its class.

https://www.enjoythemusic.com/superioraudio/equipment/1023/Art_Audio_Opus4_Carissa_Vacuum_Tube_Amplifier_Review.htm

These days, there are many choices for amplifiers and decisions are not easy without personally listening to them in your own home. Overall if I did not already have another push/pull amp available at my home to use with the Quad 63s, I would have considered keeping the lovely Opus 4 monoblock amps. I suggest anybody seeking an amp of this design and style give it an audition in your home. It is quite a remarkable achievement that the 50 Watts triode power from the Opus 4 amps managed to portray so much strength and control for the Quad 63s.

Art Audio’s Opus 4 monoblocks managed to convey an impression to me of nearly as much depth of overall musicality as the 275 Watts of ultra-linear power of my other reference system amp, the CJ Premier 8A. I ultimately decided to keep the Carissa amplifier as part of my system to use with the Quad 57s and as an alternative for the 63s when they are not connected to the big CJ amps. The power, control, and sound along with the lavish and lovely looks of this latest revised Art Audio 18 Watt SET amp as designed by Tom Willis is highly recommended to be seen and heard.

https://www.soundstagehifi.com/index.php/equipment-reviews/1827-ars-sonum-armonia-stereo-amplifier

Yes, some care needs to taken when choosing speakers to use with the amp—that’s true of almost all tube amps and other amps with similar or lower power outputs. That is where I (your friendly Ars-Sonum distributor) come in. I am more than happy to talk with anyone interested in a Ars-Sonum amplifier (new or used!) to answer any questions about compatibility with whatever gear and speakers the customer may have. As well, for those (tube-head) Ars-Sonum amplifier owners who wish to “roll” different EL34s (n.b., KT77s are not recommended), I am happy to test their set of EL34s in our Amplitrex tube tester and then try them in the Filarmonía or Armonía on my test bench to verify matching and that self-biasing measurements meet factory specs for the amp.