APPJ PA1501A Mini Tube Amplifier Impressions

JasBy

New Member
I received the APPJ PA1501A from Massdrop yesterday and have had some time so listen and would like to give my impressions for others to consider.
The amp arrived packed very nicely in a foam block, with the tubes already mounted in their sockets.
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Fit and finish was excellent, no cosmetic issues, everything feels very solidly built, volume knob is metal and mounted with no wiggle or play, and turns with a good amount of resistance.

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Tube compliment is 2x 6AD10 marked USA on the top with no apparent brand stamp. For those not familiar, this is originally a TV tube that is used as both a pre and power tube. One of the main reasons I ordered this amp over the mini-watt clone they also order is the unique nature of the tubes, it's a little quirky - just like me (and the tubes can also be purchased for $10 each in many places) Tube rolling may be limited, if at all.

The system consists of a Denon DVD-1710 acting as a CD player into a Kenwood KR-3130 acting as a preamp only, then the 1501A feeding a pair of Klipsch RF-3 floor standing speakers. Previously I was using a Fisher 202 Regent console pull receiver, so all 'comparisons' are with this. My Dual 1226 turntable was not used yet, as I have developed a hum, so I will need to play with gear positioning to try and get rid of it.

A shot showing the relative size with the other equipment:
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I first plugged it in using a run of the mill black computer power cord (not included with the amp) After powering it up, with no output I turned the volume to full - no hum with only a tiny bit of hiss only at full volume. I would guess with any speakers not in the high 90db sensitivity this wouldn't even be audible. After powering everything else up, I put on Eric Clapton's Unplugged. Soundstage is wide and immersive, you seem to be 'in' the crowd during applause, and right to left imaging is pinpoint. With my old system, the triangle that the drummer uses on this recording was very 'hot' sounding, to the point of smearing out of the stereo image and frankly being irritating. I damped the horns on the RF-3's, which helped, and no sound treatments in the room probably also contributed to this. With the 1501A the triangle was completely balanced with the rest of the percussion and was a perfect point source right above the drum kit image.

Next was Nickel Creek's 'This Side' - acoustic strings are amazing, decay is realistic, and for the first time the bass sounded realistically like an acoustic bass, you can hear the body resonating. Voices were clear and engaging, and for the first time I can hear intakes of breath while singing. The mandolin on 'Hanging by a Thread' was magical - the strings were hanging vertically in the air, with the lower notes 'appearing' higher than the higher notes on the lower strings. It was a sensation I had never experienced before. Also, the percussive sounds they make on their guitars were now immediately recognizable, rather then being faintly drumlike.

Time for something a little punchier, I played Evanescence's 'Bring me to Life' - piano was excellent, but the lead female vocal seemed a bit 'hot' - the electronic edge they give to her vocals was very apparent. Here is where I noticed the shortfall of this amp - punch in the bass. Low frequency information is there, just not punchy. Bass guitar and electronic bass sounds are smooth and focused, but kickdrums have no 'oomph'

I wanted to check out the female vocals further, so I put in Diana Krall's 'The Look of Love' The background music is beautiful and imaging is excellent, and Diana's vocals are smooth and sexy and warm - but the 2 pieces did not mesh at all. Her vocals had no sense of space that the music did, and I can only wonder if she was recorded in a small studio, and not with the band - this was the impression I got. Overall the effect was unpleasant. I also got this impression with Ana Nalick - not as noticeable, as here music is more electronic in nature, but it was still there. I then put in Little Big Town's 'Boondocks' to see if it was just a female vocal issue. Vocals here were balanced and natural again, with a sense of space around them that encompassed all 4 singers, female and male.

One last test - I put in Dope's 'Die MF Die' - a pleasant in your face wall of sound crank it up favorite of mine :) This amp can get loud with sensitive speakers - my uncalibrated phone SPL meter was over 100db. Suprisingly, the 'wall of sound' was gone, replaced by exact guitars and baselines, and the intricacies of the guitar work was evident - I had never appreciated this aspect of the song before, always just getting lost in the slam of the loud song. Again, a total lack of kick drum oomph, but the electronic bass drops were low and present.

In conclusion, I can highly recommend this amp for anyone with sensitive speakers and a smaller listening room. I think it would also be excellent for near-field with less sensitive pairings. I listen to most of my music in the 80-85db range and it is superb at these levels. I find it accurate, pleasing, and warm with no apparent roll-off in the high ranges that I have noticed. Spatial cues are great, imaging is spot on, both horizontally and vertically, and depth as well. While I received it at a discount from MassDrop, I would gladly pay the extra to get it from Amazon or another source and consider it money well spent.

TL;DR version: Great amp, worth the cost, excels at acoustic, misses some kick-drum oomph.
 
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