APPJ mini2013 vs. APPJ PA1501A Mini Tube Amplifiers

MCM_Fan

AK Subscriber
I'm looking for an inexpensive tube amp for a friend who is interested in giving tubes a try. I will be loaning her a pair of Klipsh KG4's to start out, as they are the most efficient speakers in my stable. If she likes the sound, we'll either upgrade my KG4s (Crites diaphragms and recapped crossovers) or maybe track down some even more efficient speakers.

There are two currently offered on Massdrop:

APPJ PA1501A Mini Tube Amplifier ($149.99 + $9.50 shipping):

Upgraded Tube Amp
Released earlier this year, the APPJ PA1501A is the latest tube amplifier from Gemtune. Based on the PA0901A with a host of upgrades, it features two 6AD10 tubes in a Class A configuration for improved noise performance, frequency response, and power output. This amp is beautifully built with a solid metal chassis, and delivers enough oomph to drive your favorite bookshelf speakers.

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Specs
  • Gemtune
  • Tube: 6AD10
  • Power output: 3.5 W + 3.5 W at 8 ohm
  • Frequency response: 30-40 kHz (+/- 1 dB)
  • Input sensitivity: 500 mV
  • Signal-to-noise ratio: -80 dB / 3.5 W
  • Residual noise: < 0.5 mV AC
  • Input AC voltage: 100-250 V AC
  • Power consumption: 38 W
  • Input impedance: 10 kohms
  • Output impedance: 8/6/4 ohm (Japan Z11-EI48*24 output transformers)
  • Input: RCA jacks
  • Output: Banana jacks
  • AC: Standard IEC jack with fuse protection (2A fuse)
  • Dimensions: 6.3 x 5.3 x 4.9 in (16 x 13.4 x 12.5 cm)
  • Weight: 5.5 lb (2.5 kg)
APPJ mini2013 6J1+6P1 ($99.99 + $9.50 shipping):

New Mini Tube Amp

Featuring two 6J1 driver tubes and two 6P1 power tubes, the new mini2013 6J1+6P1 mini tube delivers great noise performance, frequency response, and power output for the price. It’s beautifully built with a solid metal chassis in your choice of color, and provides enough oomph to drive your favorite bookshelf speakers.

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Specs
  • APPJ
  • Driver tubes: 6J1
  • Power tubes: 6P1
  • Power output: 3W + 3W at 8 ohm
  • Frequency response: 30–40 Khz (+/- 1 dB)
  • Input sensitivity: 500 mV
  • Signal-to-noise ratio: -80 dB / 3 W
  • Residual noise: < 1 mVac
  • Input AC voltage: 100–350 Vac
  • Power consumption: 35 W
  • Input impedance: 10 kohm
  • Output impedance: 8/6/4 ohm (Japan Z11-EI48*24 output transformers)
  • Input: RCA jackets
  • Output: Banana jacks
  • AC: Standard IEC jack with fuse protection
  • Dimensions: 4.9 x 5.2 x 6.5 in (12.4 x 13.2 x 16.6 cm)
  • Weight: 3.7 lb (1.7 kg)
  • Power cord not included
So, has anyone heard both? If so, which did you prefer and why? The mini2013 has been around longer and seems to be well regarded for the money, but the PA1501A claims to be an upgraded/improved design. I like the looks/form factor of the PA1501A better, but that's not really all that important. The real question is, does it actually sound better than the mini2013?

Also, which model would be better for (affordable) tube rolling? The 4-tube (2 each 6J1 + 6P1) mini2013, or the 2-tube PA1501A (2 each 6AD10).
 
I'm very interested in these two amps as well, I hope someone who has experience with them posts in this thread.
 
The four tube looks to be the same as the original APPJ/Miniwatt S1 and uses the same tube compliment. There are many reviews on the S1. The only place I've seen mention of the PA1501A is on AC where one guy has both. He seems to prefer the newer PA1501A which has more power. There was another post on AC's C&C from someone in China who I believe sells both but I can't find it.

http://www.audiocircle.com/index.php?topic=137607.40
 
Note that distortion specs are absent. According to the spec sheet, this tube delivers about 10% distortion in Class A, and doesn't appear to be especially linear. Thoughts?
 
A relevant quote:

On the test bench, SET amplifiers have laughably bad technical performance. They typically produce fewer than 25Wpc of output power and have extremely high distortion—as much as 10% total harmonic distortion (THD) at the amplifier’s rated output. Although most SET amplifiers use a single triode output tube, additional triodes can be combined to produce more output power. Some SET amplifiers, however, put out just 3Wpc. In fact, there’s a kind of cult around SET amplifiers that strives for lower and lower output power. These SET enthusiasts believe that the lower the output power, the better the sound. One SET designer told a reviewer, in all seriousness, “If you liked my 9W amplifier, wait until you hear my 3W model.”

From = http://www.theabsolutesound.com/articles/a-survey-of-amplifier-types-tas-217-1/
 
Another relevant quote from bubba's article:


"Despite these technical drawbacks, my listening experience with SET amplifiers suggests that this ancient technology has many musical merits. SET amps have a certain presence and immediacy of musical communication that’s hard to describe. It’s as though the musicians aren’t as far removed from here-and-now reality as they are with push-pull amplifiers. SET amps also have a wonderful liquidity and purity of timbre that is completely devoid of grain, hardness, and other artifacts of push-pull amplifiers. When I listen to SET amplifiers (with the right loudspeakers), it’s as though the musicians have come alive and are playing in the listening room for me. There’s a directness of musical expression that’s impossible to put into words, but is immediately understood by anyone who has listened for himself. You must hear an SET firsthand to know what the fuss is about; no description can convey how it sounds."
 
Speaking of that topic, where can I get advice on the best full-range drivers for the money. I am thinking about building full-range driver speakers this summer for fun. I am not looking to spend much, up to about $200 for the drivers, then I'll make some open baffle speakers/frames. Wild Burro Betsy? Dayton Audio PS220 or PS180? Other recommendations or places to find comparison reviews?
 
I'd suggest the Frugal Horn Mk3 with Fostex FE126En full range drivers ( about $50 each ). As you can see from this picture they're not as complicated as many designs. You can corner load them for more bass output. Great sound and looks. Plus they are a good match for the APPJ/Miniwatt amps.

P2130008.jpg
 
I'm looking for something much more simple, I moved and have almost no access to tools, so this has to be easy. I am thinking open-baffle, maybe with hinged wings, but that is about it.

I was thinking that 6 to 8in full-range driver would produce much better results, wouldn't they? And I had heard there were better options than fostex, hence asking about the Betsy or Dayton drivers.
 
The Wild Birro Betsy's in folding wings are the simplest OB project you will find. The Betsy lacks the micro detail of the Fostex but it sounds more spacious. Without augmentation bass is limited with the Betsy but many find it acceptable. If you buy the plywood from Home Depot they will make all the straight cuts so all you'll need is a jig saw to cut the speaker holes. I used piano hinges which seal the wings nicely but door hinges are ok if you duct tape the seams between panels. These are very large OB's and will eat up lots of floor space. Just like all OB's they should be pulled out into the room for best results. In this picture the silver MW/APPJ is powering the Betsy's.

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I have one of the PA1501A's arriving hopefully the first week of July from the last drop on Massdrop and will listen a couple weeks and give a full report. I have not heard the other version or it's Miniwatt predecessor, nor am I an experienced reviewer, but more information and viewpoints about these amps can only be good.
 
I have one of the PA1501A's arriving hopefully the first week of July from the last drop on Massdrop and will listen a couple weeks and give a full report. I have not heard the other version or it's Miniwatt predecessor, nor am I an experienced reviewer, but more information and viewpoints about these amps can only be good.


Sounds good, can't wait to hear your thoughts. I've been considering one of these to power my Omega 3i monitors that I use in my desktop system.
 
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