AkitikA GT-102 power amplifier

Discussion in 'Power Amps' started by k4rstar, Apr 13, 2019.

  1. k4rstar

    k4rstar Done his time

    Friend BWC
    Joined:
    Jun 11, 2016
    Likes Received:
    5,268
    Trophy Points:
    113
    Location:
    Toronto, Canada
    I recently acquired one of these amplifiers and I felt compelled to share about it as I think products like this deserve a lot more recognition. This isn't really a 'review' as much as it is a news bulletin for anyone interested in such a product. I understand the forum here at large is still occupied with the personal audio space but more and more members are beginning to dabble in two channel setups and are understandably intimidated with the amount of choice available with two channel equipment. I experienced this too not too long ago.

    The AkitikA GT-102 is a solid-state class AB power amp sporting 50wpc into 8 ohms that is sold direct from AkitikA as a kit or an assembled product. I originally read about it via a feature in Stereophile magazine last year and it sort of stuck in the back of my head until now. I often read about components in passing and get a curiosity about them that is not satisfied until I have heard the component. This year my partner and I were making some system changes and we realized we might be out of an amp for at least a few weeks. With the GT-102 priced at just $314 for the kit and $488 assembled it seemed like a good as time as any to try it, especially with a generous 30 day money back policy.

    Anyone who knows me knows I am a tube guy through and through and I typically do not rate solid-state amplifiers. Most of them seem to fall into the same category of mediocrity for me. My justification was that the GT-102 was inexpensive enough to warrant trying as an intermediary amplifier and if it was so-so then at least it would serve as a back-up amp on closet duty later on. After a few emails back and forth with Dan, the man behind AkitikA, I placed an order for an assembled unit.

    [​IMG]

    I almost forgot to mention that the GT-102 is a chip-amp, and this drove my curiosity as I had no prior experience with them. I know it uses the LM3886 which is popular among DIY Gainclone builders but my expertise on the subject matter ends here. I can't say how it compares to other chipamps or DIY projects. I was also attracted to the units very minimalist appearance, both externally and internally, and the attention to detail provided for a relatively low-cost amplifier.

    [​IMG]

    Due to my own lack of experience with chip-amps I was skeptical of whether or not the GT-102 could drive our JBL 4367 speakers with the authority I had come to expect from solid-state amplification. After all, the most recent amplifier used with these speakers was a Kinki EX-M1 integrated, which sported 200wpc of MOSFET output and had no issues in the authority department. My fears were unfounded as the performance of the GT-102 with the JBLs (94db/W @ 6 ohm nominal) really impressed me.

    The following paragraph will seem cliche but my initial impressions were of a clean, clear sound albeit without an insipid presentation. In fact, I can say that with my speakers and system I largely preferred the sound of the GT-102 ($488) over the Kinki EX-M1 ($2200). The more I listened the more I began to appreciate what these minimalist solid-state designs can offer as I heard a good sense of timing to the music and a lack of smearing. This shouldn't have really come as a surprise as my experience with lower power and lower parts count tube amplifiers was the same, but it did anyway due to the price of the GT-102. The GT-102 simply sounded more direct, naked and immediate which allowed me to get more involved in the piece of music it was playing.

    If you are in the market for an inexpensive solid-state amplifier or are looking to dabble in stereo equipment for the first time, I can't give any higher recommendation than to professionally documented kit-based products like the GT-102 which unfortunately have largely gone out of vogue in today's audio society. If you put in the time and effort to build it and have relatively easy to drive speakers then $314 (or $488 assembled) spent on this amplifier will be really rewarding. If it's not your thing, AkitikA will take the unit back within 30 days for a refund. It was a no-brainer for me, and I will definitely be keeping mine.

    System used for evaluation:
    JBL Synthesis 4367 speakers
    The 'Truth' line stage
    Schiit Gungnir Multibit DAC
    CAL Delta CD transport
     
    • Like / Agree Like / Agree x 21
    • List
    Last edited: Apr 13, 2019
  2. murphythecat

    murphythecat Self Imposed Exile

    Friend Banned
    Joined:
    Apr 4, 2016
    Likes Received:
    1,091
    Trophy Points:
    93
    Gainclones can be absolute world beaters, the lm3886 and lm3875 are the two best chips.

    i have compared about 10 ss amps vs my lm3875 and the lm3875 retained the best. Its only with tube amps that i finally heard a small upgrade

    the technical reason on to why lm3886/3875 are so good have been clearly explain to me by one of the designers at ifi audio and diy guru Thorsten loesch:


    Let me address the basics,not the specifics. Bipolar output Transistors and vertical Mosfets (Hexfets etc.) are all extremely temperature dependent in certain parameter. Tubes and Lateral Mosfets are not temperature dependent or in a way that stabilises the operation. Class AB works well as long as the output devices work stable with temperature, so tubes and Lateral Mosfets. It does not work well with Bipolar transistors or Mosfets, unless the whole output stage can be made from a single piece of silicon (chipamp). If the prior conditions are not met severe thermal distortion accrues, worse with more junctions in the output stage though vertical mosfets are even worse than a tripple follower bipolar output stage. I have never seen this subject addressed much after a few japanese papers in the 80's, it seems like everyone decided because there was no easy cure for the problem the best way to deal with the problem was to ignore it. If well implemented a Class A Bipolar or Mosfet Amplifier operates at very stable temperature (as long as 95% of all music is in Class A, some Class AB for high peaks is okay). As Lateral Mosfet Amplifiers are rare (the Output Devices actually cost real money - why use them if D. Self says "they measure 10 times worse than bipolars"), not only on DIYA and most of the options presented ain't great either... There are also some other measures that can improve the front-end inherent linearity and improve the Class AB output stage,all of which are applied in the LM3875/86. Degenerating the input stage, input stage current mirror and the voltage amplification stage improves linearity a great deal, as does the consequent application of buffers in front of each stage. Few discrete amplifiers apply these excellent ideas and even fewer integrated chips do, they usually aim to maximisenegative feedback at low frequencies, which is mostly pointless. So I stick to my guns. All else being equal, if the power is enough, go gainclone, LITERAL gainclone, that is copied from the Gaincard, which uses LM3875. No other chipamp's (except the LM3886). Few discrete I can think of stand a chance to match this.
     
    • Like / Agree Like / Agree x 3
    • List
  3. msommers

    msommers High on Epipens

    Friend
    Joined:
    Nov 6, 2016
    Likes Received:
    2,845
    Trophy Points:
    113
    Location:
    Calgary, Alberta
    Home Page:
    When D2 mentioned an amp like 1/5th the cost of the Kinki on CAM I was really intrigued. Glad to hear this is what they were referring to.
     
  4. restrav3

    restrav3 Likes Audio-GD

    Contributor
    Joined:
    Jun 18, 2018
    Likes Received:
    128
    Trophy Points:
    43
    Location:
    PA
    Thanks for the heads up. picked one up to see what's what. If it preforms on that level, it will be my only SS amp.
     
  5. ogodei

    ogodei Headphone Heaven Gatekeeper

    Friend
    Joined:
    Feb 9, 2016
    Likes Received:
    2,086
    Trophy Points:
    93
    Location:
    Chicago
    Mine arrived today but will be a few weeks before I can test it out :(
     
    • Like / Agree Like / Agree x 1
    • List
  6. k4rstar

    k4rstar Done his time

    Friend BWC
    Joined:
    Jun 11, 2016
    Likes Received:
    5,268
    Trophy Points:
    113
    Location:
    Toronto, Canada
    Awesome, what will you be pairing it with?
     
  7. JustAnotherRando

    JustAnotherRando My other bike is a Ferrari

    Contributor
    Joined:
    Aug 15, 2017
    Likes Received:
    1,419
    Trophy Points:
    93
    Location:
    Hong Kong
    Very tempted, thanks for posting. was toying with the idea of an an amp kit and after the OSMT, and this looks to tick the right boxes. I'll have to look into the 20lbs international shipping thing though.
     
    • Like / Agree Like / Agree x 1
    • List
  8. ogodei

    ogodei Headphone Heaven Gatekeeper

    Friend
    Joined:
    Feb 9, 2016
    Likes Received:
    2,086
    Trophy Points:
    93
    Location:
    Chicago
    PAP Trio 15, not sure what the final chain will be.
     
    • Like / Agree Like / Agree x 1
    • List
  9. restrav3

    restrav3 Likes Audio-GD

    Contributor
    Joined:
    Jun 18, 2018
    Likes Received:
    128
    Trophy Points:
    43
    Location:
    PA
    I actually meant the gainclone not the Akitakita
     
    Last edited: Apr 18, 2019
  10. Btdk34

    Btdk34 Facebook Friend

    BWC
    Joined:
    Feb 16, 2016
    Likes Received:
    109
    Trophy Points:
    33
    When you get it up and running, I'd be very curious to see how you like it. I'm looking for a a mid-range amp upgrade for my PAP Trio 15s as well, currently running an Emotiva A-700. I was leaning towards Aegir, but this could be a good option it seems.
     
  11. crenca

    crenca Friend

    Friend
    Joined:
    May 26, 2017
    Likes Received:
    2,162
    Trophy Points:
    93
    Location:
    Southern New Mexico
    I have a pair KEFQ350's and a parasound A-23 (and a small REL sub) in my office as my "computer speakers". @purr1n is right, the amp is muddled and just off (for a SS amp). Looking to upgrade. Stereophile measured the Q350's here:

    https://www.stereophile.com/content/kef-q350-loudspeaker-measurements

    As you can see, they dip to 4 ohms at 125hz and below 5 ohms at around 50hz. Opinions if the Akitika is a possible fit? My impression (which could be wrong) is that this circuit topology is problematic on a (relatively insensitive) speaker that probably should be rated at 4 ohms and not 8 ohms....
     
  12. k4rstar

    k4rstar Done his time

    Friend BWC
    Joined:
    Jun 11, 2016
    Likes Received:
    5,268
    Trophy Points:
    113
    Location:
    Toronto, Canada
    I would recommend against it. Read JA's measurement column in the review here, there are distortion and power delivery limitations into a simulated 4 ohm load. You would experience either clipping at slightly higher than moderate volumes or poor bass response. You will want to look for an amplifier that is much more stable into such a load (or new speakers!).
     
    • Like / Agree Like / Agree x 1
    • List
  13. rlow

    rlow A happy woofer

    Friend
    Joined:
    Jul 18, 2017
    Likes Received:
    6,091
    Trophy Points:
    113
    Location:
    Canada
    Used or b-stock Vidar if you want to save some money from new (and you can find one).
     
    • Like / Agree Like / Agree x 1
    • List
    Last edited: Apr 18, 2019
  14. Cspirou

    Cspirou They call me Sparky

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    6,122
    Trophy Points:
    113
    Location:
    Northwest France
  15. HAL9000

    HAL9000 Almost "Made"

    Contributor
    Joined:
    Apr 4, 2016
    Likes Received:
    365
    Trophy Points:
    63
    Location:
    Fairfield, IA
  16. JustAnotherRando

    JustAnotherRando My other bike is a Ferrari

    Contributor
    Joined:
    Aug 15, 2017
    Likes Received:
    1,419
    Trophy Points:
    93
    Location:
    Hong Kong
    So I'm thinking about putting this together, mainly for fun as an OSMT build for a niece was enjoyable, so a fairly simple looking amp seems the next logical step.

    Any thoughts on how this would work with low sensitivity speakers, either another OSMT (25 watts RMS/50 watts max, 83dB 1W/1m, 8 Ohm) or another one of the Paul Carmody design like the Carrera (bugger all info but probably ~85dB)?

    Edit: It took me a while to realise that this amp doesn't come with a volume control (huh?!) but an additional volume control can be ordered for $10, requires a hole drilled in the faceplate).


    The irony of being next to China, cheap labour and Aliexpress shipping, yet ordering bulky DIY kits from the US does not escape me.
     
    • Like / Agree Like / Agree x 1
    • List
    Last edited: Apr 19, 2019
  17. k4rstar

    k4rstar Done his time

    Friend BWC
    Joined:
    Jun 11, 2016
    Likes Received:
    5,268
    Trophy Points:
    113
    Location:
    Toronto, Canada
    Is there an impedance plot published anywhere? The OSMT uses very small drivers in a ported box, it should be fine. People run them with 20 watt T-amps from what I've seen.

    As an update, I've had a few technical difficulties with The Truth line stage, so I decided to order the matching Akitika pre-amp, the PR-101. It arrived today and I'll follow up with some impressions on that unit later on.

    [​IMG]
     
    • Like / Agree Like / Agree x 5
    • List
  18. sunnysideup

    sunnysideup Rando

    Joined:
    Oct 21, 2017
    Likes Received:
    3
    Trophy Points:
    3
    Location:
    Singapore
    I have the GT-102 with volume control as my idea was to simplify the audio chain. It is hooked up to my Marantz CD player and JBL 530 bookshelves, and subsequently adding Gungnir MB in the middle for CAS. Result was a wide and holographic sound stage. To some comments on the amp leaning towards warm signature, I neutralized it (to my ears) by swapping out the thick gauge copper speaker cables for some thin gauge tinned copper ones (Belden 9497).

    Tried using the Mjolnir 2 as a preamp, but the dynamics felt bogged down. Switching between tube sets did not help.

    Still glad I order it with a volume control even though it is unorthodox and odd looking for a power amp. I get to experience the amp for what it is.

    Just wanted to say this... I love that green industrial looking power button! Haha!

    @k4rstar: Looking forward to your opinions on the PR-101 paired with GT-102. Toying with ideas of adding a sub. ;)
     
  19. enginerd

    enginerd Rando

    Contributor
    Joined:
    Jul 2, 2017
    Likes Received:
    46
    Trophy Points:
    13
    Location:
    San Francisco, CA
    I just built my GT-102 over the holiday weekend. Bought it sometime last year but never got around to building it, but finally did. I'm a soldering n00b (have only built a Bottlehead Crack), but things seem to go fine and everything tested and worked great. I also built some Overnight Sensations MT speakers too. Initial tests last night sounded pretty decent, but haven't done any critical listening.

    I'm interested in hearing about the PR-101 too. Wish I had just ordered the GT-102 with the volume control, but I don't mind having to build a pre-amp too :)

    [​IMG]

    [​IMG]
     
    • Like / Agree Like / Agree x 9
    • List
  20. JustAnotherRando

    JustAnotherRando My other bike is a Ferrari

    Contributor
    Joined:
    Aug 15, 2017
    Likes Received:
    1,419
    Trophy Points:
    93
    Location:
    Hong Kong
    I built this about a month ago, but can't give any useful sonic impressions as all I have at home are DIY prototype speakers using drivers that nobody else has.

    However, I can say that as a DIY kit, this was very enjoyable. Packaging was rock solid and really well thought out. Very good boxing, custom foam cutouts, secondary cardboard boxes that separate different groups of parts, clearly labelled ziplocks for the same. It survived a cross country shipment then an international courier, which was a big step up from my last kit shipment- Parts Express uses extremely flimsy cardboard boxes with minimal padding, I was surprised that nothing fell out of the huge gashes that transport left in the side of their box for the Overnight Sensations kit.

    Compared to something like an OS kit, there are lots of parts. And the 50 page build manual seemed a bit daunting at first. But once I got started, I realised that the instructions were extremely well laid out and clear, and all the little ziplocks separated out the parts into logical and easy to manage sections. I built this over the course of weeks, a couple of hours here and there, as as building involved setting up on the living room table after the kids were in bed each night.

    Whenever I did have questions, Dan at Akitika would reply very promptly, well within the same day.

    If you're building this, a couple of notes:

    The optional volume control kit comes with a fairly generic potentiometer, and is a bit scratchy. If you're going to the effort of building this, you probably want to use the nicer Alps pot, RK27112A00A5. RS stock number 219-9130. Check the specs for yourself first though, I haven't installed mine yet.

    If you're building the 220V version and encounter a problem with blown fuses, use Littelfuse 021901.6MXAP, RS stock number 541-3489.

    You might have to use a magnifying glass to read the part numbers on some of the diodes- they are frikken' tiny. Seriously.

    Edit 6 months later: I can confirm that the 10K Alps pot mentioned above works fine with this amp. The best matching knob I could find for the case is RS part 259-7039. You need to shave down the pot shaft by about 5mm for a flush fit to the case (this is easy enough just using a metal file, the shaft is made of some really soft metal). Yes, it's taken me this long just to add a volume control to the amp.
     
    • Like / Agree Like / Agree x 7
    • List
    Last edited: Feb 24, 2020

Share This Page