Akitika GT-108 Stereo Amplifier Kit Review

[brunes]

I had zero experience and managed to follow the manual and get a working amp first time and it was a great way to spend a few evenings.

Its a bit addictive though, I have since made a modulus 86 from neurochrome and a 3e audio diy. Great way to spend a few evenings and super rewarding. Perhaps great amp for a second system if you are looking at numbers (+10 sinad as you made it yourself)

 

[restorer-john]

While personally, I may think driving stuff -on occasion- all the way to clipping for the sake of a uniform protocol is a bit unfair, it is easy to read between the lines, and establish if the measurements apply to your particular intended use case.

Power amplifiers and amplifiers in general are always driven to the onset of clipping. That's the number one parameter anybody wants to know first- how much power does it produce? Everything else comes after with power amplifiers.

SINAD means little if the "power" amplifier shuts down and can only produce a few watts.

However, testing the amplifier against its rated specifications is also important, but some (many) manufacturers simply don't provide comprehensive or specific enough published specs to effectively test against.

A one size fits all doesn't fit all. But special considerations shouldn't be given either. Rock and a hard place stuff.

 

[Doodski]

Power amplifiers and amplifiers in general are always driven to the onset of clipping. That's the number one parameter anybody wants to know first- how much power does it produce? Everything else comes after with power amplifiers.

SINAD means little if the "power" amplifier shuts down and can only produce a few watts.

However, testing the amplifier against its rated specifications is also important, but some (many) manufacturers simply don't provide comprehensive or specific enough published specs to effectively test against.

A one size fits all doesn't fit all. But special considerations shouldn't be given either. Rock and a hard place stuff.

I only fried one amp testing to clipping. It was a Sony with a cheap STK3042 amp IC if memory serves me correctly.
Otherwise I torture tested everything to clipping and soak tested for thermal stability and runaway by monitoring the total current draw and watching for slow spikes that increase rapidly. I used a multimeter for DC powered gear and I had a DIY plastic box with an analogue AC Volts meter and an analogue AC Ammeter in it with receptacles for power cords mounted to the case. I could run 2 AC devices from it simultaneously and it also worked with the variac for even more safety when first winding up an amp to power ON. Testing to clipping on every single amp was mandatory.

 

[pablolie]

... That's the number one parameter anybody wants to know first- how much power does it produce? Everything else comes after with power amplifiers.
...

Not me. Finesse is more important to me than power. Especially in the era of active subwoofers.

 

[Eulipian]

As someone who reminisces, disappointedly, for never having built a Hafler amp back in the day, for $425, I’d spend my funds elsewhere and use my saved assembly time to listen to some relaxing music on a Hypex, Purifi or TI based Class D amp.

I still use the Hafler I built as my primary power amp. It's 40+ years old and still sounds like nothing, soft or LOUD.

 

[Pillars]

I've had my GT-102 Z4 for many years. Well before several class D options were roaming about. Sounds really great and I enjoyed building it and a few for friends. I've tried to upgrade from it a few times but always came back to the punchy (colored?) sound this amp provides.

 

[SpecialK]

I've had my GT-102 Z4 for many years. Well before several class D options were roaming about. Sounds really great and I enjoyed building it and a few for friends. I've tried to upgrade from it a few times but always came back to the punchy (colored?) sound this amp provides.

I built Dan's original amplifier and his preamp eight years ago. The preamp was more difficult, and I had to send it back to Dan, and sure enough I had made a couple of errors which he promptly fixed. Most recently, I bought a built his phone section for the preamp, and it is really excellent. I am now in the process of replacing some old oxidized jacks on some of my reconditioned Dynaco equipment, and once again, his manuals are spot-on. I think the quality of his products is excellent and recently one of the stereo magazines (Stereophile?) reviewed his original amplifier and it got excellent reviews. Also, as has been pointed out, Dan is very responsive to questions, either over the phone or by email. I plan to keep using his products. My next goal will be using his kit to completely rebuild an old Dynaco Stereo 120.

 

[DTiberius]

I built my GT-104 amp and PR-102 pre and hooked them up to my Swan/HiVi 3.1A's (Which I also built) and it all sounds great to me! I'm not an engineer or an audiophile but the sound of this combo compared to other equipment I've had/have is substantially better in my opinion. Plus it was a blast just building this stuff!

 

[Pillars]

Nice build! It's a great amp, I really like the 102 Z4, but have built the 104/108 too. Here is one of the 104s I built.



Wish I had a use for the pre, as I've got a Hattor presently.

 

[ta240]

I had zero experience and managed to follow the manual and get a working amp first time and it was a great way to spend a few evenings.

Its a bit addictive though, I have since made a modulus 86 from neurochrome and a 3e audio diy. Great way to spend a few evenings and super rewarding. Perhaps great amp for a second system if you are looking at numbers (+10 sinad as you made it yourself)

It is very addictive. I wish I lived by Dan from Akitika, I'd assemble the amps for free. Building amps is my zen activity.
The Modulus-86 was my most recent build.
I started with Amp Camp from the PCBs, did an M2x, F5, B1, 2 of the Akitika GT-108s, LM3886DR, Modulus-86, TDA7293MOD, LM60MK2, P3A, P101, P06, P127, a SE and a PP tube amp....

 

[worktheweb]

I wanted to build a tube kit next but I might build the PR-102 because the GT-104 does sound so good. I'm using a DIY Pass Nutube preamp with a Fosi phono box X2 right now but would like to see how Dan's pre sounds.

Congrats!

 

[ta240]

I like the Nutube, I'd love to try the B1 with it.
Tubes tend to be more forgiving of build errors compared to silicone, but will bite you hard if you slip up. I did the big mistake of using one hand on the chassis and touched a hot spot with the other. I took 400 volts from one hand to the other, right through my chest. It did not feel good. With the transformer power supply at least the high voltage isn't trying to get to ground, only back to itself. I built my first tube amp in a wood chassis which made that a lot better. I treated it with fireproofing liquid and it can take a MAP gas torch and still not sustain a flame once the torch is gone.
Don't tell Tom that I killed my Modulus-86 twice with power supply errors. But even then it was pretty cheap to just replace all the silicone and the boards are so well made that they handle desoldering really well. Those are the best quality boards I've used.

 

[SONDEKNZ]

I had zero experience and managed to follow the manual and get a working amp first time and it was a great way to spend a few evenings.

Its a bit addictive though, I have since made a modulus 86 from neurochrome and a 3e audio diy. Great way to spend a few evenings and super rewarding. Perhaps great amp for a second system if you are looking at numbers (+10 sinad as you made it yourself)

It seems you have built the amp kits that I am exploring.

Which of these amps sounds best at low volumes with efficient 3-way speakers - IYHO?

[We rarely listen louder than 70dB, but need a solid state amp for the hot summer months...]

Appreciated.

 

[Fstein]

Another example of "Measures badly but sounds good". Haappens to JA and HR in Stereophile from time to time, without explanation.

 

[SONDEKNZ]

Another example of "Measures badly but sounds good". Happens to JA and HR in Stereophile from time to time, without explanation.

Indeed.

Quite rare in solid state amps - but par for the course with tube amps, IMHO.

 

[rlmartindale]

Just a few quick notes about my 2 GT108 builds.....they went fine...be patient.....

.....when adjusting bias....wait at least 15 minutes while the amp is powered up...my bias measurements went up a lot in that time (from 10.5 millivolts to 16.6 millivolts)....waiting 15 min to adjust was stable....

....install temp cardboard shims next to R32/33 to prevent shorts while testing bias (ask me how i know this is a good idea!).....

.....could this be a reason for some not so great numbers?...maybe the 108s need to be bias adjusted after 15 minutes? the manual says nothing about this....but one of the 108s, set up the suggested way to wait just one minute...had gone all the way up to 19.7 millivolts when it was adjusted originally at 10.....

.....I did mention this to Dan Joffe in an email today.....the amps sound real fine, btw.....

 

[SONDEKNZ]

I was close to buying an AKITIKA amp kit, as a cool-running summer amp.

In the end, I decided upon a pre-loved (mint) QUAD 306 that had been recapped by a reputable dealer.

Truly, I could not be happier with the QUAD 306 - and am in no big rush to reinstall our excellent tubed amps... and its still very cold here in Hangzhou, China!

With thanks to the lack of AKITIKA appreciation in this thread - and others - it seems like I dodged a bullet...

 

[worktheweb]

When I built my GT-104 I think I waited 10 minutes to bias and it was OK. I'm currently rebuilding my NuTube preamp but once that's finished I'll probably hook the GT-104 back up and re-bias it to see if it drifted. Dan has fantastic customer service if you're on the fence considering ordering something from him. I didn't buy his preamp but I did buy the phono preamp which also sounds great. I'd love to see him sell an integrated kit...

 

[rlmartindale]

When I built my GT-104 I think I waited 10 minutes to bias and it was OK. I'm currently rebuilding my NuTube preamp but once that's finished I'll probably hook the GT-104 back up and re-bias it to see if it drifted. Dan has fantastic customer service if you're on the fence considering ordering something from him. I didn't buy his preamp but I did buy the phono preamp which also sounds great. I'd love to see him sell an integrated kit...

Dan did get back….as he always does…..and agreed this "thermal strategy" (that's what he called it) was a good one

So, consider this a "Factory Approved Tip".…

Set bias after one minute and set it again after 15, and again after 30 minutes, if you want to be very careful...eat pizza while it warms up (not a "factory" approved tip)

And please please please....put in simple cardboard shims on both sides of R32/33 before setting the bias.....(also Not a Factory Approved Tip....YET)....see photo of bias testing shim install....

 

[worktheweb]

I double-checked the bias. It was right were I left it. I use the little hook leads as they're less "shorty".