[Brian T.]

Hi Brian,

What spec is your JLH? (Mine has a single psu, albeit with Elna Cerafines, fast, soft recovery diodes and 625VA transformer, upgraded electrolytics and feedback cap to poly and tin foil caps.
As per a recommendation of a previous owner in diyaudio, I have effectively disabled the high current regulators, feeding the amp output stage with rectified and smoothed dc from the psu.
This added more detail, speed and depth to the soundstage, with no downsides.

Regards,
John

Hi John,

My amp is pretty much as per the original Wireless World August '82 design.  Shortly after publication, I bought the kit from Hart Electronics.  The only major change was the loudspeaker protection circuit.  

Talking of the latter, there has been no correspondence regarding this matter on the Forum.  Do people regard the ensuing relay as a source of distortion or merely put up with the 'thump' on switch on/off?

Brian

[AKSA]

Brian,

A relay is fine, but it should have very low resistance contacts, which means, of course, precious metals.

There is no danger to the speaker from the infrasonic turn on/off surges.  DC dissipation is well below the rating of the voice coil, though excursion is a little surprising (but not dangerous or damaging).

Cheers,

Hugh

[ginger]

Soitarts, PSP, Brian T and others.

I noted your comments about listening habits changing with your new AKSA Amp.

I'm a complete audio nutter and usually have at least 2 new amps under construction or development at any time. This eventually "trains" you in how to listen to an amp critically BUT also gives you some clues early to amp sound quality without consiously listening for particular things.

Any time you find that you are grabbing your favourite CD, play a few tracks and then grab the next CD you can just about guarantee you are not quite there yet with your amp design.

Anytime you stick on a CD and are content to just sit back an enjoy an entire CD at a time, you can take it as read that your amp is pretty damn fine.

Anytime you find you want to leap up and keep  nudging up the volume you can assume its great.

Anytime you feel you need to nudge down the volume its indicative that its not quite right yet - unless of-course you went overboard in the step above.

These are the "MASTER" subjective tests. My AKSA 55N+ was one of the first amps that I'd ever experienced that particular listening behaviour.

I've now got 3 own design and build tube amps which give me the same sort of listening pleasure - the cheapest of which cost about the same as 3 or 4 AKSAs in parts. The AKSA is used mostly as a reference amp BUT I still have to have my AKSA fix for a couple of weeks every 2 months or so.

Cheers,
ginger

[AKSA]

Thanks Ginger,

It's audio nutters like you that keep me on the trail for the perfect amplifier......  I'm presently looking into zero feedback amps, have something on the test bed right now, and also very involved in N-type mosfet quasi-comp amps.  You can imagine my joy when I 'invented' a new topology recently after much tinkering, only to be told by a learned engineer friend that Siemens had been using it in all their amps from 50 to 400 watts since the early seventies......  There ain't nuttin' new under the sun, it seems.  

I'm also looking at a European output stage design from Czech Republic. It shows great promise.  I've examined Blomley in great depth, but feel that his designs and Hawksford's error correction are probably not particularly commercial.  And I think in the next decade Class A will die off because of it's horrific inefficiency and unsubtle approach to eliminating crossover artefacts.  There has to be a better way.......  Meanwhile, the best amps are, I believe, zero global feedback, but gee, the topology problem is very difficult.

Cheers,

Hugh

[kyrill]

My ears are 58 years old, the rest of me probably older.
I have gone all the way with mods to my AKSA 55 and GK-1.
I always hear a difference. It is always for the better.

I can't comment on 55 versus 100.

ah someone of my age i am 59 still looking younger

But (t)his last post is 2 years old
Still hope he enjoys his AKSA's

Lives in Sydney enjoys the coming winter..

[AKSA]

Kyrill,

Very sadly Malcolm, an extraordinarily kind and outgoing fellow, died in Sydney a couple of years ago.  The circumstances were terribly sad;  we none of us live forever.

He was very smart, and very kind.

Cheers,

Hugh

[kyrill]

ah sad for us,
Not for him
he lives like all of us will in due time,  in a so much happier place. Kind and gentle hearts are very welcome in all heavens 

 I hope the other names i still miss, are not thàt happy
Greg Erskine
EchiDna
Rocket
Carlmann ,lost81 and others

[Greg Erskine]

hi kyrill,

I'm still here, still listening and enjoying my AKSA 55. 

I'm finally about to get my AKSA 55 N+ going. Just a few more hours work, slowly does it.

BTW: I still think fondly of Malcolm, and I only just deleted his emails today.

regards

[EchiDna]

still suffering in "unhappiness" here in Singapore 

 

[kyrill]

hi Greg, Echidna, glad you are not thàt happy yet

I just upgraded my aksa 55N+ with a Dynamicap 4uF for C1 instead of the BG electrolytic.  Pff what a big monsters. I ripped off the red plastic "housing" or foil of the caps and replaced it it with paper. Careful work or you destroy the layer of metallic foil ( looks like aluminum ) underneath its red jacket
Had to completely de-assemble my Aksa and finished today one amp (4.5 hrs work)
Tomorrow the other amp

In listening after the modification on my Left amp the stereo balance was on the left. but the sound was much more free and open. Could not hear its real effect as the C39 varnish of the ribbons need another 7 days of drying.Whatever slight impression i heard of metallic influences on the sound is completely gone. Slowly the fast attack time is coming back, but not yet as it was before.

[AKSA]

Kyrill,

I LOVE it!!     You should be in aerospace!!  Your attention to detail and uncompromising stance is unusual and refreshing.......

I'm listening to Titanic on my new VSonics, 8" two ways, both drivers Peerless, with 3rd order crossover.  I'm incredibly impressed with Laurie's design work.  This is the best speaker I've ever owned!!   

Only 4C in Melbourne this morning, hopefully rising to 16C today.    I have SO much work to do, I'm drowning.....  and my wife is insisting I go to a boring party tonight.  I hope I can find an audiophile so I can press my finger to his (her???) chest!!  I should go for a quick ride on my bike later today to allay the boredom of so much work!   

Cheers,

Hugh

[kyrill]

Kyrill,

I LOVE it!!    :kiss:You should be in aerospace!!  Your attention to detail and uncompromising stance is unusual and refreshing.......

Yes but that attitude brought me to Aspen 

I'm listening to Titanic on my new VSonics, 8" two ways, both drivers Peerless, with 3rd order crossover.  I'm incredibly impressed with Laurie's design work.  This is the best speaker I've ever owned!!   

you will love now the LF's even better, and the whole chain in front of it.

.....  and my wife is insisting I go to a boring party tonight.  I hope I can find an audiophile so I can press my finger to his (her???) chest!!

which finger?

ah you are not thàt happy yet..
Only in heaven you can press yr finger on her beautiful chest while wife observes, smiles and says: "He loves audio so much"

I should go for a quick ride on my bike later today to allay the boredom of so much work!   

Cheers,

Hugh

re-discover that joy as new every time again, in the knowledge that you have the "desert" at yr disposal. Here in Holland i got mostly boring meadows and highways around where i live with no motivation to explore that..

[Johnny]

I'm listening to Titanic on my new VSonics, 8" two ways, both drivers Peerless, with 3rd order crossover.  I'm incredibly impressed with Laurie's design work.  This is the best speaker I've ever owned!!   

Mmmmm! Vsonics   aa  aa