AKSA amps

[Hartono]

Hugh............!!!!

you speak Indonesian ???

FYI: I was in melbourne for 4 yrs 1997-2001 , I studied there and got my hifi bug there. Melbourne rocks !!!!!

Hartono

 

[anatech]

Hi Hartono,

I'm not asking this to start arguing, I just want to know what's really happening. and learn from it.

I don't like to argue, I am hoping that I can be helpful to you.

Most flux agents a DIY'er will use are inert after heating. Some glues are also an issue, so you have to be aware of the characteristics your chemicals possess. A DIY PCB will not be subjected to a wave solder process. There will be a higher component failure rate due to the thermal stresses of hand soldering. Automatic processes preheat (or soak) the assembly and the thermal shock is reduced.

Flux is easily removed with solvents or another fluid depending on the flux. There is no reason for a DIY board to have a flux build up. This is also true of through hole components. If the flux being used is hygroscopic and turns conductive, the wrong flux is being used. I have found certain glues used in PCB manufacture to be a much greater problem. These glues are not the type used in SM work. I use a glue stick to keep components from moving around. That works well.

but isn't the glue just a little part of the package ? so some still creeps
the mass production have very good cleaning solution for this, but diy'ers don't

DIY production will not use these glue types. It's a form of superglue to the best of my knowledge. We solder one part at a time, so we do not need this type of glue. I doubt we could easily buy it in small quantities - I may be wrong.

pcb flexes because of heat and cooling

A great deal of work has gone into making the expansion coefficients similar with this type of construction. Imagine a normal board flexing with a large 40 pin, through hole IC mounted. The bend is along the major axis of the chip. The through hole part is much longer than the sm part. It will experience far greater stresses that the leads will partially take up. This is not good in either case. The design should therefore anchor the PCB at one end and allow the other to move while keeping the board fastened. You would have other problems with that much heat.

Best,
-Chris

 

[anatech]

Hi Hugh,

BUT, it's smaller, cheaper to make in large quantities, and damned reliable if design is good.

I'll agree with that.

Cyrus manufactures their product using sm technology. I'm comfortable fixing it. They are one of the few companies that properly plan for thermal effects most of the time. So I can't complain there. Part numbers are one thing I really hate. You need the service manual to decipher the silly parts.

Let's simply say that I agree with you completely. The other side of the coin are the rushed designs that suffer in the field due to excessive heat.

Hugh, another language! Cool!

-Chris 😉

 

[Hartono]

Hi Chris,


"If the flux being used is hygroscopic and turns conductive, the wrong flux is being used"

Thanks for the lengthy explanation, so which flux do you think is good ? is the typical RMA or RA type ok ? or must be off the no-clean type, which I read also have their own sets of problem.



Hartono

 

[peranders]

..not to mention stressing the component when the pcb flex

This is normally not a big issue really, says I when I refer to pratical use in industry.

 

[Nordic]

My flux always turns conductive... I watched in the dark one night how it arches between tracks, when I didn't clean it enough....
It actualy turned the PCB into conductive carbon.. and I had to gouge the black stuff out to make the circuit work eventualy...

 

[peranders]

Hi Tinitus,

Thanks for your email. No, he never sent me the boards; I do recall sending mine, but I never received Sonny's!!

A pity......

Cheers,

Hugh

I'll guess he has simply forgotten. It seems also that Sonny has other priorities in life right now. His website hasn't been updated in a long time.

 

[anatech]

Hi Hartono,

is the typical RMA or RA type ok ?

In my experience - yes.

or must be off the no-clean type, which I read also have their own sets of problem.

I've had trouble with this stuff. You have to make sure it's completely removed because I've found that you must clean it. There may be some types that are okay but I gave up on that entire family of flux years ago.

Most of the organic flux becomes deactivated once you heat it up. Still, I ways clean the flux off. I don't believe in no-clean. Somewhere, there is an HP article on what type of solder / flux they recommend. They strongly advise against cleaning the flux off for those types.

I still use "Kester 44". 🙂

-Chris

Edit: spelling

 

[Hartono]

Thanks Chris 😀

 

[AKSA]

I've never had a problem with flux; good cleaning is important. These days I simply use a nailbrush and meth spirits, then clear away the residue after drying with a stiff brush. Then I lacquer it; always looks good.

Pak Hartono:

Istri saya, Sri, bekas Kapten TNI, lahir di Smg, Jateng. t. 1982 saya belajar menjadi penterjemahan militer ADF.... skg tulisan bagus, bacaan kurang lancar..... Ada beberapa pepatah di Bahasa Indonesia yang menarik dan cocok; tapi lebih suka Bahasa Inggeris sebab ada lebih banyak kata!!

Melbourne, huh? Kedinginan, bukan?

Ciao,

Hugh

 

[Hartono]

too cold in melbourne ? nah...

the place I live now is -20 degree celcius at winter 😉

around 2002 I already went back to Indonesia, my friend in Australia,Vincent (Chinese born Indonesian) had the chance to audition your AKSA, he was impressed and told me that, but I was in Indonesia at at that moment, and never had the chance to hear your product.

Indonesia words is very ambiguous, I prefer to read English books.


Hartono

 

[gaetan8888]

Hello

Here some news, the Aksa amp did just beat all those high-end amplifiers in a blind test.

Those amps was: Dick Smith amplifier, Perreaux 2150B amplifier, Bryston 4B SST amplifier, Gryphon Encore (who cost arround $16,000 )


Here is the link of the test;

http://www.avhub.com.au/NewsArticle.aspx?MagazineID=5&NewsArticleID=1273

Bye

Gaetan

 

[analog_sa]

Very interesting and thanks for posting. The outcome is not so surprising. If no one heard any difference i would have blamed the preamp - it's not exactly perfect for tests.

 

[Nelson Pass]

I'm not particularly surprised, given the high quality of the AKSA, but I'm
curious - they did not mention if they had equalized the volume levels.

😎

 

[destroyer X]

I use to say... repeated times that no amplifier can beat an Aksa

at least i could not find that one those last 49 years building.

Maybe Nelson Pass amplifiers can do that... i really believe this is possible...and soon i will be trying some units from Nelson too.

regards,

Carlos

 

[GK]

Well excuse me!

Hugh made a statement that linearity is improved with larger resistance. I guess I just assumed that was an objective statement with something objective to support it other than subjective listening.

Well the claim is a load of nonsense of course, but typical.

#4 I was asked. I gave an answer. If you do not find it satisfactory, I politely point out that the onus is on you to research it and find why to your satisfaction. Experience is not transferable, but it is easily replicated. You do not have to tell anyone; no one here has placed obligations on you, Sir.

The inevitable, disingenuous evasion.

Larger emitter resistors mean greater crossover distortion and greater susceptibility to increased gm doubling (high order distortion) with temperature induced drift in Iq from optimal.

Anyone actually interested in researching this for themselves can start at chapter 5 of the Audio Power Amplifier Design Handbook:


EDIT: But then again, who gives a toss about the truth anyway?

 

[destroyer X]

Oh!... envy..... i can see that.

I felt envy reading the text..... i felt happy, but envy too.

this is natural... this is human.

Are there more folks feeling envy?

ahahahaha!

Carlos

 

[ostripper]

By DX - Are there more folks feeling envy?

Yes , me too. But my envy is short lived , will turn into 2 more
working amps. No thousands $$$ for me , but good sound
for my rear channels. 😀
OS

 

[tinitus]

Larger emitter resistors mean greater crossover distortion and greater susceptibility to increased gm doubling (high order distortion) with temperature induced drift in Iq from optimal.

I could be mistaken, but looks to me like Holton doesnt use emitter resistors at all, at least I dont see any 😱

 

[andy_c]

"sparkie" is a shill that I've pointed out before (scroll up a bit from that post).

I'm sure The Pope (TM) will be along soon with some high-hatted comments 🙂.