P61 Amplifier

[fantom_mayonaise]

Sayang di ko na-save yung image. Mukang tinanggal na nung "echoloft" yung picture hehehehe.


Ang pagkakaintindi ko, ni-contribute ni hugh yung original aksa nya sa site ni rod elliott. Then after some time, nag-decide sya na i-commercialize yung design nya kaya nya pina-pull out kay rod elliott. Dun na nagsimula yung Aspen Kit Set Amplifier (AKSA).

Yung conceptual diagram ay kulang pa din. Hugh was still trying to protect his product kaya di nya nilabas lahat. Kaya merong base suckout yung "p61" pcb ni echoloft ay dahil yun ang tutoong aksa. If you read the later pages of the baby aksa thead, nagpost si Hugh dean na meron nang naka-tsamba or naka-approximate sa actual AKSA schematic.

Anyway, sir, pakipost naman po ulit yung nakuha nyong schematic. Di lumalabas yung sa first page

Thanks thanks and plus 1 sa iyo

[jlester87]

yup p61 + vbe + base suckout + 15pf mod = aksa 55

[jlester87]

eto na pang diy amp comparison

[Engr. Dacuycoy]

baby aksa yan

[Disabled]

baby aksa yan

[Johannah Aleksandria]

yup p61 + vbe + base suckout + 15pf mod = aksa 55

So ppano ba mkakuha ng schematic nyan sis?
Gagawa ako agad ng ganito pag binigyan mo ko.

[jlester87]

baby aksa yan

Nope... P61 parin! hehehe

[JojoD818]

konti pa makukuha na...

[jlester87]

You missed it?? I thought you didn't want to show the details. Remember that on the post #340 you cannot see the value for some components.

Like I said in my earlier post in this thread, I doubt that you can achieve a quality close to AKSA with your simple feedback scheme. My AKSA clone uses all the components displayed in post #340 plus 2 more components. Yes, I use Vbe multiplier while in original AKSA I guess diode string is used instead of transistor.

Jay,

You have done a very good job of copying the original AKSA, it seems, so you can see why I moved on.....  very hard to keep these good designs secret!

My more recent work is much better than the AKSA, and I do not ever share the details in public forums...  but even so, I can assure you there is more in your AKSA yet.

Sayang tak bisa bercakap-cakap di restoran di Blok M tentang hal-2 audio......

Hugh

hmmm so may isa pa kong component na kulang... yung suckout cap lang yung nadagdag ko sa post #340 schema...

[jaguar3275]

sis pwede pa post ng complete pdf files nito at latest revision na...

thanks!

[abeTIR]

Alam nyo nakaka-frustrate magkagusto sa isang design in which later on mafind-out mo na incomplete pala yung published design...nung una  na-attract na ako dito sa design ni Hugh Dean pero nadisappoint ako. It seems to me Hugh Dean was not that cooperative (helpful?) sa mga gustong mag-DIY ng kanyang design. Para namang pinahuhula niya sa mga DIYers yung totoong disenyo, anyway wala rin naman tayong magawa kung ayaw niyang makipag-cooperate since commercially published ang kanyang product.

Fact:
Nag-comment na siya dati na hindi siya nagpo-post ng kanyang designs sa mga public forum.
and from the words of uncle Carlos (aka "Destroyer X") mahilig maglagay ng secret parts si Hugh Dean, na ayaw niyang ibahagi.
May nabasa ako minsan na merong nagsabi na merong mga dagdag na SMD (under the board) ang mga gawa ni Hugh Dean na mahirap kopyahin.

...oh well it is just me and my thoughts..

Anyway go lang sis Lester! at ng matuklasan nga natin ito, sana nga lang hindi disappointing itong "secret parts " na nawawala...hopefully 

[Johannah Aleksandria]

Extremely superior performance ba tlaga meron ang AKSA?

[tony]

Alam nyo nakaka-frustrate magkagusto sa isang design in which later on mafind-out mo na incomplete pala yung published design...nung una  na-attract na ako dito sa design ni Hugh Dean pero nadisappoint ako. It seems to me Hugh Dean was not that cooperative (helpful?) sa mga gustong mag-DIY ng kanyang design. Para namang pinahuhula niya sa mga DIYers yung totoong disenyo, anyway wala rin naman tayong magawa kung ayaw niyang makipag-cooperate since commercially published ang kanyang product.

the devil is in the details......
if you understand the design, you can figure our the details.....i do not see anything mysterious there...
Hugh Dean spent a lot of hours doing tweaking on his relatively simple circuit, i can not blame him if he does not want to share his IP, there are other ways, like buying his kits....

the things that will really make his design stand out is careful attention to details...

1. choice of trannies.......grading them and choosing them for beta and fT, Cob, Cdom......
2. choice of resistors.......low noise types
3. choice of capacitors.........low DA, low ESR....

making amps is not just stuffing parts into a pcb.......

read here, Hugh gives a lot of tips: http://www.diyaudio.com/forums/solid-state/168554-based-hugh-deans-aksa-55-a.html

[abeTIR]

I see your point sir Tony, yes considerable knowledge with the circuit reveals the hidden within but I guess I am not up to that point yet...guess I am barely scratching the surface...well just dunno' perhaps hindi ko matutukan gaano ang pagtuklas...      I do a lot of paperworks in the office but sa bahay I work on the electrons..

I did get some helpful tips and ideas in choosing design circuits while exchanging PMs with Esperado, (famous for his remake of "Crescendo Millenium" amp).

1. avoid a design with a lot of miller cap compensation, it lowers the amp bandwith.
2. resistors should work on the voltages not the transistors.
3. an ideal LTP diff input has limited resistors and should be made of a quality types (failure on this stage is critical to the design)...(dito ko nakikita ang qualification ng AKSA at P3A).

Yung recent CFP Circlophone build ko hindi ko talaga maisaayos albeit battling it out with Danielwritesbac...anyway nagkakaroon pa yata ng problema yung design ni Sir Elvee..    

[tony]

the AKSA topology was used in many early Japanese designs circa 70's pa, at that time lagi akong nagrereasearch sa National Library..........i do not think Elliot nor Hugh Dean can claim to have invented it....the difference is the attention to details in the later years....

Daniel Meyer's Brute70 power amp"



at the time, LTP input stage was not yet in fashion, but the bootstrapping is evident, also quasi-complimentary is used, Motorola has yet to come up with pnp power trannies...

[Disabled]

the AKSA topology was used in many early Japanese designs circa 70's pa, at that time lagi akong nagrereasearch sa National Library..........i do not think Elliot nor Hugh Dean can claim to have invented it....the difference is the attention to details in the later years....

Daniel Meyer's Brute70 power amp"



at the time, LTP input stage was not yet in fashion, but the bootstrapping is evident, also quasi-complimentary is used, Motorola has yet to come up with pnp power trannies...

single transistor lang sa input pero dual rail?
wala pang output cap
exciting

[tony]

yung mga naunang amplifiers ganyan ang topology....the single tranny input receives feedback from the output node by way of its emitter....

dual rails negating the need for output cap....those were the days....i built my first amps using this topology in the 70's...

see the simmilarity of the sakura and the melody amps with the one below, circa 1973:

[Disabled]

^ sir tony where did you get that images? im a bit interested on the old ones. baka makakuha ako ng ideas.
and ung mga transistors na yan pde po bang i sub ung mga transistors nowadays?

[Disabled]

yung mga naunang amplifiers ganyan ang topology....the single tranny input receives feedback from the output node by way of its emitter....

dual rails negating the need for output cap....those were the days....i built my first amps using this topology in the 70's...

oo nga pala. +1

[tony]

^ sir tony where did you get that images? im a bit interested on the old ones. baka makakuha ako ng ideas.
and ung mga transistors na yan pde po bang i sub ung mga transistors nowadays?

sa internet....google mo lang...