increrible aleph5 tiuning!!

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Hi,
I stacked up my PSU: http://www.diyaudio.com/forums/showthread.php?postid=554225#post554225

i´ll build the PSUwith 96x ELNA 6800µF Audiograde / ch.
I bought 200pc of these some months ago, really cheap.

By www.pollin.de are Aerovox/Mallory Caps with M5 screw connect for 0,95EUR available.

http://www.pollin.de/shop/images/article/small/K210577.JPG

Paralleling of caps make fantastically low ESR -> low impedance = higher current available.
At present I test my AX prototype, for first with 4 Fets only,
for last this should have 12Fets /8,5A bias:


Greetings
Adam
 

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grataku said:
I have 1 F in my alephX and I used a thermistor to limit the current at swich-on.
Fantastically low ESR makes for fantastically big short circuit at turn on. Nobody seems to have mentioned that.

I use primary (16ohm) and secondary (0,75Ohm) soft start with relay´s.

jacco vermeulen said:
Adam,

die Mallory's sind wirklich sehr billig, die muss ich haben.
Eine ahnung wie hoch die versandkosten zum ausland sind ?
Das geschaft ist in Beiern, doch ?

Die Wima's auf dem AX scheinen sehr gross zu sein, welche werte haben die ?

Tolle link, vielen dank.
J.

I bought 100pc of them :)
I dont know what international shipping costs -> look AGB by Pollin, over 150EUR is shipping in Germany free. The Wima´s are 10µF MKP4/160V. I bougt these over my company for aprox. 2EUR pc. If you wish I can buy these for you .

Regards
Adam
 
Here is what LC Audio writes about paralleling multiple caps to get large total capacity Link (below the second picture). Their solution is the VP4 network.
For high slew rates ESL is the limitting factor (my opinion) so this has to be taken into acount wireing the caps. 1" coper wire has an iductivity of about 20nH. So a bad wireing can lead to even worse results in ESL than really good big caps have (for example 12nH @ 47000uF).

illusionxx.
 
No jacco,

i didn´t swap the abbreviations. To be more precise: ESL is the limitting factor for small signal slew rate. A high small signal slew rate will give better suppression of ripple currents and HF.
If i got it right the AX amps draw a constant current from the mains. Big signal slew rate is therefor not really important cause there are no big changes in current flow. Low ESR is also important for small signal slew rate.

illusionxx.
 
I meant i swapped esr for esl.
Not you, you are right.

esr is important for large currents, powerloss and heat.
esl is important for high ps slewrates, especially high frequencies.

High frequencies usual require low energy, i read your referring to small signal as such.
High slewrate PS should be important for very wide bandth class AB amplifiers.
Which of course themselves need to have high slewrate for being able to produce the high frequencies.
Such as +100V/uS , +0.5 MHz amplifiers.
 
I don't know ESR and slew-rate? It sounds like a lot of fru-fru to me, I am looking at an AMT solid state broadband RF amp that goes up to 600MHz and this sucker's got a pair of Mallory 10000uF 75V with a pair of bleeding resistors in parallel in the power supply that's it.
Bypass caps close to the semiconductors and proper PCB trace impedance maybe much more important that paralleling 600 panasonic FC in the PS.
 
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