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I need comments about "100W power amp. elektor april 1982"

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#21
Ok,

Now we are at it, here's the (a) list of elektor stuff i know of:

apr 82 - 100 watter with BDX67/BDX66
dec 82 - cresendo
may 84 - mini cresendo with 2SK135/2SJ50
mar 85 - AXL with 2SK134/2SJ49
nov 88 - LFA 150 with 2SA1095/2SC2565
okt 90 - power amp with BD911/912
okt 91 - LFA-50-OA class A amp with 2SA1216/2SC2922
feb 94 - ulti-amp with 2SC2922/2SA1216 (better poweramp)
apr 01 - cresendo ME with 2SK1530/2SJ201

There also was a LFA150 or 50 version for electrostatic speakers iircc.

older designs than 82: EKWA, EKWIN, a 200 watt amp and the Elektornado (100w bridged). They also published tube amps and some smaller schematics (opamp+mosfet, single chip stuff, A+B amp) over the years.

Dont forget to read 'het lek' 😀
 
#22
jinkuchi said:
thank you jmateus. :bigeyes:

now I want to built ESP project 3A.
But I can't buy MJL4302 mjl4281 in Thailand.
I found MJL21193 MJL21194, can I use them instead?

Can I use TIP3055 TIP2955 ?
Click to expand...


MJL21193/21194 will work fine in the P3A, and Rod actually recommends those if you can't source MJL4281/4302.

TIP3055/2955 are far too low power, and would probably blow up. MJ2955/2N3055 may work but it is not worth it if you can get MJL21193/21194's
 
#26
here goes, i am still not impressed by the thing
 

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#33
Elektor crescendo 1982

If it's OK. jacco vermeulen, could you please scan and post the original crescendo article to. I built it many years ago and I have lost the shematics and the amp needs an overhaul..

Regards, Martin S.
 
#34
Hi guys (sorry for my bad english)
this is my first post and that amp was my first amp I build,
first I buid it with two couple of BDW83C/84C when I power on and regulate the bias i see that if I set the bias over 40mA per transistor it start to oscillate;
When I tested it with a speaker it goes into thermal runaway and selfdestroy.
I substitute the BDW with TIP142/147 and add a 10'000uF 63V capacitor per rail (total 22'000uF per rail) without C7 C8 and it function correctly.
It sound not bad, with a little emphasis to the high.
I would ask you great guru if it can deliver 100W RMS onto 8ohm with a voltage rail of 45V (that is what I'm using).

Thanks to all of you for the time spend with me.
 
#35
Went up in the attic and made some pics. It's actually the third amp i've build (and the last so far). A picture from the front with a 9v battery for reference. The case is strong, industrial stuff. You can not only dance on the music, but also dance ON the amp 😀 😎
 

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#38
the internals, left to right:

papst fan with the coolingtunnel, underneith it the speaker relay. two 20000uF caps with the pcb's below, two amp pcbs and the dc
protection/delay circuit (also from elektor with the counter counting back from 9 to 0. But i did not implement the led display).

on the right a 500VA ilp transformer and underneith the 'magnet-switch' for mains. you did not think i got away with the small power switch, did you:smash: :clown:
 

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