Peace!!!!

[SkinnyBoy]

if by scanning and posting this I have violated any copyright laws, feel free to let me know.

[SkinnyBoy]

no comments? I think I'll make one up... 2 dozen components... why not?

[hjelm]

Isn't the biasing a little low with only 2 diodes versus 4xVbe+2xVremitter?

[PMA]

Originally posted by SkinnyBoy
if by scanning and posting this I have violated any copyright laws, feel free to let me know.

This amp will have several fundamental limitations. It looks simple, but depends on the goal you have - simplicity or sound qality? This amp will have bad behaviour on high frequencies (long turn-off times, as there are no resistors in Darlingtons) and no care has been done to set up correct bias current, you can expect distorted high midrange and highs, NFB do not have a chance to correct it, especially high frequency distortion products.

[Upupa Epops]

To Pavel : It's calling on desert - guys here love simplicity , 'cos " guru " love it also .

[PMA]

This is how 10kHz from this amp looks like. Everybody can make a decision whether it is good or not

And even for 1kHz the cross-over distortion is clearly visible.

[Greg Erskine]

Hello Skinnyboy,

Just incase you don't all ready know, this schematic is a DIGI 125 designed and sold by Graham Dicker of Adelaide.

http://members.bettanet.net.au/~gtd/kits.html - Scroll down a page or two.

There has been a couple of significant threads discussing this amplifier and suggesting improvements. In summary, use toshiba 5200/1943 output transistors, add 1 extra bias diode, upgrade VAS transistor and add a bootstrap on the VAS.

I've built one, and with the extra changes have been very surprised with the performance.

Also, have a look at two of Destroyer X threads:

X Palesha X , one cooperation amplifier, Destroyer X and Palesha
Attention AKSA 55, Hugh is thinking in let us see schematics on forum

These show circuits with similiar topology but with a few extra parts.

[destroyer X]

This thopology is magnificent in sonic qualities...but not so simple that way.... need more components, and not easy to discover without long and deep research.
The way it is..... hummmm...look the triangle wave shape at 10 Khz and imagine the sound result?

No, i am not telling that waveshape is the quality "dictator"....not that....sometimes sounds good too....but, related to standards... lets say, need some little job to be very good.

Carlos

[mikeks]

Uninspired simplicity...for its own sake....excreble.......

Whatever you do...don't waste time and money building this amp.....

...You'll regret it....

[destroyer X]

You are so kind today!

grrrrrrr!

Carlos