Simple Symetrical Amplifier

[Lazy Cat]

Originally Posted by Nico Ras

Hi Hugh, I was not thinking of changing anything. I have my amps made and am happy with them.

Nico

I'm happy too with all the results, it is just that I want to explore more possibilities according to my current needs. Definitely I agree that simple solutions like a resistor on the spot is always more elegant and probably better sounding solution.

I guess it's just me the cat and my curiosity, hopefully not killing me.

[Lazy Cat]

Originally Posted by smartx21

Since Elektor's IGBT output amplifier from the 80's I've been expecting such a new approach to that technology. Yet not so simple (not so SSA=NSSSA!), this thread tells us that there is always something to be discovered, or to improve. Thank you all for the effort and invaluable teachings!
Regards,
Max.

You're welcome Max. Thanks.

Yes, always something to discover and improve ... work in progress to be continued.

[Idefixes]

Lasy cat and nico, in goal to drive speakers with "low" inpedance sink (not 1Ohms at all but more classical between 3 and 4) wouldn't it be an advantage to use double die lateral mosfet as Exicon ECF20N20/ECF20P20 or Magnatec BUZ900/BUZ905DP instesd of built in two parallel simple die. The advantage I see in is no matching between parallel devices and room feet gain. I have built several years ago a 2SK1058/2SJ162 (2 pair per rail) amp with +/-36V rail. It was able to drive in my domestical classical use a wide range of speaker sofar as a couple of bookshelf with a 4 ohms/87db scanspeak midwoofer. But what i am unable to do is to say what such an output stage need for modification in lasy cat simple lateral mosfet (one pair sk158//sj162) or in Nico triple pair output configuration => in few words : how to drive such a double die unit.

Marc

[MiiB]

Idefix..

would opt for the more resilient BD140/139 pair for the drivers and increasing current to app 10-15 mA..

[Idefixes]

Originally Posted by MiiB

Idefix..

would opt for the more resilient BD140/139 pair for the drivers and increasing current to app 10-15 mA..

Instead of 2sa970/2sc2240 in Lasy cat simple configuration?

Marc

[MiiB]

nope would go for Nico's version with the extra driver in the circuit. It has a 100 times lower distortion and a much better drive of the output..
Q-5;Q-6 to BD 140/139, change resistor R11/12 to app 140 ohm and use R13/trimmer to set the Current through the outputs.

[Idefixes]

Originally Posted by MiiB

nope would go for Nico's version with the extra driver in the circuit. It has a 100 times lower distortion and a much better drive of the output..
Q-5;Q-6 to BD 140/139, change resistor R11/12 to app 140 ohm and use R13/trimmer to set the Current through the outputs.

Thanks for advices i locate modification, i will redrawn alex pec routing as Exicon present TO3 metal can. In same time will add more space to allow more possibility in chose of 10mf smoothing cap choice : 22,5mm is not a current size in europe

Marc

[kevinkr]

Off topic posts have been removed and moved to a thread of their own. Please confine discussion here to that proposed by the thread title.

The OT posts have been moved here: Powering A Tough Speaker (Split from Simple Symmetrical Amplifier)

[Nico Ras]

Hi Miib,

I do not think it is a competition between which output stage is the best, but more so to offer different variations so that constructors have a choice.

In my humble opinion the character of the amplifier is dominated by the front end.

There is such a controversy regarding sound of MOSFET vs BJT, but I could not conclude that I heard any significant difference between the two output stages, only that they sounded excellent.

It would be like comparing performance differences between a red Ferrari and a yellow Ferrari.

Maybe I am getting too old.

Regards

Nico

[MiiB]

Ohh.. this was not meant as a competition...But the question was which version to select for a Dual-device output (both laterals-dual dies), hence my suggestion to follow your approach with the separate driver..and as the Fetzilla thread has clearly indicated the lateral fets do benefit from more driving current..and wit 2 pairs, i think It'll be vise to change to the more resilient TO126 types..

Think you have good opinions..don't be humble about them..)