My update lin topology

[linuxguru]

And finally, the simulated LTSpice AC sweep from 10 Hz to 10 MHz:

Edit: I forgot to mention, it is biased in Class-AB at the edge of Class-B, and
sounds quite exceptional - crystalline highs, mellow/open mids, and controlled but not excessively boomy lows (probably sonically similar in some respects to AKSA 55W without the Nirvana+ upgrades).

[AKSA]

LXG,

Very nice amplifier, congratulations!!

Expect an email.......

Ciao,

Hugh

[GEirin]

Hi all.
My actual design is attached below.
Any comment for improvement are welcome.
Thanks.
Guillermo.

[GEirin]

Other option:
Driver: CFP and EF output.

[linuxguru]

1) The BD139 in the VAS is probably too slow and has a high Ccb - you probably need to use a much faster NPN device like a 2sc2705 or 2sc2240 at that location. The PNP can be just about any medium power device.

2) The bootstrap from the emitter of the upper driver transistor is interesting - I need to simulate it to understand it; I haven't tried that topology before.

[GEirin]

Hi Linuxguru.
Thanks for you reply.
"I need to simulate it to understandit". OK.
I can´t to simulate circuit. I wait for you simulate.

Guillermo.

[destroyer X]

And if DHR Turbo sounds fine.. this one will sound fine too.

Coincidence or not... accident or not, you have made (created, calculated) the same amplifier.

All those amplifiers, deeply inspired into the published Aksa 55 simplified schematics, sounds excelent...in special because the bootstrap technologie used to feed current to drivers and output.

You do not need, even to simulate..just do it and will sound very good, distortion will be low and performance very high.

Aksa amplifiers, as source of inspiration is a guarantee!

regards,

Carlos

[GEirin]

Hola hermano.
Hi.
YES, the inspiration of my lin topology version is a evolution the RCA; Phase Linear; AKSA´s; DX´s; Roender output;TGM and others amplifiers. My actual intentions is to improve the VAS stage.
Saludos
Regards
Guillermo

[MJL21193]

2 things I'm not seeing:
First, the resemblance to the DHR turbo, other than they are both amplifiers.
Second, the improvement in the VAS.

<My recommendation> Try a single device VAS, but make it a good one - fast, low Cob good beta.

[destroyer X]

I think and English factory for guitar amplifiers made amplifiers this way first...do not remember the brand and model (for a while)... was around 1969 i think.... well.... very cloudy memories... this was a long time ago.

The VAS was explored too into the Precision 1.... the protection transistor BC547(Q7) and the 22 ohms resistance (R19) was because of Andrew T.... sounds better without that resistance.... he said would be dangerous...the VAS could burn...i have tried and have not burned..but i have included the protection into the schematic, to offer more reliable things to forum folks.

A pity that we have exausted, along those last years, all the options (variations) about the good amplifier topologie...i would like to have something new to assemble.... maybe patchwork will be an option, has interesting differences to explore listening.

Good luck!

regards,

Carlos