V6 amplifier

[sajti]

Hi,

files attached.

Sajti

 

[astx]

Nice build! Thanks for sharing simulation files!

Have Fun, Toni

 

[sajti]

Another version is on the way, use KSC1845/KSA992 in the input stage...

Sajti

 

[Walkalone]

Thanks Sajti!

Regard,

 

[sajti]

New version was born. Output is 140W/8ohms before clipping.
Sajti

 

[thimios]

New version was born. Output is 140W/8ohms before clipping.
Sajti

Nice work!
140W RMS/8R using +/-40v?

 

[sajti]

Nice work!
140W RMS/8R using +/-40v?

No, that was wrong label was not change on the pcb plan. It runs with +/-56V.

Sajti

 

[sajti]

The schematic of the last version.

Sajti

 

[Walkalone]

Hi Sajti,

I have a problem when try to simulate your amp, how to avoid it?!

 

[sajti]

Hi,

I never seen this message before. Maybe You have some duplicated device parameters?

Sajti

 

[sajti]

Here are my simulation results.

Sajti

 

[Walkalone]

OK, i will try again. Thanks Sajti,
Your amp make me feel pleasantly. I wonder how about if it run LMOS as output devices?!

Regard,

 

[sajti]

OK, i will try again. Thanks Sajti,
Your amp make me feel pleasantly. I wonder how about if it run LMOS as output devices?!

Regard,

I know one version which is running with IRF240/9240. It is necessary to modify the Vbe multiplier, and You dont't need the double emitter followers as drivers. Single is enough.

Sajti

 

[sajti]

The new build use 10mm thick aluminium plate to handle the transformers, and the PSU pcbs.

Sajti

 

[sajti]

Amplifier pcbs before mounting them to the heatsink:

 

[sajti]

The latest version is ready, and running since 2 days. 60W/8ohms and 110W/4ohms, dual mono.
Bias was set to 70mAfor each output devices, 77mA on the cold amplifier, falls down to 68mA after some hard running. Output offset is 25mV when the relays turn on, reducing to 5mV in 30 seconds, and finally down to 1-2mV after 5 minutes.
2x200VA toroidal tansformer, 2x40000uF in the PSU. Sanken output devices, Sanken drivers, Toshiba and Fairchild in the front end.

Sajti

 

[thimios]

Nice work!
Are these heatshinks big enough for proper cooling?

 

[prasi]

very nicely done sajti, congrats!. very stable/desirable offset and bias parameters too.

regards
Prasi

 

[sajti]

Nice work!
Are these heatshinks big enough for proper cooling?

I use the Fischer SK595 heatsinks. There was no problem with the cooling, even my speaker has the minimum impedance 3,7ohms. The backplate also acting as heatsink. It is 5mm aluminium sheet.

Sajti

 

[sajti]

Detailed picture about the output devices, mounted on the backplate: