Sonnya, Pavel,
You guys build superb looking amps, my sincere congratulations!
Like Jan, I really like the attention to detail. It shows you have passion, and we all know - the devil is in the details.
Sonnya, lots of lag compensation! Try it with an output Zobel and smaller lag comp caps, and see how you feel about the sound. It makes a big difference to the sonics.
Current feedback, huh? How is the imaging? Can you give us a sneek review (words are tough here, but all we have to go on!).
Cheers,
Hugh
You guys build superb looking amps, my sincere congratulations!
Like Jan, I really like the attention to detail. It shows you have passion, and we all know - the devil is in the details.
Sonnya, lots of lag compensation! Try it with an output Zobel and smaller lag comp caps, and see how you feel about the sound. It makes a big difference to the sonics.
Current feedback, huh? How is the imaging? Can you give us a sneek review (words are tough here, but all we have to go on!).
Cheers,
Hugh
Hugh,
my is not current feedback amp, output stage is based on push-pull class A follower, you can find it by clicking www button at the bottom. It uses CFP's (complementary feedback pair, as you know) in the output stage. There is no global feedback, but strong local feedbacks.
THD and IMD are very good, again can be seen on web. Sonic result is very good (I do not want to use too much celebrating words
, the sound is pure, clear, with tough bass, pure mids and treble, and non-agressive, non-harsh, non-grain sound.
Pavel
my is not current feedback amp, output stage is based on push-pull class A follower, you can find it by clicking www button at the bottom. It uses CFP's (complementary feedback pair, as you know) in the output stage. There is no global feedback, but strong local feedbacks.
THD and IMD are very good, again can be seen on web. Sonic result is very good (I do not want to use too much celebrating words
, the sound is pure, clear, with tough bass, pure mids and treble, and non-agressive, non-harsh, non-grain sound.Pavel
AKSA said:
Thanks Hugh, yes it is a lot of lag compensation. I do have a Zobel network, but i will try to lower the R from 10R down to 4R7.
First i think when it is not stable i dont have to do any listening tests. But now it is very stable.
It shows ringing with capacitive loading, but it dies out very quickly.
It gone within 5 microseconds. This applies to 100n,220n,330n as pure capacitive loading.
With 8Ohm in parallel in reduces only a little.
The ringing is very uniform.
I have not been able to provoke any instability with lower capacitive loading.
The imaging:
If you a live CD like the Last MTV CD, you will hear the background voices very clearly.
Also singers like Sinead o'connor. You will have a very clear image of her breathing between words. it is ike moving very close to her with you ear close to her mouth.
Drums and percusion are very fast and tight.
Compared with my fathers amp wich looks a bit like an Douglas self blameless amp(600VA+6*10000uf). It has a thinner bas and mids. first i thought that the smaller supply (300VA+4*10000uf) was the reason, but then take a jazz player on a contrabass. Then you find out the strings are vibrating more clearly (i dont know how to describe it) and the bass are not suffering....
The test are until now run at JBL L-100(80's) for the bass...
also on my Audiovector M1 super, for the voice, percusion, trumpets...
More speakers needs to be tested also cd players (preamp based on AD8610)
So anyone in denmark..... ??? near Fyn???
I hope it gives you and idear!?
PMA said:Sonny,
this is perfect. Some ringing with capacitive load as you described (330nF etc.) is normal. When stabilized in 5 microseconds there is no need to worry.
Pavel
BTW: Not that far from Prague to Denmark
When i have done some real PCB (end of august i think) i will get back to you....
I am going to add a discrete servo.
peranders said:I think some ringing with this rather nasty load is an excellent result. Other amp goes basooka for less.
Thanks to your both...
For your comments on this.
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