jmateus said:
Thanks!
This would be the version SymAsym5_2 - Project page at MikeB website.
Not the PMA modded version.
Hi lineup, these 2 versions are identical, except that PMA suggest slightly different caps for feedbackcompensation.
Symasym5_3 is still in progress, a little delayed by a bad flu...
John, thanks for posting your impressions !
Mike
Symasym5_3 is still in progress, a little delayed by a bad flu...
John, thanks for posting your impressions !
Mike
Hi Mike,
in the _3 vesion would it be possible to add a balanced input to the amp?
On my wish list there is a new pcb and a higher power version but I'll restrain myself. 😉
in the _3 vesion would it be possible to add a balanced input to the amp?
On my wish list there is a new pcb and a higher power version but I'll restrain myself. 😉
Hi Mike
The Symasym_3, does it have anything to do with the higher power version? May be not, may be it's just an improvemtent over the previous one, isn't it?
Pardon me, I'm jumping ahead of myself...I hope I don't fall
but the enthusiasm makes me rumble too. What a pain!
The Symasym_3, does it have anything to do with the higher power version? May be not, may be it's just an improvemtent over the previous one, isn't it?
Pardon me, I'm jumping ahead of myself...I hope I don't fall
but the enthusiasm makes me rumble too. What a pain!
Hi !
Grataku, right now i have no plans with balanced input, you might consider a converter/buffer ?
John, the sym5_3 is about pcb, i changed some power grounding. A high power version will be a redesign, using slightly different topology, giving a symasym6... (folded cascode with triple darlington output) Let's see if it is anything good and still has the quality of symasym5.
Mike
Grataku, right now i have no plans with balanced input, you might consider a converter/buffer ?
John, the sym5_3 is about pcb, i changed some power grounding. A high power version will be a redesign, using slightly different topology, giving a symasym6... (folded cascode with triple darlington output) Let's see if it is anything good and still has the quality of symasym5.
Mike
Mike, which output transistors do you prefer (sonically), 2SC5200/2SA1943 or the transistors of the original design ? I ask because you have tried both.
Upupa Epops said:
For output or cascoding devices ? Mosfets ?
dtrif said:
Dimitris, i am not sure, i did not make a direct comparison. I have the feeling that the Toshibas do sound softer, and the MJLs a bit more agressive/dynamic.
Mike
Upupa Epops said:
Ah, so you mean jfets as inputdevices ? Yes, they sound lovely !
Hmm, i have some sk170 and sk389 left...
Mike
complex load
MikeB, could you make a little test for me, please ?
I would like to see the output @ 10kHz squearewave with 8R + 1uF load, on half power.
Thanks!
MikeB, could you make a little test for me, please ?
I would like to see the output @ 10kHz squearewave with 8R + 1uF load, on half power.
Thanks!
Re: complex load
I can do it, and guess I had probably done it.
You have electrostatic speakers? Otherwise this test is good quite for nothing, as it is highly unrealistic load. Better think about frequencies at sides of bass speaker resonance, the immediate power is highest here.
Cortez said:
I can do it, and guess I had probably done it.
You have electrostatic speakers? Otherwise this test is good quite for nothing, as it is highly unrealistic load. Better think about frequencies at sides of bass speaker resonance, the immediate power is highest here.
Hi Mike,
most of the advantages are lost without carrying the balanced line to the input differential. Plus all the extra components in the converter.
I was thinking in would be simple to add the cold input to the feedback side of the differential.
I am all for jfet input. I have a load of them I'll probably never use.
most of the advantages are lost without carrying the balanced line to the input differential. Plus all the extra components in the converter.
I was thinking in would be simple to add the cold input to the feedback side of the differential.
I am all for jfet input. I have a load of them I'll probably never use.
grataku said:
Mark Levinson did this kind of solution. The only problem is the low input impedance of the feedback point. So they used some input buffer (double push-pull emitter followers) to get same input impedance on both + and - input
sajti
grataku said:
I have actually blown the one in my dummy load (2.2uF), though it was connected in series with 6.8R resistor. It happened during long-term square wave 10kHz test into dummy load 😀
look here: http://web.telecom.cz/macura/dummy_en.htm
Re: complex load
In paralell or series ? I guess paralell... Grataku, i would use Wima MKS2, it's likely that it wouldn't even warmup... I used them in ClassD-Filter, 300khz squarewave kept them cold.
Mike
Cortez said:
In paralell or series ? I guess paralell... Grataku, i would use Wima MKS2, it's likely that it wouldn't even warmup... I used them in ClassD-Filter, 300khz squarewave kept them cold.
Mike
Once more - why do you need it?. You know what is capacitive current?????
Ic = C*dv/dt
Depends on current derivative!!!!
For 2uF and 20V/us you get 40 Amps!!!
It's a ********, nothing more.
Ic = C*dv/dt
Depends on current derivative!!!!
For 2uF and 20V/us you get 40 Amps!!!
It's a ********, nothing more.