What, no Zinc all over the face ?
The ozon layer must still be too thick over Oz, i'll have to crank up the bias further.
For bridged mode, what can be expected if IRFP9140 is used instead of IRFP9240, as suggested by Ilimzn several times ?
Nanti kami membangun amplifiers di David Lumanauw sendiri.
The ozon layer must still be too thick over Oz, i'll have to crank up the bias further.
For bridged mode, what can be expected if IRFP9140 is used instead of IRFP9240, as suggested by Ilimzn several times ?
Nanti kami membangun amplifiers di David Lumanauw sendiri.
Hi, Jacco,
He..he..he...
Hi, Amplifierguru,
You don't look like a guru at all like Jorge pointed.
Is it possible to make the killer amp a full Nch mosfet? For upper side, can the IRF9240 is replaced with smaller IRF9610+IRF250 (like CFP config)? Could become really indestructible.
Now I wonder, why so many Australian is good with audio design?
He..he..he...
Hi, Amplifierguru,
You don't look like a guru at all
like Jorge pointed.Is it possible to make the killer amp a full Nch mosfet? For upper side, can the IRF9240 is replaced with smaller IRF9610+IRF250 (like CFP config)? Could become really indestructible.
Now I wonder, why so many Australian is good with audio design?
Hi Jacco,
Of course the first item in the medicine chest is beer, then Zn and aspirin! Here its 30C every day now - great for amp testing, and summer doesn't start until December.
I know the IRFP9140 is better for applications < +/- 50V but I didn't want to restrict the amp power. At present the +ve side clips slightly earlier because of the Rs=0.5ohm c.f. 0.2 ohm. 1V!
Hi Lumanauw,
I suppose you could convert it to Nch by replacing the IRFP9240 with a Nch CFP in common source. Hard to say the result. In your low voltage application, IRFP9140 is good and maintains the 'sexy' (Mikeks quote) symmetry.
Cheers,
Greg
Of course the first item in the medicine chest is beer, then Zn and aspirin! Here its 30C every day now - great for amp testing, and summer doesn't start until December.
I know the IRFP9140 is better for applications < +/- 50V but I didn't want to restrict the amp power. At present the +ve side clips slightly earlier because of the Rs=0.5ohm c.f. 0.2 ohm. 1V!
Hi Lumanauw,
I suppose you could convert it to Nch by replacing the IRFP9240 with a Nch CFP in common source. Hard to say the result. In your low voltage application, IRFP9140 is good and maintains the 'sexy' (Mikeks quote) symmetry.
Cheers,
Greg
Hi everyone,
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If anyone want to know about AmplifierGuru a.k.a. Greg Ball
Try this link
http://images.google.co.in/images?q=Greg+Ball&hl=en&btnG=Search+Images
Lots & different type versions of Greg Ball our friend...
Greg dont get angery with me Please............
K a n w a r
http://images.google.co.in/im...........................
Isn't this way off topic ?
Looks like we are drifting slowly.
Isn't this way off topic ?
Looks like we are drifting slowly.
Thanks PB2,
Yes I'm very pleased with it. I'm sure it's been thought of before but shied away from in the mistaken belief that it would not be stable. But there was too much going for it, so a nut to crack. I characterised the IRF's thoroughly (over 100 pairs) and tailored the thermal response, matched the pairs and it works a treat. Load stability is among the best I've worked with.
By the way here's the power supply Class AB commutation artefacts superimposed on the supplies due to a 1KHz 100W into 8 ohm output (0dB =40V peak). Just look at the spray of even harmonics. Now if your HF PSRR is declining at a typical (Vas) 6 dB /octave that will emphasize the injected artefacts as frequency rises. These are generated by the AB switching process and are not in the pure 1KHz signal.
Just imagine the piccolo plus artefacts! That's why a high PSRR topology is an audition winner .
Cheers,
Greg
Yes I'm very pleased with it. I'm sure it's been thought of before but shied away from in the mistaken belief that it would not be stable. But there was too much going for it, so a nut to crack. I characterised the IRF's thoroughly (over 100 pairs) and tailored the thermal response, matched the pairs and it works a treat. Load stability is among the best I've worked with.
By the way here's the power supply Class AB commutation artefacts superimposed on the supplies due to a 1KHz 100W into 8 ohm output (0dB =40V peak). Just look at the spray of even harmonics. Now if your HF PSRR is declining at a typical (Vas) 6 dB /octave that will emphasize the injected artefacts as frequency rises. These are generated by the AB switching process and are not in the pure 1KHz signal.
Just imagine the piccolo plus artefacts! That's why a high PSRR topology is an audition winner .
Cheers,
Greg
Attachments
Hi Mastertech,
It's a handy little window, the Audio Tester. It's shareware 30days or 28 euros. I had to build a filter to clean up the signal out part of my soundcard though.
The biggest hassle is dividing the signal down to maintain the 500mV rms for max resolution from the soundcard. I'll have to build a divider.
Incidentally the ref 0dB on my last post was 500mV rms not the 40 volt peak as it's coming straight off the supply, no divider, to the soundcard in.
If you have a stereo amp using a common PS, you can run one channel with the signal to put the artefacts on the supply then analyse the other for it's rejection with no signal. Crosstalk. PSR.
Cheers,
Greg
It's a handy little window, the Audio Tester. It's shareware 30days or 28 euros. I had to build a filter to clean up the signal out part of my soundcard though.
The biggest hassle is dividing the signal down to maintain the 500mV rms for max resolution from the soundcard. I'll have to build a divider.
Incidentally the ref 0dB on my last post was 500mV rms not the 40 volt peak as it's coming straight off the supply, no divider, to the soundcard in.
If you have a stereo amp using a common PS, you can run one channel with the signal to put the artefacts on the supply then analyse the other for it's rejection with no signal. Crosstalk. PSR.
Cheers,
Greg
Some more ++++
Another big advantage of this new topology is that there is no need for the Zobel R//L on the output to isolate from capacitative loads, as with conventional designs.
The open loop gain includes the voltage gain in the common source output stage and this is decreased when loaded with C on the output, decreasing loop gain and INCREASING STABILITY.
Also, the lack of Zobel increases the damping factor as the speaker sees only the interconnect and the output node Z.
Cheers,
Greg
Another big advantage of this new topology is that there is no need for the Zobel R//L on the output to isolate from capacitative loads, as with conventional designs.
The open loop gain includes the voltage gain in the common source output stage and this is decreased when loaded with C on the output, decreasing loop gain and INCREASING STABILITY.
Also, the lack of Zobel increases the damping factor as the speaker sees only the interconnect and the output node Z.
Cheers,
Greg
Hi Jorge,
Yea sorry my mistake. trying to write an instruction sheet at the same time, and when I realised the edit had timed out.
Of course the series RC output to ground is needed in particulat to tie down the output stage gain at HF. But the output R//L is not needed.
I've often wondered what the R//L series C is called?
Cheers,
Greg
Yea sorry my mistake. trying to write an instruction sheet at the same time, and when I realised the edit had timed out.
Of course the series RC output to ground is needed in particulat to tie down the output stage gain at HF. But the output R//L is not needed.
I've often wondered what the R//L series C is called?
Cheers,
Greg
Hi,
I think that four component collection on the output is a Thiel network (the same guy of T/S parameters). I've used the term on this forum many times and no one has corrected me (yet).
Cherry did an excellent short paper on calculating the values of the network and covered all the limiting conditions when some components become either zero (shorted) or open circuit (infinity) and everywhere in between and how to get best use out of the network to attenuate any RF being injected back into the inverting input ( the very worst place to put it).
Incidentally, most Zobels are shown wrongly compared to Thiel's formulae.
I think that four component collection on the output is a Thiel network (the same guy of T/S parameters). I've used the term on this forum many times and no one has corrected me (yet).
Cherry did an excellent short paper on calculating the values of the network and covered all the limiting conditions when some components become either zero (shorted) or open circuit (infinity) and everywhere in between and how to get best use out of the network to attenuate any RF being injected back into the inverting input ( the very worst place to put it).
Incidentally, most Zobels are shown wrongly compared to Thiel's formulae.
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