bobodioulasso said:
I have made a small GB of rectifier-boards 3 pin diodes and snubbers, if anyone is interested. (Gb rectifier )
Re: 2 thermistors
At this time, I'm building two completely new dual mono F5 amps. The first will be finished today or tomorrow latest and will test listen it for a while. In the meantime, the second dual mono set will be built with a somewhat different PSU that unlike the first one I'm finishing now, will not have the rectifiers on the PCB but MBR20100 diodes already mounted on a PC proc. heatsink. The 0.1R resistors are alredy left out and the filtering per channel (!) is 8 Panasonic capacitors of 33.000uF + 2 ICAR 50uF motor run capacitors. I'll have to push Electrostatics and a line array which has also been set to work on 4 Ohms (can't really arrange 8 pc 8 Ohm drivers any other way) and we'll go from there... With two same, yet different F5 amps, I'll have a chance to test both and make comparisons. If I hear a difference (I'm 44y.o.) I'll report about it. Once the amp is working, there's not much need to do simulations and calculations, the performance is what counts, and I'll be one of the lucky ones to hear if there is audible difference
jameshillj said:
At this time, I'm building two completely new dual mono F5 amps. The first will be finished today or tomorrow latest and will test listen it for a while. In the meantime, the second dual mono set will be built with a somewhat different PSU that unlike the first one I'm finishing now, will not have the rectifiers on the PCB but MBR20100 diodes already mounted on a PC proc. heatsink. The 0.1R resistors are alredy left out and the filtering per channel (!) is 8 Panasonic capacitors of 33.000uF + 2 ICAR 50uF motor run capacitors. I'll have to push Electrostatics and a line array which has also been set to work on 4 Ohms (can't really arrange 8 pc 8 Ohm drivers any other way) and we'll go from there... With two same, yet different F5 amps, I'll have a chance to test both and make comparisons. If I hear a difference (I'm 44y.o.) I'll report about it. Once the amp is working, there's not much need to do simulations and calculations, the performance is what counts, and I'll be one of the lucky ones to hear if there is audible difference
Those are the MUR3020's, quite okayat about35nS- the BYW29's are about 15nS (the 8ETH06 about the same) and seem to be a bit/slightly different.
I had great difficulty with those Sil Carbide ones from Creeks and never managed to get them to function properly.
Curiously, the C-R-C setup became R-C-R-C (= 0.1R0) and stayed that way even with the BHC Silt Foils, T-Networks, F&T, Siemens, Mundorfs, Nippon Chem, Sprague, etc but not with the Panas, Roe, Phillips, etc. Strange thing that - never got to the bottom of it!
I'm playing with the Charge Transfer idea from John of EC Design (Ultimate NOS dac thread) that seems to be able to get rid of the diode noise plus all the stuff on the power cord - a few of the others have also obtained excellent resullts and I think it's only a matter of time before it becomes universal. There's a company in England ("Never Connected") that's upgrading systems with something similar.
Always something new, eh!
I had great difficulty with those Sil Carbide ones from Creeks and never managed to get them to function properly.
Curiously, the C-R-C setup became R-C-R-C (= 0.1R0) and stayed that way even with the BHC Silt Foils, T-Networks, F&T, Siemens, Mundorfs, Nippon Chem, Sprague, etc but not with the Panas, Roe, Phillips, etc. Strange thing that - never got to the bottom of it!
I'm playing with the Charge Transfer idea from John of EC Design (Ultimate NOS dac thread) that seems to be able to get rid of the diode noise plus all the stuff on the power cord - a few of the others have also obtained excellent resullts and I think it's only a matter of time before it becomes universal. There's a company in England ("Never Connected") that's upgrading systems with something similar.
Always something new, eh!
Forgot to mention, you have to keep those Shottky's as KOOL AS POSSIBLE - the higher the temp, the more they leak and the noise filters thru - seperate heatsinks in free air and NOT to the case as it usually gets up to heatsink temperature.
And No, I'm not kidding! It does make quite a difference.
Stein, you've been a very busy bloke indeed - all the best with the new amps.
And No, I'm not kidding! It does make quite a difference.
Stein, you've been a very busy bloke indeed - all the best with the new amps.
Ryssen said:
Don't insist on having 0.600V bias, rather focus on getting the best balance you can and reduce offset to minimum. I found that the bias usually gets a tad higher (0.610-0.630-ish) but then, at 200mV range, I get clean 0.000 Volts... I can hold my hands on my sinks until numbness, but I have a bit of overkill heatsinks and often get burned on my job, so the sensitivity on hands may not be the best test. Where a person who works in office may feel 50C degrees to be very hot, I can rest my hand almost infinitely on that temperature. In a nutshell, if you can't get it any better than 25mV, well, it's not really that bad. Above 100mV I would be very worried (with shorted input, of course)
I thought I'll finish up yesterday, but when I checked the time, it was already today. My first properly boxed F5 is ready to go. Bias at 0.608V, 0.000VDC on output (200mV range), on both channels. AC is at 17V, DC at 22.0 +/-0.1V. That's because the transformer is 230V primary and at home, I never get more than 220V. Impressions and pictures later, when I get to listen to it.
