In one of my experiments I remember I used 10R for 180mA CCS on a 63V big filter cap, I wanted not to torture the cap and save on CCS dissipation, and it dropped from near 63V to around 55V. So I will run Duncan PSU now to see if it matches. I have to set a circa 44VAC Tx there, had a 2x21Vac that was stronger than nominal, some arbitrary big enough filter cap...
Here we go. It certainly roughly follows my case, so I simulated your case too, I hope it works for you too. Mind you 10V drop at 0.5A is 5W. 10W part will be very hot. But will stand a test.
Here we go. It certainly roughly follows my case, so I simulated your case too, I hope it works for you too. Mind you 10V drop at 0.5A is 5W. 10W part will be very hot. But will stand a test.
Attachments
10R between diodes & filter caps
Measurement Vout DC PSU
Measurement Vin AC Tx
An externally hosted image should be here but it was not working when we last tested it.
Measurement Vout DC PSU
An externally hosted image should be here but it was not working when we last tested it.
Measurement Vin AC Tx
An externally hosted image should be here but it was not working when we last tested it.
2.0 to 2.5Vac that's the averige value and I like to have the same value from my Phono Stage at my Line Stage input Signal. Remember that you can switch the inputs without need of changing the volume level, that's all I want to state.
BTW, out there exist CDPs / DACs which deliver up to 6Vac ...
Without load that is from as far I can see. Use 2R7 for 500mA CCS or 10R for circa 200mA CCS according to the simulator. To have a voltage drop you gotta have a current draw.
I wouldn't do that. Use 63-66dB for a 0.2mV cart. Your CDP cruises at much lower VRMS than max out. Your vinyl cruises at nominal cart output. All you get is a noisy and rather offensive result if you pursue 80dB gain for 0.2mV. Just my 2 cents.
I agree with Salas, you will get more noise (not more information). Could I suggest reduce the CDP signal with a voltage divider with high quality resistors.
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It would only draw around 50mA. To suck 500mA it would need to be 100R and to dissipate 25W. Would need a metal body big one on a heat sink. Like building a Zen amp with resistor CCS.
I would put 10R R1 in a working V1 reg for circa 200mA CCS to test the 10R to Cfilter already installed. If it drops around where you want for DCin to reg given your mains and trafo, I would then set it back to 3R8 R1 for 500mA CCS and use 2R7 15W to Cfilter.
Merlin, I would recheck the LED's as well, makes sure they are still matched. A color change isn't a good thing in an LED since they are typically mono-chromatic unless it is designed to do that. If not, the junction was over heated. The Orange glow was probably thermal emission and not normal.
In regards to the gain comment presented earlier. If there was more gain than the 58dB I allready have, my speakers would have glowed like the LED above at the same volume settings as my cd player. As it stands now, my volume control is very much in the same range as my cd player for the same volume.
I have some pictures coming of the DL103r on the arm and comments on the RD80 mod. The mods I did were in the wrong direction so don't get too excited.
I spent the day redesinging my 12b4 preamp. It was an old project using bird nest and dead bug technique. The bugs started to rot in the nest, if you know what I mean. I put the tube on a 10m45s CCS load with LED bias. Working well so far, at least the gain between channels is closer.
In regards to the gain comment presented earlier. If there was more gain than the 58dB I allready have, my speakers would have glowed like the LED above at the same volume settings as my cd player. As it stands now, my volume control is very much in the same range as my cd player for the same volume.
I have some pictures coming of the DL103r on the arm and comments on the RD80 mod. The mods I did were in the wrong direction so don't get too excited.
I spent the day redesinging my 12b4 preamp. It was an old project using bird nest and dead bug technique. The bugs started to rot in the nest, if you know what I mean. I put the tube on a 10m45s CCS load with LED bias. Working well so far, at least the gain between channels is closer.
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No. Actually a reduction of hiss. Quite a bit in fact. I remember your comments on the OPUS thread and was wary at first. I did have some tubes that were not stable with this.
I would like to build a discrete CCS for it at some point. Still looking for a good design.
I don't want to get OT however.
I would like to build a discrete CCS for it at some point. Still looking for a good design.
I don't want to get OT however.