My intention was you place it the first time powering up and check if everything is working as it should be. Then you don't have to use the precious tda1541.[emoji4]
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I’m aiming for 26-27V as I believe Ryan said was acceptable.
Obviously the board power inlet is labeled 26V.
I wouldn’t have had to change anything on the CMx if I had been able to stick with the 22V transformer I initially tested it with.
Unfortunately, it took up more space than I wanted so I ordered a Triad VPT48-520 which put out 27.5V after the CMx with a 200 Ohm load.
I felt that was too high and had to start playing with R4 and R5 to try and get it to an acceptable level.
After I tested my CMx board a second time with 22 Ohm paralleled with a 100 Ohm I actually got about 26.3V.
There is obviously fluctuations in my mains voltage causing it to swing. It appears to be centered on about 26V so I am leaving it for now.
Obviously the board power inlet is labeled 26V.
I wouldn’t have had to change anything on the CMx if I had been able to stick with the 22V transformer I initially tested it with.
Unfortunately, it took up more space than I wanted so I ordered a Triad VPT48-520 which put out 27.5V after the CMx with a 200 Ohm load.
I felt that was too high and had to start playing with R4 and R5 to try and get it to an acceptable level.
After I tested my CMx board a second time with 22 Ohm paralleled with a 100 Ohm I actually got about 26.3V.
There is obviously fluctuations in my mains voltage causing it to swing. It appears to be centered on about 26V so I am leaving it for now.
D3 input voltage
The voltage input limitations are set by the amount of heat dissipated by CC1 and V1 . I usually aim between 26V and 27V, but I have used up to 28V with no issues as long as the temp on CC1 and V1 are not too far above around 55 Celsius.
I would not recommend going lower than 26V - as this was the voltage that I used in the simulation to get good performance, anything lower than 25.5V may affect performance.
The voltage input limitations are set by the amount of heat dissipated by CC1 and V1 . I usually aim between 26V and 27V, but I have used up to 28V with no issues as long as the temp on CC1 and V1 are not too far above around 55 Celsius.
I would not recommend going lower than 26V - as this was the voltage that I used in the simulation to get good performance, anything lower than 25.5V may affect performance.
I liked the small form factor, I was severely limited by space with my design and I didn't want to do a full redesign.
Edit: They also performed just fine when tested with a recording at -60dB
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I was playing around with a variac and varying the input voltage to the Dac board. Absolutely correct about CC1, the temp gets to high quickly. I’ve gone as low as 24.5vdc, below 24.1v the three voltages start to go out of regulation. If the simulation was based on 26v, try to be within -0.5/+1.0 of 26v.
I thought KA was chosen because of its good performance regarding low leakage?
Try whatever caps takes your fancy.
Yes you're right, this is the most important factor. Which is why I tested them with a -60dB recording. If there was any leakage you would hear a distorted sound at -60dB.
thanks to all that helped.. I will adjust the power supply to the recommended voltage.
I've placed an order for bisesik transformer for the d3 and should hopefully get it by the end of this week. will give an update on how this works out.
Hi,
if i use a 200ohm 5w resistor to test my charge multiplier psu, then the voltage climbs slowly up to 24v and stays there. it needs about 3-4 secs to reach 24v. Any idea what i did wrong ? Or is it a wrong r at the end (15ohm).
The transformer is a 24-0-24 24VA one, so that should not be a problem.
if i use a 200ohm 5w resistor to test my charge multiplier psu, then the voltage climbs slowly up to 24v and stays there. it needs about 3-4 secs to reach 24v. Any idea what i did wrong ? Or is it a wrong r at the end (15ohm).
The transformer is a 24-0-24 24VA one, so that should not be a problem.
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