Thank you, I have 33uF / 100V at position C3, but I don't know what would be ideal at position C2, you recommend 220uF / 50V, I want to power TDA1541A D3 26V?
You can also try your spare 470uF 50V Nichicon as C2. Listen with it alone, then with a small 0.1uF MKP bypass like 50-63V Wima under the bottom. You decide what you like best in your application.
@Alexlau 84 gogo
Please post replies in English as per forum rules. Also please ensure all quotes are in English also.
please forgive my ignorance but I am trying to populate some extra boards I obtained in the GB. What are VRR resistors, Is there another name for that that is recognized by Mouser etc.? 😎
I am still confused. In the schematic there is a 20k trimmer next to a 75k vrr which cannot be adjusted...
Its just a normal 75k 1/4W resistor. Named vrr as it is working with the trimmer. Limits its ultimate value to keep max Vout where we want it to. Because trimmers come in specific values and a little less max resistance was needed.
Planning to build a Pearl 2 phono stage using UltraBIB for PSU. I have a 22-0-22v R-Core tranny and wondering if I can use it? Appreciate any advice🙂
That Tx will probably give +/- 29V rectified raw DC. Its good for 5V Vin-Vout advised difference across the Ubib assuming you plan to bypass the 7824 & 7924 Pearl 2 onboard chip regulators. It has to be a four wire dual secondaries Tx type, not three wire center tap if that's the case. Because +/- Ubib has independent AC inputs for independent diode bridges in each section.
If for some reason you want almost no thermal drift until settled there is option to use Zener instead of the trimmer. Inherently more noisy but you can filter stronger the Vref with 1000uF C2
From the pdf notes:
You can make it into a fixed output regulator by removing VR1 and replacing with a VRR having that
measured value. A fixed low ppm resistor is more long term reliable than a trimmer and possibly bit
better subjectively. You may also put a Zener in its place with its cathode looking towards R6 in the
positive and towards LED1 in the negative. It would make up for the most of the temperature related
voltage drift but its a rather noisier and harsher choice. If you will use one you should subtract 2Vbe &
2LedVf from its Vz when choosing it for a specific Vout. Use higher value C2 capacitor if for a Zener.
You can make it into a fixed output regulator by removing VR1 and replacing with a VRR having that
measured value. A fixed low ppm resistor is more long term reliable than a trimmer and possibly bit
better subjectively. You may also put a Zener in its place with its cathode looking towards R6 in the
positive and towards LED1 in the negative. It would make up for the most of the temperature related
voltage drift but its a rather noisier and harsher choice. If you will use one you should subtract 2Vbe &
2LedVf from its Vz when choosing it for a specific Vout. Use higher value C2 capacitor if for a Zener.