More problems, i am afraid.
The PSUs passed all tests, so i hooked up one to one of the main boards, using a Variac. I was unable to get anywhere near the output voltages expected, but the 10R resistors got very hot. 5 of the 6 LED's under the heatsink were lit, but none of the others were.
Reduced the input voltage to 120V, drawing 23 mA
output PSU + 15.2V - 15.5V
output RC (= input main) + 14.2V - 14.1V
TP101 + 1.1V
TP202 - 2.4V
TP102 + 0.7V
TP201 - 1.7V
TP103/TP203 + 12.5V - 12.5V
TP104/TP202 + 0.005V - 0.03V
Checked the drop across the diodes D103 and D203 and it was 13.3V and 12.3V respectively. Can not figure out why that should be, since the orientation is correct.
The PSUs passed all tests, so i hooked up one to one of the main boards, using a Variac. I was unable to get anywhere near the output voltages expected, but the 10R resistors got very hot. 5 of the 6 LED's under the heatsink were lit, but none of the others were.
Reduced the input voltage to 120V, drawing 23 mA
output PSU + 15.2V - 15.5V
output RC (= input main) + 14.2V - 14.1V
TP101 + 1.1V
TP202 - 2.4V
TP102 + 0.7V
TP201 - 1.7V
TP103/TP203 + 12.5V - 12.5V
TP104/TP202 + 0.005V - 0.03V
Checked the drop across the diodes D103 and D203 and it was 13.3V and 12.3V respectively. Can not figure out why that should be, since the orientation is correct.
Got some new 1N4004's today and replaced one of the 1N4005's installed originally. No difference, as expected, Output voltage only about 3V.
Decided to give up on these OTT voltage regulators and bought a couple of LM317/LM337 kits which i plan on putting between the PSU boards and the RC board and straight into the amplifier boards from there. Will be missing out on 50 green LEDs, but if it works i can live with that and you can't see them anyhow.
Decided to give up on these OTT voltage regulators and bought a couple of LM317/LM337 kits which i plan on putting between the PSU boards and the RC board and straight into the amplifier boards from there. Will be missing out on 50 green LEDs, but if it works i can live with that and you can't see them anyhow.
I was one of the early buyers of the PCBs which have "R2" marking on them. I have fully populated the boards and remember that they worked before everything was packed in moving boxes and went into storage. Due to several international moves I have not been able to actually finalize the build into a nice enclosure.
Although I have limited time at the moment, I don't have a phono stage and can't use my deck at the moment, so I'm considering finishing the build after such a long time instead of buying a commercial phono stage
... 2012-2022.... 10 years... A couple of questions for 2022:
thanks, good to be back at the soldering iron!
Although I have limited time at the moment, I don't have a phono stage and can't use my deck at the moment, so I'm considering finishing the build after such a long time instead of buying a commercial phono stage
... 2012-2022.... 10 years... A couple of questions for 2022:
- How does the paradise (no calvin buffers, relatively simple psu) compare to commercial offerings like Lehmann Black cube? Is it still worth finishing up or has it been surpassed in the meantime?
- From what i can see, most builders used at least 2 separate boxes (psu, paradise). I'm a bit limited in shelf space, are there any good examples of setups that use as little space as possible?
- Enclosure recommendations (I have used the italian ones for other projects, any other recommendation or group buys?)
thanks, good to be back at the soldering iron!
Hello lovely people of this thread, I would like to ask for your help.
I am helping a friend with his Paradise build. I got the shunt regulator working nicely, all the LEDs are lit and I was able to adjust the output voltages to be exactly +/-18V.
But when I connect the output of the regulator to the power input of the phono section, I get -15.5V at the output.
The output buffer is OK. Also I get correct voltages at the test points indicated in the schematic: TP5 and TP6 are 16.4V, TP9 and TP10 are -16.4V. TP3 and TP4 are 14.5 and -14.5V respectively. However, I get -15.6V at the collector of Q7 and, accordingly, at the external RIAA connector.
I checked all the transistors and resistors in the current source on the negative supply side, everything seems to check out. Frankly, I am at a loss as to what could be wrong.
I am helping a friend with his Paradise build. I got the shunt regulator working nicely, all the LEDs are lit and I was able to adjust the output voltages to be exactly +/-18V.
But when I connect the output of the regulator to the power input of the phono section, I get -15.5V at the output.
The output buffer is OK. Also I get correct voltages at the test points indicated in the schematic: TP5 and TP6 are 16.4V, TP9 and TP10 are -16.4V. TP3 and TP4 are 14.5 and -14.5V respectively. However, I get -15.6V at the collector of Q7 and, accordingly, at the external RIAA connector.
I checked all the transistors and resistors in the current source on the negative supply side, everything seems to check out. Frankly, I am at a loss as to what could be wrong.
OK, that was a bad case of RTFM on my part. I connected a 10K resistor across the input, and now I get "only" approximately -2V at the output. It actually starts at about -3V and gradually decreases as it warms up.
The output pin of the op amp sits at approx. 30mV.
Back to basics... It may be worthwhile checking for solder bridges. I had one on the left channel and another on the right channel that drove me nuts when I was debugging my build. Some of the pads are close together, and I was in a rush when I soldered the main PCB... Once cleaned up, the preamp was easy to dial in. If you are an experienced builder, please disregard... 
