Paradise Builders

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#3,541
15v isn't high offset, that's a soldering error, sounds like the voltage from the current mirror is hitting the output. Check the 2sk170 at the top of the board isn't shorted and that the op-amp isn't dead.

Do you have the small smt caps fitted on the underside of the board (not the 220pf/2.2n compensation caps)?
 
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#3,545
FdW said:
Pierre,

It seems that both positive supplies have the same problem, and I do not know what/why. Did you earlier also replace the small-signal devices in these supplies? if not then you need to do it. (for now do not worry about the 100mV problem in the negative supplies, they are not designed to run as 1.3V current sources 🙂).

P.s. I will send you a PM.
Click to expand...

Hi Frans
Yes, I had already changed the active devices, including the small signal ones, following the good advice in this thread.

Thank you for your PM. I just replied.

Kind regards
Pierre
 
#3,549
Sounds like water with coconut to me. 😀

Anyway, why I'm actually here is report back on the buffer. After a long time I have finally managed to add the buffers to my Paradise and also build a new enclosure with more space/air. I also wanted to add "switchable" load with a switch that I had laying around for a long time.

Regarding the buffer - even though I changed the Rs in the regulator to 8.2 it still takes 10 seconds for the large banks of LEDs to light up. Since I can't see/measure any irregularities I'll just leave it like that.

Unfortunately it has been a long time since I listened to the paradise the last time (without buffer) but I like to believe it really does sound better in my system. My preamp has a shunt type attenuator so the output impedance of the source is important. I think overall with the buffer it sounds a bit more pleaseant, I really like it. Finished the unit yesterday and wanted to do a quick test only but ended up with listening to 5 or 6 records straight.

Thanks again to the Paradise team and also to Calvin for the buffer.

Here are some pictures of the new enclosure, its again "low budget" with standard enclosures from Hammond and faceplates I had "lasered" by a company called Formulor.de. You can edit/order stuff directly online and the website is available in English (overall the cost for 6 Faceplates was an acceptable 90€, so check it out).



An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.



Regards
Sven
 
#3,553
Hi Sven,

thanks for the insight. Did I already say, that I REALLY like your case! 😀

Just some additional questions:
1. The yellow RIAA capacitors: Which brand? Which values? Where to get?
2. The mounting of the Calvin Buffer: How did you fix this on the Paradise Main PCB?
3. The thermal coupling of the input transistors: Is this shrink tube or what did you put over these dudes?

Cheers and, well, I like your build! 🙂
Walter
 
#3,554
Sven: If it takes long time for the leds to start to shine, you probably should increase the shunt regulator ccs current. you can parallell a small resistor on the small resistorspot marked with an X. try something like 120R or so (in my case 120R would increase current by 10mA), to see if the problem dissappears - since it seems like the shunt supply is starving.
 
#3,555
RollE2k: thanks will give it a try, I already reduced the resistor from 10 to 8.2 Ohms but that may not have been enough.

Walter:

1: Thats Philips KS I got from Ebay - unfortunately that was almost two years ago and I can't find the name anymore...
2: I actually drilled holes in the main board and used one long M3 bold through buffer, spacer, mainboard to fix it. I didn't really like the idea of just cluing it but with hindsight that would have been enough, especially since the leads once soldered add some more stability. If you drill holes you have to very carefully insolate the bolt since you will drill through copper.
3: Yes, but I didn't actually shrink it. just cut a piece open and since the tube will attempt to stay in its tube form it kind of "snaps" over the transistors and stays where it is. Its not really a thermal coupling, just a protection from moving air.

Regards
Sven
 
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#3,558
You have approx 161mA current through the shuntreg. should be sufficient if you don't run very highish current trough the calvin buffer.. just measure voltage over R6/R11 and R5/R7 and you can calculate current through the buffer. I think the paradise does use approx 80-85mA plus the Calvin buffer then. You should have at least 30mA extra current through the shuntreg. So say that the buffer uses 60mA, then you would need even more current in the shunt.
 
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