Paradise Builders

diyAudio Chief Moderator
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Here's a picture from 2015 I found in my files. Shows the bodged PSU area with wire links and CCS setting resistors (missing TIP transistors from the sink replaced by one DMOS per rail).


Paradise PSU modified.JPG
 
diyAudio Chief Moderator
Joined 2002
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"Sziklai compounds rather?" : in my textbook, available in at least
14 editions since 1969 these are called complementary darlington.
I looked it up just now and I see they are the same thing.

From Wikipedia, the free encyclopedia




Figure 1. Sziklai pair that acts like a single NPN transistor with collector C, emitter E, and base B.
In electronics, the Sziklai pair, also known as a complementary feedback pair, is a configuration of two bipolar transistors, similar to a Darlington pair.[1] In contrast to the Darlington arrangement, the Sziklai pair has one NPN and one PNP transistor, and so it is sometimes also called the "complementary Darlington". The configuration is named for George C. Sziklai, thought to be its inventor.
 
In a german version of a Paradise R3 assembly guide V5
I see a brute force method to tame supply oscillations :
https://www.dropbox.com/s/8ayxldua68hphsy/Paradise R3 assembly guide V5 deutsch.pdf?e=1&dl=0
at about 40% down the pages. This is only a hint, I do not
necessarily agree.
I had to take the brute force route with both the shunt PSUs in my Paradise build. They did stop oscillating though.

I did have one board that would not work correctly, the Servo Op amp output was nailed to the rail. I found is was the tiniest solder bridge between a pair of transistor legs. Took me a while to spot and fix.
 
diyAudio Chief Moderator
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Found my alt RIAA notes from back in the day. Here's the text:

"Miib tuning has a bit more treble and bass. +0.4db HF +0.2dB LF in my build by measurement. Add 1nF to the treble caps C2a, C2b and parallel 820k-1Meg to R9a R9b. Matter of tolerances. You are looking for 67.8k net. That way it goes near neutral so you can have an alternative listening session. Its a matter of taste and system integration mainly. That makes for 33n3 12n 9k1 67k8.
I had also used half the total mF at the emitters and deleted their bypasses. For earlier subsonic roll-off"
 
diyAudio Chief Moderator
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Thanks Salas, I couldn't find them in-thread. I'll order the resistors from Tx components.
I am sure I had also lessened the value of the DC servo output drive resistors to the R5 nodes. Probably down an order of magnitude. To make the DC offset correcting action much more aggressive. But I don't seem to have kept a note on them.