Paradise Builders

[Salas]

FdW

 

[as_audio]

In the meantime it will be hard to ask him.

 

[Simon1972]

Salas I'd played with that 1 Meg on the servo, 100k was OK anything less and I felt I could hear it hunting. Sounded a bit like when you forget to put the bias weight on.

 

[as_audio]

I am referring to the link posted by Salas today
https://www.diyaudio.com/community/threads/mpp.154210/post-2818966
as a reference of gyrator use in Paradise supply.

I found an example of a single transistor gyrator here :

Source : https://www.epanorama.net/documents/telecom/gyrator.html

Looking at the FdW schematics, Q5 and Q2 may in fact be intended to work as gyrators,
but is it still true if the Zeners, additional cap and LT1086 current sources are included
in an additional loop ?

The original cap, C1 in the figure above, is now grounded (C19, 22), not sure this makes
a difference. This however is not true for both versions of the Paradise supply.

Somebody more knowledgeable perhaps can tell.

 

[Salas]

Salas I'd played with that 1 Meg on the servo, 100k was OK anything less and I felt I could hear it hunting. Sounded a bit like when you forget to put the bias weight on.

That's the servo's RC input filter. I didn't tweak it. The output series resistors I lowered their value.

 

[as_audio]

The output series resistors contribute to the resulting corner frequency also.

 

[Salas]

Looking at the FdW schematics, Q5 and Q2 may in fact be intended to work as gyrators,
but is it still true if the Zeners, additional cap and LT1086 current sources are included
in an additional loop ?

The original cap, C1 in the figure above, is now grounded (C19, 22), not sure this makes
a difference. This however is not true for both versions of the Paradise supply.

Somebody more knowledgeable perhaps can tell.

Conceptually C20 is C1 xx uF and the CCS configured chip reg is R3 47R "current source"?

 

[as_audio]

Maybe - is it still a gyrator, probably bootstrapped ?

 

[Salas]

C19,22 arguably bootstrap.

 

[as_audio]

Please let us keep this thread dedicated to Paradise phono builders.
I am sure you can find Sziklay pair buffers elsewhere in this forum.

 

[Simon1972]

I've pretty much just completed another build, just waiting on a few parts.

No doubt my current paradise needs a bit of TLC, it's a couple of years since I twiddled the pots in it.

 

[as_audio]

Re post 4610, the original entry I referred to is completely deleted, not sure how and why. ..

 

[Salas]

Deleted by the poster. Reason noted: wrong thread.

 

[Simon1972]

Did we ever get a fix for the recent wayward paradise?

 

[as_audio]

We will never know.

 

[hesener]

Yes you will

 

[Simon1972]

Spill the beans, I'm intrigued.

 

[hesener]

Sorry i was out traveling..... the paradise"s" have been fixed (not sure there is a plural form of paradise ).....

As expected the older PCBs had some oxidation on the pads and even with careful soldering some intermittent contacts existed. In the end I only resoldered everything, and the amplifier started up nicely. Even did a quick soundcheck which gave me the urge to build another one again...

Stephan made a massive and good-looking PSU which contributed as well, i am sure.

Boards are back with Stephan and hope to get confirmation from him shortly!

 

[Simon1972]

I've just soldered up a new pair with entirely flat riaa, i just need to swap out some input stage transistors to get it dialled so the servo is doing as little as possible. I prefer to get them so the servo is running under 500mV. Just waiting for the caps to form....