Paradise phonostage pre-regboard, psu group buy v2

[shoom]

Hi Si

Your lovely PSU boards arrived this morning.

Great work and many thanks.

I'll keep you posted on the build.

 

[Simon1972]

Cheers
I still have boards left if anyone missed out.

 

[Marra]

I now have all the parts so am going to be busy tomorrow putting things together.
Si can you post a picture of how you wired up the supply please if one hasn't already been posted. tia.

 

[Simon1972]

Keith, 20ohm resistors go in the first holes between cap 1 and 2, hammonds go in second holes between caps 2 and 3 on the hacker boards.

The image below shows the actual wiring.

I've only built one that was quieter without the 4th, grey, wire fitted, it depends on your system earthing. Here's the wiring for the actual Paradise boards, showing where the 4th wire goes.

 

[Marra]

Many thanks Si much appreciated

It is now a work in progress.

 

[Marra]

I have just wired up the p/s for one channel. No magic smoke but I am getting +- 37.7vdc
How much will the voltage drop when under load?

 

[Simon1972]

That's bang on, expect circa 25v under load as the Hammonds do their stuff.

 

[Marra]

Thanks again Si. Must admit I hadn't realised that there would be such a big drop.

 

[Marra]

Only getting +- 21.5v under load. Is this sufficient?

 

[Simon1972]

Somethings wrong, you need 24.5. Can you take pictures

 

[Marra]

Does cap size make a difference as I only have 3x3300uf per rail.

 

[Simon1972]

Shouldn't do I've built them with 4,700 up to 10,000uf.

What transformer are you using? if you've selected one with too low a VA that will do it. The recco part is the talema 70065k.


List your parts or take a pic.

 

[flashgo]

Boards received in US. Thanks, Simon!

 

[Marra]

All parts as recommended in post 256 apart from the diodes which are MUR860.

 

[Simon1972]

Bom in post 256

 

[Marra]

I will post a pic tomorrow.

Some voltage readings; Mains 234V; secs. 24.9V; rectified volts +- 31vdc.
The resistors are dropping 2.2v and the chokes 6v.

All leds on the Paradise pcb's light up and I have +- 18.2vdc out of the regulators and the voltage across the Calvin buffer is zeroable.

 

[Simon1972]

Sounds ok.your mains is low though.

Trouble is the shunt won't be shunting with any authority, unless its seeing 24v, its just passing voltage. All the leds still light up regardless of whether the shunt is shunting and it has no effect on dc on output. If its not working you'll hear it as a vagueness in dynamic climaxs, the paradise should be really dynamic, remarkably so in fact.

Measure the voltage at the psu input point on your main boards, if its over 24.5v you're good if its under 24v remove the resistors from the psu. Anything up to 26.5v is fine at the input to the main boards.

Also trim the shunt output to 18v, the opamp will thank you for it. Let it run for ten minutes then do it.

 

[Marra]

Thanks Simon you have confirmed what I was thinking of doing ie removing the resistors.
The mains was low last night it usually sits above 240.

 

[Simon1972]

I seldom see anything outside of a narrow 240-242v range at home. As stated earlier anywhere between 24.5v and 26.v at the psu input on the main boards is perfect so shoot for that.


Here's Franz's advice on the matter.

CVS and CCS for the shunt.

 

[Marra]

With the 20R resistors out of the equation I now have +-25vdc

The output of the regulators has been reset to +-18v and the Calvin buffer reset to zero. It had drifted slightly. Will recheck and adjust if nescessary in a while.