Mpp

[Stefanoo]

yes it works as servo.
I have bypassed the current mirror, bring up the voltage and offset is more stable.
The module allows for easy zero out.
So it works just fine.
I am not blown by the offset created by this circuit however sound is very, very good.

Regarding the distortion, I am downloading the file thanks for the link.
What I can say is that using this discrete module to replace other servo I had used for my previous desing really outperformed sound.
It is strange as numbers would say it should behave worse.
However sound is just more natural and transparent.

Why don't you try it on your desing and tell me whar you think?


BTW on the paradise I have the custom Teflon caps.
I am running my simulated values.
I haven't double checked the accuracy with the instruments yet, but accordingly to the sound, it sounds pretty close.
It probably needs a little tweaking.

[Joachim Gerhard]

OK, so you have the Paradise running.

[Stefanoo]

I mean if expected offset once encased is +/-15mV or so, then I guess it is up and running.
Right now I am just fitting my shunt PSU with Teflon caps so adjusting the compensation cap and strategically placing bypass caps.

Like I said residual noise is doesn't look like flat trace at 2mv/div.

would you kming p[osting a screen shoot of the residual noise?

[Nick77]

Originally Posted by Algar_emi

The Paradise R3 seems to be very interesting and I'm planning in building one. I found enough information to build my own PCB. In the mean time after reading all these posts I compiled a detailed Parts List for North America using the usual suppliers Mouser, Digikey and Newark. It doesn't include the pre-regulator circuitry thought. I'll make it later on...This list may be useful to others. Feel free to point any error I may had done. I still to go through all the schematics to make sure no part is missing.

Thanks for the effort, was hoping for a Mouser break down. Any pro's able to validate this, would like to get parts underway since shipment nears.

Post from 7432

[Joachim Gerhard]

With the input shorted and the scope set to 2mV/dif you should not see a straight line but a trace that is aprox. 2mV wide and looks like noise. This is partly because the vertical resolution of the scope is limited. Also that trace will be offset by the output DC when the scope is set to DC. When you can not center the trace switch the scope to AC. In Heseners building guide you can read how to minimize the input and output offset. A scope does not work like a millivolt meter. To get the real noise output you need a true RMS wide band millivolt. The subjective noise measurement needs also an A type filter.

[Stefanoo]

Originally Posted by Joachim Gerhard

With the input shorted and the scope set to 2mV/dif you should not see a straight line but a trace that is aprox. 2mV wide and looks like noise. This is partly because the vertical resolution of the scope is limited. Also that trace will be offset by the output DC when the scope is set to DC. When you can not center the trace switch the scope to AC. In Heseners building guide you can read how to minimize the input and output offset. A scope does not work like a millivolt meter. To get the real noise output you need a true RMS wide band millivolt. The subjective noise measurement needs also an A type filter.

I absolutely don't have a broadband noise type of residual noise.
The preamp is very quite when connected to the system and residual noise at the scope with 1MHz BW has an amplitude perhaps of 0.5-0.8mV pk-pk and looks like there is thermal noise a little of 50Hz in it.
Anyhow, when I short the input the output noise becomes really strange increases instead of decreasing.
I will post a picture of the noise with both input opened and shorted.

Again the preamplifier is extremely low noise and sound is really wonderful, so thank you Joachimo for sharing this design with us.

Could you please post a link to Heseners building guide?

[pdul]

Any hfe matching needed for the psu part ?

[Joachim Gerhard]

You can find the latest schematic in post 13 of the thread " Paradise Builders".
There is also now a trimmer at the input where you can optimize DC offset at input and output. You may not know that Stefanoo.
I can not tell why the Paradise is noisy with the input shorted. Actually i never tried it.
Nevertheless you get a low noise result and very good sound in practice.
That is what counts to me.

[Joachim Gerhard]

No, the PSU does not need matching, i would nevertheless check if the BJTs work and are in the ball park. If hfe is 400 or 550 does not really matter much here.

[pdul]

Thank you Joachim