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GB for Salas Folded Simplistic Phono PCB

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#921
Hi,

I would calculate the transformer secondary voltage.

I read 35V for RAIL+ after shunt regulator in the guide.
I read somewhere that shunt regulator need 7V for a good use.
So it's done 42V a the raw psu output.
With a 1ohm Rdrop, i calculate 32V for secondary voltage.

Is it right ?
Thanks
 
#926
See your finally adjusted Vout (+Rail) for good T.P. reading in your own build first because they differ. Allow 10V distance to raw. That will do 1W dissipation on each channel's CCS sink which is a logical amount. The constant draw is about 100mA per channel.
 
#927
My calculation in post #925 is wrong because i took 1A instead of 0.1A.
So i will have 35,6V at the transformer secondary and 47,4V at raw psu output with my simulation.
I will have 12,4V / 1,24W to dissipate.
I think it's fine

Thanks a lot.
nounouchet
 
#929
Hi,

So I fired everything up, the Raw PSU outputs measure 53.7/53.8v respectively.

The RAIL+ and GND measure 34/31.3v respectively, with the 2nd board maxing out at 31.3v. The only change I have made (on both boards) is use 2.2uF WIMA4 caps at C2x instead of 4.7uF (because that's all I've currently got) and both boards should experience the same issue if the cap values were making any difference.

In addition, the TP1 and TP2 reference voltage is measuring 7.44v for both, and I can't seem to change the value at all by adjusting either VR2x or VR1.

Any tips? Thanks everyone 🙂

-Vlad
 
#930
Vlad, if your Raw PSU outputs measure that high when loaded with the FSP channels you need to take them down with 20 Ohm 5W RD/Link resistors. For less heat and less dangerous input max to the regulators.

Also, replace each R3x with higher values like adding a couple of K to them or more to the weaker one and see if your rails can go higher after that so the voltage across TP1 to TP2 gets lower. The C2x change can bring the regs closer to transient instability but that's probably not the issue behind the insufficient settings right now.

Come over to the main phono thread for more technical questions.
 
#933
Hi,
It isn't clear to me what is included in the minikit. Are the following items included (per stereo board), or are these extra?

2SK369BL matched pair - $10.00usd
2SK369BL matched quads - 25.00usd

2SK170BL's Q4 (8.2-8.5ma),Q5 (7.5-8.1ma),Q6 (8.6ma or higher ma idss) triple pairs - 28usd

PRP RIAA Resistor's 8usd for 4 resistors, enough for stereo set of boards
PRP 9372 1/4W 25ppm .1% 47K -2
PRP 9372 1/4W 25ppm .1%6.754k -2
 
#934
Pars said:
Hi,
It isn't clear to me what is included in the minikit. Are the following items included (per stereo board), or are these extra?

2SK369BL matched pair - $10.00usd
2SK369BL matched quads - 25.00usd

2SK170BL's Q4 (8.2-8.5ma),Q5 (7.5-8.1ma),Q6 (8.6ma or higher ma idss) triple pairs - 28usd

PRP RIAA Resistor's 8usd for 4 resistors, enough for stereo set of boards
PRP 9372 1/4W 25ppm .1% 47K -2
PRP 9372 1/4W 25ppm .1%6.754k -2
Click to expand...

Those are all extra parts. The pieces to the minikit are listed in the overall piece of my minikit blog.

http://www.diyaudio.com/forums/blogs/tea-bag/741-salas-board-minikits-full-kits.html

One would want to read the build guide and know the mv 0utput of their cartridge to know if you want a quad or a pair of 2SK369BL's.

Hope this helps!

Tea
 
#936
Hi Tea-Bag,

I am pretty sure that I misplaced the matched 2SK369BL's and 2SK170BL's which I bought as the matched components from you, and instead soldered whatever came with the mini-kit on the strips. I have adjusted the TP1-TP2 to 3.5v, and the RAIL+ to GND measures 35v. How will the performance improve if I swap out with the matched components given that the biasing is set correctly...? 🙂 Thanks

Kind regards,
Vlad
 
#939
Hi Tea-Bag,

As I've not participated before I'm not sure if Ive signed up or not.
I've indicated on the spreadsheet my requirements of :-

1 SALAS FSP Board
1 Folded Minikit
1 Folded raw PSU Board.

Are these the correct items for me to build the Salas simplistic RIAA pre?
Please let me know if I need to do anything else to sign up - thanks.

Kind Regards
Royville.
 
#940
royville said:
Hi Tea-Bag,

As I've not participated before I'm not sure if Ive signed up or not.
I've indicated on the spreadsheet my requirements of :-

1 SALAS FSP Board
1 Folded Minikit
1 Folded raw PSU Board.

Are these the correct items for me to build the Salas simplistic RIAA pre?
Please let me know if I need to do anything else to sign up - thanks.

Kind Regards
Royville.
Click to expand...

It's a good start.
Even if all the parts listed near the folded are purchased, It will not get you a fully manifested phono pre.
The choice of signal caps and resistors, choice of low or high gain carts need to be considered as well. I would look at build guide in first post and compare that with potential minikit options and parts listed in the first post that are available. So I supply the commonly used parts needed in this kit, and some of the harder to find parts.:yinyang:


MiniKit BOM section. This links goes to full details of all the parts included in the kits and there respective positions on the board.
http://www.diyaudio.com/forums/blogs/tea-bag/741-salas-board-minikits-full-kits.html

Hope this helps.
 
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