Pro Audio Design Forum

Hey that's cool. We got something to work from in the interim.

Hello,

A stupid cap question. In the preliminary BOM it says "0.1/100V Mono Ceramic Mouser 581-SR201C104KAR" (= radial monolithic cap, $0.40 per item). I'm thinking about implementing the MS board into the Pico compressor, which -- according to the BOM -- uses 0.1/50V caps (Mouser: 80-C317C104M5U). Is there any reason why the MS board should be stuffed with 100V caps? I guess they were at hand at the time and I think I know the answer, but just want to make sure...

Cheers,

Script

Hello everybody ,
Im adding the M/S card into a kind of mastering console im working on ( finishing Pcb )
As audio Bf i ll send it , is still asymetric , i wanted to connect it via BR BL directly ( skipping IC1 ,IC2) ,Do the same for decode , using FS FM (and skip IC7 IC8 ) .
1/ Is it a good way to go ? ( probably no because it seems that you do +3 or + 6 there and i send Audio BF to -3 ( using 1243 ) )
or should i resymetrise (using That 1246 ) to desymetrise again in M/S card ... ?

2/ also is there an easy way to adjust level between M ans S in the encode section ?? ( adding pot in CS and CM ?? ), Level in encode section is important to me because Im Also using Upward compression into MS ( ), and i finally sum them before decode .( Maybe a nice mastering tool )

Thanks for any help
Mr Flight

PS ( eh Mediatech Where did you make pcb made ?? )

Hi flight -

Yes, you can insert after the 1246 stages into B and F and skip the balanced inputs. The source impedance has to be low <<10 Ohms or it becomes part of the matrix. Use an op amp to drive the B and F inputs. Another option is to just use the 1246 as SE inputs by driving "+" and grounding "-".

If you put variable gain inside the matrix - in the M and S domain - the precision is reduced. I would not use resistors in series with the 1646 inputs in any application. Instead, if you want to vary the encoded gains, just use the decoder as encoder and encoder as decoder. They are interchangeable and almost identical - the only difference is the -6 dB 5532 stage. That allows you to vary the gain of the 5532 stage to alter the M/S ratios on encode.

Roger did the board layout and they were made using the Express PCB software and the Express PCB service. They (Roger and Express) do really high-quality work.

Wayne

Hi
anyone have compensation cap values handy for 2604 and 33078?

Thank you

Milos

Hi Milos -

I wouldn't have those values off-hand but I might suggest something in the range of 22-47 pF.

I tuned the 5532 using sqarewave response for minimal overshoot. On the board I would use the insert point just ahead of the 5532, point "G," to inject the signal. I would also suggest the NJM2114 in addition to the 2604 and 33078.

NJM2114 datasheet: http://semicon.njr.co.jp/njr/hp/fileDow ... ediaId=122

Wayne

Thanks Wayne, great.

Hi All,

I finished my build today, with mutes and bypass.

On first power up i ran it through Rightmark Analyser, the results are here if any one is interested......

http://www.grandmasteraudio.com/ms_matrix.htm

a few bad iPhone pics

http://www.grandmasteraudio.com/ms1.jpg

http://www.grandmasteraudio.com/ms2.jpg

I have to say sonically its invisible, noise floor less than -100dB, simply stunning design. The M/S mute is a wonderful and will be very useful.

I just wish I had brains as big as you guys to work this stuff out in the first place.

Thanks to all.

Best
Pete

Good work, thanks for sharing!

Thanks for sending this Pete! NIce build. Thanks for taking the measurements.

Wayne