MPP

[hesener]

Paradise first Draft on a 100 x 160 mm perfboard.

Not much space for the riaa caps....

good stuff! I was hoping to fit it all on a 100x160mm together with the shunts, let's see if that works out

 

[RCruz]

So 2.54mm = 100 thou... perfect

Here we have second draft with tracks:

 

[Bksabath]

Hi Riccardo

Grid spacing can be set to anithing you like.

Is in the units settings and you can change the snap mode to half grid or quarters or even up to 1/48

yes a tau is inch/100

but you can change that to on your units settings (you have option for 2 alternate Units)as most components (capacitors) spacing is metric.

Dig deep in the program it will let you create your own components and or modify existing ones and you could download componets library from RS.(If I remember a free program was on the same page as that download and let you import stuff from other design packages)

Is not that straight forward and I give up on it as I find easier to place the standard simbols on one layer and replace the pads with what I need in another layer and then tracks on that.

And Yes software is free to download from RS components is very similar to Easypc whic I had since it was DOS version and now cost about £350 (sic sic I could have bought a few new records instead) for the cheap and nasty one with even more very limited component library.

 

[RCruz]

Thank you for your help and guidance Bksabath

 

[Bksabath]

Riccardo you are welcome.

I am realy enjoy watching this tread.

I have not done much latley New Job Crimbo caming up and freazing cold in the loft....

My tanks to you all for all your hard work

 

[hesener]

component and schematic entry for the preamp finished at around 3:30am....now I need to find a heatsink, enter the shuntregs and start with a floorplan....

 

[Joachim Gerhard]

Thanks.

 

[hesener]

Here is the heatsink I found, with 75mm width (which would leave some room on both sides of the target size PCB) the heat resistance is 3.8K/W assuming free air flow, so I think we have a good safety margin. And it has roughly the same height as the Panasonic FM caps so that helps with mounting.

hope you like it ;-) cost is €3.69 at Buerklin

 

[Joachim Gerhard]

Looks good to me.

 

[mad_z]

Guys,

I have 100pcs BZX85C 6v2 in my stock - not exact match to our needs but still these may be of interest in scope of noise test.

Please drop me PM with mail address if you want them - I still can send the envelope before end of week for testing.

 

[MiiB]

One thing we may have forgotten is the supply for the Servo amp, in spice I just run it on 24 V... but will that work in reality..??

 

[FdW]

Here is the heatsink I found, with 75mm width (which would leave some room on both sides of the target size PCB) the heat resistance is 3.8K/W assuming free air flow, so I think we have a good safety margin. And it has roughly the same height as the Panasonic FM caps so that helps with mounting.

hope you like it ;-) cost is €3.69 at Buerklin

Nice, I like it (don't we have a button for that?)

 

[FdW]

One thing we may have forgotten is the supply for the Servo amp, in spice I just run it on 24 V... but will that work in reality..??

Was it included in the 105mA? if not we may need to change the shunt current, from 160mA to 170mA.

For the power supply of the servo 2 resistors, 2 15V zeners and 2 33uF elco's will do. Calculate the resistors for 10mA, 1K will do.

 

[FdW]

P.s. Do not make the elco's any larger, otherwise the servo may/will start to slow.

 

[MiiB]

I was includede in the 100 mA...i agree 15v zeners an 1K resistors is good for that

 

[RCruz]

can you post a revised schematic with the resistor - zener / EL voltage divider ?

 

[Onvinyl]

For the power supply of the servo 2 resistors, 2 15V zeners and 2 33uF elco's will do. Calculate the resistors for 10mA, 1K will do.

I like to use BC550/560 as small emitter followers for that -- tends to be cheaper and quieter (two more resistors, though)

Rüdiger

 

[Joachim Gerhard]

What also works is supply the Opamp ( servo ) from a string of Leds. Say we want plus-minus 15V. We have to drop 9V. We can use 3 blue Leds in series with the Opamp supply.
I would then use two 33uF and one 0,.1uF from Pin 4 to 7.
I am fine with the other solutions too.

 

[Joachim Gerhard]

I did it on this board. Voltage was plus-minus 18V. I dropped it to plus-minus 15V with 2 red Leds in both supplies.

 

[hesener]

Lots of LEDs on those boards will be, quite appropriate
for christmas... Do you guys think that blinking
LEDs will disturb the servo? ;-)))