MPP

The tin plated PCBs look great (like in old HP measurement gear).
How can one do this at home ?


Tin plating cristals from various supliers
RS Part number is 567812
But normaly you may get them much cheaper somewhere else
RS prices are baad

There is also an alternative method but a kit is needed
It uses a power suply and same special electrodes and liquids
and can do silver or gold if I remember corectley it was designed to plate mobile phones and such.
I have not tried this but the tin plating cristals work fine
Just make what you need if you do not use regularly as solution losses propities with time.
 
I started stuffing the boards.
 

Attachments

  • Gardinera stuffing 1.jpg
    Gardinera stuffing 1.jpg
    97.8 KB · Views: 335
  • Giardinera stuffing 2.jpg
    Giardinera stuffing 2.jpg
    100.2 KB · Views: 325
The left PCB is the input and output PCB. The RCA`s are directly fixed to the PCB so the ground is not soldered and does not go though several metal contacts. I need 6 RCA`s for MC, 4 for input, 2 for optional loading of the trasconductance input. The loading components are then in external RCA jacks.Therefore the additional pair of RCA´s. The MC input is switchable between transimpedance and transconductance.For this i need 4 RCA´s. Loading of the transconductance input can also being done with on board Dil switches or both. The MM input has also 4 jacks for the same purpose. The onboard Dil switches are in this case responsible for switching in loading caps. There are some exotic MM´s that like to be loaded less the 47kOhm. That can be done with the external RCA´s. The rest of the RCA´s are the output so we have 6 for MC, 4 for MM and 2 for output for a total of 10.
The natural input impedance is 10 Ohm for the transimpedance input, 47kOhm for transconductance and MM.
 
Yes, i saw that loading type first in a CAT preamp. Some people say that DIL´s sound bad so it circumvents that problem too when you put the DIL´s in the zero position. On the other hand a phono stage has to be complete with loading option when delivered, hence the way we designed it.
It is a ground plane construction but with a double mono PSU.
In a strict sense this is no star grounding.