Preamp Control - Volume, input, mute, remote

John,

thank you for sharing this really great project,
I am looking for a balanced stereo pre control
can you please confirm that balanced can be done without problems using Version 2 of boards and all I have to purchase 2 pcs for control boards, 1 pcs for display and 1 pcs for remote
 
Hi Samoloko,
The Control board (Main Board) is Balanced from input to output (except two inputs) so only one board is needed. If you look at the schematic two of the inputs, Left J4 and J5, and Right J12 and J13, are single ended only at the input, and with a trace cut at K1.3, K3.3, K16.3, and K17.3 and a couple wires run to the input connector you can restore the full balanced for those two inputs as well.
BTW the Gerbers for the main board are Rev3 which has C7 on the board, the only difference from Rev2 of the main board.
Thanks,
John
 
Hi Samoloko,

There is not any formal GB for PCBs; however, I have placed an order for 25 sets which I will be selling at cost for $17 each plus shipping from Washington DC. I should receive them in about two weeks and will be sending a set to John for his "blessing". The main board is a copy of the board that went into production and given quality work at PC Prototype should work well. John made minor changes to the Display and Remote PCBs to incorporate a replacement encoder/decoder chip as the originals were out of production. As the changes were minor, they should also work properly.

Once I receive them I will put out a notice that they are available.

Regards,

Roy
 
Board Sets

Hi Samoloko,

Consider yourself added to the list. Please send me a PM with your address so I can figure out shipping when the time comes for payment. I'll post my Paypal address when the time comes and will periodically update the list in this thread so everyone will know their status.

Regards,

Roy
 
Build Questions

John,

Your picture of the main board shows the relays for input switching mounted on the rear of the PCB. I followed your lead and mounted mine on the back as well. Reading over your first post again I found a reference to problem with the initial board that required the relays on the back that was resolved in previous releases. Given tat the Should I remove the relays and mount them on the front?

I didn't find the volume control resistance in the documentation. I was planning on installing the boards in a XBOSOZ preamp that would like to see 5K liner taper, but has some flexibility. What is the current value and what resister changes would need to be made to get it to 5K?

Thanks,

Roy
 
John,

On the main PCB C5 & C6 are listed as .15uF; however the part number you provided is for a .015uf capacitor. Which is correct?

Also, J4-J9, J12-J17 on the main board are the input connectors. Do you have a part number for the 2 & 3 pin connectors or were these to be direct solder?

Thanks,

Roy