My mcu based pre Amp projects

[abid_rehan]

With relation to the OPA 549 gainclone thread that I started lately I also started development of pre amp based on PIC mcu and PGA.
I decided to build two version of the pre amp.'
First simple version build around PIC16F876A and PGA2310, having four input selector relays through ULN2803, an output buffer around OPA2314/OPA2107 or LM4562, a 20x2 LCD five butttons for up, down, mute, signal switching and power buttons and an IR based controller. One PCB of about 5.2x4.5 inches and an output relay to prevent power off thump
Second version is a high end one build around PIC16F877A, PGA2310, four input signal switching through ULN2803, input and output buffers on PGA, input buffers around OPA2134/OPA2107/LM4562 and output buffers around OPA627, five buttons like simple version, I.R, Rotary encoder, 20x4 VFD, and extension capability to six channel (another two) PGA2310 or a bass-treble control around AD5204/6. Three PCBs one for controller, one for analog section and one for the VFD and buttons, also an output mute relay to prevent power of thump.
As PCB fabricating has never been easier for me so I got two boards each.
What is left is an eternal wait for ICD2 to arrive from USA, to burn the mcu, software is almost ready to be tested, needs a bit tweaking and testing.
Here is the progress.
Appreciate inputs from

[abid_rehan]

Top Silk of the Board

[abid_rehan]

PCB being poulated. Input/output relays and RCA
This is the simple version of Pre.

[abid_rehan]

Another view of the board, with IDC connectors for LCD and Buttons

[abid_rehan]

Schematics of the simple version of preamp

[abid_rehan]

Loaded simple pre amp.
My objective with simple version of the pre is to help those hobbyists who find it difficult to do such a project independently.
Once I see enough interest in the project I ll upload the hex file for non commercial, hobby use without any catch or I may even offer pre-programmed MCUs
For the high end pre I ll post development and populated PCBs, but I think right now it will be difficult to post the firmware as it requires a long time of research and head-scratching. Though I would offer PCBs and pre programmed mcu and a few other parts, but I ll revisit it to decide.

[abid_rehan]

now comes the high end version of the pre-amp.
This is the controller board, some sticky material could be seen on jumpers.
Controller board has two IDC connectors one for the VFD, IR and Buttons Board and other for analog board. two connectors crimp shell one for the buttoned rotary encoder and one for ICSP.
Well I experimneted of putting silicone sealant on top of them to ensure that they dont move and dont get shorted.
Right now I will use the mcu in 4MHZ mode but I tend to increase it to 20MHZ once proto soft works perfectly.

[abid_rehan]

Analog Board of the high end pre, one thing that I forgot to mention was that the both pre have two ground planes digital ground and analog ground, both planes tied together via single wire jumper and enough capacitors to prevent unwanted coupling issues, all resistors are metal film 1% type.

[abid_rehan]

Realys and Quad RCA Jacks for input selection and output. All Relays are DPDT DIP Type.

[abid_rehan]

Input Output buffers and PGA of the analog board. X1,X2,X3 are 7815,7915 and 7812 former for the PGA and Op-Amps and 7812 for ULN2803 and relays.