High End Pre Group Design Invitation

[abid_rehan]

Hi Guys:
After discussing with couple of friends we have decided to put our thoughts in the form of this thread which is intended To build a high End Pre with digipots 5.1 here are plans to buid the pre:
Inputs:
USB DAC using PCM290X
SPDIF DAC using CS8412/14+AD1865+Discrete parts

Digital Delay section:
QSound 5.1 Chip (a stereo to 5.1 channel coversion chip with build in digital delays)

Buffer:
OPA627/BUF 634 or
Star Buffer using OPA627 and discrete parts

Digipots:
PGA2310 x 3
Mute Realys

Digital Section
Build Around PIC16F877A and Choice of
Atmel AT89S8252
Both MCUs

Others
Buttons (menu, menu+, menu-, select,etc)
I.R
Rotary Emcoder (may be)
LCD 16x2 Out

Objectives:
Learning puposes only

Members so far:
Digi and Ferds have kindly consented to climb aboard this project, any other who wants join in this group deisgn effort is welcome.
Outline of the project will be posted sometime today. and then schematics of individual sections.

[hau]

this is a very nice and interesting project.
cant wait to see the finish product

best regards
ferds

[AnthonyPT]

Hi,

Sounds like a valuable project you are doing!

While you are upmarket from this SI project

you might find some pointers from it ! US$149

as a kit . How about offering balanced and

unbalanced options. That would assist DCX2496

users as well as 5:1 people. Why not plan it for

7:1 expansion so you ready for the future.

http://www.siliconchip.com.au/cms/A_30608/article.html

Regards and good luck!

AnthonyPT

[Dr.H]

Consider using the AD815, it hugely outperforms the 627/634 combo!

More resolved highs, real air and extension,
Great mids, on par with 627
Deeper, tighter bass. real low end grunt.
Open and detailed soundstaging

[abid_rehan]

Thanks guys for ur interest, sometime today or tomorrow me or hau will upload the project outline and schematics too, intent here is to learn from the experiences of others and help others do such a project themselves.
No doubt the project at silicon chip is very good but i m sure they wont give schematics, layouts and most of all firmware for the micrcontroller, which is intended to be posted here (may be)

[carlosfm]

Originally posted by Dr.H
Consider using the AD815, it hugely outperforms the 627/634 combo!

More resolved highs, real air and extension,
Great mids, on par with 627
Deeper, tighter bass. real low end grunt.
Open and detailed soundstaging

That's right.

[maf_au]

So, can someone translate what this high end pre will be capable of?

Could I use it to replace the Receiver in my HT?

Michael

[digi01]

Originally posted by Dr.H
Consider using the AD815, it hugely outperforms the 627/634 combo!

More resolved highs, real air and extension,
Great mids, on par with 627
Deeper, tighter bass. real low end grunt.
Open and detailed soundstaging

thank you.

P.S.
I am planing a HDAM structure.

for mcu,It will be a couple of board design for 8051 or MAXIM.

for the output buffer,I will try AD815.and I have a solid based buffer design,I have finished the archetype test lately.

photo attached

[abid_rehan]

here is the project outline done in a hurry though, now we will start posting schematics of individual sections and open for suggestions.

[digi01]

here is mine buffer sections,for HDAM structure need 6 units.the board has footprint for PDIP packaged BUF634 or solid buffer.

layout below,