Group Buy: Linkwitz-Riley 24db/oct xover PCB's

[substrate]

Hey guys,

Just wondering if there is any interest out there for a group buy on some Linkwitz-Riley (LR) crossover PCB's. The circuit itself is very easy to design (straight from his site) but getting PCB's is another story.

We can get PCB's made from any one of the many fabricators (such as PCB Express) but there is a minimum quantiy required if you want to get good quality boards.

I've pretty much got the PCB layout finished, and I will post pictures of it for everyone to verify, etc.

There will be 2 boards essentially: one highpass and one lowpass. Both are 24db/oct (cascaded 12db/oct butterworth). Really, you could use any allignment that you want but I believe most would go with the LR allignment.

If I get enough interest I will start pricing the boads, but I believe they should be around $8 or $10 each. It really depends on how many people are in on the group buy. Prices may be cheaper if you guys know of a cheaper place (these prices were through PCB Express).

If there is interest in doing power supplies let's do some of those too. I already have a design based on the LM340/320 but we could always design a board around another part if prefered.

Anyway .. post a message if you think you'd be interested in the group buy(s). I'm just seeing how many of you would take part before we move forward with anything.

Thanks,
-Brian Cleven

[Will]

I'd be interested in 2 pairs i.e. 2 stereo pcbs.

regards,
will.

[Bill Fitzpatrick]

I'd want to see a schematic before I commit.

[Coulomb]

I could be interested if it is truly a high fidelity design.

Anthony

[theChris]

i've been working on a similar project for some time. i may be making a test unit tomorrow. Right now it is a 24dB/oct design with high, low on one board. standard dual opamp per 2-stage filter. Milled PCB, coated copper (some shiny metal...). Was looking at doing the following:

single amplifer biquad
gain setting resistor option
resisitor (CCS) option.
local adjustable regulator (lm317/337 pinouts)
locations for 100nf capacitors in closest location to power pins.
quasi-ground plane (milling cannot remove large areas of metal, leaving large unconnected metal surfaces. these can be used as a pseudo ground plane.)
customization -- i can mill the initials of whomever onto the top of the PCB.

i am currently looking into how cutting top traces as well as bottom (i can do 2 layer as easy as 1 layer) can reduce input and output capacitance, but at the further damage to the ground plane. also looking into the jfet CCS mod, but likely will not be in rev A, as it won't be tested with suitable JFETs.

if there is interest, i may redesign the board a bit to fit larger, audiophile capacitors and resistors. as well as an IC socket that was left out of my initial design.


a note to the op, I am not trying to take your buisness. i will not be able to make a large quantity of these PCBs, if i do make a run, i plan to charge:
$20 for the dual (high, low) board
$25 for a customized board.
+$10 for extra boards
+$15 for extra customized boards.

i will donate $5 + $2.50/extra board to the forums.

these boards take a fair amount of time to mill out. I will make a design tonight and hopefully a test board tomorrow.

Please note, that because of the time required per PCB, i may not be able to take all orders. I am a college student, not a buisness!

[KT]

I'm interested once I find out a little bit more.

KT

[DonoMan]

Depending on when they're ordered.. If next month or later, then quite possibly.

[Russ White]

I am also interested, but would like to see the PCB first.

[Hornlover]

You can get a great LR 24db/octave stereo crossover complete with regulated power supply here. These are proven, and sound very good, and are extremely quiet. Bare boards as well as complete kits are available.

https://secure11.websitecomplete.com...t.asp?dept=528

[theChris]

i was just thinking -- doesn't sound.westhost.com also do these?