Quad 405 DCD mod3 - PCB

[vzs]

Hello,

I just finished to rework the PCB for a Quad 405 based on the schematics of Keith Snook DCD Mod-3. I used a PCB M12565 iss. 7 (so without Tr4) as starting point and reworked it to meet the modified schematics and sizes of my components.
I reintroduced N1 and N2 in schematics but without C18, C19 wich could be soldered on N1, N2 (if are used).
The size of the fuse holder might not be good, it has to be modified. There are three connections that have to be made with a small wire (the ones wich have grey pads).

If you have some ideas how should I improve the design feel free to write it as I plan to make it in 1-2 weeks.

Regards,
Zsolt

p.s. Some transistors in the schematics differ as I couldn't find them among the libraries, so don't write for this issue!!!

[vzs]

I forgot... if somebody is interested I can send the project files. It's made with Altium DXP.

[kiwiandy]

Hi,
it looks pretty good to me, much neater than my efforts to date! You might want to make a bit more space for R30 & R31 though. They dissipate just over 1 watt each when the amp is idling and get quite hot. I use 3 or 5 watt resistors for these and try to mount them well above the PCB. By the way, what are you using for the inductors, or are you winding your own?

Andy

[vzs]

Hi,

I reworked the PCB and kept only the components from DCD-Mod3.
My goal was to keep the tracks in the operational feedback and in the bridge as short as possible and to widen the gnd, earth and high current tracks. I've added Tr3 + R18 in this final version but in case of instability I will replace them with a wire link as suggested by Keith Snook.
In this version there is enough space left for R30/R31 (placing them vertically as lead pitch is 10mm), fuse holders, bigger capacitors, etc...

Hopefully I will have the board manufactured soon and I will post some pics with it.

Zsolt

[RogerGustavsson]

Hi Zsolt,

Have you finished your Quad yet? My second Quad 405-2 just gave up and I am now prepared for some rebuild of my two units. New PCBs seems to be the best way to go. Where do you order your PCBs?

Roger

[vzs]

Hi Roger,

Unfortunately I haven't finished my Quad yet cause I didn't have enough free time. Hopefully tomorrow I will do a first burn-in test with one of the boards.

I ordered the boards from a Romanian pcb manufacturing company and they cost me ~32euros for 2 boards (plus the shipping another 13 ...). Probably you can find a company closer to you.

You can see an image of the boards in the attachment.

Regards,
Zsolt

[vzs]

The alpha test of the finished Quads. I'm very satisfied with them. In the near future I have to put a push-button on the front of box as I cannot turn it on/off only from the power cord

[vzs]

The closed amplifier

[ben62670]

Well I thought I had a good idea. I have a bunch of Toshiba sd424's, and a 60v per rail PS. (50v stock Quad 405)
So I bought these Quad 405 boards figuring that it would be easy to fill them. I can't find the transistors anywhere. I figured with a PS, heat sink, case, and outputs I would have a fun little project. No fun so far

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWN:IT&ih=002

[rjb]

Re transistors. Don't despair. Common equivalents will work fine.
I will try to dig out my old files to see what I used. Anyway there is plenty of info on the web.