2 days ago, I bought roughly 2800 SMD parts (resistors, caps, other stuff, all thrown together) from eBay for only €25 (including insured shipping), so I decided I needed to do something with it once the parts get here.
The Chu Moy has been my circuit of choice more than one time for testing purposes, so I decided to use it again. To add some extra difficulty and "coolness" I also decided to try a double sided PCB (since I'd bought a small one for testing a few weeks ago). I routed this in about an hour, so I'm sure it can be done better, but still, it's got a star ground, so that's something.
I haven't got the SMD parts yet, so no pictures of the finished circuit yet.
The PCB size is 1.8cm x 2.6cm. It came out almost perfect (except for some text with traces less than 3mils wide, another text with traces 3 mils wide came out perfectly though). The transparencies for this were made with a laserprinter, I tried to print it with an inktjet, but it just wasn't up to the job. I only had a bit of trouble with the drilling, since I still do it by hand and it had to be perfectly straight. The first 3 holes are a bit angled, but all the others are nice and straight, right through the pad on the other side of the PCB.
Anyway, here are some pictures. First the top layer:
And the bottom layer (you can see tiny spots of copper in the upper right, that's the text that failed to etch correctly):
I also put it on my website, but there isn't a lot more info on the page than there's here: http://members.lycos.nl/anthonyvh/index.php?page=chumoy-smd
*In case you don't know what the Chu Moy amp is, it's really just an opamp with only the necessary resistors (kind of like a gain clone
). Here's the "official" page: http://headwize.com/projects/showfile.php?file=cmoy2_prj.htm
I don't use the rail splitting method with resistors though, I use a TLE2426 (Texas Instruments), which is better. Opamps will be OPA134 or OPA227.
The Chu Moy has been my circuit of choice more than one time for testing purposes, so I decided to use it again. To add some extra difficulty and "coolness" I also decided to try a double sided PCB (since I'd bought a small one for testing a few weeks ago). I routed this in about an hour, so I'm sure it can be done better, but still, it's got a star ground, so that's something.
I haven't got the SMD parts yet, so no pictures of the finished circuit yet.
The PCB size is 1.8cm x 2.6cm. It came out almost perfect (except for some text with traces less than 3mils wide, another text with traces 3 mils wide came out perfectly though). The transparencies for this were made with a laserprinter, I tried to print it with an inktjet, but it just wasn't up to the job. I only had a bit of trouble with the drilling, since I still do it by hand and it had to be perfectly straight. The first 3 holes are a bit angled, but all the others are nice and straight, right through the pad on the other side of the PCB.
Anyway, here are some pictures. First the top layer:
An externally hosted image should be here but it was not working when we last tested it.
And the bottom layer (you can see tiny spots of copper in the upper right, that's the text that failed to etch correctly):
An externally hosted image should be here but it was not working when we last tested it.
I also put it on my website, but there isn't a lot more info on the page than there's here: http://members.lycos.nl/anthonyvh/index.php?page=chumoy-smd
*In case you don't know what the Chu Moy amp is, it's really just an opamp with only the necessary resistors (kind of like a gain clone
). Here's the "official" page: http://headwize.com/projects/showfile.php?file=cmoy2_prj.htmI don't use the rail splitting method with resistors though, I use a TLE2426 (Texas Instruments), which is better. Opamps will be OPA134 or OPA227.
It's cool you guys think it's cool . I'll sure post pics when it's finished! I won the eBay auction 2 days ago, but the payment is international wire transfer, so I'm not sure if the seller's received the money yet. Once she does I guess the SMD stuff should be here in 2-3 days. So, expect some more photograps next week .
. I'll sure post pics when it's finished! I won the eBay auction 2 days ago, but the payment is international wire transfer, so I'm not sure if the seller's received the money yet. Once she does I guess the SMD stuff should be here in 2-3 days. So, expect some more photograps next week .- Status
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