Help with EQ Build

[Bufo Bill]

Thanks for the link Craig. That's quite a resource you've put me on to!
Cheers from Bill.

[Bufo Bill]

Okay, I have come up with a plan, which I would like to run past you all. I will buy a blank PCB, the copper side of which will make up my ground plane (hope that's spelled correctly). I feel like with all the advice you have given to me so far, the dead bug method may be the best way for me to prototype the layout. I thought perhaps I could build the final version on the Fibreglass side of a PCB blank for a more rugged construction, drilling through for the ground connections to be soldered to our copper ground plane.
So what do you chaps think? Viable plan? Or off my rocker?
Cheers from Bill.

[Cruisin Marine]

Okay, I have come up with a plan, which I would like to run past you all. I will buy a blank PCB, the copper side of which will make up my ground plane (hope that's spelled correctly). I feel like with all the advice you have given to me so far, the dead bug method may be the best way for me to prototype the layout. I thought perhaps I could build the final version on the Fibreglass side of a PCB blank for a more rugged construction, drilling through for the ground connections to be soldered to our copper ground plane.
So what do you chaps think? Viable plan? Or off my rocker?
Cheers from Bill.


Hi Bill,
In my eyes a no. It will make your life very difficult and lead to no flexibility at all, and unnecessary , if it is all on the copper plane, you can move things about as you wish EASILY.
I however get your drift, but I would jump from copper plane prototype to PCB design.

If it was me, I would have the basic work on one board and the individual EQ sections on another board connected with thin colour coded wires, or coloured ribbon cable would be better, the complexity of the design may drive you nuts otherwise, your EQ unit is not an easy undertaking at any skill level.

The first stage for me would be to place all chips etc. on some graph paper and play about with the positioning until it all starts to look and feel right. This is essentially what you would do with PCB design anyway, but much more intuitive to the eye and brain.
The key is patience, patience and yet more patience.

Everyone has different ways to approach this, it is all down to what works for you.

[Bufo Bill]

Thanks. Will get out the graph paper and give it a go.
Thanks from Bill.

[Radio Wrangler]

Originally Posted by Bufo Bill

Okay, I have come up with a plan, which I would like to run past you all. I will buy a blank PCB, the copper side of which will make up my ground plane (hope that's spelled correctly). I feel like with all the advice you have given to me so far, the dead bug method may be the best way for me to prototype the layout. I thought perhaps I could build the final version on the Fibreglass side of a PCB blank for a more rugged construction, drilling through for the ground connections to be soldered to our copper ground plane.
So what do you chaps think? Viable plan? Or off my rocker?
Cheers from Bill.

I've been doing it entirely over the copper, no drilling, for many years. Plastic/ceramic DIP ICs go upside down with superglue or a snippet of double sided tape.

TO-99 opamp cans are not floating, so need an insulating Kapton washer and glue.

When sticking IC down remember to mark pin 1, cos the dot will be on the unseen side. Remember pin counting is as seen undersidem not topside.

You can crack things loose and move them around if necessary.

Having a supply of sleevein and tinned copper wire helps.

David

[Craig Sawyers]

Originally Posted by Radio Wrangler

Jim Williams was the author of many superb applications notes from Linear Technology inc. Highly recommended reading. LT (as also in LT Spice!) got taken over by Analog Devices, so LT stuff can be found via ADI's website. There was a sort of farewell doo for Jim rather than a formal funeral. To compound the loss to the electronics community, Rob Pease died on his way home when his beloved Beetle left the road and went down a canyon. Rob was National Semiconductor's analogue guru, and boy did he act up to it.

There were some interesting characters around in those days.

David

Williams and others used to play jokes on each other. The two I can remember Williams doing was routing a small plastic tube in the middle of a colleagues lash up circuit, and every now and again puffing a little smoke down it. Drove the guy nuts trying to find the part that was smoking hot. This was revenge for a stunt that the guy pulled on Williams.

Or the boss's accurate clock, that he made a big show of. So Williams put a different crystal in and made it run fast. Then another to make it run slow. He reckoned the most difficult one was to make it run backwards, which involved profiling the pole pieces in the motor.

Lots of anecdotes on the web.

Craig

[Bazz4CQJ]

Closer to home is the old guy "Radiofun 232" who used be with Philips in Holland and is now something of a cult on "YouTube" (over 14,000 followers). He builds using either with Manhattan or pin-mounted bread-boards. He's got hundreds of posts on YouTube, often quite small projects. e.g. https://www.youtube.com/watch?v=7J_ppNyJWbU. I think he sells indexes of the projects for a nominal fee.

B

[Bufo Bill]

Hi guys, thanks for your interest. Just a quick update: I am at the building stage but progress is slow, I have never built a dead bug style build before, and this is no simple "egg-timer circuit," as David says. Progress will probably be slow, but I'll keep at it and let you know if I have any success.
Cheers from Bill.

[Cruisin Marine]

Good luck Bill, I am rooting for ya pal. I am sure you will crack it.

[Bufo Bill]

I keep reading words to the effect of "proper lead dress is vital", but never explain what you should be doing to make your leads well dressed. Can anyonegive me some advice or pointers on this topic?

Getting this thing down to a size that would fit in a large project box is a nightmare with the dead bug approach. I might never have started this if I knew then that Veroboard was not a good option.

Nearly ready to test the circuit though, maybe a few hours more work. That will be spread over a couple of weeks though, so don't hold your breath.
Cheers from Bill.

[Bazz4CQJ]

That phrase "proper lead dress is vital" is something I've never heard before in ~50 years. Can only guess at what it might mean.

B

[Bufo Bill]

Bazz I don't know what it means and never heard it/read it before this project. I think I read it in the National Semiconductors handbook (1977). It's been buzzing around my brain for a day or two.
Cheers for the rapid response, Insomniacs Anonymous meeting anyone?
Cheers from Bill.