Design Challenge #2

[Chuck D. Bones]

Some kind soul made some prototype boards, so I built one up. I ended up changing 4 resistors to brighten up the first stage a little bit.

Top row: BASS, MID, TREBLE
Bottom row: LEVEL, GAIN



Hadn't installed the LED when I took this pic and I'm fresh out of power jacks.

 

[MattG]

Hi all,

I made the prototype PCBs for this overdrive, and with Chuck's help, fixed some silly issues. I now have a stack of revised PCBs. I'm happy to give these away for no cost, while supplies last. PM me with your mailing address, and I'll drop one in an envelope and mail it to you (USA addresses only). I'll say one per person for now, until they run out or demand appears to have waned. Give me some time to get them shipped, as I'd prefer to do them in a few batches to save time. If you want a more robust shipping option, I can do the USPS small flat rate priority mail box if you PayPal me $8 to cover the mailing cost.

I'm also attaching to this post several files:

• A ZIP file containing the BOM in multiple formats
• The Gerber files I used for fabrication. I used JLCPCB, so if you want to have your own fabricated, you can use this zip file directly with JLCPCB. These Gerbers "might" work with other fab houses.
• The circuit schematic
• A PDF with the layout of the pots - you can print this and use it as an enclosure drill guide (at least for the knobs)
• A ZIP file containing the Mouser Project with most of the parts (in multiple formats) (note: this was an edit after the initial post)

I can post the KiCad files if requested.

Here are some pics of the bare boards, and my completed build.

 

[Chuck D. Bones]

This is the kind of post that deserves the emoji.

 

[Sturdag Lagernathy]

So what do you call it, Chuck?

 

[Chuck D. Bones]

So far, I've been calling it CMOS Overdrive, which is both accurate and boring. So if anyone has a better name, I'm open to suggestions.

 

[zgrav]

CMOverdrve
CeeMO Head Room

 

[Barry]

Some kind soul made some prototype boards, so I built one up. I ended up changing 4 resistors to brighten up the first stage a little bit.

Top row: BASS, MID, TREBLE
Bottom row: LEVEL, GAIN

View attachment 12558

Hadn't installed the LED when I took this pic and I'm fresh out of power jacks.

View attachment 12559

What were the resistor changes you made?

 

[Chuck D. Bones]

R1 -> 4.7K
R3 -> 15K
R4 -> 3.3K
R14 -> 100K
C2 -> 470nF

Lowers Q1's gain a little and improves the top end. It's not a huge improvement, but I like it better. Lowering R14 recovers the lost gain.

 

[Barry]

R1 -> 4.7K
R3 -> 15K
R4 -> 3.3K
R14 -> 100K
C2 -> 470nF

Lowers Q1's gain a little and improves the top end. It's not a huge improvement, but I like it better. Lowering R14 recovers the lost gain.

Thanks

 

[Chuck D. Bones]

So you're building one of these, hmmmm?

 

[Barry]

So you're building one of these, hmmmm?

Actually I think he's sending two

 

[music6000]

I would build it but I'm down under in Australia!

 

[Chuck D. Bones]

You could roll an eyelet board!

 

[music6000]

You could roll an eyelet board!

Yes, but then it would be my version & I want an official C.D.B PCB !!!

I have already done the Hyper Pak with Tone control in Eyelet Board

 

[Chuck D. Bones]

An IC seems out of place on an eyelet board, but you made it work! Looks great inside & out, as always.

 

[MattG]

I would build it but I'm down under in Australia!

I hate to exclude folks outside the USA, but international shipping is really expensive (and kind of a hassle). Just as an example, the USPS small flat rate priority mail boxes cost just over $8 to ship domestically. I've shipped a few of those to Europe, and it's over $50!

For those of you outside of USA who are interested in the boards, it's probably worth checking out JLCPCB - you can upload the Gerber files (the single .zip file I posted above) and get a quote. IIRC, it's only $2 for five or 10 boards, and the least-cost shipping option to the USA is generally under $10. I suspect the total cost would be similar to what it would cost for me to ship a single board. And if you can find a buddy in your part of the world, you can split the cost!

 

[Sturdag Lagernathy]

I got a board coming my way to, hopefully. In honor of Chuck, Imma call mine "The Bone Driver"... or maybe "The Bone Screamer"..."The Tone Bone"? Well, I'm sure I'll know after I hear it!

 

[Barry]

I got a board coming my way to, hopefully. In honor of Chuck, Imma call mine "The Bone Driver"... or maybe "The Bone Screamer"..."The Tone Bone"? Well, I'm sure I'll know after I hear it!

Boner Overdrive

 

[MattG]

Boner Overdrive

Or how about just "Boner-drive"

 

[Barry]

Or how about just "Boner-drive"

Or Driving.....eh, I better leave well enough alone