My Carolina ODS layout.

[Joel]

Merry Festive Season all.

I present my very first DIY Layout Creator layout for your review and feedback.  It's a Carolina ODS using Mr. Tubenits Carolina Overdrive Special 5879 plus 6-2018 schematic (attached for reference).  This is version 1 of the layout, designed to fit into a spare blank Fender style angled-front chassis I have. 

I've used the Valve Wizards bus grounding ideas from his pre-amp book with each stage HT filter cap located close to their respective stages and only one ground reference point (at the input).

I only included Channel and Mid-boost relay switching.  I didn't include the extra Mid cap switching or other relay based options in this layout.  But with a 5 pin DIN for the footswitch there is room for add-ons.

Seriously thinking of including a capacitor multiplier circuit.  This is a Valve Wizard idea from his power supply book.  I've used one before and they do work quite well at taking the place of a choke.  The capacitance is effectively multiplied by the hFe of the transistor.  Since the circuit I plan to use has a darlington pair the hFe is around 3000, making the 22uF look like a 66000uF for smoothing purposes.  It's a pretty cool idea I think.

The FX loop bypass switch and wiring looks a bit untidy, and I'm unsure whether or not its needed.

Heater elevation via the power stage cathode resistor.

I've drawn in some optional D*mble style local negative feedback on V1 (like in #124) and V4 (like in the Dumbleator schematics I've seen).  The theory says they'll lower the gain a bit and widen the bandwidth.  Not sure of the audio effect though.  But it's a D-style amp so I might as well try them hey?

* All of the thick grey wiring is supposed to represent coax/shielded wire.

Cheers.

** edit: added pdf of the layout for those who don't have DIY Layout Creator installed.

[tubenit]

Wow!  I've not traced the schematic to layout to verify everything, but I will say I really like the layout design that you've come up with.  I think you'll
have a very quiet amp at idle & that you have thought thru this amazingly well. 

I hope you will build this with the idea that it's an amp to build and then tweak to taste.  I've made small changes to mine over time based on what guitars and speakers I am mostly using with it. Typically those minor tweaks don't necessary make it "better" but just different or maybe preferred.

Have fun with the build!  Hope you post a lot of pictures and updates.  Very impressive work.

I will be interested to hear if you get the similar strong contrast between the "clean" and the OD channels.  I've done a few D-inspired amps and I feel like this one has the best defined change from clean to OD of the ones I've done.

With respect, Tubenit

[sluckey]

Seriously thinking of including a capacitor multiplier circuit.

I used that circuit on a few ss projects back in the '70s. Worked very well for my light load projects. I never tried it on high current ss loads or tube circuits though.

[DummyLoad]

too much lavender in the layout - it'll never work! - j/k   


nice layout.


--pete

[tubenit]

Here are some changes that I've done OR wished I had done to begin with. These aren't "needed" but are more tweaking or seasoning to personal taste.  I am finding I like the overdrive to reasonably clean and that is why I wished I had the OD drive at 50ka and the OD level at 500ka.  However, if you like the OD more overdriven then the original values may suit you more.  I still have the original value pots in mine.

Again, I encourage you to consider this a tweaker's amp. 

I've used a Warehouse  ET-65 with the amp and it excels with some overdrive.  Clean is still great with this speaker.

And currently, I am using an Emminence  Pro-Delta 12A speaker.  The cleans are even better with this speaker but the OD isn't quite as smooth as with the ET-65.   

With respect, Tubenit

[Joel]

Thanks for the feedback guys.  I really appreciate it.

-----------------------------------------------------------------------------------
Version 2 attached. 

Changes;
* I'd missed two ground wires from some pots...   
* Changed the front panel switches to switched pots, and made the treble cap on the preamp volume pot switchable as well
* Added some nice bright asterisks as reminders for future tuning ideas based on your input Mr. Tubenit. 
-----------------------------------------------------------------------------------

Mr Sluckey, I used a cap multiplier in a AX84 SEL style build years ago.  For this build I've beefed up the transistor to a TO-220 style and I'll have a small heatsink attached. 

I've been planning to build this as a head cab.  That way I can run it through my 2x12 loaded with ET-65 paired with Retro30, or into a 1x12 with whatever (probably a ET-65 when I change my Deluxe Reverb over to a G12C).

I plan on attempting to get the Clean channel to go from sweet cleans to light OD territory, and the OD channel from light/mild to classic/hard rock territory.

Lavender is what you get when you ask your youngest daughter how the layout looks.  Apparently it lacked pink.  I'm assured it'll sound better if there is more pink.

[tubenit]

I plan on attempting to get the Clean channel to go from sweet cleans to light OD territory, and the OD channel from light/mild to classic/hard rock territory.

I think that is do-able with this amp. 

In light of that as a goal, I'd probably stick with the original pot value for the OD drive 100ka and OD level use 500ka.  And for V1, you might substitute a 5751 instead of 12AY7?

I look forward to build pics and your progress on this.

With respect, Tubenit

[pullshocks]

Joel, I'll pile on here and say that is a nice layout. 
I would like to use elements of your layout in another amp.  Could you post Version 2 in *.diy format so I can cut and paste from there??
Thank you.
Mark

[Joel]

Sure thing. 

Some of the components I drew from scratch (and badly at that) are now available as proper components in Dougs template files.  Like the fuse holders.  Literally one day from having to draw my own to Doug releasing his component template...