Digital BBD concept looking for comments and beta testers

[Passinwind]

I had to build up a second feedback mixer, the first one had stability issues. I may have herked the SMD opamp during hand soldering, which thankfully has only rarely happened over the last several years. Spent an hour or two tracking that down, whipped up a new board, and everything acts as intended now. Got in an hour plus with my new acoustic guitar into a very high resolution AudioKinesis 112 + horn cab with my DIY 500 watt amp. I ran the test pedal through my effects loop, it sounded great and the noise floor was exceptionally good, easily better than many or maybe even any of the rack processors I’ve owned over the years. I’m very impressed so far!

I’ll write up my first feedback email this evening, there’s plenty to unpack already. My build was a bit too quick and dirty, but now that I know what I’m working with I’ll clearly have to clean things up. Really looking forward to the production version, the board size reduction will be a nice bonus when I go from modular to a one or two board format.

 

[Passinwind]

Update: still playing with a single two tap delay, mostly working on fine tuning feedback schemes and gain staging. I've ordered some new five channel mixer PCBs of my own design to facilitate working with the 4 tap delay program, along with some simple eBay function generator boards to get me started on modulation effects. Still very happy with the sound quality for acoustic guitar, will start testing with bass later today probably. I'm waiting on a new pickup for my electric guitar and will get to testing with that too as soon as it comes in. And finally, I'm rebuilding an old two way cab to get set up with a stereo monitoring rig, and also have a little 2 x 4" cab I want to try as a satellite/ambience speaker.

 

[Cabintech]

From this mess...



To this...



CT3680 development/breakout board. Sorry beta testers, this does not fit the prototype modules...!

 

[Passinwind]

Satellite/acoustic guitar 8" + horn cab is now up and running:



Even with that big scary horn running pretty hot the noise floor of my various delay configs has been excellent so far. I'll be bumping up the complexity now, and start concentrating on the stereo aspect, including the new stereo image panning feature as soon as we get the firmware update done to my board. I'll be doing that on my end in a few days, so I can and will keep working on other bits and pieces until then. My LFO boards came in yesterday so I'll be making smoke as soon as I'm properly caffeinated.

 

[Cabintech]

Satellite/acoustic guitar 8" + horn cab is now up and running:

Nice! I want a pair of those!

 

[Passinwind]

Nice! I want a pair of those!

Me too, a local friend of mine has the matching one of the original pair and I am seriously thinking about trading something back for it and putting an 8 in it as well. There are some smaller versions of that horn that would probably work great in this application too, the cast aluminum 18 Sound one is massive overkill really. But since I already had a box for it and could just use the existing LPF I didn't see any point in buying a different one.

 

[Passinwind]

I'm on to my newly revamped electric guitar and program 4 now, finally. Working really well for slapback and doubling, and I'm noticing that in this config delay control interaction between taps feels noticeably different, i.e. more predictable. But I was getting some very useful 'verb effects using programs 0 or 1, so I think program switching will have to make it to my control panel eventually.

Sorted out a number of things in my wiring layout to make life a little easier as I get into stereo modulation effects. The cheap LFO I built up works fine but I need to add a simple DC offset circuit to plumb it into the DBBD. Time to decide how many knobs is too many, I reckon.

 

[Cabintech]

In the mail today... lots and lots of through-hole adapters, and rev 2 of the development board. Oh yeah, and a solder mask for the 40-pin SMT connector to see if we can speed up populating the DIL adapters and dev boards. That is a HUGE sheet of stainless for a TINY little mask area!

 

[Cabintech]

And the good news... from the beta testing we are confident in the hardware design, so the first run of CT3680 modules is now in production! We have more firmware ideas to implement, but the hardware is well settled.

That also gives us the ability to answer the question many have asked... what is it going to cost? If there are no surprises, single piece cost will be about $39, production quantities around $25, with some price breaks in between for small batch builders. In addition to the module itself, we also plan to stock:
40-pin edge connectors
DIL through-hole adapters (bare or with connector)
Dev boards (bare, with connector, or fully populated)

 

[Passinwind]

Great to see that your pricing came in a little under my ballpark estimate/recommendation I sent along in email feedback.

 

[Cabintech]

Great to see that your pricing came in a little under my ballpark estimate/recommendation I sent along in email feedback.

We try to always be conservative when estimating future pricing, just too many variables to have high confidence. Like when the builder's pricing system told us our boards weighed over 50 lbs and would cost >$400 to ship. Yup. They missed like 2 decimal places when entering a component weight... that got fixed, but there is always something unexpected every time we do a build...

 

[Passinwind]

We have created a means to update the CT3680 firmware in the field, although it requires some specialized hardware. For beta testers we can loan out that hardware if you are interested in the new features, just let us know.

I bit on this and just did my first in-field firmware update yesterday. There were a few swerves while I worked out getting everything to play nice from the command line on my new Win11 desktop box, but the process was pretty simple beyond that. So now I have the means to tweak stereo panning and depth via pedal control, with very minimal effort on my part as far as wiring and hardware. Onward!