Hey Mark, how's the weather out east?
I remember you mentioning that there were errors in the BBD "reverb" schematic on your site...
http://ampage.org/hammer/files/reverb_sd.gif
Do you remember what the problems with the circuit are? Anyone else know? BTW I look forward to a great spring reverb photoessay. That'd be a real treat, I've been tryin to figure those out forever now...
Take care,
For starters, take a look at the feedback path. You will note the complete and total absence of any capacitor from the point where the bias circuit feeds the input pin of the BBD, through the regen pot back to the mixer stage (second op-amp). Now THERE'S a design feature for ya - unrestricted DC feedback.
The other thing you may notice is where the regen path comes back to. It would appear the first stage is run pretty much open-loop and the regen comes back to the inverting pin of the first op-amp. Yep, another "design feature".
The other thing that is missing is any reference to Vref and supply regulation. Not a bad design but enough gaffs in the drawing to explain why Tom G took it down.
As for weather, I've described it to people like trying to reel in spring as if it were a fish, a little slack a little reeling, a little slack a little reeling.