[sdiy] ripple counter vs synchronous counter in DAC-less R2R quantizer

[anthony]

So I have all of these 4518 BCD counters (well they're actually ancient RCA 
307-146's but = same thing) and I thought, "Hmm if I could use these it'd be 
gravy, but BCD output would be wonky for this quantizer app wouldn't it?" 
Well I also have a bunch of MM74C42's & a 4028: BCD-decimal converters. 
Hmmmmm... The 74C42's I'm using for a Nixie counter, but the lone 4028... I 
reiterate: hmmmmm...

I realised that this way I could have the counter be completely synchronous 
because I would only need ONE section of the 4518, whereas the 4520 that I 
am using for my DAC stairstep quantizer needs to have both sections 
connected together, but this connection is ripple & not synchronous. It 
probably is't that big of a deal but maybe it MIGHT be. The only 
disadvantage is increased parts count by one, but oh well...

It occured to me that this may be the most original and clever idea I've 
come up with - well in a while anyway. I suppose if I had synchronous 
decimal counters it wouldn't have mattered. Is there a synchronous 1-10 
decimal counter? I have 4017's but those are ripplers.

Actually, I had a thought: I could even use 4518's for my sequencer and I 
could use one counter chip and two 74C42's (for an 8-step sequence). If I 
was going to make a 16-step sequencer I'd probably use a bunch of 4516's.

I'm glad I have this really big protoboard. I'm putting 2 quantizers and a 
sequencer on it! The S&H channels will be on another board - well I'll have 
one or two on this board, but since I plan to be using LOTS of channels 
(like at least one for each sequencer stage and each stage of my analog 
shift register and gated comparator - well you get the idea!

***UPDATE***

I am now only using one quantizer and I've abandoned the 8-bit DAC quantizer 
scheme for my sequencer. I plan on making another separate quantizer that 
will be my experimental one - using the DAC (since I have it and can't think 
of anything better for it.)