ASM-1 Boards Arrived

[gstopp at fibermux.com]

     Hi List,
     
     I've received my batch of ASM-1 circuit boards, and built one up. It 
     works great. So - I'm sending off a few to some "beta tester" list 
     memebers so they can try them and report back to the list.
     
     Don't order yet - the documentation isn't ready! Also I've been 
     thinking about how to handle the money thing as a member of an email 
     list. I've decided to let the beta testers take the chance that I 
     didn't just make all this up to scam on a couple hundred bucks, and 
     depend on them to tell the list that I'm on the level. That way I hope 
     that people will feel a little less nervous about paying the full 
     amount up front.
     
     So - I'll take orders via mail, *not* email. When I get a check I'll 
     ship out the boards. I've kept all of the responses from people who 
     have stated their intention to purchase, and I used that data to come 
     up with the quantity (50) buy I just made. Besides, I tend to delete 
     emails by mistake all the time.
     
     Some little technical tidbits about the board - I've done some parts 
     exchanging and have found some flexibility in parts. For one thing you 
     can replace the 2N4856 FET with a 2N4391/2N4392 FET with no noticeable 
     change in performance. This is cool because I found a couple dozen of 
     these in my parts drawers - no more spending on FETs for me!
     
     Also I tried Chris List's tempermental tempco in the VCO, and it looks 
     like it works. I guess the ordinary resistor divider works better than 
     the (inductive?) component in the op-amp feedback loop. The ASM-1 uses 
     100K CV input summing resistors, with 100K resistor/10K trimpot in the 
     summer's feedback loop, to a 56K/1K divider into the NPN base. For the 
     2K tempco, it's 82K resistor/50K trimpot summer feedback into a 
     100K/2K divider into the NPN base, with the tempco as the 2K. I 
     haven't done tracking or drift tests yet, but on the scope I can set 
     the VCO frequency, turn it off, swap out the resistor with the tempco, 
     turn it on, and see the same frequency, over the frequency range of 
     the VCO. I know the metal film works, so I'm assuming a match.
     
     I'll post my address for orders soon. In the mean time the beta 
     testers will get their boards and I'll finish up my documentation.
     
     - Gene
     gstopp at fibermux.com