12 comments


  • Allie

    I came across this site in a Google search. I’m interested in a JP04 oscillator and JP04 filter. Is any this actually available to buy?

    February 13, 2018
    • amsynths

      Hi
      The JP04 VCO and VCF are in development and will be launched around April time
      Rob

      February 18, 2018
    • Allie

      Great thank you!

      March 01, 2018
  • Osa

    Remarked (or refurbished) BA6110 on your photo.

    January 31, 2019
  • Synths 'n Stuff

    We made clones of the LM13700. I know you are going to say “well that’s easy”, but we did a lot of research and select the clones on our dedicated tester, just like Roland did. So, we can supply clones that fit at least on 90% of the positions the original BA662 needs to replaced.

    https://m.facebook.com/story.php?story_fbid=2125381720877632&id=826416797440804

    May 04, 2019
    • amsynths

      Thanks for the info, great idea! I may well need an accurate BA662 clone if the ones in my JP4 Voice Card have failed. Rob

      May 04, 2019
  • JT Foster

    Regarding the SMT BA662 pinout, there seems to be one extra functional pin compared to the SIP component. An extra buffer control input? If one were to adapt the SMT chip to replace the through hole part, how would this extra pin be best handled? Tied to the other control input? Tied to negative power rail? Left floating?

    August 28, 2019
  • amsynths

    I was planning to leave floating and see how it performs

    September 02, 2019
  • Thanks very much for this article, for your work on these chips and synthesizers in general, and for the 2022 updates regarding the new AS662 and V662A devices!

    July 19, 2023
  • Jason Willy

    Thank you for this excellent info and the new SM chips.
    My question:
    How can i go about matching the forward transconductance of an AS662 adapted replacement in my SH-2 which has yellow paint?

    Breaking down this question a bit:
    Can you share a test circuit for measuring transconductance?
    Do i need to order lots of chips and test them til i find a match or can i adjust the bias current to achieve a matched gm for my synth?

    April 03, 2024
    • amsynths

      It is wise to match the gm on the SH-2 to ensure you get self oscillation down to 20Hz. You need to measure the gm of at least 20x AS662 chips, and match to the gm of a yellow dot BA662.
      I have a test circuit and PCB layout, which I will post tomorrow. You cant adjust the bias current, as its going to all 4 chips.

      April 03, 2024
  • filipp

    Thank you

    May 01, 2024

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