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Karl Schmeer

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About Karl Schmeer

  • Birthday 07/05/1963

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    State of Misery
  1. I guess anything is possible, but it would be like counterfeiting dimes. Not really a big money maker.
  2. All right!! they have poly's. Thanks for this Markyboard!! The downside I see, is it's surplus. Which means that once they have sold them all that's it. Need to do a "lifetime buy" if you are using for production. Also no factory to complain to if you have problems. Serious Thank You!
  3. You won't find a large range of values for mica caps as they get impractical beyond a certain range. Polyester is considered the "economy style" for film capacitors. Their low cost come with trade-offs that are a compromise for an industry where cutthroat retail prices rule. Polypropylene is a good dielectric for S&H and tuned circuits. They are good for S&H because they have better dielectric absorption than the original polyester. They are better for tuned circuits like filters and EQs because their tolerance, ESR, and tempco are better than polyester. The phasor in my ARP piano sounded a lot better when I replaced the original polyester caps with polypropylene. Walt Jung did some pretty extensive studies with caps of different dielectrics and also found that there was a marked change in tuned circuits. Yes they will alter the sound; whether it is better is subjective. This is a pretty good primer on capacitors, although it's a little out of date (polycarbonate caps are unavailable). I usually buy film caps from WIMA or TDK, had good luck with them. Thank you much for this. I need to find a new supply of these for upcoming projects. I will check out WIMA and TDK I have been asked a few times from folks wanting to recap their M12's if they should also replace the poly's in their DMUX circuit. I advise not to because: 1) the self-healing effect of polypropylene 2) scarcity of parts. As far as I can tell they last darn near forever. Thanks Again!!
  4. Yes I did. Those white polyester caps have a limited age. That was a big job but seeing this is an early unit from 1982 and the caps are 30+ years old then it was justified, especially for critical CVs. I will eventually do that to my own unit. How about polypropylene caps. The only caps I know of besides mica, that have zero drift with temperature change. I suppose it's possible that this could alter the sound. You see these in the filter circuits of pro audio graphic/parametric EQ's, Oberheim synth DMUX circuits etc.. Panasonic used to make them but I can't find them anymore.
  5. Yah your right. I think they actually designed that one themselves. You probably already know this but those CA/NS 13700 VCA chips are the exact same die with a large boost transistor added to it. ( and larger package) It was used to train a new chip layout designer. So they took the old CA3080 layout and gave it to her and said "add a transistor to this". Almost as old as a 555 and still selling. I love these restoration threads of synths from the 60s, 70s, and especially the hybrids of the 80s. So many electronic concepts working together. They are excellent teaching examples. Please keep doing this.
  6. Over the years I have personally replaced many defective RCA chips. You would think the inventers of CMOS integrated circuits (RCA) would have made better chips, but no. It was a good idea to replace them all.
  7. Really liked let it snow. (Blackbird is really cool too) Thanks Dave Best Karl
  8. Hi Dan, Yes, Not too many keyboardists around here, but loads of guitar players. I have been meaning to catch you guys at House of Rock. - Karl
  9. Hello All, I have been lurking/posting a little here for awhile and realized I have never introduced myself. so.... I have been playing organ since I was 10 yo. I am 45 now. I have been playing in basement/bar bands for most of my life. I tought night school electronics for 20+ years. So I usually lurk for repair/tech questions to help with. I have to say this is such a great collection of musical knowledge. I can't believe the quality of the advice (or the personal). I have a bunch of keyboards/synths but currently ( like many of you ) I love to gig with my Electro 2. The last few years I have been playing with my alesis HD24, learning much about recording. When not backing up string bangers and shouters, You can usually find me moderating on the Combo Organ Nation. I have a lot of posts on there helping folks keeping these early machines running. ( as well as a dirty little secret about the Nord Electro 2). http://combonation.proboards89.com/ and, you will also find me helping people repair their Oberheim Xpander/M12 ( My most favorite synth ) on the Xpantastic user group. http://launch.groups.yahoo.com/group/xpantastic/ I don't teach anymore, but I am happy to help with techie questions or repairs. Karl Schmeer
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