Recent content by topher
  1. topher

    Panasonic SL-CT470,570,590 differences

    posted 03-19-2003 08:25 AM CST (US) | Msg Admin: Can anyone tell me if the 590 is as good as the 470/570? I have one of each and have not heard of anything as good. Electronics emall and Amazon have the 470 and 590, but I can not find any 570's.
  2. topher

    Sony d-cj01 vs d-cj500

    Does any one know the difference, especially in sound quality?
  3. topher

    Cascode Current Source

    I want to play with their BJT's as much as the ls-840's. You don't see other 600MHz pnp's with good voltage, let alone good current gain. I sure wish the heterostructure parts would go commercial... Anyway, a price list would sure be nice.
  4. topher

    Cascode Current Source

    ppl, Did the guy at Linear Systems ever give you a price on the LS-480? Or anything else? I asked him twice months before I gave you there address, and I still haven't received a response. He said he would on the phone, but it hasn't happened.
  5. topher

    Building amps with high speed opamps

    Joobu, if you play with a .25 inch drill bit I think you will find that you can remove copper pretty well by hand. It's extremely easy if you remove the copper around a hole in perfboard, but not hard even if you don't have a hole. Apheared, Do you HAVE to show us stuff like that...
  6. topher

    DIY Equipment Spikes

    ppl, What 2 inch mid are you using? I was thinking of a morel mdm55.
  7. topher

    Skin Effect

    aos, You are thinking of the capacitance of center conductor to center conductor. If the "sleeves" are grounded that is _vastly_ reduced, but not reduced much if the sleeves are not grounded. The _amp_ sees twice as much capacitance _to_ _ground_, if you use two lengths and ground...
  8. topher

    Skin Effect

    aos, when I do it, I will use one coax to each driver. That uses the single coax exactly as it should be. If you twisted two coax a little and used the center wires for speaker connections, you would have twice the lumped capacitance, and a LOT more lumped inductance. But I doubt it...
  9. topher

    Building amps with high speed opamps

    Joobu, I think I have seen people cut the copper with an exacto knife and then peel the copper within the cuts... Usually, we just put a piece of tape down. If you want to remove the copper near the inputs to cut capacitance to ground, can you just totally cut away the board there?
  10. topher

    Skin Effect

    aos, Do you want to make a speaker cable or an interconnect? For a speaker cable, I really like ppl's idea. I would love to find out what others hear when they try it. I'll give it a whirl when my speakers are done. For interconnects, I can't see anything being better than using...
  11. topher

    Building amps with high speed opamps

    You liked the sound from that Eval board right? Well, if someone wants to follow your lead, say with a dip opamp, they can build it like this: Get a perf board with copper on one side. Use a drill bit to remove the copper around the holes that the pins go through. Do the same...
  12. topher

    Skin Effect

    Tomo, you seem to be thinking of microwave style wave guide. That has no center conductor and does have modes. Coax with a center conductor handles everything from dc up to a point where at which the dielectric and maybe the outer "conductor" gets lossy. It happens as low as tens...
  13. topher

    Skin Effect

    The whole idea behind coax is that the fields are COMPLETELY inside the outer conductor. The "cross connection technique" is not beneficial. You lose the immunity to outside field interference, and you lose the BENEFITS of the "good" dielectric inside and are in reality using the...
  14. topher

    Skin Effect

    As far as I am concerned, this is NOT how to use coax, not for speakers or anything else. http://www.geocities.com/jonrisch/FIGB.GIF
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