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.

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

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.

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.

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...

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

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...

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...

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?

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...

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...

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...

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...

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

If I remember right, 89259 is good for interconnects, but it completely misses the point of ppl's idea. ppl's coax has a center conductor that you could use to jump start your car.

ppl, I LIKE! Wonderful! I would never of thought of coax for the _speakers_. Interconects, yes. Big loads like speakers, NO. Coax has wonderful shielding and loads of bandwidth. It has to have less capacitance as a lumped load than things along the Litz line. Even such...

Tomo, This is exactly what guarantees stability when using opamps with BW's over 50MHz. Chip caps to a gnd plane and really short leads are what helps. Joobu, That's called semi-rigid coax. Teflon or polyethylene dielectric(sometimes foamed or "Gore-Tex") and a solid copper jacket...

"Twisting the conductors greatly reduces capacitance and inductance in the cable. " Am I missing something? Is this a typo? I suppose if two wires were perfectly adjacent but untwisted, the capcitance would not go up, but "reduce" it!!

I thought someone might be interested in seeing pictures of one technique that can be helpful in using parts prone to oscillation. I put up some pictures of old projects I did on bare copper board. These are harder than using dips on copper plated perf board, but you can see how long...

22ga is a good choice. At 20KHz, the center of a 22ga wire is conducting almost the same as at 1Hz. On a long run, a single 10ga might just be affected enough to sound different from an equal amount of braided 22ga.

While everybody seems to hate ceramics, I have seen a lot of reason to believe the NPO/COG dielectric materials are very good and handle much higher frequencies than the polymer types. While I would not use a ceramic as a coupling cap (I don't want to use coupling caps at all), they...

Nice. Also a great idea to post to headwize too.

I follow what ppl says very closely. I also pay a lot of attention when ever someone describes what they hear when they build something. Just because I can design a bunch of different kinds of opamps doesn't mean I have a clue on what they will sound like. So I just try to help...

shinew, when you found you needed to parallel buf634's, did you notice if the bandwidth control made a difference? For example, did 2 buffers set to high bandwidth do as well as 3 on low bandwidth?