Al Klappenberger Posted March 22, 2005 Share Posted March 22, 2005 Jc, Any if my networks with the adjustable transformer tap wires will work with any impedance driver. This includes the universal type A or any of the extreme-slope netwroks. It simply requires a different tap setting for different impedance drivers. You ae stuck with the k55 driver on the Cornwall design though. Al K. Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted March 23, 2005 Share Posted March 23, 2005 Al K sez: "Any if my networks with the adjustable transformer tap wires will work with any impedance driver. This includes the universal type A or any of the extreme-slope netwroks. It simply requires a different tap setting for different impedance drivers. You ae stuck with the k55 driver on the Cornwall design though. " Does this mean that your design would not work with a K57 driver and B3 network? There were some Cornwalls made with this driver. I understand it is 3 dB more efficient than the K55 so the user might change the tap to adjust for the driver's sensitivity. I think that is what Frz and possibly Dean told me when I bought this configuration. Al, can you quote me (PM if you like) on mods/rebuilds to my B (-1) and B2 networks. I have a pair of each. Also a single B3 that will be the center channel. Thanks, Michael Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 23, 2005 Share Posted March 23, 2005 Michael, OPPS! If it's true that the K57 is 3 dB hother than the K55 then I screwed up big-time! The Cornwall design I did was level-matched to the B-3 netwrok. I don't think what you say is true though. I think the two squawkers were equal sensitivity. Anyhow, I know it will work ok in place of the B-3. In any cast though, you MUST NOT change the tap setting on this design. It will mess up the filters. I don't build that network any more though. Ask Dean Wescott. He builds them under license from me. Al K. Quote Link to comment Share on other sites More sharing options...
Deang Posted March 23, 2005 Share Posted March 23, 2005 http://www.trueaudio.com/st_mr2.htm Quote Link to comment Share on other sites More sharing options...
kegman Posted March 24, 2005 Share Posted March 24, 2005 Here's probably a stupid question. If you have a xover that runs two caps in series how much if any does it matter that you use the same value of cap originally used for both caps as long as your final result is the same capacitance as the original? EXAMPLE: say the original has a 10uf followed by 4uf in series so you get 2.857 And you used a 12uf followed by a 3.75uf so you get 2.857 Does it matter what you use as long as the end result is the same? What about more or less caps to get the same capacitance? paralel or series Is there a cutoff of extremes that will make a difference if the above example does not? Thanks! Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 24, 2005 Share Posted March 24, 2005 Kegman, I have never seen two caps in sereis to get another value. It's a BAD idea to do that. Putting them in sereis casues their losses to get worse. You want to put two smaller values in parallel instead. Al K. Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted March 24, 2005 Share Posted March 24, 2005 >>Putting them in sereis casues their losses to get worse Wouldn't that also cause a phase shift for the driver the caps are feeding? Quote Link to comment Share on other sites More sharing options...
BEC Posted March 24, 2005 Share Posted March 24, 2005 I used to see two caps in series pretty often in old tube type radio transmitters back in the Air Force. If they needed 2 uF at 800 working volts, they would often put in two 4 uF caps in series rated 400 volts. Double the working voltage and half the capacitance by putting them in series. Al is right about the losses adding. That is why such a dramatic improvement is seen with replacing the old caps in a Type AA crossover tweeter section. It has two 2 uF caps in series and the losses in the old caps add. Bob Crites Quote Link to comment Share on other sites More sharing options...
kegman Posted March 24, 2005 Share Posted March 24, 2005 Well that's very interesting as that's whats in the rc7 xovers! They have a 12uf followed by a 3.75uf in series with each other! Quote Link to comment Share on other sites More sharing options...
BEC Posted March 24, 2005 Share Posted March 24, 2005 ---------------- On 3/24/2005 9:57:45 PM kegman wrote: Well that's very interesting as that's whats in the rc7 xovers! They have a 12uf followed by a 3.75uf in series with each other! ---------------- I don't have a copy of the RC-7 crossover schematic but I expect that something happens in the circuit between the two caps and that makes them need to stay at those values. For instance, the Type AA that I mentioned earlier has a tweeter inductor that come off the circuit between the two 2 uF caps. Bob Quote Link to comment Share on other sites More sharing options...
kegman Posted March 24, 2005 Share Posted March 24, 2005 I don't believe there is anything between those caps but I'm going to take it apart again to look. Quote Link to comment Share on other sites More sharing options...
kegman Posted March 24, 2005 Share Posted March 24, 2005 "I don't have a copy of the RC-7 crossover schematic but I expect that something happens in the circuit between the two caps and that makes them need to stay at those values. For instance, the Type AA that I mentioned earlier has a tweeter inductor that come off the circuit between the two 2 uF caps." Still have'nt taken apart the xover yet. But now that I think of it your probably right as there are 2 inductor's on that board all beit they don't come directly in between the 2 caps on the board it is very very possable the tail end of each caps is directly conected to each inductor making a 4th order xover. cap in series 1st order, inductor in paralell 2nd order, cap in series 3rd order, then inductor paralell 4th order. MAKES SENSE DUH! So in that estimation yes the caps will definatly matter as it will change the xover point. Ok I got it now. Time to double check that is the case. Allrighty then! Can't believe I didn't even look for that, DUH! Well if that is the case I will probably build a set of first order xovers and experiment as at the moment I'm running 8watt set. Thanks guy's Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 25, 2005 Share Posted March 25, 2005 Guys, I just thought of one case where two caps are used in sereis. This is where a non-polorized electrolytic is needed. Two normal ones are connect in opposite directions. It's not the best way though. They will be of the same value though, not two different values like you suggest. The only reason I can think of doing that is of you got tons of the wrong value caps in your company stock room and combing two will get you what you need. That kind of thing goes on a lot! Sometimes two are in sereis as filter caps in high voltage power supplies. These will have equalzing resistors across them though. You see the same thing with silicon diode rectifiers too. Again with resistors across them to equalize the back voltage between them. No.. Two caps in sereis change phase no more or less than a single cap of the equivalant value will. AL K. Quote Link to comment Share on other sites More sharing options...
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