Inductors for Heresy I's tweeter & squawker?

[Erik Mandaville]

It was modified to test a switching device to toggle back and forth between different setting on the autoformer. It was no different than going to the trouble of doing it manually, either by desoldering or by way of solderless connectors -- both of which are archaic and difficult. Up to that point there had not been any effort made toward switched tap settings, and this worked fine. I have preferred to build the bandpass differently, which is reflected above, the one for which I wound my own coils.

I'm really not sure what a doozy is as the term is applied to a crossover network, but if you want to elaborate concerning this or the other one I made, that would be fine. The same approach in the doozy network can be used with different values of fixed resistance, which would be my preference. I don't care for the autoformer.

Erik

[Deang]

O.K., well, it's been the topic of much discussion in the past, and it would seem that no matter how many times I say or explain it -- you continue on, completely oblivious. Since I'm at my wits end, I suggest you email or call Al, and allow him to explain to you what happens when you swamp the autoformer and move between the taps if you 1) don't remove the tweeter leg from the autoformer, and 2) don't float the common connection for the squawker.

[IB Slammin]

"I gots ta ask. What is a fixed L-Pad? Makes me think of........ jumbo shrimp."

Sure: A fixed L-pad consists of a set value of resistance in the form of a resistor -- like 25 ohms, 40 ohms, and so forth. The autoformer on the older Heritage networks also uses fixed, individual steps of attenuation, but goes about the process of attenuation differently. Each tap is essentially a fixed step in attenuation, but what changes is the reflected impedance load seen by the amplifier rather than simple resistance.

A variable (as opposed to fixed) L-pad operates much like a volume control, which is why it's referred to as variable. It's continuously variable in that the user is able to dial in the exact amount of attenuation needed/wanted and then stop. See the picture below? The two white rectangular components on the left, literally in the shape of an upper-case letter 'L' together form a 'fixed' amount of attenuation for the squawker. They perform the same function as the autoformer. I had used them in the past on other systems I built, but never on the Klipschorns. With both the A and AA designs, I preferred the resistors, which doesn't mean they are inherently better -- just that it's what I prefer.

It's possible to also use a single resistor in series, which is still a fixed value.

Erik

"literally in the shape of an upper-case letter 'L' together "

Thanks Erik.

[Erik Mandaville]

1) I almost invariably connect the tweeter directly to the input -- something which has been tested and yields essentially the same crossover frequency as its more common association with the autoformer. The reason for that has in part to do with the similarity in net capacitance between 13uf and 2uf in series (for the original factory connection on the top of the autoformer), and using a value of 2uf as the filter to the tweeter connected directly to the input. Capacitors can equal that difference in just their tolerance specifications alone. I suggested a direct tweeter connection to the input to Al many posts ago, and still have his response to that. It was actually an interesting and constructive discussion.

2) I actually got rather reasonable performance from this network. I'm sure you're right though. Thanks -

Erik

IB Slammin: You're welcome.

[kg4guy]

That did the trick