Heresy squawker attenuation

[ttaylor]

I looked at Johns squawker mod and I just dont understand the schematic. It shows moving the leads down but the terminal numbers on the schematic dont correspond to the numbering on my type E. The squawker is attached to #6 and #5 (out of 8) What am I not seeing? Are there numbers on the other side of the XO that I cant see that refer to the screws on the terminal block opposite the numbered/label hookup screws? The schematic link is below.

http://forums.klipsch.com/idealbb/download.asp?mode=download&fileID=26353&sessionID={94D5926A-75C2-4505-AE07-23C96E1C7E68}

Also, Ive noticed that the K-77 in my 1978 LS look nicer (logos and paint) that the plain metal and ink stamped versions in my 1969 Heresies. Are they essentially the same driver?

thx ttaylor

[JohnA]

Your tweeters should be essentially the same, other than the dates.

The schematic you listed is the esperimental version. If you don't have a T2A, you'll have to post some close-up pics so we can help figure out what you do have. If you have an AC voltage source, like an AC adapter (4 to 8V), it could be used to help figure out the taps on your autoformer. The crossover will have to be out of the speaker, of course.

[ttaylor]

Thanks John.

Heres a picture of the XO still mounted. I put my LS tweeters in them just to give them a listen since the originals are blown and Im awaiting diaphrams. They sound great although the mids are not quite what Im used to after the LS but they sure fit in my office better!

taylor

[JohnA]

That sure looks like a T2A, on the right. Are you sure you haven't misread the tap numbers? My modified Heresy center sounds nearly identical to my Type AA La Scalas done like the schematic attached.

[JohnA]

Here's the finished picture.

[djk]

"The squawker is attached to #6 and #5 (out of 8) What am I not seeing? "

You are looking at numbers on the terminal strip, not the T2A autoformer.

All references to tap numbers refer to the numbering scheme on the T2A autoformer.

Nothing is changed on the terminal strip.

[ttaylor]

Okay, now I see whats going on. So what I thought was just a choke is an autoformer with 5 numbered solder terminals that werent visible upon general inspection. Thanks djk.

John, how much of an improvement does your XO make? Did you just swap like values with upgraded components? I dont recall seeing a list of the parts you used in the archives but then I may have missed it.

taylor

[JohnA]

I don't recall a huge improvement in sound, but the design goal of making the Heresy sound like my La Scalas was achieved, as much as that was possible.

I had 2 speakers tested at a local speaker manufacturer. Attached is the graph. The lighter blue line is my modified crossover. Somehow I did not get an impedance curve from it. The test was done indoors with the speaker facing the unfinished 12' ceiling of his commercial building. I don't know what to make of the curves except that they are useful for the differences. Oddly, the speaker generating the light blue line has the "superior" solder terminal K-55-V and K-77-M. The other Heresy has the spring terminal K-55-V and K-77. Except for 3 dB in the midrange, there is little difference. I don't know what happened to the -3 dB the tweeter circuit was supposed to show. Maybe the K-77's magnet is weak.

[acidmilk]

Hi John,

I did the mod you suggested in the other thread, the one with 16 ohm resistor. And then I found this thread, with changed cap values and a 11 ohm resistor. Could you please tell me which mod is better to your ears? Thank you very much!