JohnA

You're welcome!

100 watts of music will be no problem. As always, with all speakers, turn it down at the first hint of distortion and you will never hurt anything. John

TTT

Kelly, Thanks for the links! They must be knew. I've searched the net for info about this arm for years, off and on. They've been out of production since the 80s sometime. Mine is olser than the ones in the pics, it has no plastic. I tried to pay someone to replace the wiring and nobody would take my money. John

I'd like to get anything I can on a Decca London tonearm. Anybody have a manual, or parts?

I don't keep up with the Cornwalls too well, but I believe the Type B network was originally used with a K-55-V squawker. If so, the K-55-M will work perfectly.

There is a panel on the bottom that should be screwed to the cabinet, I'm not sure how many screws it should have as I have La Scalas. There is a rubber gasket that seals the back air chamber and it often sticks tightly. Perhaps that is the shape you're in. Maybe a previous owner removed the screws and could not get the panel off and forgot to replace the screws. If this is the case, use a wide putty knife, say 6" and drive it gently between the cabinet and the panel in several places to loosen the gasket. I use a plastic hammer for this. Done gently, it will leave no marks. The woofer faces rearward and looks through a 3" x 9" slot into the mouth of the bass horn. The bass horn is very similar to the common W-horn used in concert sound systems. You will find great rewards from changing the crossover in that year model. Go with a Klipsch Type AA or AB-3(? the pre 2002 xover whatever it was) or ALKs.

I agree. And thanks to those who are serving now protecting my rear end from Al Qaeda. et al. I wish I could do more. Making cheap electricity and doing RR inspections seems hollow. I'd like to blow up at least one cave! I was able to supply a rifle for 2 Naval Reserve Officers to requalify, at least. John

Max, It was common practice several years ago to use a transformer with MC cartridges to step-up the voltage for a MM input. Have you looked for one of those? John

After reading that I'm pretty sure I'll never end up with tubes. The mania would be more than I could stand. Never mind the maintenance. Replacing recepticals? Potholders? Dean! John

I'm a little surprised at a -M falling off like that at higher frequencies. The Type AA network makes that worse, too. I expected little output above 15k and that's what you got. John

Q, Which crossover are you using in the test above. The Type AA is designed to do just what the K-77 is doing. The network peaks around 6k and falls with rising frequency. Was the K-77 the AlNiCo version?

Yes, I disconnected one diode. That removes a lot of hash at high dB caused by the diodes turning the HF waveform into square waves above 2 watts to the tweeter. You then have full responsibility for the health of your tweeters! I have replaced the caps with Hovland musicaps. I have air-core inductors for the woofers, but have thus far been too lazy to install them. I experimented with the tweeter inductor's screw, but put it back in because I didn't like the extra brightness at 6k.

Do a search. It's been discussed beaucoup times.

Eric, Your impressions mirror mine quite closely, especially the part about overtones and after ring of drums. With my modded AAs, I can often tell, or think I can, the material used in the drum head, if it is something unusual like skin rather than mylar. The Type AL left everything muddled together like leftover beef stew! Al K's xovers are another step out into the light.

Varying the capacitance will not affect the roll-off slope too much. What can be done is to choose values that produce a sag and then a hump as frequency rises with a steeper slope above that. The slope *may* only be 14 dB/octave, but it will be slightly steeper. This could be used to reduce a sag in the system's response curve at the crossover point. The Type AA network does this with the tweeter. Other values could be used to correct response errors at other frequencies. Al Klappenberger's program can do what you want. However, it is aimed at industrial users and is priced accordingly.

It depends entirely on how and what you listen to. 8 watts into 92 dB speakers is 101 dB peak. That's not that loud for peaks. You can expect average levels to be 10 to 20 dB below peak.

The K-77 and the K-77-M are interchangable.

Klipsch often uses the crossover network to contour the speaker's response curve. Others do this as well. They may not be using a Butterworth crossover, either.

Andy, They are already black, but weren't well done. I have a guy that does great work finishing and refinishing and I may take them to him. However, I was thinking of doing these myself. They'll have to be stripped, puttied and sprayed. I'll have to do all of it by hand. I'm just trying to assess to amount of work. If the black paint comes off well enough, I could stain them to match the fronts.

Thanks, D. The -R woofer has a round magnet rather than square, so I had wondered what the difference was. One of the K-77s is dead; the same speaker with the replacement woofer. I don't yet know if it's an open coil or something else. I have a modern diaphragm upstairs with tinsel leads. I can do the soldering, but are there any tricks needed to OH the AlNiCo versions? I guess I'm concerned about cleaning out the voice coil gap and disturbing the top plate, killing the magnet. BTW, I've had Bruce Brown over to hear my La Scalas. He says he remembers you from a past life and a set of La Scalas you built for sound reinforcement. You get his recommendation as a good guy (we won't tell)

I just bought a pair of HBR Heresies, SN# 87T877 & 8. That makes them 1979 models. They were painted black by a previous owner, apparently by brush! That will change shortly. The rear stampings are "USA", "OD" and "AS". The signatures are Janet Latham and N.W. Bradford. the crossevers are Type E. They have K-77 tweeters. I could be persuaded to swap them for K-77-Ms if someone wants the AlNiCo. One has a K-22-R woofer and the other one has a K-22-EF woofer. Which is correct for '79. Does one perform better than the other? To properly paint them black, how do I hide the edge plys of the plywood?

I think you all are missing some or most of the quoted poster's points. Look in "Odds and Mods" for Q-mans post. His corroded Monster cable reduced one of his tweeter's output by 3 dB. The poster says replace the corroded Monster cable, I agree. The Klipsch speakers used 16 ga zip cord for all connections through the 70s and into the 80s; that should be good enough. However, should you have extra large speaker wire available, it won't hurt to use it. He also said replace the caps. I partially agree. Replacing the tweeter caps in my Type AAs was an audible improvement. So, I next replaced the squawker cap; no difference. He recommends replacing the inductors; again, I partially agree. Another menber tested the iron-core woofer inductor and found its inductance changed with voltage, even in the ranges one would see in normal operation. Changing inductance changes the crossover frequency, bad. I have been too lazy to change out my woofer inductor to the Alpha Cores I bought, but may this Christmas. The tweeter inductor is an air-core of fine wire and will not likely be improved much with another one, but I've not tried it. There is some science behind the changes recommended. John

This is basically a theoretical discussion. In theory, a 2-way that performs equally is superior due to the reduced phase shift and distortion introduced by the crossover. To perform equally, a 2-way must have much higher quality, tougher drivers that inevitably cost more. Mr. Paul's AES paper introducing the K-400 horn showed just this. He had a lab quality driver that ran from 400 to 16k Hz and was quite smooth. However, the K-55-V and K-77 easily performed as well and was cheaper, including the extra crossover components. John

The HII should have the same sort of woofer the Heresy has, a paper cone with accordian pleat treated fabric. It will not noticably deteriorate in 30 years. While you'll have to try them, on the floor, in a corner should work well for an HII.