soundbug1 Posted May 7, 2003 Share Posted May 7, 2003 How are these drivers recognized? If possible, can a picture of one be posted? Why are they desireable? Thanks for any help or input about them. Mark Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted May 7, 2003 Share Posted May 7, 2003 Mark, Good to see you here. I'm currently enjoying a Scott 222C that I got from you on ebay, it sounds great with my LaScalas. Thanks for providing an example of what a reputable ebay vendor is all about. The Alnico K-77 tweeter is easy to recognize. The magnet is round. The ceramic version is square. I'm not as sure on the k-55, K-55-V is alnico, K-55-M is "mud magnet." I don't know if the woofers ever had Alnico, but there are round and square magnets on the woofers. The claim is that the Alnico versions "sound better", however this seems (like a lot of other audio stuff) to be difficult to verify with tests. IMO, it may be just because the Alnico stuff is the older stuff, and the ceramic is regarded as a cost-saving substitute. No mojo, IOW. feel free to hang out here when you've got a few minutes. Scott gear is very popular here, you might find a few customers. Craig Ostby is a regular over in the two-channel section. You might know him as NOSValves. Tom (tmoble) Quote Link to comment Share on other sites More sharing options...
JohnA Posted May 7, 2003 Share Posted May 7, 2003 Ceramic magnets are the dark gray exposed stuff you always see. AlNiCo will be a small cylinder covered with a "U" shapped steel bar that completes the magnetic circuit. The magnet and steel bar are almost always covered with a steel cup. That makes them easily recognizable. Modern shielded speakers will have the cup, but it will be larger and it is rare nowdays to see a new AlNiCo driver. Early Klipsch used AlNiCo woofers, too. Quote Link to comment Share on other sites More sharing options...
Malcolm Posted May 8, 2003 Share Posted May 8, 2003 To amplify what has been said so far... It is not always possible to tell what kind of magnet a speaker or driver has from looking at it from the outside. For example, early ElectroVoice SP12Bs had alnico magnets that were totally enclosed within the basket. Later SP12Bs had mud magnets that were totally enclosed within the basket. The clue to which kind of magnet is inside is the style of the basket. A lot of speakers with alnico magnets have an alnico slug in the center with a steel U shape around them. Some have a nonmagnetic panel sealing off the U on either side to keep dust out. This kind of alnico magnet structure is easy to recognize. Other speakers have alnico ring magnets. The actual magnetic material is on the outside and there is a plate on the back. Again pretty easy to recognize. Both kinds can have their magnet structures hidden under a metal or plastic cover. In that case, the only way to tell for sure would be to remove the cover. Like John said, if you see the grey ceramic material in the magnet circuit, it has a mud magnet. Another clue to the type of magnet a speaker of driver has is the age. Alnico magnets were pretty much the standard up through the 50s and into the 60s with the switch over becoming pretty complete around the mid 70s because of the soaring cost of cobalt, a key ingredient of alnico. As far as which is bette, well, that is something that can start a war among audiophiles. As far as I am concerned, properly engineered, a mud magnet speaker can sound just like an alnico magnet speaker. That does not mean that certain speakers with alnico magnets may not sound better than similar speakers with mud magnets. But the reason for the difference is not the magnetic material emplyed. The one real advantage of alnico speakers I have found is that some designs produce must less of a stray magnetic field that can affect a CRT in close proximity. As far as the K77 variants go, the K77M with the mud magnet is technically superior to the K77 with the alnico magnet because it has extend slightly better high frequency response. OTOH I cannot hear the difference. Quote Link to comment Share on other sites More sharing options...
tubelion Posted May 11, 2003 Share Posted May 11, 2003 I bought a pair of K77 at ebay, it is better than the original K77m sonically in my Belle and SET tube gear. Again, K55V sounds better than the m-version , I bought it a bit earlier, it is the partner of K77, with the help of K77, the performance is synergistically better. I am looking for bass woofer of alnico, but hard to find, never see one in ebay, anyone know the source to buy one pair. Would like to like the performance of the latest x-version which is alnico. Tubelion Quote Link to comment Share on other sites More sharing options...
mopar dave Posted May 11, 2003 Share Posted May 11, 2003 i read in one of al klappenberger's post's that the square mag. was the better one. i don't know why. i suppose someone could ask him. later dave Quote Link to comment Share on other sites More sharing options...
TBrennan Posted May 11, 2003 Share Posted May 11, 2003 MoPar---I presume the ceramic magnet K-77 has a more powerful magnet and more magnetic force in the gap. For a given diaphragm mass one can extend the highs by increasing the magnetic force in the voicecoil gap, you can "brute force" the highs. An example is the JBL 2420 compression driver which has more extended highs than the 2410 which uses the same diaphragm, the 2420 having a more efficient magnetic circuit and more force in the gap. This brute force method is how Lowthers, which use VERY powerful magnets, get decent highs from a 7" cone speaker. Quote Link to comment Share on other sites More sharing options...
soundbug1 Posted May 21, 2003 Author Share Posted May 21, 2003 Thanks everybody, for all the info. I thought the U shaped cover designated the Alnico version. I just came across a pair of 700s or Heresy speakers that I believe were made in 1970. ALL the drivers are EV, even the woofers. Looks just like an SP12 driver. I've never seen this in a Heresy before and thought I'd ask about alnico to clear up some of my confusion. Some people are really into the Alnico and I guess some others couldnt care less. Thanks again! Mark Quote Link to comment Share on other sites More sharing options...
Malcolm Posted May 23, 2003 Share Posted May 23, 2003 Hmmm... squawker driver in a 1970 model should be K55V which was manufactured by Atlas. Of course, it could have been replaced by a K55M which was manufactured by EV. Anything else is not correct. Quote Link to comment Share on other sites More sharing options...
soundbug1 Posted May 24, 2003 Author Share Posted May 24, 2003 The K 55 with the curved edges. That is what is in those old Heresys. I just found out that they are 1967s instaed of 70s. They have the "F" in the serial number. Maybe these are Atlas? I always though EV. So much to learn about three little speakers! Mark Quote Link to comment Share on other sites More sharing options...
Malcolm Posted May 24, 2003 Share Posted May 24, 2003 K55V is correct for 1967. It will be grey with rounded back edge. It is basically an Atlas PD5V. Quote Link to comment Share on other sites More sharing options...
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