vinylithicum wrote:

Here are some of my observations regarding the Wolf von Langa RCA 1428 replica. I long time wondered where mr. von Langa gets his phase correction elements and the diaphragm for his RCA 1428 replica. It's obvious that a niche-manufacturer such as W. von Langa doesn't have the production facilities to cast his own phase correction elements, especially since the original RCA 1428 phase correction element is a very elaborate engineering masterpiece and even nowadays very difficult to cast. Most foundries wouldn't even bother to try. Way too expensive.......... So, where does mr. von Langa get the parts? Last Friday, I figured it out, because I more or less incidently came across the B&C speaker website. This Italian manufacturer enjoys a good rep in the professional audio business. Suddenly, I clicked the B&C DCM50 2" HF driver spec sheet and when I saw the picture, I knew where mr. von Langa gets the parts he needs to complete his RCA 1428 replica. Feel free to explore mr. von Langa's kilimanjaro-website and compare the pictures of his RCA 1428 replica with the picture of the DCM50 driver on the B&C speaker website. Besides from the magnets, the resemblance is striking. Mr. von Langa buys B&C DCM50 drivers, discards the original neodymium magnet, then cuts of the from the back of the original DCM50 protruding "cooling-fingers", in order to be able to bolt on his huge elecromagnet. Then he sells this contraption as RCA 1428 replica, which it is obviously not, it's a modified B&C DCM50 HF driver. And it costs a lot of money too. I bet that the original B&cC speakers are way cheaper than the von Langa modified ones. Maybe it would be interesting to buy 6 B&C DCM50drivers and then leave one pair original, rebuilt one pair with field coil motors and rebuilt the last pair with alnico magnets. Then one would be able to make a precise assessment regarding the sonic differences between the magnetic circuits. Yours sincerely, Maurice.

vinylithicum wrote:

Here are some of my observations regarding the Wolf von Langa RCA 1428 replica. I long time wondered where mr. von Langa gets his phase correction elements and the diaphragm for his RCA 1428 replica. It's obvious that a niche-manufacturer such as W. von Langa doesn't have the production facilities to cast his own phase correction elements, especially since the original RCA 1428 phase correction element is a very elaborate engineering masterpiece and even nowadays very difficult to cast. Most foundries wouldn't even bother to try. Way too expensive.......... So, where does mr. von Langa get the parts? Last Friday, I figured it out, because I more or less incidently came across the B&C speaker website. This Italian manufacturer enjoys a good rep in the professional audio business. Suddenly, I clicked the B&C DCM50 2" HF driver spec sheet and when I saw the picture, I knew where mr. von Langa gets the parts he needs to complete his RCA 1428 replica. Feel free to explore mr. von Langa's kilimanjaro-website and compare the pictures of his RCA 1428 replica with the picture of the DCM50 driver on the B&C speaker website. Besides from the magnets, the resemblance is striking. Mr. von Langa buys B&C DCM50 drivers, discards the original neodymium magnet, then cuts of the from the back of the original DCM50 protruding "cooling-fingers", in order to be able to bolt on his huge elecromagnet. Then he sells this contraption as RCA 1428 replica, which it is obviously not, it's a modified B&C DCM50 HF driver. And it costs a lot of money too. I bet that the original B&cC speakers are way cheaper than the von Langa modified ones.

Maurice, you might be right. I do not know RCA drives well to be able to confirm or deny what you are saying. Frankly speaking to me it is very much irrelevant if Wolf von Langa made it from RCA blueprints or converted B&C to electromagnet. I more interested in the performances of a driver then from it’s history. If you read my site then you know that that fact the driver (or anything) is by “RCA blueprints”, or by “WE blueprints”, or “Klangfilm blueprints” is absolutely not indicative to be about the diver sound. I do not support the stupid devotion to vintage brands. It is not because I do not admit that very few selected vintage components were very good performers. It because I know that absolute majority the vintage people, who are choking with saliva and  losing consciousness while they are gluing to their horribly- sounding playbacks labels “Bell Labs” or “Telefunken”, are in fact Morons.

You see, we have very few true personalities in Audio, mostly whoever in audio are ether idiots or retards, personality-wise. How many people you will see in audio today who would say”Fuck all your WE and Marconi. I am the master of my sound, I know how the things need to be done and here is the result”, saying all of it while demonstrating the result that would be a true personal statement about Sound. You do not see those people in audio too frequently. All that you see today are hundreds of Wolf von Langas who know that the audio retards would “bite” the “RCA” label and this is what he is trading to them. I have to note that I use Wolf von Langa name as an illustration. I have no idea what his drivers are and how they sound.  They might be better than RCA, who knows.

BTW, one thing you are right – the source of the diaphragms is the key. If I would be able to make my own diaphragms I would be making my own drivers. I know a number of people with good drivers ideas but with no good diaphragms. In fact if I were interested in audio business then I would make “specially sounding” diaphragms. There is no competition in this market and the demand is not fulfilled.

vinylithicum wrote:

Maybe it would be interesting to buy 6 B&C DCM50drivers and then leave one pair original, rebuilt one pair with field coil motors and rebuilt the last pair with alnico magnets. Then one would be able to make a precise assessment regarding the sonic differences between the magnetic circuits.

http://www.goodsoundclub.com/Forums/ShowPost.aspx?postID=1929#1929

There are a lot of people who convert perm magnet to electromagnets but listening what they say I find their comments absolutely not credible as it contains many ether technical or methodological mistakes. If you find one public attempt that you feel worth to read then let me know.

vinylithicum wrote:

Hi audiofilofine. Nice drivers, although the picture is a bit fuzzy. Can you tell more about your drivers? Maurice.

audiofilofine wrote:

All parts of the tweeter shave been designed and built.All are built in magnetic steel in preferenceto pure iron because pure iron is heated during processing and after processing was not possible to check that the characteristics of the metal were the same as before processing. Solenoidsto180voltssaturatethe core. Diaphragm shave been modified by eliminating the resonance. We tried two types of diaphragms and two types of horns with spinnerPFC. With the horns of the first photo, the answeris within 1 db from 6000 to 23500 hz spl 110 d b 2.83V1 m,with the second type of horn  is within1.5dB from 4000 to 19500Hz with an SPL of 114 db 2.83V1m http://audiofilofinehighendproduct.blogspot.com/2011/01/tweeter-horn.html

Romy the Cat wrote:

I have a few comments and questions. First about the posting. I guess you are from Italy and your use some kind of text editors that user a lot styles that are not renders properly a browser with western meetings. I just would like to let you know that my posting window has a tool that will fix all formatting problems. In the right corner or “reply” interface you will see a blue “W” button that says “Clean All MS Word formatting”. It is very helpful. Also the buttons on the extreme left “Preview Window” would allow you to preview your post before submitting it. Yes Italy OK Now about your tweeter. If it is not some kind of trade secret then what diaphragm you used, how did you dealt with alleged resonances and the most important how methodologically you concluded that the problems that you reportedly had were resonance-related? Another thing, you chose to close the return magnetic system with a solid cylinder that prevents hit dissipation from electromagnet. Do you driver get too hot? Can you report it’s temperature after 3-4 hour of operation? Sorry but I prefer not to say the brand of the diaphragms . I used only moving parts and not the structure, the suspensions were treated with a silicone resin The metal structure at the beginning was open but the magnetic circuit was not working well,the magnetic force of the solenoid was lost,I arrived at the solution completely closed after several prototypes. http://audiofilofinehighendproduct.blogspot.com/search?updated-max=2010-11-08T12%3A59%3A00%2B01%3A00&max-results=7  Half an hour aftert he meta lreaches a temperature about 46 to 50 degrees(depending on ambient temperature) and the temperature remains constant, even leaving under tension. The metal trumpet acts a sheat sink Sorry but i dont say Now, some more important thing. It is a pure speculative guess on my part but I would say that considering the type of the horn you use and the sensitivity numbers that you provided I can estimated that you do not saturate your gap hard enough: ether you run too little current or your use too low permeability of core. You see, this type of the horn (absolutely ridicules for a tweeter in my view) shall heave you over 10dB equalization gain. With 100% of driver efficiency and no horn EQ the sensitivity would be 111dB (1W converted at 100% to sound pressure).So, with this type of the horn and proper high saturation (for tweeter only) you shall have 118dB or even more. You might have problems to drive more current with this air-restricted electromagnet. Take a look how Cogent did their drivers – they did cooling in a very right way. Rgs, Romy the Cat

audiofilofine wrote:

Sorry but I prefer not to say the brand of the diaphragms . I used only moving parts and not the structure, the suspensions were treated with a silicone resin

audiofilofine wrote:

The metal structure at the beginning was open but the magnetic circuit was not working well,the magnetic force of the solenoid was lost,I arrived at the solution completely closed after several prototypes. http://audiofilofinehighendproduct.blogspot.com/search?updated-max=2010-11-08T12%3A59%3A00%2B01%3A00&max-results=7

audiofilofine wrote:

In my opinion,the magnetic circuit of Cogent is not closed properly but I could be wrong because I saw them only in photos The black horns used with  phenolic diaphragms and not look up very high but the highest spl.

audiofilofine wrote:

Half an hour aftert he meta lreaches a temperature about 46 to 50 degrees (depending on ambient temperature) and the temperature remains constant, even leaving under tension. The metal trumpet acts a sheat sink

audiofilofine wrote:

Solenoids bear up to 200 volts without problems, but with increasing voltage increases the spl but the responseis less linear with a 3 db boost of around 12,000hz

audiofilofine wrote:

Tweeters area  workin progress and no thing is final I have yet tounder stand why changing the valve of power supply sound changes a bit even though the same voltage

One more thing, at your blog you reported that retard Angelo from Brazil as your friend. It is totally up to you how you are willing to compromise your standing but be advised that in my books the people befriended with that that Brazil idiot does not deserve my attention. That guy is ultimate nightmare, so pathetic and so primitive that it does not deserve my criticism. I know that by saying it again publicly I again will receive in no more that I hour a bombardment of emails from that idiot insisting that I need to embrace Christianity, to love Angelo and do not deny him my attention. Well, if Christ out there then I wish him to expire that piece of shit from Brazil. Now, he is your friend, deal with it.

audiofilofine wrote:

After several tests of listening and somehow I felt that the best solution is fully closed. The heat is part of the project and not to damage the diaphragm, also the hot air is compressed better than cold and thus distorts less. Even leaving the container open the diaphragm would have been nearly the same temperature. The drivers I build them for me and so far I have never sold any.

Kerry Brown wrote:

The RCA1428 is a great sounding driver on RCA multi-cell horns. Not that I like multi-cell sound.

Kerry Brown wrote:

There is nothing slow about my modified DCM50s. The B&C drivers are more detailed, and 'faster' than 375s but have way better low frequencies. I have never heard any driver that sounds better. In fact nothing I have ever heard even comes close.

Kerry Brown wrote:

From what I understand the only reason high voltage motors were used on vintage drivers has to do with the existing power supplies, not sound quality. In any case, my 14V drivers sound wonderful. Dramatically better than 375s. No kidding.

Kerry Brown wrote:

Maybe you should try a pair of stock DCM50s, I think you'd really like them.