Info/ help needed with jbl mpro mp415 comps |
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charlysays
Registered User Joined: 16 June 2015 Location: Wales Status: Offline Points: 413 |
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Posted: 13 August 2017 at 9:25pm |
I've been after some alright sounding compact tops for a while so I got a pair of mp415s today for 240 quid.
In investigation of a cab rattle (turned out to be a loose comp, I got money off due to it too) I have discovered that the comps are certainly not original unfortunately. The magnet structures have nothing to identify them by expect a sticker. One says A4W-JBF and the other says 94X-JBF. I assume these are jbl magnets but are they the correct ones? They look identical apart from having different numbers on the stickers. The diaphragms have no name on them so I assume they're aftermarket replacements. How much worse are they going to sound? How much would it cost to put them back with original jbl as they should be? How do I tell which pole is which... No plus or minus that I can find. Lastly I accidentally got the two magnet assemblies stuck together, have I damaged them? I didn't expect them to attract for some reason! I'm unfamiliar with anything regards comps as I've never blown one and only built subwoofers so far so this is new territory for me. The woofers are atleast original and seem fine Any advice much appreciated |
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MarjanM
Old Croc Joined: 10 February 2005 Location: Macedonia Status: Offline Points: 7810 |
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Pictures please
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Marjan Milosevic
MM-Acoustics www.mm-acoustics.com https://www.facebook.com/pages/MM-Acoustics/608901282527713 |
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djeddie
Old Croc Joined: 26 April 2004 Location: Bristol Status: Offline Points: 4125 |
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The comp should be a JBL 2406H. Just Google that and look at the pics, if they're the same then that's whatcha got... if not, they've been changed.
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Chas n Dave : it's like Drum and Bass but with beards. E=mc² ±3dB
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_djk_
Old Croc Joined: 23 November 2004 Location: United States Status: Offline Points: 6002 |
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"A4W-JBF and the other says 94X-JBF."
Production codes for a JBL compression driver. http://www.jblproservice.com/pdf/MPro%20Series/MP415.pdf Will accept a genuine BMS 4538 diaphragm (about $65 in the USA, $140 with the JBL sticker). Edited by _djk_ - 15 August 2017 at 12:11am |
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djk
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charlysays
Registered User Joined: 16 June 2015 Location: Wales Status: Offline Points: 413 |
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charlysays
Registered User Joined: 16 June 2015 Location: Wales Status: Offline Points: 413 |
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Cheers. I did gather that from the jbl tech sheet however there are no stickers on my comps... However they do look like 2406s so I guess they probably are the original motor units just with no name diaphragms fitted. |
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charlysays
Registered User Joined: 16 June 2015 Location: Wales Status: Offline Points: 413 |
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Thanks. Do the differing codes mean I have two different motor units despite them being externally identical bar the code on the sticker? So best cheap bet for optimal sound quality is a bms diaphragm? Thanks for this. I looked these BMS drivers up... what is the difference between the diaphragms for the BMS4540 and the 4538?... They look the same and seem to both be suited to the JBL2406.... 4538 is quite a lot cheaper. Is it just a ferrite version of the 4540? Edited by charlysays - 15 August 2017 at 12:14pm |
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_djk_
Old Croc Joined: 23 November 2004 Location: United States Status: Offline Points: 6002 |
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" Do the differing codes mean I have two different motor units despite
them being externally identical bar the code on the sticker? "
They are like date codes, or serial numbers, same part, different time off the line. "So best cheap bet for optimal sound quality is a bms diaphragm? " Yes. "I looked these BMS drivers up... what is the difference between the diaphragms for the BMS4540 and the 4538?... They look the same and seem to both be suited to the JBL2406.... 4538 is quite a lot cheaper. " The 4538 is less expensive due to higher production volume. "Is it just a ferrite version of the 4540?" Pretty much. |
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djk
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charlysays
Registered User Joined: 16 June 2015 Location: Wales Status: Offline Points: 413 |
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Thank you djk very much appreciated. I'll get some tomorrow ☺
Not only do these no name diaphragms have no name but also no plus or minus so simply getting that right will be nice! On that note, do I connect the yellow and black to the positive or the yellow? I take it a bms diaphragm won't have that confusing reverse polarity like other jbl drivers? |
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_djk_
Old Croc Joined: 23 November 2004 Location: United States Status: Offline Points: 6002 |
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Yellow goes to positive.
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djk
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charlysays
Registered User Joined: 16 June 2015 Location: Wales Status: Offline Points: 413 |
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Thanks again.. And they're 8ohm drivers? Can't find multimeter to test the old ones atm! |
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_djk_
Old Croc Joined: 23 November 2004 Location: United States Status: Offline Points: 6002 |
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The 'H' indicates an 8Ω driver.
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djk
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