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H.J.LEAK Sandwich Loudspeakers


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#1 OFFLINE   mali

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Posted 30 December 2016 - 02:28 PM

   Buna ziua!

 

   Am achizitionat o pereche de boxe englezesti,confectionate in anii 60.

   As dori sa ma ajute cineva cu inlocuirea condensatorilor din filtre, dupa atatia ani banuiesc si-au pierdut din randament.Poate aveti alte sugesti pentru filtre,scheme ,valori etc.

   Atasez mai jos poze si rewiuri despre ele precum si parametri tehnici,cu mentiunea ca nu cunosc valorile celor doua bobine si nici a rezistentei :

 

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*Famous original version of the H. J. Leak "Sandwich" Loudspeakers with HUGE AlNiCo (Aluminum Nickel Cobalt) magnets on the tweeters, and heavily damped and braced cabinets. The cabinets are in good condition with minor marks, and with a little re-finishing they would be absolutely gorgeous! Grills are in good shape too with very minor snags and badges in place. Woofers have cambric/fabric surrounds which will never need replacing, but a re-alignment should be considered (about $30 each). These are LARGE "book-self speakers" at 26" tall x 15" wide x 12" deep, and 45 pounds each. They are my daily listeners, and I'm only selling to fund another speaker project.

 

**Description: This model Sandwich loudspeaker is a two-way acoustic suspension system with a 13-inch woofer and a 3-inch tweeter crossed over at 900 Hz. The speaker cabinet is damped and sealed at a volume of approximately 2 cubic feet. The cabinet walls are very heavily damped as well, according to the sandwich principle with a thick bituminous lining. The magnet of the woofer is rigidly attached to the rear wall of the cabinet for increased cabinet rigidity.

With the "Sandwich" Loudspeaker (circa 1960) H.J. Leak and Co Ltd. had considerable success in revolutionizing loudspeaker design in the industry by innovating cone materials to produce cone stiffness 200 times greater than conventional paper cones. The resulting cone movement follows the waveform of the incoming signal with great accurately for most detailed sound reproduction.
The "Sandwich" loudspeaker received it’s name due to its diaphragm, which was made from a thick section of expanded polystyrene sandwiched between two outer layers of aluminum.
The Sandwich loudspeaker had considerable success in the professional audio industry, where it was used extensively, and in applications where listening is critical.
 
***The original Sandwich loudspeaker was a two-way system with a 13-inch woofer mounted in a damped, sealed cabinet of approximately 2 cubic feet. The free-air resonance of the woofer was a low 19Hz, but when mounted the system resonance was 58Hz. The suspension of the woofer featured a cambric roll-surround which allowed for a low resonance and long throw.
The system crossover frequency was 900 Hz. The treble unit was approximately 3 inches in diameter and also featured a sandwich diaphragm (although early units appear to have had a fibre-cone tweeter).
The loudspeaker cabinet for the Sandwich system featured some novel design features also. The cabinet walls were only 12mm thick, but were very heavily damped with a similar thickness of bituminous lining. The magnet of the woofer was rigidly attached to the rear wall of the cabinet, thus increasing cabinet rigidity.
Leak had considerable success with the Sandwich loudspeaker, with it being used extensively in the professional audio industry and in homes both in Britain and overseas.
 

 

   Astept parerile voastre,multumesc!!



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#2 OFFLINE   shambala

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Posted 31 December 2016 - 01:19 AM

Condensatori gasesti la TME; rezistentele mai bine le lasi in pace.

Daca vrei condensatori mai buni  (are sens in special C2), gasesti la AudioAlchemy.



#3 OFFLINE   mali

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Posted 31 December 2016 - 09:10 AM

de la AudioAlchemy as vrea dar  sa mi spuna unn specialist ce tipuri de condensatori sa cumpar,mentionez ca pun calitatea inaintea pretului.



#4 OFFLINE   shambala

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Posted 31 December 2016 - 11:28 AM

Condensatori Jantzen
C1 = Z-Cap albastru sau daca nu exista in stoc, Cross-Cap negru
C2 = Z-Cap albastru (se poate pune 8,2uF), sau Mundorf M-Cap 250V sau 400V.  Daca se considera ca tw. este f bun si merita, un Janzen rosu sau un Mundorf M-Cap Supreme.
C3 = Cross-cap negru 

Edited by shambala, 31 December 2016 - 11:48 AM.


#5 OFFLINE   mali

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Posted 31 December 2016 - 03:00 PM

Multumesc!am sa revin dupa ce schimb condensatorii.



#6 OFFLINE   mac01

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Posted 31 December 2016 - 03:59 PM

De ce vrei sa schimbi condensatorii? I-ai masurat si nu mai sunt buni?



#7 OFFLINE   shambala

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Posted 31 December 2016 - 08:19 PM

Pt ca au peste 50 de ani. Oricat de buni ar fi fost - si in acei ani nu erau chiar asa de buni, o jumatate de secol isi pune inevitabil amprenta asupra lor.

In al doilea rand, pt ca in filtre sunt mai potriviti condensatorii cu dielectric solid (film foil).

In al treilea rand, pt ca, in special pe medii si inalte, un condensator MKP for audio suna ferm mai bine.


Edited by shambala, 31 December 2016 - 08:20 PM.


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#8 OFFLINE   mali

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Posted 01 January 2017 - 01:20 PM

Am probat dif. de medi-inalte pe niste filtre cabasse se aud mult mai bne,probabil ca ar trebui sa schimb filtrele cu totul dar nu stiu nimic despre difuzoare decat impedanta si puterea ,cabinetele sunt facute destul de bine pt vremea aia!






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