Results 1 to 6 of 6

Thread: F 22 stereo and power relay

  1. #1
    Senior Member pyonc's Avatar
    Join Date
    Dec 2009
    Location
    Maryland
    Posts
    700

    F 22 stereo and power relay

    Hi guys,

    Have you heard about JBL F22 stereo balance and power relay? I'm curious about this vintage item.
    To the best of my knowledge, it was used with JBL SG520 preamp in the 1960s...
    I appreciate any comment from those of who actually used it or have some knowledge.
    Thanks much in advance.


  2. #2
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    9,985
    Well... you've come to the right place to find out, however I am afraid that is one obscure part.

    I'll speculate that it may be some type of signal sensing device that activates power outlets for other equipment? Just a wild assed guess.


    Widget

  3. #3
    Senior Member grumpy's Avatar
    Join Date
    Oct 2003
    Location
    SoCal
    Posts
    5,338
    http://www.jblproservice.com/pdf/Vin.../JBL-SG520.pdf

    see pg 20. Power relay (energizer(s)), and unusual test/null (speakers) relay... If the
    "balance" were off, you'd hear a signal while the test button was pushed. I assume you
    can then tweak the balance control on the pre to maximize the null. Then release the test
    button.

    Sounds like a convenience really (power relay part), and (important!) only for use with
    the intended equipment. The null thing sounds like an unnecessary set of relays in the
    signal path, as well as an odd wiring requirement that would confuse most.

    Neat thing to have with an SG520. But, for me, it would be to play with, then put away.

  4. #4
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    9,985
    Quote Originally Posted by grumpy View Post
    Read the manual? Really!

    Amazing age we live in with pdfs and Google...really!
    Not to mention, Harman ain't so bad... posting ancient manuals on their service site.


    Widget

  5. #5
    Senior Member pyonc's Avatar
    Join Date
    Dec 2009
    Location
    Maryland
    Posts
    700
    Quote Originally Posted by grumpy View Post
    http://www.jblproservice.com/pdf/Vin.../JBL-SG520.pdf

    see pg 20. Power relay (energizer(s)), and unusual test/null (speakers) relay... If the
    "balance" were off, you'd hear a signal while the test button was pushed. I assume you
    can then tweak the balance control on the pre to maximize the null. Then release the test
    button.

    Sounds like a convenience really (power relay part), and (important!) only for use with
    the intended equipment. The null thing sounds like an unnecessary set of relays in the
    signal path, as well as an odd wiring requirement that would confuse most.

    Neat thing to have with an SG520. But, for me, it would be to play with, then put away.
    Thanks much, grumpy. Actually I've obtained one on ebay as I have a SG520 in nice condition.
    You said "Neat thing to have with an SG520" but I find myself hesitating about putting it to test until I'm reassured.
    Even without this power relay, I've had no problem with SG520...

  6. #6
    Senior Member grumpy's Avatar
    Join Date
    Oct 2003
    Location
    SoCal
    Posts
    5,338
    With the SG520 set to use this switch/relay, the pre
    sends dc voltages on the line-out connectors (shield
    -and- center conductor) to drive the relays... but so
    the amp -shouldn't- see it if the circuit is all working.

    I'd want to be sure this all was tested
    as operating properly before attaching it to an amp.

    Fortunately, the manual describes this.
    Fun to have the set Interesting find!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Sansui AU-7900 - damaged relay?
    By Kreshna in forum Consumer Amps
    Replies: 0
    Last Post: 07-11-2013, 01:34 PM
  2. Tube power amp what is enough power per RMS ?
    By dino in forum General Audio Discussion
    Replies: 1
    Last Post: 06-15-2012, 09:35 AM
  3. Help please with repairing speaker relay issue on JBL UREI 6260
    By vintagchris in forum Lansing Product DIY Forum
    Replies: 1
    Last Post: 02-29-2012, 04:20 PM
  4. DBX Driverack PA+. How do you power on and power off?
    By gsb001 in forum Electronic Crossovers
    Replies: 10
    Last Post: 05-17-2010, 07:36 AM
  5. 16 ohm speakers 8 ohm stereo ???
    By frugilistic in forum Lansing Product General Information
    Replies: 1
    Last Post: 09-21-2009, 02:07 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •