Saturday, March 2, 2013

1970s Marantz and JBL System



HiFiCollector.com community member, Gary sent in this great write-up on the 1970s system in the photos above. Thanks Gary! :)  

If you have any stories to share, send it along with pics to hificollector88 [at] gmail.com    Thanks.

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The pictured system is comprised of Marantz electronics including a 3300 Stereo Control Console, 120 Tuner, 240 Amplifier and 6100 Turntable. The speakers are JBL 4311’s. Everything is mid 1970’s vintage.

I originally purchased the 240 Amp and the JBL’s new for a small recording studio in the mid 1970’s. All of that is long gone but I could not part with the speakers and the amp. Over time I purchased the other Marantz components to complete the system in period pieces.  I have not used this as my main system in a number of years but kept the equipment setup and would give it a listened from time to time when feeling nostalgic.

I never had the individual cabinets for each of the Marantz components so they were just black metal boxes behind the aluminum face plates. I did some cap replacement just because the electrolytic caps were old. I had to refinish the JBL cabinets using the method JBL suggested in the late 1960’s which is a mix of Linseed oil and turpentine (a messy and smelly blend to be sure) along with some touchup on the black painted areas. I also had to reattach one of the JBL logo plates and replace the foam rings around the tweeters.

Tip 1: If you need to replace the foam rings around the JBL LE-25 tweeters you can purchase them on-line. Be VERY Carful when removing the old foam rings. The tweeter voice coil leads are exposed under the foam adhesive and if you get rough you could damage them. Just take your time and peal the old foam ring off while watching for the leads.

Tip 2:
One of the tweeters had suffered the classic damage of having its dome poked in. This was a very slight poke not the devastating damage that was typical of store show models in the good old days. I repaired this by taking a small artist paint brush and using a very small amount of water dampening the damaged area of the dome to soften it. Then, using a short rubber hose with an inside diameter slightly larger that the damaged area of the dome, I placed the end of the hose over the damage and created a suction on the hose by sucking on it. This pulled out the dimple and restored the dome to its original shape – or at least very close. Unless you look very closely you cannot tell this was repaired.

Caution – this requires steady hands and an understanding that if you sneeze in the process you can do more damage than good. I bought a foot or two of various diameters of clear rubber hose at the local hardware store to pull this off. You will also need to trim the hose to fit around the damaged area making an acceptable air seal. Also I had to suck much harder that I thought I would initially – it took several attempts.

Tip 3:
If you are going to refinish the cabinets using the original JBL mixture of 3 parts boiled linseed oil to one part gum sprit turpentine the speakers will remain a bit oily for some time and stain anything you place them on. Just put down some paper/padding that you can trash later and give it a month or so. No matter how hard you try you can never wipe off all of the finish and it will leach out slowly for a while. You may want to turn them over from time to time to even out the drying.
  
Now that everything is working and looking its best I decided the components needed a cabinet that was both functional and would also provide a display case of sorts. I wanted something with a feel for the times when this equipment was manufactured while still focusing attention on the equipment and not the cabinet.  The results are what you see in the photo. The cabinet, like the speakers, is veneered in Walnut but since there is a 40 year difference in age you can only get so close when it comes to the wood tone. I still need to come up with an isolation base for the turntable but, surprisingly, there is not too much vibration from the speakers that affects the turntable. Just don’t try to rock the house. 

I get a little smile each time I walk by the system and have a desire to reach down, turn it on and crank up some appropriate 1970’s tunes. I may listen to it a little more often now – at least I like to think I will.



2 comments:

  1. That is a cool looking system!
    I hope you have a nice leather lounge chair right in front of it.
    I've got the 4311 bug only I flipped mine upside down,
    and they are hooked up to sansui stuff right now.
    I love that hose trick for the domes.
    Great article!
    TP

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    Replies
    1. Travis,
      Thanks for the positive comments. I tried the JBLs upside down to get the tweeters higher but the upside down name plates drove me nuts. Sometimes you must compromise perfect audio setup for aesthetics (hope that does not get me kicked out of the audio purest club). Also the length of the legs on the cabinet puts them up a bit and the speakers can be tilted back.

      The JBL/Marantz system is in the same room with my Dynaco and Advent systems so I can spin the chair and pick a system depending on my mood. Both the Dynaco and Advent are now on wall mounted shelving, not pictured, so I have ended up with a retro stereo room.

      Here are the links to the Dynaco and Advent photos.
      http://hificollector.blogspot.com/2010/04/community-photos-1970s-advent-stereo.html
      http://hificollector.blogspot.com/2010/04/community-photos-dynaco-system.html
      Gary

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