Jennings Research speakers

2

Comments

  • If I'm seeing this right, it couldn't be simpler.
    One high pass cap for the tweeter.
    Two inductors for the woofers.

    I'd get rid of the hong kong cap asap. :)
    Others can recommend one for you.

    @ 6 ohms 75w max you won't need a lot of power with these I'm guessing.
    Just good power.
    cortico wrote: »
    Can anyone explain the crossover designer?

  • cortico
    cortico Posts: 587
    edited September 2017
    Interesting, the other speaker has different cap. Apparently a bipolar electroliyltic, not sure about the capacitance, can't read the values.
    o2co6g3mlqo3.jpg

  • cortico
    cortico Posts: 587
    edited September 2017
    The cap is 8uf, I'll get 2 sonicaps and replace them. I only have one grill, today I templated the frame on acad all I will have 2 new ones Lazer cut on mdf

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  • cortico
    cortico Posts: 587
    edited September 2017
    Planing to use a CNC machine to cut the new baffles, it's Petry enjoyable to watch it working. This one is cutting door frames and routing for recessed pulls for one of the millwork pieces of an apartment I am renovating...

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  • cortico
    cortico Posts: 587
    edited September 2017
    Here is the nude existing screen frame, 469hpufum36r.jpg
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  • cortico
    cortico Posts: 587
    edited September 2017
    By the way, I was experienent with different polyfill placements and noticed drastic changes:
    6lwbekji5w76.jpg

    Scheme A had better bass response which makes the sound more coherent, the mids seemed more balanced...
    Post edited by cortico on
  • Funny you should try this as I was thinking what if...
    what if you redesigned this as a three way speaker.
    Leave the bottom woof full out and make the upper
    a mid woof. I couldn't find any specs so I kept my
    mouth shut. :|
  • cortico
    cortico Posts: 587
    edited September 2017
    Yeah, I am all about experimenting.

    Although, these speakers sound really well in my humble system. I am sure the Marantz imprints it's own thing...

    but hey! I play electric guitar, I love coloration, why shouldn't I?! Haha B)

    Anyway, this was a great find. I have to new 8uf caps coming in. Two different capacitors on left and right crossovers makes my OCDness kick in... can't deal with that. Argh!
  • A fun project for sure.
  • cortico
    cortico Posts: 587
    edited September 2017
    Here is a sloppy vid closer to the speaker

    https://youtu.be/20aG_IE81a8
  • cortico
    cortico Posts: 587
    I had a chance to recap the speaker today. Finaly was able to read the existing caps properly, the film was 8uf but the electrolytic was 4.7uf. I suspect the last one was replaced at some point, judging by the way it was soldered in.

    Anyway, I have replaced both with a 8uf, the speaker where the 4.7 was seems to have a tinny bit more highs, could be just my brain but this is fixable with just a click on the Marantz independent left and right treeble control...

    Any thoughts on this?

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  • [Deleted User]
    [Deleted User] Posts: 10,716
    edited September 2017
    Yes, one (or both) of these is/are wrong.
    You need the original specs. :|
  • cortico
    cortico Posts: 587
    edited September 2017
    Yes, one (or both) of these is/are wrong.
    You need the original specs. :|

    Yeah, I have scavenged the interwebs and can't find any schematics.

    I am sure the black is the original, the aluminum cap was soldered to the leads of the previous capacitors.

    Let's see as the new caps "acclimate" :), I like the sound...

    Today, I am dropping off the grille frame to the millworker shop, he will generously scan it and replicate. This is a must-have, my 2-year-old likes to scratch speaker cones.
  • xschop
    xschop Posts: 4,598
    Stick with the 8uF. It crosses lower. That and it was probably the original type they used, looking at other images.
    Don't take experimental gene therapies from known eugenicists.
  • cortico
    cortico Posts: 587
    edited September 2017
    xschop wrote: »
    Stick with the 8uF. It crosses lower. That and it was probably the original type they used, looking at other images.
    Yes, this makes sense, the new ones are 8uf.
    x7lqvtcbkxvl.jpg
  • cortico
    cortico Posts: 587
    I was able to source this info:
    Jennings Research was based in Los Angeles, California, USA and founded in March, 1975 by Tom Jennings. Mr Jennings had been the head of marketing for JBL in the late 60’s, early 70’s and was instrumental in the success of the JBL Aquarius series. In a different time he was also CEO of Wald Sound. As it is with most driven entrepreneurs, Jennings stuck out on his own, brought in a dedicated group of talented associates and made some amazing speakers. The initial product line at Jennings Research was called the “Contrara Group”. At the top of the line was the "Contrara Elan Pedestal" with twin Audax tweeters and Audax woofers. Next up was the "Contrara Group Pedestal", which features twin woofers and a single tweeter. Also included in the model series were the "Contrara Group MKii Rectangles" which had single woofers and tweeters in each cabinet. Other than the high quality drivers and crossover networks, the most striking thing is their physical appearance: all the Contrara Group pedestal systems feature hand-rubbed, solid dark walnut cabinets with mosaic tops. The Rectangles have the same high quality finish but without the mosaic tops. The pedestal models also have very heavy cabinets mounted on swivel bases which is quite unique, to say the least. There were a few other speaker models, not as well known but still carrying the Jennings Research badges. They were introduced in the summer of 1975 and the company initially made quite a splash with an advertising campaign in national magazines such as "Popular Science" and the "New Yorker Magazine". The well-designed systems sold well, but, unfortunately, the very high cost of materials and labor, let alone the cost of marketing and sales, put Jennings Research in a precarious position compared to the well-funded competition. There was no question the product is excellent but, as happened to so many companies in the crowded high fidelity market, they just couldn't stay afloat. Occasionally, Jennings Research speakers turn up for sale but are considered very rare because, generally speaking, they sound VERY good and most audiophiles tend to consider these "keepers". The company also introduced a line of amplifiers the next year, but they appear to have only been in production for only a couple of years.
  • cortico
    cortico Posts: 587
    edited September 2017
    I am glad I changed the capacitors, right and left channels are balanced and smoother now, caps seem a good choice too. The original binding posts are solid and the cabinet is completely airtight. I may redo the internal wiring at some point down the road.

    I have to say, that the solid wood intrigues me. is common sense that solid wood is not desirable in speaker cosntructuction due to resonance, wood movement, etc... Unless if it's used intentionally, I learned some manufacturers have done this, obviously the case here.

    Important to mention that not all cabinet panels are solid wood. When looked from the inside, The interior sides, drivers baffle, and bottom panels look like a compact wood agglomerate. it could be interior agglomerate lining panels, difficult to tell.

    In my non-audiophile opinion, these speakers are easy to listen and sound pretty good along with the rest of my rig. Charlie Byrd & Stan Getz, "Jazz Samba" sounded incredible detailed and real through these speakers.

    Very focused, super smooth highs and natural sounding midrange and bass. The tweeters are fantastic and the four 8" drivers displace decent amounts of air and slam too :) when Listening Radiohead "The Bends" at a moderate-high volume level. The cabinet construction imprints a mellow acoustic character that gives a realistic sound to some instruments.




  • VSAT88
    VSAT88 Posts: 1,225
    Talk to the king of wood @F1nut ;)

    ^^ ^^^
  • VSAT88
    VSAT88 Posts: 1,225
    Viking64 wrote: »

    Jessewood was the original name for Hollywood... though Jesse's wood is now highly sought after on the west side of town.

    "If you drop your wallet in West Hollywood, you better kick it to Beverly Hills before you bend over to pick it up." :p

    LORDY !
  • VSAT88
    VSAT88 Posts: 1,225
    cortico wrote: »
    Thanks all for the useful comments B)

    Here is a pic of the crossover, pretty minimalistic 3 inductors and a cap and the woofers numbering... Sound is decent acoustic instruments have pretty good realism.

    Going back and forth between this and my restored and upgraded CRS, the CRS sound smoother but seem mid scooped in comparison.
    plj6a5d6rjes.jpg

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    Those woofers look a lot like the Norman 10's I had. Rubber surround an all. The crossovers were very simple as well.
  • cortico
    cortico Posts: 587
    edited October 2017
    VSAT88 wrote: »
    cortico wrote: »
    Thanks all for the useful comments B)

    Here is a pic of the crossover, pretty minimalistic 3 inductors and a cap and the woofers numbering... Sound is decent acoustic instruments have pretty good realism.

    Going back and forth between this and my restored and upgraded CRS, the CRS sound smoother but seem mid scooped in comparison.
    plj6a5d6rjes.jpg

    u46x5lttepk9.jpg



    Those woofers look a lot like the Norman 10's I had. Rubber surround an all. The crossovers were very simple as well.

    I read that they were made by Audax, other information on these is inexisting. I am lucky mine are in mint condition, I foresee many trial and error if one fail
  • cortico
    cortico Posts: 587
    edited October 2017
    Got the screen frames back from the shop!! I will paint it flat black paint before wrapping it with cloth.
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  • cortico
    cortico Posts: 587
    edited October 2017
    Another update, I am not fully happy with the cloth. I think I found something a little heavier and more period correct.
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  • Tony M
    Tony M Posts: 11,007
    edited October 2017
    Beautiful speakers.
    I love finding older rare speakers in great condition or close to it.

    The instrumental " Riviera Paradise " by Stevie Ray Vaughn you played in your video was a song I used for years as a demo to show off Polk Audio speakers and some other kinds once in a while. But that instrumental on my SDA-SRS2"s is PHENOMINAL or SPECTACULAR ! People would ALWAYS ask me after playing it, "Who is that again and the name of it ?" It's a very, very well recorded instrumental !!
    Most people just listen to music and watch movies. I EXPERIENCE them.
  • cortico
    cortico Posts: 587
    Tony M wrote: »
    Beautiful speakers.
    I love finding older rare speakers in great condition or close to it.

    The instrumental " Riviera Paradise " by Stevie Ray Vaughn you played in your video was a song I used for years as a demo to show off Polk Audio speakers and some other kinds once in a while. But that instrumental on my SDA-SRS2"s is PHENOMINAL or SPECTACULAR ! People would ALWAYS ask me after playing it, "Who is that again and the name of it ?" It's a very, very well recorded instrumental !!

    Thanks Tony!

    Finding old rare old speaker and restore them its rewarding.

    I also think the "Riviera Paradise" by Stevie is an great performance and tasfuly recorded, great player and track. There is a plephora of playing style nuances and overtones i use as reference when listening gear.