|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
64.222.49.246
I found some parts in my grandfather's workshop and he gave them to me. Tried to put images here but it wouldn't work. I don't know much about speaker parts of this vintage, so any help would be appreciated. I'm tempted to keep them, but my credit card says 'sell,' so if you know the approximate value of anything, please share. All are in excellent cosmetic condition:Jensen A-402 crossover network (16 ohm);
Jensen m1131
Jensen RP302 tweeter, looks exactly like this one:http://tinyurl.com/ywvk9f
but the code is on the barrel of the tweeter and it reads RP302-C6068-2 220817
The serial numbers on the three are very close: A-402 is 220815, M1131 is 220812, tweeter is 220817. Does this suggest it might be worth digging around there for more parts?
I'd like to learn about what exactly these pieces are, but I'm worried it's going to get me started on yet another speaker project (several are in the works).
Follow Ups:
Vintage Jensen catalog scans are available at HiFiLit (link below).The EIA manufacturer's "secret" code is explained at
www.webervst.com/codes.html and links therein.The RP-302's are indeed quite valuable.
all the best,
mrh
The 402 is a 4,000hz crossover, the m1131 is nothing I've ever heard of, and the RP-302 is a relatively rare 'super-tweeter' which can go for as much as $200 each. The serial numbers you mention assert the manufacturer, Jensen (220), the year of manufacturer, 1958 (8) and the week of the year of manufacture, (15, 17, etc). If you can find a second RP302, you've got a great high efficiency tweeter pair. You wouldn't think so to look at it, but I swear it's true!!
I have eather 3 of 4 of those tweeters that were left over from my father. I had no idea that they were so valuable!
It's kind of an accident of history. Most high efficiency horns are large bodied guys with turnover frequencies in the 400-1200hz range. Now horns amplify real well, but they don't really have a wide bandwidth, which was okay for the high fidelity standards of 50 years ago. However, by todays standards those large honkers give it up above 10,000hz or lower. There really aren't many vintage, high efficiency, high frequency drivers and horns because no manufacturers thought it would be necessary. Maybe the Electrovoice T-350 or, to a lesser extent, the T-35. That's it. So, the RP-302 has become valuable by default. It's sort of humorous. It has the same Alnico V magnet as the RP-103, which isn't worth much because the RP-103 horn is tuned down to 1,000hz. But the RP-302, which is tuned to 4,000hz, which means a much smaller horn, is more useful in a three way system. Cool,huh!!
That is cool! Is there any reason they are still sounght after. There is a lot of stuff out today that will do over 4Khz.
Let me give you an example. My big Altec speakers are two way; a 15" woofer and the 811 horn that crosses over at 800-1,000hz. This was a standard package from Altec. A more desirable system would have a beefier 15" driver with the 511 horn. Now that's the better one because it can cross over at as low as 500hz. The only reason why I mention this is because I know that my system has difficulty above 8,000hz, so I know that the 511 based system is going to be worse than mine. And while there are tweeters out there that can produce a strong output above 4,000hz, there aren't any that can put out, using only passive components, at somewhere close to 104 SPL with one watt at one meter.It's not the frequency range itself that's the problem, it's the frequency range and the high efficiency to match those big horns with their 16 lb drivers. JBL have a couple of good tweeters that can play high and are efficient, but they really cost a fortune. The little Jensen is an affordable alternative and often they show up unexpectedly for real cheap. For instance, there's one up on the ebay right now listed as RP 320 that will probably go cheap, being incorrectly listed.
I am familiar with the Altec drivers you mentioned but had not considered them to be used with the Jensen tweeters. Now you've made me want to keep the tweeters and try them out with some 1-2" compression horns and pro woofers! I know were there are some VOTs that I could probobaly snare for cheap. I can't use those huge cabinets but I could put the woofers in a BR and go from there. Even if I can't get those, there are lots of vintage pro drivers floting around. What are the HF limits of the Jensens?
Dave, I used the Altecs just as an example. My high efficiency system is from an Altec Valencia. Whenever you try to mate a conventional woofer with a compression driven horn, you're going to have to attenuate the horn. In the Valencia, the crossover into the horn is a 12db type which uses a series cap and a parallel coil, but that crossover is into a series 20 ohm fixed resistor and a 25 ohm pot before the driver. Now I didn't use the stock crossover, opting to set up a 6db crossover and using fixed resistors. Using a spectrum analyser, I got pretty good results with a 5uf cap into a series 10 ohm resistor and a 10 ohm resistor in parallel with the 16 ohm driver. This gave me a 16 ohm load which matched the output of the 15"woofer. So, then I started auditioning high frequency drivers. I tried Advents, Dynacos, EPI's, even EV T-35's and found that as soon as I set up a cap small enough to mate to the midrange horn, the output of the tweeter was reduced to nothing. The only two kinds that I had which had a chance in hell of working were the RP-302 and the Motorola Piezo tweeters. I only had one RP-302 when I set up the system so I wound up going with the Piezo's. However, the RP 302 does work.The RP-302 was used in the Jensen G-610, triaxial 15" driver which cost abut $250 in the early 1950's. It was used in their top of the line Tri-plex system and was optional on the 12" Concerto. If you want to see pictures of the Concerto, Henrybastardo has posted pictures of his on this actual page. Now on Henrybastardo's speaker, there was no RP-302, but in the view from the back, you can see the bolts on the front baffle which would enable an owner to upgrade with the optional tweeter. It's located just to the right of the mouth of the midrange horn, viewed from the back.
Anyway, I don't have any info which would offer you modern specs, but this is what they offered in 1952...
Thanks for all the info! I think I should play around with these!
...One bid @ $150 (at time of this posting) indicates to me that the seller probably knows something about this thing. Another reason it won't go cheap: You've advertised it here. A third reason it won't go cheap: Seller did get designation correct in the description and any experienced auction troller ALWAYS searches "title and description". A fourth reason it won't go cheap: Now that its been outed, Asians will be bidding. Asians seem to appreciate these gems more than most and are willing to pay the price of admission.
Sorry, Steve. I feel like I should apologise to someone, but I don't know who that would be.I should say, though, that if you think $150 is cheap for RP 302 horns, you should look around a bit. The second RP 302 I got from a friend of mine who had listed his on ebay under the title 'Jensen Tweeter', and it received no bids for a week at $19.95. So rather than throwing the tweeter out, he gave it to me.
Besides which, I heard recently that someone had 4 or 5 of these tweeters just hanging around, and didn't know what they were worth. I would like to tell you who I heard it from, but I know how you feel about proprietary information. Perhaps I should just point.....^
See how silly it gets?:)
Just pointing out that the art of searching for desired items on epay and elswhere is very highly developed. One of the techniques is to consider all of the possible ways of misspelling/misdescribing the object of your desire and conducting searches on them. Certainly you must be aware that serious flippers troll the forums for leads such as this. I'm sure that person you're reluctant to reveal has already had a few PMs from hopeful buyers. Are bargains to be had? Absolutely, but I suspect they're far less common than they used to be or that anecdote on message boards would have us believe.My main intention of the post was to point out to any hopeful but inexperienced RP302 desiree that it probably won't come cheap. It was also a maybe-too-highly disguised rant against the extremely competitive and sometimes nasty environment that vintage audio has become. I already have my quota of RP302s and don't need to find-n-flip to survive so I guess you misunderstand my feelings about "proprietary information".
This is why I resolve to:1. Never again post a "Hey did you see this on ebay" until after the bidding is over, and probably not even then.
2. Seriously work on my compulsion to wax poetically about how great I think this vintage piece of gear is or that piece of gear.
3. Will keep posting in BIG BOLD letters how much wonderful vintage gear can be hand on the cheap at thrift shops and garage sales.
4. Will faithfully point out to overpaying ebayers "Hey its not that great of a deal if you factor in the shipping".
Hmmm....thought I could at least get my top ten. Guess I'm not Letterman.
I believe there are still "great" deals to find if you look for them. They are getting fewer though.
Sounds like I should be glad I have mine already! Disregarding retail price, how good do you feel this tweeter is?
IMO and only IMO, the RP302 is probably the best sounding of the vintage HF horn drivers. Blows away anything from EV or University. Even holds its own with modern horns in terms of clean, effortless sound although it can't compete in terms of ultimate SPL/power handling. Others may justifiably argue that other devices such as the Decca ribbon or exotics like the Dukane Ionovac are better. They're rarer and more costly too. The usual disclaimer: YMMV.
That sounds like strong praise to me! Thanks!
This post is made possible by the generous support of people like you and our sponsors: