View Full Version : "new" olympus build

12-11-2004, 07:07 PM
absolutely new here, so thanks for any info you can give me. I would say that I am no an audiophile, but more like a middle of the road guy. I like good sound, but I am not buying $300 wires, if that will tell you where I am coming from. My experience with JBL is as follows: 1. when I was 16, I bought some 4311b's from a store just on a whim (they were going out of business and I got them for under 400$ for the pair). I have used them to this day and I have been pleased with them. 2: When my father in law packed up all his stuff and went to Chili for a job, he gave us some speakers to hold for my wife's brother. I hooked them up and fell in love with them, but had to turn them over when her brother came through town. They were C50 Olympus speakers. Her brother was telling me that their dad "built" them in the 60s and that he had plans for the cabinets, original from JBL. I have no idea where he got them, but if you knew this guy, it would not suprise you. He gets all kinds of info that nobody is supposed to have....I am sure you guys know similar people. Well, I emailed tonight and he still has the plans and is mailing them up in a few days. He confirmed that he built the speakers.

So my questions: I am thinking of building or have the speaker cabinets built. I have a sizable sitting room that has no sound and I like the "furniture" aspect of the larger speakers. Are there drivers and crossovers still available for the same model? I would think substituting modern equipment would be best..and if so what do you guys suggest? I will probably be using some serious watts (I would guess in the 200W per side range) to run them and that would speak more for the modern substitutes. Of course, I will happily post the plans when they arrive. Thanks again for any info.


12-11-2004, 09:54 PM
Original components and complete systems for the Olympus are readily available on eBay and elsewhere. They have long since (30 years) been discontinued by JBL, though contemporary "equivalent" and similar components are, or more recently were, still made. The basic systems were S7, S7R and S8R. The "R" versions included passive radiators. The S8 used the 375 2" midrange compression driver in lieu of the 1" LE85, and added the 075 ring radiator tweeter.

A complete S7 system pair with 075 upgrade just sold on eBay for $1026:


You'll easily pay twice that for S8R components.

Fine, if you want "vintage." However, as you're no doubt aware, technology has advanced during the intervening 40 years. Basically, you're building 6 cu.ft. boxes, and you've got lots of options as to what to put in them. No matter what, though, that overhanging top is going to be problematic, probably. Here's one approach to fixing it, LOL:


I took a stab at upgrading Olympus about 15 years ago using 4430 drivers. The 2344A horns wouldn't fit, of course, and I didn't have 4430 crossovers, so I added biradial tweeters. Here's the result:


If I were doing it today, I'd try again to make two-ways with 4430 crossover topology, using one of the new Progressive Transition waveguides for the mids and highs, PTF1010HF, perhaps:


tomp787 is also looking at JBL OASR horns in this thread:


Also, read up the various 43xx threads in the forums here. You have lots of options available for loading those boxes....

12-14-2004, 10:53 AM
Crossovers in the Olympus retros there are 3110A (800 Hz) and 3105 (7000 Hz). 3110A has built-in HF boost compensation for constant directivity horns like the 2370A. It itsn't ENOUGH boost to to obviate the necessity of adding the UHF drivers, though. Something else to fiddle with, it operates on the tweeters mostly now, as the crossovers are cascaded.

Crossover info here: http://www.jblpro.com/pages/pub/obsolete/3105-3115A.pdf

The 2426J's have additional discrete resistor attenuation after the crossovers (6 dB, IIRC) to balance their sensitivity with the 2235's.

The "notch" in the 2370A horns was done on a rotary table to match the exterior radius of the 2235H's. There's edge-mounted 2X4 horizontal bracing behind the baffle at that point, a tight fit.

I need to get an RTA in here to see if I got them anywhere CLOSE to right.

[Sound good, tho....]