Discussion in 'Speakers' started by scribby31, Jun 26, 2010.
Any feedback on these mid-70's speakers? How do they rate?
They are very good speakers. Nice well constructed oiled walnut cabinets and surprisingly good sound quality. The level controls will no doubt need to be cleaned and replacing the crossover caps is also overdue by now. Both are very easy and inexpensive things to do. The Optimus 5B is a close cousin to the highly regarded Nova 8. There is a lot of information on AK about the 5B and the Nova 8s. Search and you will find a lot of good information and owner reviews about them. Check the 1976 RS catalog for the specs. I am not on a computer that has the link to the online RS catalogs but I am sure that someone else will post it.. (Try radioshackcatalogs.com, that might be the site, I just don't recall at the moment.)
Howdy, scribby......Prepare to be deluged with response.....
Radio Shack speakers have recently made a big splash here on AK, as well as elsewhere......I suggest you use AK google search for Optimus 5b speaker....and see what pops up......
AK member franksta Had(?) a pair of these (along with 49 other pair at the time...he had to thin the herd)....He may jump in to comment......
I haven't heard this particular pair myself, but I am very happy with my Realistic Optimus 25 pair.....The problem is that RS speakers were sourced from several different manufacturers, and the range is not totally consistent thru all models..... Most opinions rate them at least ..Good to VERY (surprisingly) Good....
I would give them some thought.....read up on 'em...Vintage RS speakers almost always offer very good ( if not outright fantastic) value in today's market....
P.S. See....Ultra-Hog beat me in, and has knowledge of this particular model.....He likes 'em....more to follow, for sure........
I'd certainly give them a try. Afterall...
I used to have a pair of them. Here is the instruction manual from them. Before that I had a pair that looked like Optimus 5's but had no ID on them at all. They sounded about the same.
I made a big mistake selling mine just a few years after I bought them.
Got to love that 20-20KHz spec Yeah, right...
They were "inspired" by the KLH Five.
pg 46 of http://www.radioshackcatalogs.com/catalogs/1976/
Great all around speakers.
It would be more like kissing cousins with the Nova 8B.
Optimus 5B share the same configuration including the woofer with unique ceramic type reinforcement around the dust cap.
They should be had cheap.
I have a couple of pairs. They are surprising performers. I recently replace the tweeter on one pair and they are in rotation at this very moment (in the man cave). They sound great and the tweeter replacement provide a significant improvement.
Any one here aware of a 5b crossover modification? Or, what is the crossover design of the Nova 8s? The 5bs have a very simple crossover. I suspect that the 8s (with the very same drivers) have better crossovers. I would like to experiment.
I have a pair of Optimus 5's (not b) that I brought back from the dead. The 5's send the midrange signals to the mids and the tweeter plus the tweeter gets the HF. I don't think the 5b's or Nova 8b's do this however.
I re-capped mine and replaced the non-working tweeter with Vifa domes. They sound great. Very well built cabinets with good bracing and imbedded nuts and machine screws to anchor the drivers. Good luck with yours as these are fine speakers.
Here's an 8B crossover.
Here's another interesting quote about the crossovers:
That said, I loved the Nova 8Bs when I had them and thought they did equally well with all types of music: Jimi Hendrix, Firesign Theater, Andre Segovia, Les McCann, Tangerine Dream, Alan Parsons, Crosby, Stills, Nash & Young, Lennon, Beatles, etc. I gave away the Nova 8Bs because the lattice grills were perfect for a family of finger poking youngsters. I still look upon them as the reference. Are my current speakers better or worse, detail and sound wise?
Don't scoff at the 20-20khz claim. There's an explanation involving error tolerances which I can't explain. All I can say is thiis was before Home Theater and a subwoofer was commonly required for thunderous lows with those now the rage puny satellites. With the 12" woofer (ok maybe 10-11") that took bass down to where I still had complaints from the apartment manager. Of course I also had a smaller pair of 8" rear speakers which might have helped. Picture window vibrated and your skin tingled. but then it could have been the drugs. Just kidding... kind of...
I did get some 5Bs since the above post. And they sound close enough to the Nova 8Bs for my memory. I may do the caps though.
Here is the 5b crossover, very similar. 4.7 microfarad cap on the left (for tweeter) and 10 microfarad cap on the right for the mid. Different resistors, but probably not a significant difference.
Thanks, I was assuming (different superior) electronics on the 8.
BTW, ya gotta love this place.
I wonder if resistor values are any different. The 8B has, left to right: 6Ω, 4Ω, 4Ω & 6Ω. Can't quite make out the 5B values.
Both 5B and 8B cross over at 1kHz and 7kHz with 3 position mid and tweeter level switches. The earlier Optimus-5 crossed over at 1kHz and 5kHz (Nova-8 at 800Hz and 5kHz) with mid and tweeter level adjusting pots or L-pads.
The B model woofers run free. A possible crossover mod to play with could be a low pass filter for the woofer. May or may not offer some benefit.
Noticed that the 5B in the '76 catalog's picture has the cast alloy basket woofer of the 5 (and 8) rather than the steel basket of the 5B and 8B. I wonder if they just didn't have an updated picture yet when they put the ad copy together, or if the later woofer was introduced mid-production. Anybody had/have cast woofers in "B" models?
In those xover photos, I'd slip some electrical tape between the cap's lead and the coil's lead to be sure. That's too close for comfort.
But of course, I admire the old Realistic label.
VG speaker that stayed in my line up for a long time until other vintage speakers came along. Would not pay too much for them but you will be happy with them if you pick them up and they are in good shape.
the 5b resistors, from left to right - 6Ω, 4Ω, 4Ω & 6Ω.
Year's ago my older brother managed some Radio Shack stores and I sometime's helped him out with late night inventory's. We alway's had music cranking pretty good, and it was alway's the Nova 8B's. We had our choice of lot's of other's, but these really stood out. Didn't like the Mach One's at all.
I have a pair of Optimus 5's, what's different from these and the 5b's?
AFAIK, differences are in the woofer and crossover.
Your 5 woofer should have a cast alloy basket.
5B went to a stamped steel basket.
(this example purloined from the net; possibly even from AK)
Your 5 should cross over at 1kHz and 5kHz, and has continuously variable level controls for mids and tweeter.
The 5B crosses over at 1kHz and 7kHz and uses 3 position switches for both mids and tweeter level control.
I own a pair. They are what got me into the vintage sound!
Like others said they are pretty damn decent. Personally I find them a bit dull (compared to my Advents) BUT I have yet to recap them and that is most likely the issue.
While they are no longer my main speakers they still remain as sound reinforcement for my Advents, along with working as stands for my Advents!
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