Hi
I recently bought a pair of beo 45 it says: Beovox s45, HT S45 type 6302, on the back side. I don't know much about beo's speakers, but these seemed okay (they were cheap too). My plan is to give them to my son, but before I do I'm gonna change the caps, and maybe resistors. I might give them a touch up on the exterior as well.
It seems the original caps are still in them, must be over 40 years old by now... I guess they are electrolytic, just by looking at them. What would you do, go for some fancy schmancy caps or just get caps from the beo spare part site? My gut feeling says mid-range like polypropylene caps. If the resistors gives me good measures I think I'll stick with the old ones. Finally I think I'm gonna stick sound dampening to the interior as I've liked the results in prior speaker touch ups I've done.
Any advance on how to proceed would be highly appreciated!
I recently bought a pair of beo 45 it says: Beovox s45, HT S45 type 6302, on the back side. I don't know much about beo's speakers, but these seemed okay (they were cheap too). My plan is to give them to my son, but before I do I'm gonna change the caps, and maybe resistors. I might give them a touch up on the exterior as well.
It seems the original caps are still in them, must be over 40 years old by now... I guess they are electrolytic, just by looking at them. What would you do, go for some fancy schmancy caps or just get caps from the beo spare part site? My gut feeling says mid-range like polypropylene caps. If the resistors gives me good measures I think I'll stick with the old ones. Finally I think I'm gonna stick sound dampening to the interior as I've liked the results in prior speaker touch ups I've done.
Any advance on how to proceed would be highly appreciated!
I've dealt with these. The capacitors are NP electrolytics and I would replace them with modern equivalents. There's little point in changing the resistors.
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The S45 6302s are "Uni-Phase" loudspeakers. The midrange driver was designated as a “phase link” unit, and was intended to reduce phase distortion.
The technical details are here: https://www.tonmeister.ca/wordpress/2015/10/29/bo-tech-uni-phase-loudspeakers/
Nice site! He's pretty straight forward inhis analysis. However, I find that with speakers and sound systems a solid transfer-function isn't always enough, the devil is very in the details; dampening, caps, resistors, routing, wiring, etc.
When I look at the schematics it is however not crystal clear that there are 2 2d order Butterworth filters in the xover..?
I might! I'm not really short on $$. Is the difference noticeable?
Edit, I would opt for Jantzen in that case.
Edit, I would opt for Jantzen in that case.
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There is likely to be an audible difference between electrolytic and film.
If money is no object, I suggest you try both types and decide which arrangement sounds best to your ears.
If money is no object, I suggest you try both types and decide which arrangement sounds best to your ears.
In the mid and high region you may notice a difference. I never found any film capacitor sound worse than electrolitic.
With these speakers I would go with good industrial film caps. You often find some good quality as surplus on ebay.
Most boutique brands are just rip off.
Resistors usually don't wear. If they measure right, just keep them, just like coils.
With these speakers I would go with good industrial film caps. You often find some good quality as surplus on ebay.
Most boutique brands are just rip off.
Resistors usually don't wear. If they measure right, just keep them, just like coils.
I'm trying to source the things I'm looking for. Doing so it seems I just stumbled upon the first tricky part of this project.
What, exactly, are you finding tricky?
If you are UK based, I can suggest a supplier of sensibly priced, but good quality capacitors - both polypropylene film and bipolar electrolytic types.
There's no need to go overboard with esoteric components. 😉
If you are UK based, I can suggest a supplier of sensibly priced, but good quality capacitors - both polypropylene film and bipolar electrolytic types.
There's no need to go overboard with esoteric components. 😉
Na, it's just that it seems hard to source all parts from the same vendor. A lot of them don't have the items on shelf currently.
I'm in Sweden, and I think I've found a vendor that have everything in stock.
The exterior looks fairly okay, with some minor dings here and there. Currently my plan for the interior is to replace caps, and rewire the circuit, it looks as if it was wired by a chimp. On the exterior I'll replace the grill fabric, sand the wood veneer and give it a re-varnish, I'll wet sand the alu rim to make it tidier. Also, I think I'll add a banana jack somewhere on the back.
If the veneer sanding goes south, I'll replace the veneer altogether.
I'm in Sweden, and I think I've found a vendor that have everything in stock.
The exterior looks fairly okay, with some minor dings here and there. Currently my plan for the interior is to replace caps, and rewire the circuit, it looks as if it was wired by a chimp. On the exterior I'll replace the grill fabric, sand the wood veneer and give it a re-varnish, I'll wet sand the alu rim to make it tidier. Also, I think I'll add a banana jack somewhere on the back.
If the veneer sanding goes south, I'll replace the veneer altogether.
I don't know how these will sound with functional capacitors... What's your take, are they well balanced when it comes to bass/treble response? From my experience the bass response often needs a dB or 2 in older speakers to sound more balanced. Do you know the inductance in the coils in the circuit? It would help me a lot in the calculations if I feel like alter the xover.
Checking back, it was the two-way Beovox S45 (see attachment) that I dealt with.
That particular S45 was manufactured 1983-1986, whereas your S45 is an earlier model manufactured 1976-1977.
So, unfortunately, I don't know the value of the inductors in your model.
You could invest in an LCR meter like the one attached.
That particular S45 was manufactured 1983-1986, whereas your S45 is an earlier model manufactured 1976-1977.
So, unfortunately, I don't know the value of the inductors in your model.
You could invest in an LCR meter like the one attached.
Attachments
Well, I'll see how they sound with new caps for starters, if I'm not satisfied I'll look into the xover. Without all the component values, like coils, I can't calculate the transfer function I need for a Bode plot.
I just ordered something called: Beovox Front Grill Locking Pin. Both front panels where kind of loose and it turned out to be snapped locking pins.
I just ordered something called: Beovox Front Grill Locking Pin. Both front panels where kind of loose and it turned out to be snapped locking pins.
Yours have a bit lighter in the veneer color. Looks really good! The pair I'm tinkering with are a bit to dark i think...
Long story short, the two-way S45 speakers that went through my hands had been carelessly stored in damp conditions and I deemed them unworthy of renovation. The rotted foam surrounds of these particular mid/bass drivers were just the tip of the iceberg - the enclosures and contents were "foosty", a word we use in Scotland which means extremely mouldy or musty.
However, I retained the matching stands and the crossover components!
P.S. Given the unusual arrangement of the 'midrange' driver being used as a 'phase response corrector' between the mid/bass and treble drivers, I would not alter the crossover circuit. I would favour simply replacing the old electrolytics with modern electrolytic equivalents, as this would be the action most likely to restore the sound balance of the speakers to that which the designers intended.
And, I would replace the capacitors in just one of the speakers first so I could gauge the difference the new caps make.
