Solarvox Speakers and generalpolarity question

[spm]

I picked up a pair of Solarvox TK 19 s speakers on freecycle in really nice condition. However they are fixed wire and I can see no markings on the wire. Wires on both have been intermittently painted so I wondered if anyone has these speakers and can confirm whether they have markings to see whether it is worth trying to remove the paint. I suspect they are not marked given I can find no markings on unpainted sections of either speaker wire.

The other problem I have is that there seems to be no way to get the covers off these speakers without damaging the cabinets or covers which would be a real shame so if there is no markings and no way to see the speakers is there anyway to determine the polarity?

Sean

[Firebottle]

The ultimate polarity doesn't really matter. To match the polarity of the two speakers place then facing one another quite close together.
Play some bass heavy music, when they are in matched phase you will hear good bass, when in antiphase the bass will be a lot less.

Hope this helps,
Alan

[spendorman]

You could try laying the speaker on its back, placing a piece of A4 paper over the area where the bass unit is, connect a 1.5V battery to the speaker.

If the paper moves away from the speaker, the wire that is connected to the Positive end of the battery, is Positive.

[spm]

thanks for the suggestions, Ill have a play.

[spendorman]

Another way is to carefully push a needle through the speaker cloth so it just touches the speaker cone, connect a battery as mentioned before, see if the needle is pushed out when battery is connected.

But the easiest way is to place the speakers facing each other, about an Inch away from each other, you should still get bass if connected correctly, reverse the connections to one speaker and then bass will tend to cancel out.


There seem to be two Solavox brands, common in the UK was the Solavox sold by Comet. Was a cheaper range of equipment. I have only experience of their amplifiers, and they were quite good, appeared to be very similar to Teleton, which was made by Mitsubishi. I have a feeling that the speakers were not up to the standard of the amplifiers. Some info here:

http://www.vintage-radio.net/forum/showthread.php?t=77181

[spm]

thanks for the help. I did the paper trick but had to use a 9v battery to see the paper move, probably took a risk with the extra voltage but seems ok. I wired them up and had a quick listen before dinner and my first thoughts were that they were ok, not great but not bad. After dinner I compared them directly with some Castle Clydes and perhaps not surprisingly there is quite a big difference, the Clydes seem much clearer and warmer. The Solarvox seem best at fairly low volumes and sound a bit bright and not as clear as the Clydes. At moderate to high volume they sound harsh to me.

I did a bit of googling at lunchtime and someone on a forum suggested they are likely to be made by radionette with Seas drivers. Radionette appear to have made TK 18s and TK20s.

They look nice and if a bit smaller I might be tempted to keep them but will probably look to give them away after playing a bit more. I will also look to double check they are in phase using the alternative test with them facing each other.

Sean

[spendorman]

thanks for the help. I did the paper trick but had to use a 9v battery to see the paper move, probably took a risk with the extra voltage but seems ok. I wired them up and had a quick listen before dinner and my first thoughts were that they were ok, not great but not bad. After dinner I compared them directly with some Castle Clydes and perhaps not surprisingly there is quite a big difference, the Clydes seem much clearer and warmer. The Solarvox seem best at fairly low volumes and sound a bit bright and not as clear as the Clydes. At moderate to high volume they sound harsh to me.

I did a bit of googling at lunchtime and someone on a forum suggested they are likely to be made by radionette with Seas drivers. Radionette appear to have made TK 18s and TK20s.

They look nice and if a bit smaller I might be tempted to keep them but will probably look to give them away after playing a bit more. I will also look to double check they are in phase using the alternative test with them facing each other.

Sean

On the Vintage site one guy reckoned that they were Leak cabinets with end of the range Wharfdale drivers. Main thing is that they sound OK.

[spm]

The ones I have say made in Norway on them so I guess that rules out Leak/Wharfedale but it was suggested somewhere I read this afternoon that there was a change in manufacture in the mid 70's, possibly at the same time as dropping the letter r. The info on the stickers on the back of the speakers is similar to the info given in these links albeit the Solarvox say 8 ohms

http://www.hifisentralen.no/forumet/vennetra-der-hifimerker/77046-radionettes-fanklubb.html

post 7 and in the following.

http://www.mypaper.se/show/radio-tv-bladet/show.asp?pid=345248697265856&page=18

Also in the first link the Solarvox I have look very similar to those shown in post 2. Not that it matters greatly but I find it all quite interesting, just wish they sounded really good rather than ok.

Sean

[system7]

I would think you can get the grilles off the Solarvox TK 19S speakers easily enough with a blunt knife. I'd guess they might be stuck on with 6 blobs of glue.

These look like Tandberg speakers with a bit of badge engineering similar to the 4 ohm 20L Radionette TK 18S and TK 20S. I'd guess they departed from the usual 4 Ohm DIN specification for the 8 ohm British market. 8" SEAS 21TV-GW 8 ohm bass, and 3.5" SEAS 9TV-LG 15 ohm cone tweeter crossed at 3kHz.

Quite a nice combination, though you might fit an extra smaller cone supertweeter for the top end if you wanted to get them just right. Visaton TW70 and Monacor HT22-8 spring to mind.

Those drivers might even be AlNiCo.

Obviously some cost cutting has been done here, but the bass with a corrugated surround looks well suited to a closed 20L box. The tweeter may be closed back. With some crossover work, I'd reckon they could sound very good. Because the crossover is likely the bit that has been skimped.

The thing I like about this sort of project, is that for a fun hobby and an outlay of about £50, you are really getting a £600 speaker at modern prices.

Those old drivers were really rather good, and 8" bass is quite easy to improve. Troels Gravesen does interesting things with your drivers here:
http://www.troelsgravesen.dk/blackcones.htm


14851

[spm]

Steve

thank you for the response. I can't say I'm really up for the modding challenge, I can just picture bits of speaker and broken grilles lying around what is supposed to be the kids playroom for months. I also have a tendency to google things to death so would probably lose days of my life seeking the best components/things I should be doing. I should also say that I recently took some persuading to change a bulb in a vu meter on a tape deck.

I am however intrigued as to what you could do to these speakers and wonder whether you would be up for the challenge. The speakers are in pretty good condition and it would be good to understand the extent to which they could be improved - it might be with a different set up to mine they sound pretty good in the first place. If you were willing to post a step by step blog with pictures of the modifications I would be willing to donate the speakers. I would also be willing to pick up the postage costs to maximise the budget you might be willing to spend on the components to get the best results.

Let me know if you are interested.

regards
Sean

[awkwardbydesign]

Go on Steve. You know you want to! And I have a load of polyprop, polycarb and polyester caps I could donate. Plus a bunch of ceramic or Jantzen MOX resistors. Maybe even some inductors.
Go on!

[system7]

Well, I really can't adopt every stray cat that wanders past my door. :)

I have my own projects to get on with. But I hope spm might appreciate he has picked up some "Gold Dust" there.

http://www.troelsgravesen.dk/blackcones.htm

I'm struggling to attach an image to this post, but the 8 ohm filter looks like below. For a 15 ohm tweeter, you halve capacitance and double inductance and resistance. You probably won't need the series resistance on the tweeter circuit.

I'm gonna post and hope it works.

[spm]

A fair point Steve. I'll do some reading and see whether I can whet my appetite but don't hold your breath.

Sean

[spendorman]

Definitely a Wharfedale look to these ones, were a bargain price:

http://hove.greatbritainlisted.com/audio-video/solavox-pr30-hifi-speakers_3562003.html

[walpurgis]

Solarvox did use Wharfedale drive units for a while. I'm sure their products were OK, but they were at the budget end of the market and not regarded as serious contenders in the Hi-Fi game back then and were avoided by the audio buffs (certainly by me and my friends). The cheaper Wharfedales had much the same lack of cache (Dentons and Lintons? Yuk). I don't recall ever seeing a mention of Solarvox in the Hi-Fi press. They were nowhere near as ghastly as the Amstrad speakers of the time though.

[spm]

Spendorman, those are Solavox after the R was dropped. Mine are the same as these

http://www.ebay.de/itm/rare-Vintage-Tandberg-SolarVox-TK-19-S-speakers-Made-in-Norway-nice-condition-/281375299230?nma=true&si=Cu%252ByfpCcmUKnN2eZ%252F16fBjdmRu4%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

The description is in English and you can see the made in Norway label with other data on one of the photos. Not saying any better or worse than the later ones. As I said earlier don't sound particularly great at the moment but I think Steve is suggesting that the drivers can work very well if set up well.

Sean

[system7]

I'm quite familiar with Tandberg designs, which were usually very good. They'll sound a whole heap better with a proper crossover! These things often just had a simple 3.3uF capacitor to the tweeter. Not good enough. :)

The bass section is quite sophisticated with a 9kHz notch, and rolls off the harsh cone breakup around and above 5kHz. It has a a tidge of bass boost too, aka bafflestep. The tweeter section is a 3rd order 3kHz KEF design that wires in negative polarity. It filters out the low frequencies that make a tweeter sibilant. It's always worked well for me. Very clean sound.

You can get most of the hardware at Maplin, including a 40W soldering iron and cables and zip ties and wire-ties. Maplin have a good stock of 10W wirewound resistors and that 0.33uF capacitor. I use tagstrip for the soldering.
http://www.maplin.co.uk/p/5-way-tagstrip-fm34m

The Crossover components are available from Wilmslow Audio. I use ferrite inductors on the bass, and air coils on the tweeter. Capacitors can be 250V MKP:
http://www.wilmslow-audio.co.uk/bits--pieces-16-c.asp

Get within 10% on component values, that's near enough. And keep the product of inductance and capacitance the same if you struggle for exact values when doing that 15 ohm conversion, which keeps the filter frequency the same.

[spm]

Steve I am getting interested in giving this a go, the fact that I could build the crossovers before I touch the speakers gets over the problem of having bits lying around for ages.I would at least make sure I can get the grilles off first! I could only find a 7W 0.33uF capacitor on Maplin, would that be fine and 10W for everything else? I already have a soldering iron albeit only 15w. I'm also thinking it would be good to replace the crossover in one speaker and then do a mono test of both speakers to see how much of a difference I can detect. What wire do you use for the connections?
Sean

[system7]

I think you'll enjoy this. But see what crossover is currently fitted. It often gives you a clue what levels will need adjusting.

Modern tin solder needs a hotter 40W iron than the old lead stuff. You must also tin the irons' new tip THE FIRST TIME IT WARMS UP. Once it oxidises, it's done for, kaput! You can't sandpaper the dirty tips like you did the old copper ones. It doesn't have flux either, so your wires must be clean AND UNOXIDISED. In and out in 5 seconds is my approach. If you leave component leads long, there is less risk of heat damage and you can reuse them more easily. Capacitors are fragile, coils and resistors are tough as old boots.

http://www.maplin.co.uk/p/40w-soldering-kit-n90ll

I use 22swg tinned copper wire from electrical wholesalers for hookups. 24A rating. Quite honestly, 15 and 30A fuse wire is the same stuff, if you have it lying around.
http://cpc.farnell.com/1/1/54505-tinned-copper-wire-22swg-tcw22-500g-unbranded.html

This 42 x 0.2 speaker cable is quite adequate for all uses, though I have a lighter weight one I use on tweeters usually, because it's easier to to fit in the tagstrip holes along with the components:
http://www.maplin.co.uk/p/hd-speaker-cable-20-m-drum-white-n20ap

Lastly, the capacitor I was thinking of was this 330nF (aka 0.33uF) MKP polypropylene:
http://www.maplin.co.uk/p/lcr-audio-grade-polypropylene-axial-630v-330nf-capacitor-vm89w
You could possibly use a cheaper chunky MKT 100V polyester here too. A 630V capacitor is slight overkill IMO. Maplin's higher value 630V capacitors are way too big for convenience!

The only select on test component is the red resistor tweeter level. Each 2 ohms takes a 15 ohm tweeter down a dB. 3dB is half power.

[spm]

confession time, I've wimped out of modding the Solarvox speakers. Someone came round to pick up a 70's pioneer amp today and was taken with the speakers during testing so I let them go. I wouldn't rule it out if something else suitable cropped up, but preferably something easier to get into. Interestingly I couldn't resist a Sansui amp and Mordaunt Short speakers on Gumtree for a £5 on Friday. When I picked them up the speakers were MS15, they have no spec on them so I googled and the first thing that came up was Steve taking a pair apart on another forum!