Technics SB-4000 Phase Linear

Spied in local thrift in half-way decent condition for $20. I've found minimal info searching the net including AudioKarma (and what is there seems pretty mixed reviews).

Unverified specs I found:

- frequency response of 40Hz - 20kHz
- sensitivity : 90.5dB / 1W / 1m
- nominal impedance of 6 ohms for 50W - 70W RMS power handling
- Bass reflex ported 2-way staggered configuration phase linear design
- Dimensions 22 x 11 x 10in

- found an ad from 1979 - sold for $250 (Canadian) a pair

The cabinets seem decent. the speaker grills and frames and badges are intact but could use a recover. The drivers visually seem fine (and treated cloth surrounds on the woofers so no foam rot). However, there is acoustic foam mounted under the tweaters that is missing on one speaker and damaged on another.

Anyone have any experiences / comments? Should I save them? Any ideas what the foam could be replaced with?

I have a pair of MCS branded speakers that are exactly like those. They're OK but nothing special. IMO that makes them worth $20
The question is do you have need for a pair of $20 speakers?

Well, I decided I didn't need $20 speakers, but actually I was looking at a couple items yesterday in that thrift and must have messed up writing down the price. I dropped by again today and they were actually $12.99 (Can) = $10.65 (US), plus tax .... so I bought them.
They are labelled on the back 6-ohm, 50W.

We will see what they are like.

Sigh, tweeters are dead.

SB-4000 Speaker - Tweeters?

Anyone have any ideas of where to source some new tweeters - or something close?

They are labeled EAS-6PH01S. 6-ohm speaker with paper cones about 2-5/8 inches in diameter (I think - will have to remeasure and take pics when I get home).

I am a bit concerned about why these things blew - I suppose I should try to check the crossovers? They are only 50W speakers so perhaps someone decided to try their 100wpc HT "theater in a box" amp on them?

Further Specs on SB-4000?

Anyone know what the crossover frequency is on these? I am thinking of finding a set of non-technics tweeters to fit to these. Any suggestions?

Thriftstore finds are the best for a swap!! Find a set of speakers with rotted out woofers cheap!! Make an offer on them! I do it all the time...you'd be surprized what you find sometimes...Lots of good Danish Vifa tweeter out in our area!! Where are you? ...on The Island?

Yup - God's country - Victoria (currently getting covered in snow!!!)

Well, I am thinking of these:

Pioneer replacement FP66AP45-54

Outside Dim....................73 x 73 mm
Impedance...............................8 ohm
Power...............60 W / 12 db / 5 KHz
Freq. Resp................2 KHz - 20 KHz
Magnet Wt ..................................2 oz
Voice Coil Dia .........................13 mm
SPL...........................................93 db
Depth ......................................32 mm
Baffle Opening........................64 mm
Mtg. Cntr.....................79 mm BC x 4
Min. X-over ..................2 KHz / 12 db

Stylewise and sizewise they are very close to the original paper cones. I thought about a small set of horns but this I believe would throw off the time-alignment of the speaker. Plus a lot of the speakers I have located have had zero technical data - frequency response for example - and since I don't have full specs on the original units .....

I realize they are 8-ohm. From what I understand this will raise the crossover point slightly. I thnk the crossover on the SB-4000 is 2kHz (not sure where I picked that up but I have it in my notes). I guess it all depends on where the woofer's rolloff is in comparison to the crossover. I also see from the Vintage Technics site that the SB-4500's sensitivity is 91db - I expect the 4000's would be basically the same, so these replacements should match that OK?

Plus these pioneer units appear in a local electronics supplier's online catolog for a mere $8.20 each. I have to call to check if they actually have them.

I have to check the crossovers (something caused those original tweeters to fry - maybe just old age - maybe not) ... and will probably recap them.

Anyone suggest any other options?

I actually picked up a pair of Paradigm 3SE Mini's for $10 at a local SA, that have a 6-ohm Vifa tweeters in them (the tops and bottoms of the face plates of these are even flat so the would fit into the SB-4000's like a charm). While I realize the Vifa would blow these Pioneers out out of the water once I cleaned up the mini's they look pretty darn good - just need new foam on the woofers - no way I am going to part those out!

I had a pair of SB-4000's one time. I thought they sounded like ****. I got rid of them.

Those are perfect candidates for the EconoWave.

When you are checking the crossovers, disconnect the tweeters and see if they make any sound when hooked up full range (at very low volume, obviously!). It could be that the caps crapped on them.

The new tweeters work fine. $8.80 (Can) + tax each!

I checked the caps on the crossovers. 4.7uF. They read 5.10 and 5.17 on my elcheapo multimeter and all other continuity on the boards and the inductors seemed fine. I have not replaced them yet as my local electronics supply store was out of that size.

The old tweeters both tested at 0 ohms on the multimeter - and not a peep out of them.

The only things I had to do to get the new tweeters was use a drill to expand the spacing on the mounting holes slightly, and crimp on wider spade lugs on the positive leads.

I'm going to run these speakers for a bit of time on my Sansui AU-4400 ... while I am refoaming my Mirages and Advents.

p.s. thanks help guys (.... most of you had helpfull suggestions )

I run a few dozen albums through them and overall not too bad. Jack Bruce's Harmony Row on the TT right now - old record (one of my brother's originals that suffered one too many spins on our parent's Phillips console unit) but overall the speakers are pretty good. Quite balanced overall. Of course, with the new tweaters, I can't speak to what the originals were like.