Speakerlab S7s Rebuild and Modding (Ribbon Tweeter Model)

[Bratwurst7s]

I finally found some good foam to use as edge diffusion on the high/mid baffle plate. A roll of 25mm foam used for air ducts. It was easy to cut a strip in half and works out to the perfect width for both speakers from one strip. Installed it looks exactly like the original even to the medium gray color.

After getting that done I realized that I've completely neglected to post pics and measurements of the speaker grill frames. My apologies and I'll try to get that done within the next week.



Cheers,
James

 

[Bratwurst7s]

What i should do is remove the 10 and 12 inch drivers till i am done with the recap - stop me from just listening to them.

Hi Mark, did you go ahead and pull those woofers? Would you consider pulling a mid and a tweeter? If so and you want to record the tags from Speakerlab, and perhaps more importantly carefully peeling back the stickers to see whats written under them we could get an idea exactly what drivers they used and perhaps who they were made by. I could use the information to add to my history spreadsheet.

Thanks,
James

 

[Bratwurst7s]

Well. I just spent the last 3 hours negotiating with a fellow at plus-elektronik.de for new midranges and tweeters. Pretty impressive. He was willing to work at home on Friday night working out a deal, so I'm buying 2 Wavecor WF160WA01 mids and 2 of the Visaton MHT-12 ribbon tweeters. I have zero affiliation with them. Just passing on information for any AKer's in Germany to use. In the end I got some pretty damn good prices. I'm happy.

Replacing/improving the mids is for my purposes mandatory, and I guess the new tweets could be called an expensive experiment. I just want them. The best part is that my wife didn't even blink an eye. Total friendly acceptance! Of course promising her a Kindle Fire HD 8.9 for Christmas might have greased the skids a bit I suppose. Yes, it's true. I would stoop to that to improve my speakers. Shamelessly.

Cheers,
James

 

[Bratwurst7s]

As I start to measure the grill frame I realize that I made a real noob error when measuring the tweeter/midrange baffle plate corner radiuses. I measured using a diameter. A radius is half of a dia, so the corner radiuses should be 3/8" (9.5mm) and 1/2" (12.7mm) rather than 3/4" (19mm) and 1" (25mm). Sorry about that, the earlier entry has been edited.

 

[markdi]

I have done nothing to my sevens yet

I had a huge infected spider bite on my arm and now i have the flu

I did buy a haffler p 500 amp

The haffler has a huge power supply

400w rms into 4 ohms

I have not tested or hooked it up yet

Should i add fuses to the tweeters

And my clothes dryer almost caught fire

Going back to bed

 

[Bratwurst7s]

Sorry to hear that. I hope that you feel better soon. Dangerous things those clothes dryers. Gotta watch em.

 

[markdi]

What do you use to power your speakerlab s7 speakers ?

I have only used my 70wpc technics reciever.

And it seems to drive them quite well.

Sounds great and will drive most of my friends out of the room.

I bought a haffler p500 amp that puts out 400wpc at .04% thd

I have not hooked it up to the sevens yet.

I wonder if i really need that much power.

I should have used one of my many 100 to 200wpc amps.

Do you think it would be a good idiea to add a tweeter protection fuse and holder on a upgraded speaker terminal. Plate

 

[Bratwurst7s]

What do you use to power your speakerlab s7 speakers ?
I have only used my 70wpc technics reciever.
And it seems to drive them quite well.
Sounds great and will drive most of my friends out of the room.

I bought a haffler p500 amp that puts out 400wpc at .04% thd
I have not hooked it up to the sevens yet.
I wonder if i really need that much power.
I should have used one of my many 100 to 200wpc amps.

Do you think it would be a good idea to add a tweeter protection fuse and holder on a upgraded speaker terminal. Plate

The last 30 years I've only used 2 different amps. '83-'98 I had a Yamaha C-50 + M-50 pre and main amp that delivered 150wpc rms @ 4ohms, and at present have a Yamaha AX-1090 that gives 145/8ohms-185/6ohms so I'm guessing something in the neighborhood of 200+wrms into 4 ohms. It never gets turned up high enough to use all of that.

The '86 version of your DAS-7 is rated at 275wpc rms max. Your Haffler will probably be fine if you don't get carried away. You should have the DT100PF polypropylene dome tweeter. The catalog states "200 watt power handling at 3khz at 12db/octave slope". I myself would just be careful with the volume knob rather than add a fuse to the signal path, but that's a choice that you have to be comfortable with rather than me.

Cheers,
James

 

[markdi]

I should fix my laptop or goto the library and look at the speakerlab catalog again.
My tablet does not work with the catalog - blank screen.
Thanks for the tweeter info

200 watts wow i thought maybe 25 to 50 watts

How do they get a 1 inch tweeter to handle 200 watts ?

That is a little over 1/4 horsepower.

Now i want to see the motor assemblys of the tweeters and midranges.

So the speakers are robust even the tweeters.

As soon as i am done fixing my dryer and stuff i will write down any numbers and take pictures of the crossovers drivers etc for your database

Thanks

 

[Bratwurst7s]

Do you have openoffice or libreoffice on your laptop? Go here and dl the spreadsheet...
http://www.audiokarma.org/forums/showthread.php?t=557341
All the specs that I've been able to find about your speaks are in there. But a tablet probably will be to small to read it.

My guess is that they are talking so called "system power" rather than actually claim that that tweeter can handle 200wrms all by it's self. I think that your guess of 25 to 50 watts is probably more realistic.

James

 

[Bratwurst7s]

I've been having a capacitance hum in my system for a long time. To get rid of it I have tried rewiring my living room and grounding my system to the water pipes, with no success. And I've also been disappointed with the imaging of my system. When I recapped my speakers things got a good bit better, but the hum buildup was still there lightly in the background. and when I sat and closed my eyes and listened I've still not been happy with the imaging.

Yesterday I read the "Speaker wire Gauge??your preferance" thread and saw a comment by cratz2 about Kimber kabel and high capicatance. Hmnm. I have used Kimber speaker wire for 30 years. First the cheaper pvc coated line and then since 2000 the 4 wire per pole teflon coated stuff. And it never occurred to me that my speaker wire could be the cause of this problem.

So today I went out and bought some 4mm² wire (about awg 11) where my son works, figured what the heck for EUR12 it's worth a shot. But I also figured that I'd end up laughing at myself for doing it.

Oh My. The humm is gone. And much to my surprise imaging is dramaticly improved. We're not talking "I think that perhaps it's a little better". This is a clear and serious improvement. I just listened to the same Golden Earring Moontan that I listened to 2 nights ago and the difference blew me away. Color me surprised. For a tenth of the price that I paid for that Kimber stuff.

I'm very glad that I did this before my new mids and tweeters arrive. And I'm dancing around in circles waiting for them. Soon I hope.

And I can add Pyle to the list of companies that don't answer email. Haven't heard a thing from them about my questions.

Cheers,
James

 

[Bratwurst7s]

Now isn't that some timing. I just got an email that my speaker chassis have shipped! Yippee! That means that they could be here by Friday or Saturday. Probably won't sleep till then...

James

 

[GuyK]

Have you re-tried the old cables? Just curious if there might have been a poor connection that was un-noticed for some reason. Regardless, you've had some good luck recently.

 

[Bratwurst7s]

Have you re-tried the old cables? Just curious if there might have been a poor connection that was un-noticed for some reason. Regardless, you've had some good luck recently.

I'll address this in a backwards fashion. Without a doubt the best luck that I've had recently (at least in audio terms) was joining audiokarma. Being exposed to so many good ideas and people has been great, and has been enriching. Being around so many careful thinkers is forcing me to try to reduce the sloppy thinking that I've been guilty of using concerning my music system.

A few points about the old cables that I didn't think through correctly before but should have. The new cheap cable that I bought is made up of many fine strands of what appears to be very soft copper. Looking at the Kimber again I see and remember that each wire is made up of relatively few relatively thick strands of pretty hard copper. It's just not very flexable and it doesn't seem to clamp down very well. It's actually fairly difficult to work with and to get each of the 4 wires on each pole to go in the clamps an equal length.

And you are correct, when I removed the neg connection on the right speaker it wasn't as tight in the banana plug as I would like, and I remember doing my best to make them very tight when I installed those banana plugs last month. Funny thing is that it was the left speaker that I had noticed that didn't play as loud as the right. Those hard wire strands in the Kimber just don't seem to lend themselves well to a good tight connection.

And iirc soft copper conducts better than hard copper, and the electron exchange is happening along the surface of the wires, so it stands to reason that many fine soft strands would conduct better that fewer hard strands. This is something that I should have noticed and thought through before buying the Kimber back in 2000, but I let myself get caught up in the hype of it and turned on my "I'll go ahead and be stupid today" switch and paid something like EUR250 or DM250 (don't remember which) for that stuff.

Cheers,
James

 

[Bratwurst7s]

I was hoping that the new drivers would arrive today but no such luck. Mabye tomorrow. But I was able to finish measuring a grill frame and make a sketch.

2 notes not on the sketch. The cutout corners are measured from the theoretical square corner position. And the outside edge of the frame has a (approximately) 20° bevel.

And as I was digging around in a drawer today I found a sheet from Speakerlab with the S7s cabinet dimensions so I got that scanned too.



Cheers,
James

And I just saw my first mistake. The lower corners of the upper cutout are 2-3/4"" in from the outside frame edges and the upper corners of the lower cutout are 3" in from the outside edges. I'll correct the sketch and rescan it.

edit 07.12.13: modified sketch with corrected dimensions

 

[Bratwurst7s]

My new mids and tweeters finally arrived today! I'll write in depth tomorrow but for now just a couple of quick thoughts.

They are now installed and the improvement is night and day better. My fun meter is going off the scale. And my wife is out for the evening, so now I have no other choice but to shake the walls a bit. More info later...

Cheers,
James

 

[Bratwurst7s]

OK. It took an extra week for these new drivers to be delivered because DHL screwed the pooch. They reached Munich a week ago, spent 4 days going in circles without getting near my apt, and then went back north. Plus-Elektronik were helpful with finding out what happened and did a good job of quickly turning them and I was surprised to actually see my package today. I expected it tomorrow or more likely Monday.

So my excitement factor went way up in spite of having a nasty headache all day. I got them unboxed quickly and pulled the old Goldwood mids immediately. The Wavecors have the same cone OD but the cones are deeper and the domes are smaller so have a larger Sd. They are a little shorter, and the baskets actually look a good bit lighter.



I knew when I ordered the WF160WA01's that I might have to mod the baffle plates because they are squircles rather than round. I had measured the cutouts and it was close. Sure enough the Wavecors needed a little extra clearance.

I used my Dremel with a long straight carbide cutter bit and the tile grout cutting standoff attachment. That way I had a stable surface and was able to set the depth to at the point where it was brushing the main baffle plate, and just lightly contoured the area next to the clamp cutouts and rounded the corners. It was just enough to allow clearance for the mids to drop down into the cutouts without touching the edges. A router would do the same thing but the Dremel is so light and handy that it was a breeze to do, took about 20 minutes all told.

One more thing about the new mids is that the negative lead is smaller than the M654P, 2.8mm instead of 4.8mm, so I had to replace that connector on the crossover wire.

 

[Bratwurst7s]

A little black paint on the modded areas and I was ready to install the new mids. After that I decided to exercise a little patience and do a listening test before doing the tweeters. I had just listened to Steely Dan's Can't Buy A Thrill yesterday so I choose that to compare.

Goose bumps. Just amazing. Clarity, seperation, loudness, all the special words can be used. I got as far as the 4th song and couldn't handle it. If this was so good, such an amazing improvement, I couldn't wait any longer to install the new Ribbons.

 

[Valveglow]

I remember the Super 7 and liked it. Years ago, I sold Speakerlab.

 

[Bratwurst7s]

The Visatons are a drop in replacement for the LT215S ribbons with 2 exceptions. 1 - The positave lead is a 4.8mm lug rather than the 2.8mm on both leads of the LT215S so I had to crimp on a new connector on the wire from the crossover. 2 - The mounting screw holes on the MHT-12 are a little smaller than the LT215S, so i had to use smaller but longer screws or drill out the holes. Knowing that I was voiding my warranty I decided to enlarge the holes in the tweeter frame. I only have metric threaded screws and didn't want to take the chance of messing up the holes in the baffle plate. Most people would probably think that that is backwards thinking, but there ya go.

Other than that even the rubber seals that I had cut for the LT215S were a perfect fit. The visatons are considerably taller than the old tweets, and with the alluminum faceplate and substantial magnets a good bit heavier. The magnets are strong enough that when I laid my small steel ruler on the face it immediately twirled around 90°. The radiating area of the MHT-12 is also much taller, about 70mm compared to about 50mm.

One thing that I forgot to mention about the new mids is that the negative lead is actually smaller, 2.8mm instead of 4.8mm, so I had to replace that connector on the crossover wire also.