LST auto transformer Mr Kantor & AR 9 woofer crossover

[roundhome]

If anyone has one in the San Francisco area, or is willing to go to the trouble of getting one to me, I'd be happy to to measure the crossover response, and design passive networks that approximate each tap on the autotransformer. I'd only need the speaker for 15 or 20 minutes.

A 10pi might be interesting, too.

Ken Kantor

Did you do this and if you did can i have a copy please?

I can't open the AR 9 stuff with my mac and need the information. can some one send it to me Please.

last what type of problem would you have with two AR12 inch woofer next to each other in one cabinet ?

Jim:-)

[Guest]

I have a LST cross-over if you want it. It's a complete unit board, transformers, cap's, coils and all. I'll send it to you if you pick up the shipping costs. Then when your done you can just keep it. I've been trying to get rid of all the parts I've been saving.

Just want them to go to good use somewhere.

Let me know if your Interested,

ED

[roundhome]

Hello Ed

Yes i will pick up the shipping. I have two empty LST cabinets I have found two woofers and the tweeters and one mid but know cross-overs yet you will help me out alot . My Email Is roundhouse@sisna.com

Thank you

Jim

[kkantor]

Hi,

Sorry, I don't have LST's anymore. Measuring the crossover response was something I kicked myself for not doing before I sold my pair a couple of years ago.

If you need any assistance testing them, I'm here.

[Guest Bret]

Did you ever get and measure the LST crossover?

Bret

[kkantor]

No, nobody ever contacted me with a pair available. Always willing to do that kind of thing, provided the owner is willing to transport them to the lab.

[roundhome]

I got a crossover from a LST. things are a little (lot) up in the air right now. I will get time to look at it more right now i have a few ?

In the schematic it has four caps for a total of 5000 uf I have only one for 2500 uf with a strange ohmite 4761 on it not sure what this is. and this looks to be fun to figure out the color codeing of the driver wires there is a red and black pair that come strait of the board I think are the woofer but sure is small wire.

next were can you get the fuse for one of these fusetron fnm 2

would like to find a sorce for the 2500 uf cap. np.

is there any way to simulate the db range swithching of this using electronic crossover stuff like a dbx driverack pa electronic crossover

thanks

and i will get the specs out of this thing if i have to interagate it.

jim

[r_laski]

I apologize in advance for length of this post. I’m working on a pair of LSTs right now and have some of the same questions.

1- >>In the schematic it has four caps for a total of 5000 uf I have only one for 2500 uf with a strange ohmite 4761 on it not sure what this is.<<

-Both of these LSTs have a single 2500uF/60VDC cap instead of four caps strapped together for a total of 5000uF. There is no indication that these are “dual” caps in a single can.

-Ohmite is a brand name for a resistor. I don’t have a resistor mounted across the posts of the cap. However, there is a 10 Ohm 10% 10Watt resistor that is parallel to the cap leads. It is mounted to the negative binding post and one of the fuse posts. These are the same posts the leads coming off the 2500uF cap are soldered to (redundant for emphasis and clarity). This resistor is not shown on the schematic in the LST manual.

1) Does anybody know if these were ECOs (Engineering Change Orders) to the LST crossover during production that changed the capacitor value and added a 10 Ohm resistor?

2- >> There is a red and black pair that come straight off the board I think are the woofer but sure is small wire.<<

Yes, the red and black go to the woofer. Red wire to the “marked ” (red dot) or “+” terminal on the woofer. Black to the unmarked or negative woofer terminal. All the wires should be the same gauge – 18 AWG. The woofer wires are short in length.

3- >>and this looks to be fun to figure out the color coding of the driver wires.<<

There are two wire bundles on the LST crossover:

One has 6 wires and is connected to the spectral balance switch. Four of the wires (orange, yellow, green, light blue) go to the transformer. The other two wires – white to a fuse post and red to a woofer terminal on the terminal strip.

The other bundle starts with four wires (2 light orange, brown, and dark blue) and is connected to posts on the terminal strip and goes to the midranges and tweeters. There is a separate yellow wire that comes off the spectral balance switch that joins this bundle. There are also red, light blue, gray, and green wires that join into this bundle.

2) Do you have complete “wire harnesses,” as described above, connected to your crossover? Can you post a digital picture of what you have? My camcorder still pictures do not have good enough resolution.

3) Are your LST cabinets the front wired models or back wired models?

The LSTs I’m working on are front wired. I can give you specifics for each wire for either model if you’d like. I’ve just completed refinishing the cabinets on these and am just getting started on the crossovers.

Basically, the speaker wire harness runs counter clockwise starting at the crossover terminal strip, going to the right side midranges first (as you face the speaker cabinet looking inside the woofer hole). Orange (positive) and brown are midrange (red joins the midranges). Yellow (positive) and dark blue are tweeters (light blue, gray and green joins the tweeters). Its important to know where each wire is connected to maintain polarity (phase) and impedance – the midranges and tweeters are wired in a series / parallel combination to maintain nominal impedance of the driver set. I’m getting ready to trace each wire and matching it to the schematic. I can let you know all this in detail if you need it. I’m looking at how hard it will be to upgrade this wiring.

4- >>next were can you get the fuse for one of these fusetron fnm 2<<

FNM fuses are manufactured by Cooper Bussman (www.bussman.com). I did a google search on “FNM fuses” and found these two places that sell FNM 2 fuses on line:

http://www.newark.com/product-details/text/CD121/2333.html

You can buy individual items here, however orders under $25 have a $5 service charge.

http://sescodatasystems.com/bussmann/fnm.html

Minimum is carton of 10, but quite a bit cheaper per fuse. You can sell the extras. I'd consider splitting an order with you.

I’m still looking for a place that sells the fuse blocks/ holders/ clips for these fuses. In the Bussman catalog, It looks like the BM Series fuse block is what they manufacture for the FNM fuses.

5- >>would like to find a source for the 2500 uf cap. np.<<

4) I’m still looking for source for these also. Let me know if you find one. I’ll do likewise. Anybody out there that knows of one?

6- >>is there any way to simulate the db range switching of this using electronic crossover stuff like a dbx driverack pa electronic crossover<<

You stumped me on that question, I’m not familiar with that piece of equipment.

Rich

[roundhome]

Hello I have the LST crossover up and running now and just need to be told what type of test need to be ran on it.

If Mr Kantor has time to walk me through I would be glad to do it. I have switched it around a lot and can tell the diff in all positions I like it with just a little bit of the highs bright that might be the years around Navy Weapons fire. You think.

Thanks

Jim