SDA's are annoying.

[madmax]

I finally moved out the SDA-SRS and put the 1.2's in their place. The reason was because I needed an isolation transformer for the monoblocks and couldn't do it with the older SDA-SRS.

So all is together and I find out the SDA doesn't work. The stupid interconnect cable has both wires in the cable connected to the pin, nothing to the blade. I figure I'll go ahead and check the other cable I have. It too only has the pin wired, nothing to the blade.

I guess I'll have to make my own connector. Is this odd or does all the standard cables only wire to the pin?

madmax

[ben62670]

Pin to pin is normal. Test with an Ohm meter between pin and the negative speaker conector. It should be 2-3 ohms.

[madmax]

It is. The problem is I cut the cable hoping to install an isolation transformer. Since the blade doesn't connect to anything it can't supply the ground.

[ben62670]

Think now I gotta cha. You can connect the blade directely to the ground for Isolation purposes in the cabinet if you don't have continuity from speaker blade to ground. My pin blade cable did have both wires. Can you connect one of the pin wires to the blades?

[madmax]

The transformer must have a ground and signal to work. Inside the cabinet the blade connection is hooked to ground. Just the wire in the cable isn't connected to the blade.

[ben62670]

I know someone here had a line on the connectors. I am thinking it was maybe HTrookie.

[madmax]

I remember the blade/blade ones used to be available from RS. I might just wrap a wire around the blade and solder it. I can always install a different connector and cable later. You can probably tell I want to listen to music tonight. :)
madmax

[hoosier21]

There has never been any signal on the blade connection, of a pin blade cable, your is correct Chuck. Yep , you cut a good cable for nothing.

[madmax]

After drilling a hole in the blade and soldering a wire to it there is now... :)
madmax

[schwarcw]

The following is an except from a communication I had with DarqueKnight on this topic:

If you look at the schematics of all pin/blade SDA's, you will see that the blade IC is wired to the negative input terminal. While this wiring essentially "leads to nowhere" when the IC cable is in place, it is used in some diagnostic test modes. Refer to pages 38 and 39 of the Compendium and you will see that both the blade (pin 1) and pin (pin 2) are used in diagnostic testing.

In normal operation, removing the wire from the blade terminal would have no functional effect. However, such removal would prevent some diagnostic tests.

[madmax]

Still sounds crappy. Very low volume on the SDA. WAY too much center image too. I'm thinking the transformer is loosing too much signal OR I have it wired in reverse. My room has always sucked for the center image anyway but now it is REALLY loud.
madmax

[madmax]

Last night I finally decided to use the non-isolated cable. My reasoning: The amps should not be hurt since the grounds were not being tied together through the cable (as I thought they were) and the outputs are going through transformers so the potential should be very close anyway. The worst thing that could happen is that the SDA wouldn't work properly. SS amps without a transformer, different story. On the outside it would seem you could tie transformered tube amp outputs together without problem however, Manley says not to, so I wont.

So here I am. A little risk but great SDA.

Those stancor 6512 isolation transformers (I think thats the number) SUCK big time. So much loss the SDA hardly functions at all.

madmax

[engtaz]

No, all the driver could blow if it's a non common ground amp. Trust me I have done it.
http://www.polkaudio.com/forums/showthread.php?t=55233

[ben62670]

What amps are you running?

[madmax]

No, all the driver could blow if it's a non common ground amp. Trust me I have done it.
http://www.polkaudio.com/forums/showthread.php?t=55233


Yea, and I know of others too. That is a bit of a different scenario though because when you bridge that sort of amp the ground potential actually becomes the same as the negative supply of the amp, somewhere between 35 to 70 volts. Since both sides tend to stay at that same voltage you are typically ok for awhile, until they drift apart for some reason. It could happen with mine too, just less likely. Thats why I will say :FOLKS, DO NOT TRY THIS AT HOME. ;)

My amps are the Manley Designers Series monoblocks.

[F1nut]

Get the Avel isolation transformer, much better.

[madmax]

I think I will continue to go unprotected until I pick up an Avel xformer. I have other problems though. The room is the wrong size for SDA. The symptoms are a thin sounding front center and massive full amounts of SDA on the sides. An 11 x 18' room really sucks for these. the 11' wall is too short and the 18' wall isn't far enough away. The 18' wall is the best though. Bass response gets low when I spread out the speakers enough to help give the center some body. I don't know, I may just need to get some non-SDA's until I have a bigger room.
madmax

[Lasareath]

I think I will continue to go unprotected

Going unprotected is risky. But it feels a whole better!

[ben62670]

If you don't use the IC cable at all you will not hurt anything.

[madmax]

Sounds too icky without the cable.