SDA IIb Single active wire in the interconnect isolation transformer question.

VSAT88

let me see if I can word my question the way I should. When I bought my SDA IIb speakers (a right and a left) they came with no interconnect. I made one. When I looked on the back where the interconnect plugs in it was "blade blade" so I took the cup / off where the interconnect plugs in. I found that only one cable actually connects these two speakers. The other terminal was not used so I built one straight thru cable and all was well however I would like to use my Parasound amp. It is an HCA 1206 a six channel that can be bridged mono on two of the channels for 360 watts per channel. I would like to try and build a proper isolation transformer and have found all the info. to make the purchase however the wiring diagram that I found was for hooking up SDA speakers that use two active wires in the interconnect not one (as far as I can tell anyway). could someone please show me a link or tell me where to go from here because as of now I have no extra cash for a 300 watt + per channel amp and would like to realize the full potential of these speakers. By the way, I know that the amp is rated at 8 ohms per bridged channel but I have tried it without the interconnect and it shows no signs of problems so far, no overheating and such. Really do not run it at high volume levels for any period of time. It would be a semi-temporary situation anyway. Thanks all.

agfrost

I have a blade-blade set of 2Bs; I also built a Dreadnaught transformer. I chose to change out my blade-blade socket in favor of a Speakon setup (I believe I got NL4MP-UC female and NL4FX male). http://www.neutrik.com/en/speakon/

The only real difference to make in the crossover is that the 2nd wire of the interconnect needs to be attached to the negative binding post (or its electrical equivalent on the crossover) on each speaker.

Here's a side-by-side of the two crossovers; the B-B's connection is the same as the pin of the P-B model. You can see how you'll need to add some hookup wire to make the connection between the "blade" connection of the pin-blade setup.



...and the lovely Dreadnaught, along the cables I fabricated (I made a straight cable as well in case I were to ever move along the speakers without the Dreadnaught).

westmassguy

VSAT88 wrote: »

let me see if I can word my question the way I should. When I bought my SDA IIb speakers (a right and a left) they came with no interconnect. I made one. When I looked on the back where the interconnect plugs in it was "blade blade" so I took the cup / off where the interconnect plugs in. I found that only one cable actually connects these two speakers. The other terminal was not used so I built one straight thru cable and all was well however I would like to use my Parasound amp. It is an HCA 1206 a six channel that can be bridged mono on two of the channels for 360 watts per channel. I would like to try and build a proper isolation transformer and have found all the info. to make the purchase however the wiring diagram that I found was for hooking up SDA speakers that use two active wires in the interconnect not one (as far as I can tell anyway). could someone please show me a link or tell me where to go from here because as of now I have no extra cash for a 300 watt + per channel amp and would like to realize the full potential of these speakers. By the way, I know that the amp is rated at 8 ohms per bridged channel but I have tried it without the interconnect and it shows no signs of problems so far, no overheating and such. Really do not run it at high volume levels for any period of time. It would be a semi-temporary situation anyway. Thanks all.

Without the interconnect cable, the stereo portion of the crossover is active. On the dimensional side, the stereo signal below 150Hz is also being routed to the dimensional woofer(s) via the sub-bass drive circuit. Once the cable is connected, the dimensional portion of the crossover is fully active from 150Hz - 2KHz or there abouts. Your amp may or may not be able to handle the additional load. That being said, since the 4 ohm woofer is in the circuit below 150Hz now, you "may" be ok for short term use.

On the interconnect socket/plug/cable issue, Polk used leftover cabinets, and electrical components when transitioning from one generation to the next. 2Bs seem to be the most common recipients, but I've also seen 1Cs with bl/bl interconnects, and even 1B circuit boards jury rigged for 4th generation use.

What matters, going forward, is the correct configuration for either common ground or isolated/mono-block amplifiers. You should replace the bl/bl sockets and interconnect plugs with SpeakONs. The blue dimensional wire from the harness is connected to the 1+ SpeakON terminal, and a new (white) ground lead installed between the negative binding post, and the 1- terminal on the SpeakON. You should mount the SpeakON socket in the binding cup. If the hole's not already there, drill a new one, and plug the hole left by the bl/bl socket in the cabinet.

VSAT88

agfrost wrote: »

I have a blade-blade set of 2Bs; I also built a Dreadnaught transformer. I chose to change out my blade-blade socket in favor of a Speakon setup (I believe I got NL4MP-UC female and NL4FX male). http://www.neutrik.com/en/speakon/

The only real difference to make in the crossover is that the 2nd wire of the interconnect needs to be attached to the negative binding post (or its electrical equivalent on the crossover) on each speaker.

Here's a side-by-side of the two crossovers; the B-B's connection is the same as the pin of the P-B model. You can see how you'll need to add some hookup wire to make the connection between the "blade" connection of the pin-blade setup.



...and the lovely Dreadnaught, along the cables I fabricated (I made a straight cable as well in case I were to ever move along the speakers without the Dreadnaught).

Very very very nice work on the unit you built BTW.

VSAT88

agfrost wrote: »

I have a blade-blade set of 2Bs; I also built a Dreadnaught transformer. I chose to change out my blade-blade socket in favor of a Speakon setup (I believe I got NL4MP-UC female and NL4FX male). http://www.neutrik.com/en/speakon/

The only real difference to make in the crossover is that the 2nd wire of the interconnect needs to be attached to the negative binding post (or its electrical equivalent on the crossover) on each speaker.

Here's a side-by-side of the two crossovers; the B-B's connection is the same as the pin of the P-B model. You can see how you'll need to add some hookup wire to make the connection between the "blade" connection of the pin-blade setup.



...and the lovely Dreadnaught, along the cables I fabricated (I made a straight cable as well in case I were to ever move along the speakers without the Dreadnaught).

Very very very nice work on the unit you built BTW.

VSAT88

Seems as if none of the amps I have "in stock" are going to work out no matter what I try. I suppose it's time to sell some equipment and buy something that will work without hassling you kind fellows. I really do like the Sunfire two channel amp. I do have a "flame linear" that I am fixing up however even restored I am going to be scared of it..

agfrost

VSAT88 wrote: »

Very very very nice work on the unit you built BTW.

The heavy lifting was done by others--Forum member DarqueKnight did a lot of the pioneering with the transformer (and gave it the name "Dreadnaught"); the case for my 1 kVA Avel-Lindberg transformer was machined by member Toolfan66. All I needed to do was select some speaker wire, some mounting hardware, and do a little bit of soldering. Fun project, though!