Question on SDA ICs

geppy1

Hi, When ever i get a pair of SDAs I alway make a twin run of 12G monster cable with bananas for the IC cable and put a banana jack on the speaker. I have 2Bs right now and I am wondening if going from the stock cable to this kind of setup (while it may do some good things) makes the speaker a little more phasey sound?? Keith

george daniel

my .02--nope

Toolfan66

Nope!!

ben62670

I have tried 14ga OFC cable, and it was better than stock. I also have been selling a lot of Silver plated copper 14ga with teflon insulation. I have received many comments that the mids are cleaner and the bass is tighter. Also some say the sound stage is wider. If you want to build a copper cable I would look at AQ's 14/2. If you want to build silver plated teflon you can usually get a piece fairly cheap on Ebay. I also build the silver IC cable to Polkies at a real low cost if you don't want to build one or have to deal with getting all the parts from different suppliers. BTW if you break the "petals" of an RCA plug the pin diameter is the same as the stock pin blade connector.

brgman

That's right Ben.I'm still waiting on a price for a B/B and P/B both 20feet.

ben62670

P/B is $55 shipped at that length. I don't make the BB version. Maybe I should with some AQ wire.

brgman

Great deal.Guess i'll get one on order with you.PM on the way.Thanks Ben

xoaphexox

I don't mean to thread hijiack but this seems like a good opportunity to ask a question that has been driving me nuts.

I bought a pair of 1.2TL's without the IC and made one myself using the method mentioned above, pulling the "petals" off a female RCA cable and soldering them to some 12ga OFC cable.

Here is my question - do I need the blades or is the pin the only source of signal between the two amps? I am running with a common ground amp (Kenwood 700M) so I don't need to worry about that issue.

The reason I am second guessing this is that on my speakers when I put the source to mono and move the balance the whole way left, I hear the left speaker as well as the dimensional array out of the right speaker. When I move the balance the whole way right, I hear only music out of the right channel, the left channel's dimensional array is completely silent.

Is this normal?

Thanks so much, great forum here!

Rob

Toolfan66

Yes the pin is what sends the signal. The blade is for the AI non common ground amp SDA cable.

What you experiance with the balance knob is normal when in Mono.

Enjoy!!

xoaphexox

TOOLFORLIFEFAN wrote: »

Yes the pin is what sends the signal. The blade is for the AI non common ground amp SDA cable.

What you experiance with the balance knob is normal when in Mono.

Enjoy!!

Thanks Tool Fan (I myself am a huge Tool fan)!

So say the source is in stereo, should I hear anything out of the left speakers dimensional array if I move the balance all the way right? I hear it but very very faint. When I move the balance to the left, the sound out of the right speakers dimensional array is much more noticeable.

hoosier21

xoaphexox wrote: »

The reason I am second guessing this is that on my speakers when I put the source to mono and move the balance the whole way left, I hear the left speaker as well as the dimensional array out of the right speaker. When I move the balance the whole way right, I hear only music out of the right channel, the left channel's dimensional array is completely silent.

Is this normal?

I do not think this is normal, see SDA Quick Troubleshooting Information at the bottom of this page:

http://www.polkaudio.com/forums/showthread.php?t=55888

xoaphexox

Thank you! I will diagnose.

F1nut

Definitely not normal.

Toolfan66

I have my Adcom 750 in mono now, and when I use the balance to the left or too the right I have sound coming from the SDA drivers. I always have, and I asked about this a couple years ago, and was told this is normal.. I have everything hooked up right and everything sounds fantastic..

So what is it???

Toolfan66

It does the same thing in stereo mode as well..

If the SDA cable is sending a signal from right too left wouldn't this be normal for the dimensional drivers to be receiving a signal??

Toolfan66

Ok so I read the trouble shooting guide again!! And everything says that I'm receiving my signal correctly..

Unless I am misunderstanding what is being asked?? Then using the balance controls left or right you will still get sound coming from the opposite dimensional drivers..

ben62670

If you turn the balance to the right the outer(dimensional)speakers will play fairly muted and out of phase. The same thing happens when you turn the balance the other way.

You beat me Larry!

Toolfan66

Nevermind I just reread what was asked.. It is not normal you should be getting sound out of both sides of the dimensional drivers..

Sorry it's what I get for using this freaking Iphone to post and read..


Larry..

xoaphexox

OK in light of your comments it sounds like I do have an issue with the speakers. I will take the readings in the troubleshooting PDF and see what I find.

xoaphexox

I did the troubleshooting guide and they suggest that your right speaker may be out of phase if you get the symptom I'm having. Sure enough, if I switch polarity on the right channel and fade all the way right, the left speakers dimensional array produces sound.

What is so troubling about this to me is that I verified that my speaker wire was in correct phase - it's color coded. Red to positive, Black to negative.

Now with red to negative and black to positive on the right channel, I get the SDA effect.

I may pull the crossover and check it out - something doesn't seem right here. Ugh!

Update: when I pull the black cord from each speaker and listen to the difference signal this way it doesn't work the way it should. However, if I put the speaker wire back to the "correct" polarity, then at noon on my balance knob I hear silence - this is supposed to happen.

So, I have to reverse the leads of my right speaker to get the SDA effect in the left, but I have to keep the polarity correct for the difference signal to null out.

It's starting to make me think something is wrong with the right speaker crossover itself.

xoaphexox

OK, took the readings and there is an anomaly.

The readings differed in three areas. I have bolded the ones that are wrong

Left Channel Pin > Black = 2.2 ohms
Right Channel Pin > Black = 3 ohms

Left Channel Pin > Red = 3 ohms
Right Channel Pin > Black = 2.2 ohms

Left Channel Pin > Blade = 2.2 ohms
Right Channel Pin > Blade = 3 ohms

It would seem to me from these readings that the IC connector to the xover is reversed or something, since the readings are what they should be for the opposite polarity. I guess this also explains why I get the SDA effect when I intentionally reverse the polarity to the right speaker.

Thoughts?

hoosier21

I would first look at the wiring diagram of your speaker and compare it to your speakers, check this first to make sure they correctly wired and make sure the plastic red and black speaker terminal nuts are installed on the correct speaker terminal.

What amp and preamp are you using?

xoaphexox

Update: I removed the connector plate from the back of the speaker and traced the wires. Everything is as it should be. Thoroughly confused.

I will trace the drivers themselves now. Confirming the dot of red paint indicates the + terminal? And there should only be black for stereo and blue for dimensionals going to these red dots...

I am using a Kenwood 700C preamp feeding in to a Kenwood 700M power amp.

One typo I found on the silk screening of my crossover BE2001-C is that the input pins for the xover are labeled -++-IC when in fact they are +-+-IC, as shown in the schematic.

xoaphexox

Well, I checked the polarity on the 12 drivers and they all match the schematics I downloaded off this forum.

I guess the only place this issue could be, then, is the xover itself.

I will check that later on, I've had a full night of walking these 185lb monsters across my carpet, which is no easy task with giant brass spikes on them!

gimpod

xoaphexox wrote: »

I will trace the drivers themselves now. Confirming the dot of red paint indicates the + terminal? And there should only be black for stereo and blue for dimensionals going to these red dots...

Correct Red dot is the positive side of the driver. Black is stereo and Blue is dimensional.

xoaphexox wrote: »

One typo I found on the silk screening of my crossover BE2001-C is that the input pins for the xover are labeled -++-IC when in fact they are +-+-IC, as shown in the schematic.

NO! Your silk screening is correct. Check the Pin #'s on the schematic. On the schematic there numbered 4,5,3,2,1 (+,-,+,-, I.C.) Top to bottom and on the crossover there 5,4,3,2,1 (-,+,+,-, I.C.) Left to Right. One thing you might want to check is that the wires (P,R) are plugged into that big inductor under the crossover. Also don't freak if it looks like the tweeter's (P3) are wired backwards, on the TL's there suppose to be.

xoaphexox

Ahh, you're right. I missed that in the schematic that the pins were out of order. Thanks for setting me straight.

I'll pull out the xover and look for the issue another day. I just ordered binding posts as some have stripped plastic caps. Figured I might as well do that too while I have these torn apart!

Thanks

F1nut

make sure the plastic red and black speaker terminal nuts are installed on the correct speaker terminal.

Make sure you check this.

xoaphexox

F1nut wrote: »

Make sure you check this.

Thank you, on both of my speakers the color of the end caps match the picture above - positive terminals on the left, negative terminals on the right.

I presume I made a mistake on the xover when I recapped it with Soniccap/Mills. I will go over it and compare against the left channel to see if I can spot anything. I don't know what else it could really be.

I will try to remove the HF/LF jumpers and just amp one half at a time to see if I can isolate the issue to a particular area of the xover.

xoaphexox

I have both xovers out and on my bench for testing. I spent about 20 minutes going over the values and connections and cannot find a difference between the two.

I will take electrical readings next.

Do the P and R pins have to go on the big coil a certain way or does it not matter? I believe I had them on correctly but want to be sure.

ben62670

P and R don't mater as far as polarity.

xoaphexox

ben62670 wrote: »

P and R don't mater as far as polarity.

Thanks, I figured since its essentially a jumper but I was hoping I would find any kind of clue as to why these darn speakers are acting this way. I'll keep looking!