Newly Aquired SDA 2B - Destined for Refurbishment... How to test for SDA Effect?
ProPerDoper
Posts: 12
New to the forum:
I just picked up a set of SDA 2B speakers for $75.00. Now, the cabinets are in need of refurbishment and one of the MW6511 drivers is locked up (possibly magnet shift from what I read...) but they do sound nice even so.
I have the replacement driver on order from Polk at $48, and have fashioned an interconnect cable using two spade and two modified rca connectors, but I'm not sure I'm hearing the SDA effect as when I pull the connectors from one speaker mid-play, I don't notice a change.
Is this possibly due to the one bad driver on one speaker? Is it because I've used a stereo RCA connector for the pin type side of the interconnect cable? (Something I thought of just as I'm typing this here...)
I'm anxious to hear these with the new driver and full SDA effect working. I have accessed a troubleshooting guide from this forum also, and will be doing some testing after I install the replacement driver.
My plans are to replace the tops and bottoms of these with solid Oak or other hardwood, and also the cloth covered sides with the same material, then stain all in Red Mahogany to match my office furniture. Should be really nice. (I've done quite a few vintage speakers this way, in either Oak, Ash Black, or Mahogany)
Appreciate anything that I can learn from you folks, comments, or other direction.
I just picked up a set of SDA 2B speakers for $75.00. Now, the cabinets are in need of refurbishment and one of the MW6511 drivers is locked up (possibly magnet shift from what I read...) but they do sound nice even so.
I have the replacement driver on order from Polk at $48, and have fashioned an interconnect cable using two spade and two modified rca connectors, but I'm not sure I'm hearing the SDA effect as when I pull the connectors from one speaker mid-play, I don't notice a change.
Is this possibly due to the one bad driver on one speaker? Is it because I've used a stereo RCA connector for the pin type side of the interconnect cable? (Something I thought of just as I'm typing this here...)
I'm anxious to hear these with the new driver and full SDA effect working. I have accessed a troubleshooting guide from this forum also, and will be doing some testing after I install the replacement driver.
My plans are to replace the tops and bottoms of these with solid Oak or other hardwood, and also the cloth covered sides with the same material, then stain all in Red Mahogany to match my office furniture. Should be really nice. (I've done quite a few vintage speakers this way, in either Oak, Ash Black, or Mahogany)
Appreciate anything that I can learn from you folks, comments, or other direction.
Post edited by ProPerDoper on
Comments
-
Welcome to CP! Lots of helpful folks here.
I'm not all that knowledgeable about the 2B's, but your non working driver is definitely contributing to your problem with the imaging. Getting your replacement installed should make a big difference.
Sounds like you have pin/blade sockets on your speakers. Unless you have trimmed the outer shell of the rca plug on the IC cable you're using, the pin is probably not inserting deep enough to make contact with the signal carrying part of the socket. The SDA driver won't get a signal so no sound from it.
When you put your ear to the good driver with the cable connected do you hear anything?"Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer -
Thanks for the reply...
I have trimmed the outer shell of the RCA connector... Wonder if a stereo RCA works okay?
Maybe I should check for continuity across the RCA connectors.... -
One reason that there is no SDA effect is because of the locked MW6511 driver as you were thinking. This is the dimentional driver and since it's no longer functioning, you will not get the SDA effect as you need both MW6511's working. If you are using a modified RCA connector for the "pin" connection, the pin may not be inserted far enough into the jack to function correctly (i.e. there is no signal getting through). Typically, RCA jacks are too big to function as a "pin" connector in SDA's. If you talk to pepster (Paul, here on the forum) he makes "pin" SDA cables for very cheap and work great. Once you get the new MW65111 driver and a proper SDA cable you will then have a functioning set of SDA 2B's. You will be very happy with the audio they produce if you have them set up and powered nicely. Please let us know what you think of them when you have them up and running fully.
Greg
Taken from a recent Audioholics reply regarding "Club Polk" and Polk speakers:
"I'm yet to hear a Polk speaker that merits more than a sentence and 60 seconds discussion."![:\](https://forum.polkaudio.com/resources/emoji/confused.png ":\")
My response is: If you need 60 seconds to respond in one sentence, you probably should't be evaluating Polk speakers.....
"Green leaves reveal the heart spoken Khatru"- Jon Anderson
"Have A Little Faith! And Everything You'll Face, Will Jump From Out Right On Into Place! Yeah! Take A Little Time! And Everything You'll Find, Will Move From Gloom Right On Into Shine!"- Arthur Lee -
Greg is right about the 6511. Until you get the replacement driver the speakers will not function as intended.and have fashioned an interconnect cable using two spade and two modified rca connectors
On the standard SDA cable there is no connection between the blades. If you made your cable with continuity between the blades undo it now before you damage something.My plans are to replace the tops and bottoms of these with solid Oak or other hardwood, and also the cloth covered sides with the same material, then stain all in Red Mahogany to match my office furniture.
I realize it's a matter of personal taste and this is mine. Red mahogany stain has no business on oak. It looks cheap, like someone couldn't afford mahogany, so they used oak instead...ugh!Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Appreciate the advice and direction...Greg is right about the 6511. Until you get the replacement driver the speakers will not function as intended.
On the standard SDA cable there is no connection between the blades. If you made your cable with continuity between the blades undo it now before you damage something.
I realize it's a matter of personal taste and this is mine. Red mahogany stain has no business on oak. It looks cheap, like someone couldn't afford mahogany, so they used oak instead...ugh!
Hmm... I'm looking at a schematic obtained from Helen at Polk which clearly shows a connection going to both sides of the SDA IC (Pin #1 being the blade, and Pin #2 being the round pin above the blade) There is also a note however, which states: "The IC wire from the crossover should always be connected to Pin #2 (The round Pin)"
I've skimmed the entire SDA Handbook (Also provided by Helen) copywritten by R.F. Smith 2011, and about the only info on the IC is on the crossover schematic.
What I really need is directions and/or a schematic to fabricate my own pin/blade IC cable, as I prefer that route. Hoping someone can help with that....
Thanks! -
You can use the RCA for the interconnect. You only need the pin not the blade. Trust me I have owned 3 pairs of SDA2b's.
I would suggest replacing the pin blade socket with a dedicated binding post in each. This way you can use heavier wire than what is in an RCA connection.
You will not get the SDA effect until you replace the 6511. -
I now see at least two other posts around the web that seems to confirm that only the Pin is used to carry the signal, so thanks for that info guys...
In fact, there's an SDA cable on eBay for $50, newly fabricated and his ad states that the blade connector is only used with the A1 transformer when connecting to mono-block or non-common ground amps.
I can do this, I just need to figure out what connectors to buy, or as stated above switch them out to binding posts. For testing purposes, it seems what I'm hearing is that the stereo RCA connector will do fine... -
I now see at least two other posts around the web that seems to confirm that only the Pin is used to carry the signal, so thanks for that info guys...
In fact, there's an SDA cable on eBay for $50, newly fabricated and his ad states that the blade connector is only used with the A1 transformer when connecting to mono-block or non-common ground amps.
What, you didn't believe me?
So now that I hopefully have some credibility, believe this. You do not want to buy that cable on eBay, the guy is a complete hack.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
What, you didn't believe me?
So now that I hopefully have some credibility, believe this. You do not want to buy that cable on eBay, the guy is a complete hack.
You had credibility from the first post.
My response was one of confusion given the schematic I was looking at, not one of doubt regarding your ability. Keep in mind that I've come here because you know, and I don't.
So....if I was to make my own pin to pin IC, what's the best connector to use if I choose to keep the standard sockets? -
All good, I should have added a
Anyway, any good quality RCA jack will do the trick.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
All good, I should have added a
Anyway, any good quality RCA jack will do the trick.
Thanks...
I've fashioned one now with an RCA as mentioned earlier. I'll try and improve on the quality of the IC later. Parts Express replied after sending them a copy of the photo from the eBay ad, stating they didn't have that connector but suggested I try www.fullcompass.com, which I will do.
I'm surely anxious to get the replacement driver in and test these in full working mode.
BTW...My Adcom GFA555II sure doesn't seem to like these speakers much, even though they're rated at just 6 ohms. (Not all that difficult a load) Right channel cuts out after playing a bit. It comes back once shut down, and I'm playing some vintage Infinity Crescendo CS3008's on it now, never a problem with those.
Since that problem I've been running the SDA's on my B&K ST-140 at half the power of the Adcom without incidence.
Curious, it is..... -
I don't think that Adcom is common ground and therefore should not be used with SDA's unless you use the AI-1 cable.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Do you still have the bad driver connected? That would not be a good idea for the amp.
Disconnect the interconnect until you get the driver replaced. -
I checked before playing on each, and I get continuity between the negative speaker outputs on both amps. From what I read online this confirms both are common ground amps....yes?
I have the one bad driver disconnected currently, although when the Adcom right channel cut out, I have to admit that I did not. Lucky for me it appears that I didn't damage the amp. (I hope, I hope) -
The Adcom should run those beautifully. Many including myself have run an Adcom 545 or 555 on SDA's without issue for years and years. It's a good match so since it works with other speakers I'd look at your connections on the SDA's, mainly the interconnect cable you have rigged, and be sure you aren't shorting something or perhaps you have another internal cross-over issue. Or even the bad driver could be causing the issue if it's somehow shorting out.
H9"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul! -
Will do. Once I have the bad driver replaced, and now that I've learned to connect only the pin on the IC, I'll heft those 80 lb. bad boys downstairs and hook them up to the Adcom again for a trial.
-
I don't think that Adcom is common ground and therefore should not be used with SDA's unless you use the AI-1 cable.
The 545, 545II, 555 and 555II are all common ground. Not sure on the 535 and 535II since they are dual mono's and have a seperate transformer for each channel, can't remember how those are configured.
The 5400, 5500, 5800 and 5802 are NOT common ground
H9"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul! -
ProPerDoper wrote: »I checked before playing on each, and I get continuity between the negative speaker outputs on both amps. From what I read online this confirms both are common ground amps....yes?
I have the one bad driver disconnected currently, although when the Adcom right channel cut out, I have to admit that I did not. Lucky for me it appears that I didn't damage the amp. (I hope, I hope)
I just checked the schematic for that adcom and it is a common ground amp. Most likely it was that frozen driver, I would not use those speakers until you get that driver replaced. What happens when you get a frozen driver (magnet shift) the pole that go's through the voice coil shifts and jams the voice coil against the base plate causing a short.“The two most important days in your life are the day you are born and the day you find out why.” ~ Mark Twain -
ProPerDoper wrote: »I now see at least two other posts around the web that seems to confirm that only the Pin is used to carry the signal, so thanks for that info guys...
In fact, there's an SDA cable on eBay for $50, newly fabricated and his ad states that the blade connector is only used with the A1 transformer when connecting to mono-block or non-common ground amps.
I can do this, I just need to figure out what connectors to buy, or as stated above switch them out to binding posts. For testing purposes, it seems what I'm hearing is that the stereo RCA connector will do fine...What, you didn't believe me?
So now that I hopefully have some credibility, believe this. You do not want to buy that cable on eBay, the guy is a complete hack.
As I said, if you are looking to buy a pre-made quality SDA cable talk to pepster (Paul) here on the forum. As Jesse said, you would be better off steering clear of the seller of the Ebay SDA cable. Just our opinions.
Greg
Taken from a recent Audioholics reply regarding "Club Polk" and Polk speakers:
"I'm yet to hear a Polk speaker that merits more than a sentence and 60 seconds discussion."
My response is: If you need 60 seconds to respond in one sentence, you probably should't be evaluating Polk speakers.....
"Green leaves reveal the heart spoken Khatru"- Jon Anderson
"Have A Little Faith! And Everything You'll Face, Will Jump From Out Right On Into Place! Yeah! Take A Little Time! And Everything You'll Find, Will Move From Gloom Right On Into Shine!"- Arthur Lee -
Hmm...
I can't send a private message until I have 10 or more posts.... -
So hopefully, I'm approaching that privilege soon.... :cheesygrin:
-
The 545, 545II, 555 and 555II are all common ground. Not sure on the 535 and 535II since they are dual mono's and have a seperate transformer for each channel, can't remember how those are configured.
The 5400, 5500, 5800 and 5802 are NOT common ground
H9
Adcom GFA 535ll are indeed common ground amps... listening to a pair of 2Bs as I type this! So, are you willing to put forth a little effort or are you happy sitting in your skeptical poo pile?
http://audiomilitia.proboards.com/ -
ProPerDoper wrote: »I checked before playing on each, and I get continuity between the negative speaker outputs on both amps. From what I read online this confirms both are common ground amps....yes?
I have the one bad driver disconnected currently, although when the Adcom right channel cut out, I have to admit that I did not. Lucky for me it appears that I didn't damage the amp. (I hope, I hope)
Were you using the homemade SDA cable with the blades connected at the time?Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
I was, in fact. With both pin and spade connectors on both speakers
-
So I just arrived back in town and awaiting my installation is the MW6511 driver. Installed it this morning in my bathrobe, I'm so darned eager to hear these.
Oh....now I get it. What a wonderful difference!
Love it.
