Can I bi-amp SDA 2b's?
Wayfarer
Posts: 3
I just picked up a Denon AVR-787 receiver to put together a HT system.
According to the Denon manual if you want to run a 5.1 instead of 7.1 I can biamp the fronts which will be my SDA 2b's.
Can the 2B's be bi-amped and if so how do I do it?
I have the pin/blade interconnect.
I am confused about the common ground, etc sort of thing.
According to the Denon manual if you want to run a 5.1 instead of 7.1 I can biamp the fronts which will be my SDA 2b's.
Can the 2B's be bi-amped and if so how do I do it?
I have the pin/blade interconnect.
I am confused about the common ground, etc sort of thing.
Post edited by Wayfarer on
Comments
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Welcome to the club. The 2b's aren't setup for bi amping. You would have to install an extra set of post to bi amp them, which would involve considerable amount of crossover work. Not really worth it. The best improvement you could do would be to add an external amp. A lot of guys use Adcoms, and you should be putting about 200 watts to them. Your speakers are 6ohms so look for an amp that puts out at least 200 watts at 4 ohms. Enjoy your speakers.
BenPlease. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
Thanks
Ben -
Your Denon is common ground so no problem there, most amplifiers are common ground, but its best to check with the manufacturer in each case.
Since you say you have pin/blade you might be able to run bridged mono or a non-common ground amp if you use the Polk AI-1 interconnect cable. These are no longer sold so we make our own. I would get the serial numbers of your speakers and post them up or call Ken Swauger at Polk Customer Service. I seem to recall some serial numbers where running mono or non common ground was a problem even with pin/blade. I thought the 2B were blade/blade, but its been a while since I checked the book, someone here will know, or I will look tonite. If you are going to use a common ground stereo amplifier it does not matter. Anyway, there are many amplifier choices for you to consider, some of the ones tossed around here include
NAD
B&K
Carver
Rotel
Anthem
Sunfire
These are just a few, there are many more, in any case you want a high current amplifier, rated at least 25-30 amps peak to peak, the more the better, as an example my B&K is 75 amps pk to pk. The SDA line is quite efficient, folks like to have the power to really open them and get them singing, of course everything is most dependant on your listening room itself. I would not push the Denon real hard, but I would use it and enjoy the speakers until such time as an external amp is feasable.
Many folks change the tweeter out with the Polk Replacement, silk dome RDO, it is generally considered as a smoother sound over the original sl2000. They are available from Polk, mention you are a member for a discount. There are a few replacements, you need the one for the SL2000.
The 2b are very nice speakers made to fit the average or smaller room, enjoy them.
RT1 -
I'm guessing not.
Your Denon probably has 7 seperate binding posts on it. Since the SDA-2 only have one set of posts (I'm pretty sure), you can't biamp them the way Denon probably has in mind. They probably want you to put L-Front, R-Front on one set of posts on each speaker and L-Surround, R-Surround on the other set of posts (which you don't have).
In order to do this you need speakers that are set up to be biamped top/botton. These "biampable" speakers have two sets of binding posts on each speaker (one for bass, one for treble).
As mentioned above, you can biamp them Left/Right (Instead of top/bottom), but then you will need matching seperate amps for each side and the AI-1 SDA cable (which has a transformer in it). The regular cable is just a straight through connection and requires a common ground amp to keep things from smoking.Jolida Tube
Polk 11T, 7, 5, 5jr, 4
Standard equip not worth bragging about. -
Wayfarer wrote:I am confused about the common ground, etc sort of thing.
I used to be, too. Almost every amp you buy is common ground. That means that the negative (-) terminal of both the left and right channel are tied together. You can actually run a cable between the two negative speaker posts and you haven't changed anything. Hence, "common ground".
You can check an amp by putting an ohm meter across the negative terminals. If it shows a short, then it is a common ground amp.
The straight SDA cable assume you have common ground in order to work. If you don't, the AI-1 puts a transformer in the cable to decouple the speakers so they can run off of different grounds (amps) without frying the SDA crossovers.Jolida Tube
Polk 11T, 7, 5, 5jr, 4
Standard equip not worth bragging about. -
Lets not confuse bi-amping with bi-wiring. You need two sets of posts to bi-wire but not to bi-amp.
A lot of the 2Bs can be bi-amped with the use of an AI-1. You just have to know the serial numbers and where they stand... -
Can I or can't I?
If so, how do I do it?
According to the chart my serial number says ok. -
If you can build or otherwise acquire an AI-1, then you can use non-common ground, dual mono or mono block amps. That's it, no bi-wiring, no bi-amping.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 -
F1nut wrote:If you can build or otherwise acquire an AI-1, then you can use non-common ground, dual mono or mono block amps. That's it, no bi-wiring, no bi-amping.
Hummm, If I remember correctly in a conversation my brother had with Polk about this matter years ago they said that it could be done. He then proceeded to do it for a few years himself.
The only problem he encountered (a very bad one at that) was that during the original trial period he didn't have the use of an AI-1 and so through talking to Polk and the amp manufacturer they came to the conclusion that strapping the amps together would take care of that. Following the directions given the 2Bs were bi-amped in this manor. The system worked OK for a few months and then one of amps crapped the bed. Both amps were sent back and repaired (under warranty at that!) and it was decided that indeed an AI-1 one would be necessary so Polk sent him one (yup, still available then). After the AI-1 was put into the setup it worked just fine. -
Vertical bi-amp uses one stereo power amp for each loudspeaker. One channel on the top end and one amp channel on the bass. Horizontal bi-amping uses one stereo amplifier for both left and right bass speaker connections and the second power amplifier for the left and right treble and midrange connections.
The 2B's have only one set of binding posts per speaker. They can not be bi-amped.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 -
yea, what he said.
Get a nice stero amplifier and enjoy the speakers.
RT1 -
F1nut wrote:Vertical bi-amp uses one stereo power amp for each loudspeaker. One channel on the top end and one amp channel on the bass. Horizontal bi-amping uses one stereo amplifier for both left and right bass speaker connections and the second power amplifier for the left and right treble and midrange connections.
The 2B's have only one set of binding posts per speaker. They can not be bi-amped.
I read too quickly and missed the point that he was looking to power both highs and lows rather just going monos left and right.
BUT!
Not all is lost! This information is not for the weak or squeamish!!! :eek:
Note:
To those interested and inclined to do so (I'm not) you could probably biwire the 2Bs if you wanted to make a project of it. :cool:
The Story:
You see, a long time ago in land not so far away (from me that is)
my brother was interested in biwiring his 1Cs, so on the phone he went to Ken. Ken said "not a problem, I'll send you a schematic and tell you what to do." A short time later with a little work on the crossover and another pair of binding posts in place the job was done and is still working fine to this day. Now my brother lives happily ever after. 
The moral:
Where there's a will, there's (usually) a way.
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Excellent point, Bob and certainly something that could be done to the 2B's as Mike did to the 1C's.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 -
See post #2Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
Thanks
Ben -
I see post #2. 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 see post #2 and raise you one.
Heck, it's just that you made it sound so difficult and uninviting. Quite the opposite. It was a snap, Mike had fun doing it, and glad he did it. DIY custom bi-wire-able 1Cs for very little time and expense. Not too shabby.
