SDA-2 causing amp to shut down

OnlyPolk

My right channel SDA-2 came back from a speaker shop who replaced the terminal posts with new connects. We had discovered one tweeter to be bad so I ordered 4, and replaced both tweeters in this speaker with the new RD-0149. When I connected it up, my AVR shut down whenever the music I was playing ramped up in volume. I took the speaker back to the shop to have them double check. All they did was to connect two terminals to the wires in the back. They checked ohms across the speaker terminals (3.8) and they will look into it further.

The AVR plays fine with this speaker disconnected (Yamaha DSP A1000 with separate amps for each channel - 7 of them)

Meanwhile anything I can do to determine if it's the Yamaha amp? (1) Connect another speaker (I have an old large Advent) to that channel? (2) switch the left SDA-2 to the right channel and see if that causes the amp to shut down?.(3) Install new tweeters in the remaining left speaker and see if that causes the amp to shut down?

xsmi

Try connecting the Advent to that channel. If all is well then it is the speaker that is the problem.

ND13

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OnlyPolk

the speaker shop is as their web site says ..." a factory authorized speaker repair service center for: Electro Voice, Cerwin Vega, JBL, Infinity, Acoustic Research, Advent, Gauss, Altec-Lansing, Celestion, Jensen, University, RCF, Tannoy, Community, and Yamaha". They may not work with Polks that much but they sure have a lot of speakers in there and have been in business 30 years, so I'm not sure I can start blaming them yet. They checked it by playing it with their power amp before they sent it out and did again when I took it in.

I haven't tried the Advent on the right side yet. Someone in here mentioned polyswitches in the SDA. If these are bad could it cause the problem?

ND13

...l.

OnlyPolk

I don't think they had to know anything about an SDA. They were replacing the speaker terminals which were screws, that actually broke some years ago (been using a shaky connection). SO all they did was to take off the back panel and put in new posts and connect back the wires that go to the + and - terminals.

ND13

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OnlyPolk

No I don' think that's it. I've had the Yam. AVR almost as long as the Polks which I bought new in 85. Besides as I said before each channel has its own amp in this Yamaha which is why it weighs 50 pounds. So you have one main channel amp that is driving the left side just fine...

F1nut

Did the Yammie and SDA's get along before you had the speaker worked on? If so, the problem should be with the speaker. Double check that you wired the new tweeters correctly and have the shop call Polk, ask them for a schematic for your speaker, so they may check the rest of it without hunting blind.

In the event that the Yammie and SDA's are a new couple, it very well could be that the Yammie isn't rated to drive 4 ohm loads. At lower volume levels it will be ok, but when cranked up, it will go into protection mode to prevent itself from cooking.

OnlyPolk

The Yammie and the Polkie have lived together for years. Now there's been a tweeter out on that right speaker for some time, I don't know how long since I discovered it when I took it in to the shop to have the terminals redone. So that right channel amp has not taken the full load (not sure if that statement is correct, the tweeter was not working, I guess that means it does not present any resistance). What if I connect the left speaker to the right channel and see what happens.

OnlyPolk

Also the AVR cuts out when the musical passage increases in volume with the tweeters working hard at a given setting of the volume control. So it will play at fairly moderate levels till there is this transient in the music. Another thing I found is that cutting the "effect" switch off (this is the switch that disables the DSP mode) will enable the protection circuit fairly quickly. I'm beginning to think it's the amp. I will experiment with right speaker on the left to see if that causes the problem

heiney9

OnlyPolk wrote:

Also the AVR cuts out when the musical passage increases in volume with the tweeters working hard at a given setting of the volume control. So it will play at fairly moderate levels till there is this transient in the music. Another thing I found is that cutting the "effect" switch off (this is the switch that disables the DSP mode) will enable the protection circuit fairly quickly. I'm beginning to think it's the amp. I will experiment with right speaker on the left to see if that causes the problem

The above quote leads me to strongly believe it's a receiver issue. This is a 7 channel AVR all in one receiver, correct? You keep stating 7 seperate amps, to me that means 7 mono block amplifiers with the AVR as the pre-amp. Which is huge difference than a 7 channel receiver.

H9

OnlyPolk

You are right heiney about the 7 channel. It's 7 power amps. (i'm not sophisticated about these things). I hooked up my left SDA to the right channel and the receiver works fine. I replaced the tweeters in this one with the new silk domes to make it just like the right SDA that overloads the amp and that works too.

So it's either something in the speaker or the receiver being unable to drive two SDA's (could that be the pre-amp section?). A 1991 review of the Yamaha states that the protection circuit activated with a 2-ohm load.

OnlyPolk

Should I look for another receiver. There are two Yam ASP's for sale on AudioGon. One is my model ASP1000 and the other the upgraded ASP1. Any advice on a good 7 channel integrated amp? My speaker is in the shop being checked out.

F1nut

Geez, just wait until the shop checks out the speaker. Get them a schematic so they know what they're looking at.

danger boy

i'd say.. for testing porpoises, unplug the tweeter in the speaker that is causing the problems.. then power them both up again. see what results are after that. it may help isolate and narrow the problem down some.

I too think the Yammie is struggling now with the increased load of all the speakers pulling juice from it.. and it's shutting down at increased volume.

read-alot

"my AVR shut down whenever the music I was playing ramped up in volume"

I have spoke on this until I finally gave up in another thread about "Powering SDA2 Speakers". I also mentioned in OnlyPolk's other thread he started that the Yamaha I had (DSP-A1000) was not suited for these speakers.
If you want a receiver to do the job look at B&K, I have two sets of 4 ohm SDAs on one and it just begs for more. I would also look a running a dedicated power outlet, she runs alot of current.

OnlyPolk

Readalot: the A1000 might not do justice as you said. But it has worked with these speakers since 1991. Something in that speaker, since that repair, is presenting a low resistance (impedance I guess) that the amp can' take.

Have you looked into the new breed of Yamaha integrated amps. Like the RX V2600?

heiney9

OnlyPolk wrote:

Readalot: the A1000 might not do justice as you said. But it has worked with these speakers since 1991. Something in that speaker, since that repair, is presenting a low resistance (impedance I guess) that the amp can' take.

Have you looked into the new breed of Yamaha integrated amps. Like the RX V2600?

OnlyPolk, you're new here and I'm not trying to be flippant but you asked us what the problem was, you gave use 2 choices to choose from, explained your situation and we are giving you the most appropriate answer based on the info you have provided. Based on what you've written it's most likely the receiver, UNLESS the shop that is repairing your speaker has done something other than replace the tweeter and terminals.

I understand the Yammy has worked all these years, but obviously there is a problem now and it's most likely the receiver. Just replacing a tweeter and doing nothing else shouldn't cause the problem you are having. Personally, I get irked when people ask questions like yours and then want to argue with the answer.

Your next step is to hook up another set of working speaks to the Yammy or hooking the Polks to another working receiver or sending the Yammy for repair. At this point we can't seem to help you any further.

I suppose as 1 last suggestion it is possible that during transport of the speaker to the repair shop something coul've come loose in the x-over etc. Call Polk CS as they have a troubleshooting guide specific to the SDA series and start there. If there is an issue with the speakers that should flesh it out. Or, if you really trust the shop, get the troubleshooting guide and give it to them to work on.

H9

OnlyPolk

Wow! I seem to have stirred some people up when I sincerely did not intend to. First, I am very grateful to this forum. I don't know much about home electronics and for the past 15 years I have not done any reading or paid any attention to what was going on. So the information I've received here has been very valuable.

I did not intend to argue with anyone about the answers nor did I expect someone here to solve my problem. I thought I was simply providing answers to questions. (It's interesting but one of you seems to have edited out his replies perhaps to make my replies seem combative when they were not).

Thanks for your help again and I apologize if I seemed to have been a bull in your little china shop..

heiney9

Printed word is hard to interpret. You didn't offend me and it was not my intention to offend you. I think the best course right now is to call Ken @ Polk CS and get a copy of the SDA troubleshooting guide. Once you've ruled out everything in there then we can move forward.

I understand your mild frustration in that everything worked fine together before the repair and tweeter swap and now it doesn't. SDA's are a very unique "animal" and perhaps the shop replacing the binding posts took it upon themselves to make some other "good intention" changes that mucked everything up.

That's hard to tell until you go thru the series of checks in the SDA trouble shooting guide.

Good luck and I'm sorry if the tone of my post was too harsh, it wasn't intended to be that way.

Trouble shooting like this has to be done in a certain order otherwise you end up chasing your tail

H9

P.s. FWIW, the tweeter swap in and of itself shouldn't have this effect. Perhaps the issue that caused the tweeter to fail in the first place is now rearing it's ugly head. It's rare that a tweeter would just fail for no reason.

ND13

One more thing to check would be the polyswitch that protects the tweeter from getting damaged. When it starts to go bad, it slowly worstens over time and eventually will shut down at lower and lower volumes. Have your shop check it out. You have to remember that the crossover in the SDAs isn't just a simple 2 way. It's a little more complicated than that. It has to do more than just roll off frequencies.

If you have a friend that will allow you to try another AVR to see if the same thing happens when everything is hooked up to it, you might want to try that. That way, you can rule out the receiver as the culprit.

I edited my earlier posts, because they weren't helping and didn't want to confuse anyone that might search for the same problem in the future. Plus, redundant "guesses" at the cause of your problems were starting to come in.