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timg544
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Replacement home audio amplifier questions

Hi, love the forum!

I have a question about replacing an amplifier.  I am trying to hook up my dads old Technics SB-A32 system, and am running into some problems.  For one, the mids aren't working on both towers.  Also, the amp keeps turning off under high load, so i'm pretty sure it's overheating.  The fan doesn't work anymore, so i think that may have something to do with that.  In regards to the mids, i am going to see if replacing the amplifier will solve that problem before i go in and replace the crossover, to see if that's the problem.

 

I was wondering what kind of replacement amp i should get.  I saw this one:  http://www.bestbuy.com/site/Insignia%26%23153%3B+-+200W+2.0+Channel+Ster...

 

But, i looked on the back of the current amplifier, and it said it has 355 watts.  I'm not sure how many watts the speakers are, but i am pretty sure a 200 watt amp wouldn't be able to power these.

It seems that there aren't many two channel amps that go above 200 watts.  So, should i get a 5.1 amplifier, that has around 400 watts?  Since i'm only using two channels, would i be able to get that extra wattage into just two speakers?

 

Hope this makes sense, i can clarify anything if you need.  Thanks in advance for the help!

 

Also, heres a picture of what the Technics look like:

http://www.google.com/imgres?imgurl=http://gallery.audioreview.com/data/...

John Atkinson
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Re: Replacement home audio amplifier questions

timg544 wrote:

Hi, love the forum!

I have a question about replacing an amplifier.  I am trying to hook up my dads old Technics SB-A32 system, and am running into some problems.  For one, the mids aren't working on both towers.  Also, the amp keeps turning off under high load, so i'm pretty sure it's overheating.  The fan doesn't work anymore, so i think that may have something to do with that.  In regards to the mids, i am going to see if replacing the amplifier will solve that problem before i go in and replace the crossover, to see if that's the problem.

I suspect that both midrange units are blown and that is also possibly why your existing amplifier overheats - the fault may have resulted in a short circuit in each speaker's crossover. Your first step should be to borrow a different pair of speakers and see if the amplifier still overheats.

Quote:
i looked on the back of the current amplifier, and it said it has 355 watts.  I'm not sure how many watts the speakers are, but i am pretty sure a 200 watt amp wouldn't be able to power these.

Don't take any notice of these power specifications. The are misleading in the extreme. The speakers, if they are not broken, will play fine with an amplifier of 50 watts or more.

John Atkinson

Editor, Stereophile

timg544
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Thanks for the reply! All i

Thanks for the reply!

All i have is pair of 2 way speakers.  Would they work in testing?  I'm thinking no, since the other speakers were 3 way.

John Atkinson
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Two-Way Speakers Are Okay

timg544 wrote:

Thanks for the reply!

You're welcome.

Quote:
All i have is pair of 2 way speakers.  Would they work in testing?  I'm thinking no, since the other speakers were 3 way.

Those will be fine. Listen to a track you know well and if you are getting a full range of lows, midrange, and highs from both speakers, and the amplifier doesn't overheat, then you know it was your tower speakers that were the problem.

John Atkinson

Editor, Stereophile

timg544
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Speaker test worked!

I hooked up, and was DEFINITELY, without a doubt getting full audio range out of them(i'm still on a small high that my Dads' 20 year old amplifier still works, haha).  Also, the amplifier was operating at near 3/4 (didn't want to blow the smaller speakers out)capacity for 20 minutes, so the amp seems fine.

So, is the problem not the amp at all?  It seems like it is just the mids.  Should i replace the mids?  I took the mid out, and all the wires are connected, on both towers.  It appears there is a crossover with three transistors, and one main coil.  There are 7 wires coming out of that crossover, two to the tweeter, two to the mid range, and three(seems strange) to the subs(there are two subs, so 4 speakers total on each tower).  I thought there should be four going to the two subs(two wires to each), but it seems there is three.

Thanks!

-Tim G.

John Atkinson
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Replacing Midrange Drivers - Not for the Faint of Heart

timg544 wrote:

I hooked up, and was DEFINITELY, without a doubt getting full audio range out of them(i'm still on a small high that my Dads' 20 year old amplifier still works, haha).  Also, the amplifier was operating at near 3/4 (didn't want to blow the smaller speakers out)capacity for 20 minutes, so the amp seems fine.

Good. That was what I suspected.

Quote:
So, is the problem not the amp at all?  It seems like it is just the mids.  Should i replace the mids?

Try contacting the manufacturer to see if they have spare parts. If not, there's not much you can do. I doubt that you will be able to find a replacement driver that works correctly in the speaker and has the appropriate impedance and sensitivity. Sorry.

John Atkinson

Editor, Stereophile

ikymagoo
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Speaker repair

If you want to repair or replace the mid range driver, I would go to parts-express.com send them an email or you can chat online with them, they should be able to help 

timg544
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John, are you sure it is the

John, are you sure it is the speaker that's the problem?  I just feel like it's weird that they both stopped working at the exact same time.

timg544
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So, i had my other speakers

So, i had my other speakers hooked up, and my amp just shut off again.  It's not hot at all though, so it seems strange.  I had the amp at high power for about 20 minutes this time.  Yesterday i had it cranking for about an hour with no problem.

 

On the other hand, when hooked up to the tower speakers(the ones with the mids not working), the amp shuts off after about a minute.

commsysman
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Speakers

Unless you can get exact speaker repacement parts from the original manufacturer, there is no way in hell they will ever work right again. Fixing them right will probably cost more than they are worth anyway.

By the way, there are NO transistors in a crossover; it will consist of inductors (coils), capacitors, and maybe a resistor or two. Technics SB-A32 is the number of the speakers, not the amplifier. It will have a model number on it somewhere. The wattage rating you gave was the total maximum AC power it will draw from the wall, which has nothing to do with its audio power rating.

When you find the model number of the amplifier, go to cnet and search for it and you will probably find specs for it.

Since the amplifier apparently came with a fan to cool the heat sinks, that needs to be replaced before you can expect it to work properly for more than a few minutes. FIX THAT FIRST!! Don't hook it up to those old speakers again unless you want to permanently damage it.

THe power rating of a speaker is only the MAXIMUM power it can handle before you burn it out. Any amplifier that plays them loud enough without distorting audibly is fine.

NEVER operate speakers when there is audible distortion; NEVER! They WILL fry.

Buy a new set of speakers.

Suggestion- Sony SSF-5000 speakers on Amazon for $100 per pair (these are almost certainly better speakers than the originals ever were in the first place). It is also a very good price on those speakers.

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