blowing circuit in amp

twmackey

Well-known member
Jun 25, 2012
53
#1
I have yamaha 5.1 stereo amp and outdoor speakers and a six speaker volume control to adjust differnet speakers in the garden but I hook them up they keep shutting down the amp. I know if you do not get the wiring just right it can cause a short. I have done every thing I kow to ensure this doesn't happe but it keeps shutting down the amp. all the speakers are at 8oms. When I use a cheap off the shelf home theater system it works fine and I do not blow the amp. Any sugesstions?
 

holmern

Well-known member
Jun 27, 2012
48
Austin, TX
#2
How did you wire the speakers? If you do more than one speaker off of each output (Daisy chain) your impedance will be lower than what your amp can handle and that will give you problems.

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dremin2flyhi

LifeTime Supporter
Jun 4, 2010
121
Darlington, SC
#4
Double Check on the back of the receiver-- Most of the Yamaha's had a switch for the 6 or 8 ohm also.. Also might help to get a speaker switch box for the selection of speakers.
 

CraigMW

LifeTime Supporter
May 19, 2011
696
Orange County, CA
#5
Sounds like the impedance is not set to 8 ohms or around there. Most non-pro amps will choke if they drop below 4 ohms. Is the volume control supposed to do impedance matching like the ones from OSD? I set up a system using OSD's impedance matching 300W controls and never had trouble with this. Before, I had just run a couple pairs of speakers in parallel and this would cause the HK amp to thermal out at moderate levels. If you have more than one pair of speakers, either get separate amps to drive them, or get impedance matching volume controls. Unless specifically stated, speaker switches don't necessarily do impedance matching either.
 

Ohm_Boy

TFP Expert
May 1, 2007
1,344
Orlando, FL
#6
If the speakers are wired in parallel, the resistance (actually, impedence, since it is an AC circuit, but I digress) will be lower than 8 ohms. The resistance of two 8 ohm speakers in parallel is 4 ohms, three parallelled would be 2.666 ohms, and six 8 ohm speakers in parallel would be 1.33 ohms. The actual relationship is R[sub]total[/sub] = 1/(1/R[sub]1[/sub]+1/R[sub]2[/sub]+1/R[sub]3[/sub]...+1/R[sub]n[/sub])

When you wire two 8 ohm speakers in series though, the resistances add, thus two 8 ohm speakers in series would be 16 ohms, etc.

If you have to connect a few speakers together, they can be arranged in a combination of series and parallel connections to end up with a target overall impedence.
 

twmackey

Well-known member
Jun 25, 2012
53
#7
Thanks for getting back with me I do not bleave I have a switch on the back. I will check more closer. The speakers are wired from the amp into the input of the volome control, each wired seperately for 6 different pairs of speakers. I do know if my niles has OSD. Speakers say eight ohms.
 

jlentz32

Well-known member
May 27, 2011
61
#8
As mentioned earlier, it's most likely a low impedance problem. If you've got six speakers in parallel it's gonna choke the amp. Even serious professional amps don't do below 2Ohms very well. I try to target my stuff at 4Ohms.

What length and gauge are your speaker lines? This will also screw up the impedance. The fatter(&shorter) the better.

I've got a separate amp to control my outside speakers. Still trying to figure out a good output from my Sony though. I'm spoiled by pro gear at work...


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jlentz32

Well-known member
May 27, 2011
61
#9
Come to think of it what niles stuff are you using?
One other thought.
Is it for 4/8 Ohm or 70/100V? Huge difference.

70/100Volt is what you use to hook up a ton of speakers on a long line. Think paging/outdoor sports announceing/etc.


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twmackey

Well-known member
Jun 25, 2012
53
#10
Looks like my model HTR 6230 has the ohm selection built into the program of the receiver. I have to take a look at the Niles. May be I have to use OSD products. It is a a Niles SSVC-6 speaker selection system. It says it safeguards amp ad receiver. 100 watts and a selectable impedance magnification for up to 6 pairs of speakers.
 

CraigMW

LifeTime Supporter
May 19, 2011
696
Orange County, CA
#11
Sorry, OSD=Outdoor Speaker Depot, just one of several vendors for speaker level controls that have impedance matching. Lowes sells the OnQ version (that does impedance matching, but is quite a bit more expensive). The point is that these need to be properly wired to maintain a load that does not dip too low below 8 ohms, as doing so will cause the amp to clip and then overheat. The ones I prefer to use have transformers instead of variable resistors, and have a fairly clean frequency response. If wired correctly, you can one or a dozen pairs of speakers connected to a single amplifier (though a dozen would not make much sense).
 

twmackey

Well-known member
Jun 25, 2012
53
#12
I sat down last night and tried it with just 1 pair speakers and it keeps tripping the circuit in the receiver. In all honesty I bought this at radio sahck they repaired it and I got it home and it woudn't turn ou so they traded it out for a new one. that was last summer. So I haven't tried to use it i a year. I was using a cheap home theater system that was using out in the yard and was working great until stopped working on the cable TV side, workig great for a five disk CD changer. So I'm interested in a amp that has a tanformer in them. I do have an old yamaha receiver I may try that one and see if that one will work for my applicaion.
 

CraigMW

LifeTime Supporter
May 19, 2011
696
Orange County, CA
#13
Old Yamahas are great. They really knew how to build good amplifiers using monolithic op amps. Now, they are just like the rest, more concerned about video than audio. But, the old ones are built like tanks and usually sound great. It might require some de-oxing of the pots and switches, but I'd recommend you use that in a heartbeat.
 

twmackey

Well-known member
Jun 25, 2012
53
#14
I bought it at a flea market I will try it and see if that will suit my needs. I do not know how old it is. I have to correct that, it is a sansui A7 amp. I thought it was a old Yamaha. I have had the black face series Sansui I got in Guam when I was stsayined there.
 

twmackey

Well-known member
Jun 25, 2012
53
#15
But it doesn't have the inputs like the yamaha How wuld I connect them if I wanted use it with the yamaha, assuming I can keep it from blowing circuits.
 

twmackey

Well-known member
Jun 25, 2012
53
#16
I have the Sansui 7 and I hooked to a pair of speakers and are work ing fine so far. I put the TEAC 5 disc changer into the tuner input and then took the out put of audio on the digital cable box and put it into the AUX of the AMP. I will hook up the other five pairs of spears to the Niles later. I like the simplicity of the Sansui Amp, it has adjustments like balance, Bass and trebble and left and right chanel. I can crank the volume with out blowing a circuit.
 

CraigMW

LifeTime Supporter
May 19, 2011
696
Orange County, CA
#17
The only input that won't work on that Sansui amp (also a good solid brand) would be the phono input. They are a different impedance than other inputs, and have an RIAA equalization curve designed for LP playback on a turntable. You should be able to source a 1/8 to RCA cable to connect up an iPod or MP3 player if needed.
 

twmackey

Well-known member
Jun 25, 2012
53
#18
Well the sansui A7 blew fuse I put a new one in and it imediately blew again. I'm back to using my surrond sound amp which is working fine. It is a cheap insignia.
 

CraigMW

LifeTime Supporter
May 19, 2011
696
Orange County, CA
#19
Hmm. Maybe the Sansui bit the dust? Did it blow the fuse when all of the speakers were loaded up on it, or with a single pair. Have you tried a different pair of speakers with different wires on the Sansui? Could be some bad speaker wiring somewhere.
 

twmackey

Well-known member
Jun 25, 2012
53
#20
I will put another fuse in it and disconnect all the speakers and see if it has a problem then. It worked for for 2 days and I put in another fuse and then it blew right away.

Maybe some one post what kind of setup they have. I have 2 pair deck speakers that are 8 oms Auvo speakers and I have 4 pairs of rock speakers at 8 oms and using 14 guage direct burial wire in the yard and outdoor speaker wire on the deck.