Very strange problem when bi amping

Seth=L

Seth=L

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#41
brad said:
In case anyone is curious, here is the whole system.
I'm not an audiokarma member, so I guess I'm SOL on that.

It seems like everyone has given up on you.:eek: You stated in your first post that when the Eminence was used exclusively that the crackling sound went away. This alleviates the bad cap theory.

I have some more questions about the system to maybe better understand the problem. When the crackling occurs is it during a peaks from the source recording? Which preamp are you using to connect to both the Eminence and Citation amplifiers? How are the two amplifiers connected to the preamp? Low level distortion, like crackling is usually low level electronics clipping. It's possible that by connecting two amplifiers to the same set of stereo preouts is putting too much of a load on your preamp's output.

Given what you stated thusfar it would be the most logical scenario based on that the problem went away after you connected just the one amplifier. You also stated you have a power conditioner. I don't think you are losing high level power anywhere.
 
Rickster71

Rickster71

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#42
Sorry, the picture is a bit fuzzy, I used my phone. I use banana plugs at the other end, they are similarly clean. The cable is 14 gauge and for what it's worth the woofer connection is on the left.

The picture is a little blurry, but it looks like (from here) the red insulation is stuck under the lug.
 
P

PENG

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#43
I'm not an audiokarma member, so I guess I'm SOL on that.

It seems like everyone has given up on you.:eek: You stated in your first post that when the Eminence was used exclusively that the crackling sound went away. This alleviates the bad cap theory.
Seth, when he uses the Eminence to power the whole speaker he would have re-connected the jumper back between the hi and lo crossovers. The complex (combination of resistance, inductance and capacitance) load nature would be different and that could have some effects on bad caps. I know it is unlikely that bad caps would be the root cause but it cannot be completely eliminated.
 
Seth=L

Seth=L

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#44
Seth, when he uses the Eminence to power the whole speaker he would have re-connected the jumper back between the hi and lo crossovers. The complex (combination of resistance, inductance and capacitance) load nature would be different and that could have some effects on bad caps. I know it is unlikely that bad caps would be the root cause but it cannot be completely eliminated.
I thought I was on my A game with that post. I've been incredibly off lately in a lot of aspects.
 
brad1138

brad1138

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#45
Seth, you don't need to be a karma member to see the pix. Rick, I know it looks that way but it isn't. Also I do the switching with the banana plugs at the amps.

Thanks,
Brad
 
Seth=L

Seth=L

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#46
Seth, you don't need to be a karma member to see the pix. Rick, I know it looks that way but it isn't. Also I do the switching with the banana plugs at the amps.

Thanks,
Brad
When I click on the links it requests a login for me to view them.

What do you mean you do the switching with banana plugs at the amps?
 
P

PENG

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#47
I thought I was on my A game with that post. I've been incredibly off lately in a lot of aspects.
I thought you were on A+ in terms of logically thinking.:D I also thought that 'bad cap' being the cause is highly unlikely. One would think that even if his amp has output caps that are defective it would affect low frequency signals, yet he is having issue when driving the speakers without the bass drivers.

The only thing is, we are dealing with complex loads so things can get weird. For clarity, by 'complex' I do not mean just impedance, but the nature of that impedance. The impedance of two filter networks can be the same at a particular frequency, but their frequency response curve would be completely different. The way they interact with external capacitors would also be different. Okay I am willing to downgrade the 'bad cap' probability to 'near zero'.:):eek:
 
brad1138

brad1138

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#48
When I click on the links it requests a login for me to view them.
That is weird, I logged out and could still view them, I'll post them here later.

What do you mean you do the switching with banana plugs at the amps?
I was replying to PENG, I wasn't quite sure what he meant about how I switched between amps. Just meant I don't move the cables at the spk., not a big deal.
 
Seth=L

Seth=L

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#49
Here's something you could try. Does your Yamaha have an all channel stereo mode? Try connecting the Eminence to the surround preouts while the Citation is connected to the front preouts and see if the crackling continues. If it does then you can be sure the problem is at line level.
 
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PENG

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#50
I was replying to PENG, I wasn't quite sure what he meant about how I switched between amps. Just meant I don't move the cables at the spk., not a big deal.
I never said anything about switching amps. I was saying when your amp was driving only the mids/tweeters, you obviously have to remove the jumpers between those terminals and the bass drivers terminals and when you use the amp to power the whole thing you would have to re-connect the jumpers.

My point is, the load presented to your amp is quite different when you switch between (again, not amps) powering all the drivers and just the mids and tweeters.
 
highfigh

highfigh

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#51
I think it's time to call some of your old contacts in the business who service amps, etc. Then, they can put the amp on a load and connect it to an oscilloscope so they can see when the signal changes. Guessing won't work and at this point, it's just confusing the issue.
 
brad1138

brad1138

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#52
Here is my system, I put it in the AudioHolics system gallery thread, it is the second listing on that page, #342. I will post more when I have time to do some more tests, real busy at the moment though.

Thanks,
Brad
 
TLS Guy

TLS Guy

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#53
Here is my system, I put it in the AudioHolics system gallery thread, it is the second listing on that page, #342. I will post more when I have time to do some more tests, real busy at the moment though.

Thanks,
Brad
I have been pondering your problem for some days.

It will not be possible to give a definitive answer, to your problem without oscilloscope, signal generator at the minimum.

I suspect your problem is voltage related.

It is not understood by many that you can clip all amps at zero watts. In other words any amp can be sent into voltage clipping, even when producing zero watts.

Now in most speakers impedance drops below 600 Hz except for tuning peaks.

Now with passive biamping both amps are reproducing the same signal although power output is different. Now you seem to think that when biamping the power available is the sum of the amp power. Nothing could be further from the truth. The HF amp will deliver signifivanlt less power than the bass amp. In fact the power increase is usually less than 3db and negligible.

However, once you decouple the crossover sections the impedance seen by the HF amp in particular is drastically changed. The impedance will be high and the voltage at the output terminals high.

So in your situation, I suspect you are either sending you HF amp into voltage clipping or you are sparking caps in the crossover from excess voltage. Either way if you keep this up there is a good chance you will do serious damage.

There really is no case at all in my view for passive biamping. The reason for biamping is to get away from problems of passisve crossovers, which passive biamping does not do.

The next issue is that you are using different amps for top and bottom. I would bet you don't know the phase. response of the amps. There is a very good bet they are different. Many amps are phase inverting and many are not. The owners manual is almost always silent about this.

If you are going to use different amps for biamping of any type, you must have instruments and know how to use them. You need to measure the phase response of your amps or you don't know how to wire them up.

My strong recommendation to you is to forget passive biamping, which I never recommend, despite what you might have read elsewhere.

If you are going to contemplate biamping, of any type, you need to be expert, and if you use different amps you must own instruments, and know how to use them.

The types of problems you are experiencing are not unusual, and in fact to be expected.

Courses of action like biamping are usually recommended by very ignorant journalists who have no grasp of the real issues involved.
 
brad1138

brad1138

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#54
I have started using the Citation in bridged mode and started a new thread about it here.

As for my problem, I am not going to worry about it now. I have started using the Eminence 300 to run my center channel spk and that is sounding great. The new thread also contains my final thoughts on the biamping I was doing.

Thanks,
Brad
 

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