Integrated amplifier is dual mono with left and right pre-outs. When connecting an RCA (L & R) from integrated pre-out to subwoofers Left and right inputs, both speaker makes a sound even if the balance is all the way to the right, reverse is true if the balance is all the way to the left. Removing the RCA cable from pre-out to sub removes the problem. Would it help if I only connected the "+" from left and right and connect only a single "-"?
You mean the main speakers make sound when rca is plugged into the sub input and the balance is turned? Take pictures of the back of the amp connections and the sub inputs for us. What does +&- have to do with RCAs? There should be no speaker wire from the sub to the main speakers at all.
It may sound a bit tedious, but lets get it correct about 'speakers'. When reading the original post, I can read it more than one way. that makes answering impossible. So, yes, you have two main speakers. Do you have one or two subs? And yes, by preamp outputs, you are referring to RCA outputs? I gathered yes, until I saw +/- mentioned. That made me think that you might be using power outputs, not RCA. Some subs will allow speaker/power amp inputs, but I see less of this these days.
Amplifier is Musical Fidelity A3, dual mono, with pre-outs, no schematics available
only one subwoofer with RCA inputs, No speaker level inputs
Connection is left and right rca cable from amp to subwoofers left and right rca inputs
The main speakers, left and right makes a sound even if the amp is sent a signal to the left channel or right channels only. This happens when an RCA cable is connected from the amps pre-out to the Left and Right inputs of the subwoofer, Removing the RCA cable solves the problem.
How do i connect the sub without having this problem ?
only one subwoofer with RCA inputs, No speaker level inputs
Connection is left and right rca cable from amp to subwoofers left and right rca inputs
The main speakers, left and right makes a sound even if the amp is sent a signal to the left channel or right channels only. This happens when an RCA cable is connected from the amps pre-out to the Left and Right inputs of the subwoofer, Removing the RCA cable solves the problem.
How do i connect the sub without having this problem ?
Very well explained. Thanks. Now I really have to think about it! Seems as though it somehow back feeds the signal, but that still doesn't make good sense to me. Hope that someone here has an idea.
The sub probably has a simple resistor adding circuit to combine the preamp channels into mono.
But this won't affect the main speakers when both of the preamp channels are connected
(as is normally done) to the A3 amp. The preamp's low impedance op amp output shorts out
the other channel that comes through the sub's mixing resistors.
But this won't affect the main speakers when both of the preamp channels are connected
(as is normally done) to the A3 amp. The preamp's low impedance op amp output shorts out
the other channel that comes through the sub's mixing resistors.
Your intention is to get rid of cross talk, is that right?
Here the 2.1 kits use a 4558 and filter to segregate the low frequency signal and feed the sub woofer.
The sub woofer is driven by the third power chip, meaning (usually) a 2030 class chip, with a separate volume control.
So there are three chip amps on a 2.1 board, left , right and sub.
4.1, 5.1 and 7.1 are also sold., the extra .1 means an extra woofer drive chip, and the number of main channels used.
Search for 2.1 amp circuit, that will give you a pretty good idea of what is going on, and do your modification after going through the circuits used.
The populated circuit boards ('kits') are sold in different variations, with woofer volume, bass/treble control and other features as options.
Here the 2.1 kits use a 4558 and filter to segregate the low frequency signal and feed the sub woofer.
The sub woofer is driven by the third power chip, meaning (usually) a 2030 class chip, with a separate volume control.
So there are three chip amps on a 2.1 board, left , right and sub.
4.1, 5.1 and 7.1 are also sold., the extra .1 means an extra woofer drive chip, and the number of main channels used.
Search for 2.1 amp circuit, that will give you a pretty good idea of what is going on, and do your modification after going through the circuits used.
The populated circuit boards ('kits') are sold in different variations, with woofer volume, bass/treble control and other features as options.
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You mean when you connect the sub RCAs to the A3 preamp out, the resistance
between the preamp out RCAs is zero?
If so, the sub just shorts the two inputs together. That would be a bad approach to say the least.
If this is the case, you could add an in-line resistor to each preamp out going to the sub, say 10k.
Like in post #8.
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When i used the connectivity test on the multitester, the tester rang like a doorbell. Resistance is between left and right center pins is 0.5 and 0.9 ohms depending on how hard I insert the probes...
EDIT: Center pins was measured on the pre-amp output of the integrated amp
EDIT: Center pins was measured on the pre-amp output of the integrated amp
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That is definitely a problem! It should be around 20k or more between center pins on the sub input. You could always use just one channel input and get 3db less output from the sub so just turn up the gain. Low low frequencies are usually monoed out anyway.
If this is true, your amp is playing MONO all the time 🙂
You measured with the amp switched OFF and the muting relay shorted both outputs to ground.
Why don't you tell us about your sub? It seems to be the problem which I still have not really understood. Also measure it.
Is it maybe custom build by a specialist?
You measured with the amp switched OFF and the muting relay shorted both outputs to ground.
Why don't you tell us about your sub? It seems to be the problem which I still have not really understood. Also measure it.
Is it maybe custom build by a specialist?
I measured my amp when it was OFF, tried it when it was ON and the short is no longer there.
The subwoofer is an SVS SB3000 subwooofer
The subwoofer is an SVS SB3000 subwooofer
The problem is when the subwoofer is connected via RCA cable, both speakers are working even if only the left channel is receiving a signal, same goes if the right channel is receiving a signal