Just wondering that can we use output transformer 1:1 to convert a dual channel amplifer (each channel 180 deg out of phase) like in a bridge mode to drive on singe channel for noise cancellation, and noise reduction,
I have dual Focal 2.150 amplifiers with 150 w per channel on each , i need two channels only and was wondering that whether i could use a custom made transofrmer to get less distortion like Mcintosh does in in car and tube amplifier. would i be getting 150 w or 300 w from each channel.
Seems interesting avenue for diy. Regards
I have dual Focal 2.150 amplifiers with 150 w per channel on each , i need two channels only and was wondering that whether i could use a custom made transofrmer to get less distortion like Mcintosh does in in car and tube amplifier. would i be getting 150 w or 300 w from each channel.
Seems interesting avenue for diy. Regards
You can only bridge two amplifiers IF the load presented to the output stage given the increased voltage swing does not result in the amp exceeding the power/current capability of the output stages.
In the case of a 1:1 output transformer connected to the two HOT (+) terminals, one each channel, you would have to invert the input to ONE of the two channels. Then connecting the outputs each to one side of a transformer would have no difference in terms of power then connecting the speaker to the same terminals.
Of course there is a difference, since the transformer looks like an inductance between the two terminals, and the load is then has galvanic isolation from the amps. But the impedance remains the same.
The classic McIntosh output stage does not use a simple 1:1 transformer.
You would be getting 600 watts with the bridged pair.
E = I * R and P = I * E so P = I^2 * R OR P = E^2 * R.
This last one is the key. You are going to see the square of the doubled voltage swing divided by the load as the resulting power.
example:
P = 10v^2 /10 = 10 watts
P = 20v^2 /10 = 40 watts
So your output stage has to be able to handle the extra current. Or <poof>.
You will NOT get THD reduction, except to the extent that you run the amp at a lower average level (not significant, in all likelyhood) and there will be no noise reduction, unless there is a signal that can be inverted and cancelled, but it would have to be a common mode signal entering equally at both inputs to the amp, since you would FIRST have to invert the input signal.
If you do NOT invert the input signal then you need a DUAL primary on the transformer, and you are running in parallel, not in P-P.
Either way the transformer will likely introduce some distortion and the cost will not be inconsiderable for one that can handle the power.
Buy another amp if you want more power, or bridge this one with care. (check the manual, it may NOT be bridgable).
_-_-
In the case of a 1:1 output transformer connected to the two HOT (+) terminals, one each channel, you would have to invert the input to ONE of the two channels. Then connecting the outputs each to one side of a transformer would have no difference in terms of power then connecting the speaker to the same terminals.
Of course there is a difference, since the transformer looks like an inductance between the two terminals, and the load is then has galvanic isolation from the amps. But the impedance remains the same.
The classic McIntosh output stage does not use a simple 1:1 transformer.
You would be getting 600 watts with the bridged pair.
E = I * R and P = I * E so P = I^2 * R OR P = E^2 * R.
This last one is the key. You are going to see the square of the doubled voltage swing divided by the load as the resulting power.
example:
P = 10v^2 /10 = 10 watts
P = 20v^2 /10 = 40 watts
So your output stage has to be able to handle the extra current. Or <poof>.
You will NOT get THD reduction, except to the extent that you run the amp at a lower average level (not significant, in all likelyhood) and there will be no noise reduction, unless there is a signal that can be inverted and cancelled, but it would have to be a common mode signal entering equally at both inputs to the amp, since you would FIRST have to invert the input signal.
If you do NOT invert the input signal then you need a DUAL primary on the transformer, and you are running in parallel, not in P-P.
Either way the transformer will likely introduce some distortion and the cost will not be inconsiderable for one that can handle the power.
Buy another amp if you want more power, or bridge this one with care. (check the manual, it may NOT be bridgable).
_-_-
Bear, does a 1:1 transformer not result in an impedance transformation of 1:4 as well? I am speaking under correction.
You can use the transformer to invert one of the outputs, allowing you to bridge it.
Because you can doesn't mean you should: inversion is best made at the signal stage, for both economical and technical reasons.
The best of the transformers is still worst than the worst amplifier, and you will get none of the expected benefits: noise reduction could only happen if both channels have a large, correlated noise like a buzz, and although some even-order distortion cancellation is in theory possible, any effect will be swamped by the transformer's own distortion.
And don't forget the transformer will also degrade the frequency response and the efficiency. Better use it as a paperweight, that's the optimum use for any audio transformer.
Nico, I dunno... I took the OP's spec of 1:1 to mean that somehow the result is the same as a simple isolation transformer, no change in ratio... Vin = Vout, no impedance change then?
_-_-bear
If you can drive one channel of each amp in opposite phase, you can just connect the speaker between the two outputs. Gives the effect you want without needing a xformer.
jan didden
Assuming the outputs can handle the extra current...
In which case the place for a transformer would be at the input, so that one can invert the phase without doing much work...😀
Hi Jan. I see from ur avatar you are doing "blind testing"? 😀
_-_-bear
In which case the place for a transformer would be at the input, so that one can invert the phase without doing much work...😀
Hi Jan. I see from ur avatar you are doing "blind testing"? 😀
_-_-bear
I'm one of the few here that actually trust their ears enough to base my judgements on what I hear only 😀😀
Quite differently.....you expect a serious answer? 🙁
Take a look yourself on the WWW: there is enough to be found on that subject.
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