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PROJECT UPDATE: β24 BI-AMPING

beta24

Re: PROJECT UPDATE: β24 BI-AMPING

Postby SonusBonum » April 19th, 2017, 2:24 am

Morning Ti,

Hypothetically speaking... Since R2 and R4 define attenuation can I replace them with variable resistors in order to fine tune volume...?
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Re: PROJECT UPDATE: β24 BI-AMPING

Postby amb » April 19th, 2017, 4:04 am

It's not advisable. Those two resistors must track each other very accurately in order to preserve the CMRR performance of the amplifier. It's not feasible to accomplish this with two separate pots, and no dual pot that I know of could track well enough.

If you're thinking of putting the pots on the front panel, then it would make matters much worse because these resistors are for negative feedback, and should be kept onboard with short traces (i.e., no air wiring).

Last but not least, changing the gain of the amp requires concurrent change to the compensation capacitor values. It's not possible to do that (there are 6 capacitors minimum).
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Re: PROJECT UPDATE: β24 BI-AMPING

Postby SonusBonum » April 19th, 2017, 1:31 pm

Ok, I'll forget that then... Thanks...!
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Re: PROJECT UPDATE: β24 BI-AMPING

Postby SonusBonum » February 1st, 2018, 4:47 am

Goodmorning Ti,

Been a while, amps still goin' strong...!

Suppose I want to double the output, half the damping or I have "single wire" speakers: Can I parallel the two amps I have available on each side...?
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PROJECT UPDATE: β24 BI-AMPING

Postby amb » February 1st, 2018, 6:33 am

Absolutely not! By paralleling the two amps, when each have super low output impedance, will cause one to look like a dead short to the other and vice versa. They will fight and the result will be instant output stage destruction.

Even if such a thing does not happen (it will, but let’s just hypothesize) paralleling two amps does not give you twice the power. You get the same power output, because you’re not getting any more voltage output headroom.

P = V^2 / R
We have the same V and the same R (speaker impedance).
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Re: PROJECT UPDATE: β24 BI-AMPING

Postby SonusBonum » February 2nd, 2018, 3:04 am

You had me at "not!"... Thx...
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