At the PIO capacitors the reinforcements are made of aluminum foil, at the capacitors with plastic dielectric the reinforcements are made by spraying a mixture of aluminum, zinc on the dielectric surface, usually polypropylene. Never the sprayed layer can have the homogeneity of the solid aluminum foil. From here and the sound differences.
Change the capacitance of the coupling caps at your own risk.
If the negative feedback works now, it may not work when you change the frequency response (and more importantly the phase versus frequency) of those RC coupling networks.
It is not nice to fool mother nature, you may end up with a power oscillator, instead of a power amp.
Check what the phase margin of the amp will be with higher capacitance, or with lower capacitance, before you make a change on what might be a deal breaker. Global negative feedback is also affected by both the load impedance and phase of the loudspeaker as the frequency changes. What works for a coupling cap on one persons speaker, might not work on your loudspeaker.
If the original amp is designed right, the coupling caps values are such that the amp is stable on almost any speaker. But when you change the capacitance, that may or may not still be true.
If the negative feedback works now, it may not work when you change the frequency response (and more importantly the phase versus frequency) of those RC coupling networks.
It is not nice to fool mother nature, you may end up with a power oscillator, instead of a power amp.
Check what the phase margin of the amp will be with higher capacitance, or with lower capacitance, before you make a change on what might be a deal breaker. Global negative feedback is also affected by both the load impedance and phase of the loudspeaker as the frequency changes. What works for a coupling cap on one persons speaker, might not work on your loudspeaker.
If the original amp is designed right, the coupling caps values are such that the amp is stable on almost any speaker. But when you change the capacitance, that may or may not still be true.
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Sweet Spot
I have Yaqin 100B amp being driven by an Emotiva UMC-200 preamp/controller via front inputs.
I'm running it in triode mode into a pair of Gallo CL-4's, 92db sensitivity.
I have plenty of power available, even in triode mode so the question is if I lower the amp output via the front vol control by say 20% is the amp providing additional headroom and dynamic capacity in so doing.
The UMC-200 has very low noise floor, so I can crank it up easily to drive the amp when the amp vol control is lowered by 20%.
Of course the Yaqin runs quieter when the vol. is lowered a bit and there is no noise from the preamp.
Are there any advantages or disadvantages to doing this?
Not an engineer. I can't figure this out.
Any help much appreciated.
I have Yaqin 100B amp being driven by an Emotiva UMC-200 preamp/controller via front inputs.
I'm running it in triode mode into a pair of Gallo CL-4's, 92db sensitivity.
I have plenty of power available, even in triode mode so the question is if I lower the amp output via the front vol control by say 20% is the amp providing additional headroom and dynamic capacity in so doing.
The UMC-200 has very low noise floor, so I can crank it up easily to drive the amp when the amp vol control is lowered by 20%.
Of course the Yaqin runs quieter when the vol. is lowered a bit and there is no noise from the preamp.
Are there any advantages or disadvantages to doing this?
Not an engineer. I can't figure this out.
Any help much appreciated.
To the OP - threads merged, please do not start multiple threads for the same project/amplifier.- Status
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