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Deleted member 550749
May b some kind of circuit error, generally never seen zobel with 22uf that's huge cap for zobel let's see who is gonna fix this ,best of luck
What DC offset do you measure at the amp's output?
Does it also pop without signal/program?
Does the amp oscillate without the Zobel? Requires scope.
22µ looks way too large.
Does it also pop without signal/program?
Does the amp oscillate without the Zobel? Requires scope.
22µ looks way too large.
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Deleted member 550749
In my one amplifier this types of problem happened before, that's jus because of lower emitter resistor causes , tip441+42 i think there u need a resistor like 0.22ohm hope this will fix the problem
If open the DC power supply ( 16V ,- 16V , 0.4A , 0.4A ) About 0.25V.
No.
If doesn't have Zobel circuit，the sound are great.
The purpose of a Zobel network is to prevent the amp's output seeing a light or inductive load at very high frequencies, which could lead to destructive VHF instability of the output stage itself. It's needed with non-global-feedback amps too.
It must be before any inductor for this reason, and as close to the output devices as you can make it. 100nF is plenty, do not use more or you may burn out the resistor. The resistor should be about the nominal amplifier load, so 10 ohms for an 8 ohm amp is commonly used. Thus at very high frequencies this resistor is seen as the main load, making it definitely resistive upto 100MHz or beyond. This prevents the output stage from being an inadvertent RF oscillator.
A 22uF capacitor will likely be inductive at VHF and allows the audio signal to heat up the resistor excessively. Use 100nF unless you have a very good reason not to.
The inductor (air-cored, several µH) is to avoid the amp seeing an overly capacitive load from long cables, which can oscillate the GNFB loop by adding more phase shift. This is not needed if there is no global feedback loop.
It must be before any inductor for this reason, and as close to the output devices as you can make it. 100nF is plenty, do not use more or you may burn out the resistor. The resistor should be about the nominal amplifier load, so 10 ohms for an 8 ohm amp is commonly used. Thus at very high frequencies this resistor is seen as the main load, making it definitely resistive upto 100MHz or beyond. This prevents the output stage from being an inadvertent RF oscillator.
A 22uF capacitor will likely be inductive at VHF and allows the audio signal to heat up the resistor excessively. Use 100nF unless you have a very good reason not to.
The inductor (air-cored, several µH) is to avoid the amp seeing an overly capacitive load from long cables, which can oscillate the GNFB loop by adding more phase shift. This is not needed if there is no global feedback loop.
What's the reason for the TIP transistor output stage when the LM1875 can drive a 4 Ω speaker directly?
The 1875 has better transistors already in it for that speaker. Also if you try to pick off the feedback After that inductor you certainly Will get "mixed sound", maybe even a little smoke.
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Deleted member 550749
R u trying to boost wattage from lm1875 by adding another output transistor, if yes then shearch for propper schematic , don't play with this beautiful ic otherwise that gonna fry 😉 search , search, search until u get the proper one or two some expert, who makes amp like this, circuit is basic opamp direct coupled amp but I thing there will be more circuitry