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β22

beta22

Re: β22

Postby KASaudio » March 17th, 2019, 3:16 pm

DEFL wrote:Where: Clamp the wires that go from beta boards to output jack (TRS in your case?) in the hinged ferrite beads. What: The link is quite self explanatory what you need. Just try it and report back if it helps.

I installed Zobel networks on speaker terminals as well as on the 6.3 mm neutrik socket, this does not affect this effect.
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Re: β22

Postby amb » March 17th, 2019, 3:28 pm

Are you testing this with no source connected? That is not a valid mode of operation...
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Re: β22

Postby KASaudio » March 17th, 2019, 3:42 pm

amb wrote:Are you testing this with no source connected? That is not a valid mode of operation...

With the connected source is exactly the same effect(at minimum volume, exactly at the maximum don't know, can't check). I myself will study this problem more closely, then I will add a review.
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Re: β22

Postby KASaudio » March 19th, 2019, 12:01 pm

There is some clarity in the source of the noise, it is ground chanel, for some reason it works unstable, constantly on the resistor R9 voltage floats, because of this, the quiescent current changes, but that's what this noise I do not know. If ground chanel is excluded from the chain then everything works fine and there is no noise. What are your ideas on this?. After the amplifier is disconnected from the mains for several hours, the voltage drops to 3.2 V on the resistor R9, but the quiescent current also drops to 20-30 mA, and the noise disappears.
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Re: β22

Postby KASaudio » March 19th, 2019, 12:37 pm

I forgot to tell you that only on the ground chanel I have not changed BJT 560-550,left "on semiconductor", they are very much heated, on other boards are philips and they are very little heated,(could not install all philips due to the lack of 8 pieces BC560C, 550 I have a lot, but 560 there are only 4 pieces) what considerations do you have about this?
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β22

Postby amb » March 19th, 2019, 12:37 pm

KASaudio wrote:There is some clarity in the source of the noise, it is ground chanel, for some reason it works unstable, constantly on the resistor R9 voltage floats, because of this, the quiescent current changes, but that's what this noise I do not know. If ground chanel is excluded from the chain then everything works fine and there is no noise. What are your ideas on this?.

Check thoroughly the ground channel board that you have installed all the correct value resistors and capacitors, in the right locations. There are some differences between the ground channel and the left/right channels.

After the amplifier is disconnected from the mains for several hours, the voltage drops to 3.2 V on the resistor R9, but the quiescent current also drops to 20-30 mA, and the noise disappears.

This makes no sense. How can there still be that much voltage and current when the board had been powered off for several hours?

I forgot to tell you that only on the ground chanel I have not changed BJT 560-550,left "on semiconductor", they are very much heated, on other boards are philips and they are very little heated,(could not install all philips due to the lack of 8 pieces BC560C, 550 I have a lot, but 560 there are only 4 pieces) what considerations do you have about this?

I don’t know why there is a problem with the On Semi versions. Where did you get them from? Are they genuine?
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Re: β22

Postby KASaudio » March 19th, 2019, 12:54 pm

I said it wrong, after the amplifier has been disconnected for a few hours and then I turn it on, then the resistor R9, the voltage of about 3.2 V. Although I set to 4.5 V.
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Re: β22

Postby KASaudio » March 19th, 2019, 1:03 pm

amb wrote:
KASaudio wrote:There is some clarity in the source of the noise, it is ground chanel, for some reason it works unstable, constantly on the resistor R9 voltage floats, because of this, the quiescent current changes, but that's what this noise I do not know. If ground chanel is excluded from the chain then everything works fine and there is no noise. What are your ideas on this?.

Check thoroughly the ground channel board that you have installed all the correct value resistors and capacitors, in the right locations. There are some differences between the ground channel and the left/right channels.

After the amplifier is disconnected from the mains for several hours, the voltage drops to 3.2 V on the resistor R9, but the quiescent current also drops to 20-30 mA, and the noise disappears.

This makes no sense. How can there still be that much voltage and current when the board had been powered off for several hours?

I forgot to tell you that only on the ground chanel I have not changed BJT 560-550,left "on semiconductor", they are very much heated, on other boards are philips and they are very little heated,(could not install all philips due to the lack of 8 pieces BC560C, 550 I have a lot, but 560 there are only 4 pieces) what considerations do you have about this?

I don’t know why there is a problem with the On Semi versions. Where did you get them from? Are they genuine?

I can not verify the authenticity of the transistors "on semiconductor" bought from a very well-known supplier, but philips himself for a long time looking on the Internet, bought everything he could find, something from Germany, something from Austria.
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Re: β22

Postby KASaudio » March 19th, 2019, 1:07 pm

I'll check the Board again for errors, but I don't think that's the case.
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Re: β22

Postby KASaudio » March 19th, 2019, 1:26 pm

Yeah, there's definitely one error with the resistor. tomorrow will fix that. On ground chanel R1=475Om? Or resistor to use?
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