My 1st post here: hi all of you!
I want to remove ALPS Blue Velvet from my integrated amplifier and I read somewhere that a resistor of the same value should be replaced with (some say in parallel others in series), but I would like to see a simple schematic, if possible, in order to be sure.
The potentiometer is a motorized ALPS 10KΩ Blue Velvet Stereo (RK27112) just as the picture in attachment.
How to do that?
So many thanks for any appreciated addressing!
I want to remove ALPS Blue Velvet from my integrated amplifier and I read somewhere that a resistor of the same value should be replaced with (some say in parallel others in series), but I would like to see a simple schematic, if possible, in order to be sure.
The potentiometer is a motorized ALPS 10KΩ Blue Velvet Stereo (RK27112) just as the picture in attachment.
How to do that?
So many thanks for any appreciated addressing!
Attachments
If you want to remove it then all you need do is link in and out for each channel. That will pass the full audio signal from the stage feeding the control into the stage receiving it.
If that level is to high then you need to make a divider by fitting a resistor between in and out and then another resistor from out to ground. So four resistors in all. Aim to keep the total resistance similar to the 10k of the pot. So for example a 4k7 and 4k7 would cut the signal in half and present a total load of 9.4k.
The leads that went to the motor should be insulated so that they can not touch anything.
If that level is to high then you need to make a divider by fitting a resistor between in and out and then another resistor from out to ground. So four resistors in all. Aim to keep the total resistance similar to the 10k of the pot. So for example a 4k7 and 4k7 would cut the signal in half and present a total load of 9.4k.
The leads that went to the motor should be insulated so that they can not touch anything.
Mooly, thank you very much for your quick and clear reply!
Just to be sure I do understand your appreciated explanation in attachment there are 2 simple schematics: are they correct?
Resistor 1/4W is sized enough?
Thank you again!
Just to be sure I do understand your appreciated explanation in attachment there are 2 simple schematics: are they correct?
Resistor 1/4W is sized enough?
Thank you again!
Attachments
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Why just not set it to 10 and leave it there?
It has 3 advantages:
* it passes full signal level
* it does not affect impedance; next stage sees just the driving stage output impedance
* previous stage sees a DC resistance to ground it´s designed to handle well
It has 3 advantages:
* it passes full signal level
* it does not affect impedance; next stage sees just the driving stage output impedance
* previous stage sees a DC resistance to ground it´s designed to handle well
Thank you for your appreciated reply, JMFahey!
I need more room inside my amp since I want to replace the pot with a volume control board.
And that is the only way to do it.
That's it 
You just vary the ratio of the resistors to get the level you want, for example reducing the 4k7 between out and ground will lower the level. Just try and keep the overall value to close to 10k as I mentioned earlier.
So 8k2 and 1k8 would cut the level a lot, while swapping them round to 1k8 and 8k2 would reduce it only a little.
You just vary the ratio of the resistors to get the level you want, for example reducing the 4k7 between out and ground will lower the level. Just try and keep the overall value to close to 10k as I mentioned earlier.
So 8k2 and 1k8 would cut the level a lot, while swapping them round to 1k8 and 8k2 would reduce it only a little.
That's it
You just vary the ratio of the resistors to get the level you want, for example reducing the 4k7 between out and ground will lower the level. Just try and keep the overall value to close to 10k as I mentioned earlier.
So 8k2 and 1k8 would cut the level a lot, while swapping them round to 1k8 and 8k2 would reduce it only a little.
Thank you again, Mooly!
Your great explanation was very clear and accurate!
If I may, only one more thing please: since the potentiometer no longer exists and then considering the pins in the attached picture just as wires terminals where/how I have to solder GND terminals?
suddenly I got confused for a moment... 🙄
You should use the same ground terminal that the original pins on the volume control used. To use any other points could introduce noise/hum as it may not be a 'clean'ground.
If you find you don't need the resistors (you just link in and out) then you leave the ground terminals floating (not connected to anything).
You should be able to solder the resistors very neatly on the print side of the PCB directly to the holes/pads that the controls pins used.
If you find you don't need the resistors (you just link in and out) then you leave the ground terminals floating (not connected to anything).
You should be able to solder the resistors very neatly on the print side of the PCB directly to the holes/pads that the controls pins used.
Please note that really the pot is cabled with loose wires, so I have 4 shielded coaxial cables terminals (2 red + 2 white + 4 shields + 2 leads that went to the motor) free to move inside my integrated amplifier cabinet (please look at the picture in attachment).
I can only solder link or resistor from end of a cable (red) to the end of the other one (white) for L channel and to do the same for the R channel and for GNDs.
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The 10k simply loads the driving stage with 10k.
Its impossible to say whether that is doing anything useful without knowing the exact circuit details... the only thing I can think of would be it terminating capacitor coupled stages correctly and providing a ground reference point. That is quite likely actually because volume controls should never have any DC present on them at all as it can make them noisy.
So yes, keep the resistor even if you do link in and out.
It might be easier adding the resistors (and linking the wires) elsewhere in the unit such as at the input or output of the PCB's. With no control fitted you don't now need the two leads coming through that hole to the front panel. Make the connection more direct if you can.
Its impossible to say whether that is doing anything useful without knowing the exact circuit details... the only thing I can think of would be it terminating capacitor coupled stages correctly and providing a ground reference point. That is quite likely actually because volume controls should never have any DC present on them at all as it can make them noisy.
So yes, keep the resistor even if you do link in and out.
It might be easier adding the resistors (and linking the wires) elsewhere in the unit such as at the input or output of the PCB's. With no control fitted you don't now need the two leads coming through that hole to the front panel. Make the connection more direct if you can.
Tacking onto this since it is the same topic.
I want to implement a bypass switch with the pot still in. Thinking about it, I was concerned that simply shorting the In to the Out (wiper) might not work correctly, depending upon what rotational position the pot is in at the time. It als is a 4-gang (balanced) pot, making it a bit more difficult.
Thoughts/advice?
I want to implement a bypass switch with the pot still in. Thinking about it, I was concerned that simply shorting the In to the Out (wiper) might not work correctly, depending upon what rotational position the pot is in at the time. It als is a 4-gang (balanced) pot, making it a bit more difficult.
Thoughts/advice?
It works if the pot is at max position, at min position You short the signal.
Better use a switch which switches both wiper & signal