If you use two ganged pots per channel in an H, you can maintain constant impedances to your signal source and your input stage. The input signal connects to the "top" of one side of the H, and the input stage to the other. The bottoms of the H go to ground, and the wipers are connected to each other. You need four ganged pots for stereo. I had a Sony preamp at one time that had a switch next to the volume control. Up was full open and down was 20 db down (I think). At low volume, you had a lot more control.
With low voltage circuitry - opamp preamp for instance - you get the chance for using a digital potentiometer, which means you can have the advantage of no scratchiness and a good number of attentuator steps (512 for instance). Of course you then need an actual rotary encoder or some such physical control and a microcontroller to drive the pot, and all the associated circuitry. One trick you can play with stepped attentuators is to have a coarse one and a fine one, say 24 x 3dB steps for coarse and 12 x 1/4dB for fine adjustment, many ways to do it.
I have used ALPS pots for more than 20 years, and I have pulled them apart and made one good one out of two broken ones. I have always measured them for best matching and they are never the same, obviously with a close tolerance. The good thing with them is they have a wide carbon track and also they have 5 fingers which makes contact as the wiper onto the carbon track. Five points of contact as opposed to one point of contact. I have had stepped attenuators with the surface mount resisters and they have failed too. One can never get stepped attenuators to go as quiet as a conventional pot.
I think there are some designs that grounds the signal over the wiper, so the part of the signal that goes to the amplifier doesn’t go across the wiper. Hence you got less distortion from the volume control.
Excellent tutorial Mark. I actually like the feel of a good stepped attenuator but they can be expensive -- $200 + I'm using one I got for free, but sometimes the switch on one channel doesn't make good contact so I think it is important to buy a good one. Maybe like the Goldpoints which I've been looking at. Thanks
a typical volum potmeter is not linear?A good autenator has only one smd resistor pr step. They are pop free if pcb layout are done rigth.I use 21 step dact type copy sold by lazer collection on ebay.in my stax amp and benchmark dac.both have multi turn vr,s inside to adjust the channel balance.I use the one marked special hifi grade curve 10kohm witch is the same value as the pots a replaced.Also use 2 stereo on the inputs on my 4 channel amp to adjust all my amps down the db amount i need to let my dsp crossover run in unity gain after rommcorection and or speaker system is calibrated.The filters wil turn down midrange and tweeter section some db.To get the Best i turn it up again and turn down at the amp instead..It is a active speaker system.The 4 channel amp drive tweeter l/r.and midrange l/r. this amp is diy has no local or global feedback and they are quiet.No hiss.In a active system with high efficent thinfilm type midranges and amt type tweeter comersial amps is to noisy.You can hear the hiss in listening position.For the second time in my 46 years of hifi and diy i can honest say those this amp design is the best i have heard.It is famus to be linear.companies like bruel kjær use a verson of this amp design.They made or make messurement equipment.My woofers i use a big pa type power amp.C vega it say but it is a modified verson of a spanish brand.Dx1000.would use a autenator any day. Potmeters are crap and noisy to the sound signal. Sorry for my bad english
Left out resistor noise. Carbon resistors are noisier then metal resistors. Most pots are of the carbon type and most stepper attenuator are of the metal type.
I have stepped volume on my VTA SP-14 tube preamp and the only thing I don't like is you are stuck to the volume level of each step and can't choose a little louder or quieter than the step provides. I generally always play music at one preferred "step" but feel it's just a little too loud there. The step below is too low and the step above is too loud so I feel it's not "just right", kind of like the Goldilocks phenomenon....LOL I don't think precision is a factor, but a stepped attenuator feels nice.
What about a stepped attenuator with a linear wiper between steps? Does anything like this exist? So you keep the feel and precision of a linear pot, but the perfect balance of a stepped attenuator?
Is there way to achieve volume sensitivity on gain POT on parametric EQ. I am wanting to make my EQ to from 1db increment to .5 db increment. Would that accomplished by putting resister on the middle pin? By the way POT on the EQ has center dented with boost to right and cut to left function. Thanks
I don't follow the part about 'what if your amplifier isn't balanced? The gain of an amplifier is normally set by the ratio of two resistors, not by the strength or weakness of a valve.
anyone knows what is the vr1 potentiometer on logitech z 533 pcb? it has a switch and 6 pins 3 back and 3 front. just can't find it anywhere, what a crazy component is this?
Why didn't you show wirewound potentiometers? they are the best. I would disagree that linear and logic are the same they're not the outcome is similar but the operation is different and the sound quality is different from both
Well, in my 30 years of working on audio gear, I've never once seen a wire wound resistor used for a volume pot. I wouldn't put them on my list of good, much less the best for this application. They are jumpy and don't provide a constant sweep at all times.
John sweda No you can't. All that does is reduce the effective range of the pot. A 500R pot after a 100K resistor will have only .05% effect on the output voltage.
If you use two ganged pots per channel in an H, you can maintain constant impedances to your signal source and your input stage. The input signal connects to the "top" of one side of the H, and the input stage to the other. The bottoms of the H go to ground, and the wipers are connected to each other. You need four ganged pots for stereo.
I had a Sony preamp at one time that had a switch next to the volume control. Up was full open and down was 20 db down (I think). At low volume, you had a lot more control.
I expected you to cover the aspect of stray capacitance, which I’m told is much worse in a variable pot versus a stepped pot.
With low voltage circuitry - opamp preamp for instance - you get the chance for using a digital potentiometer, which means you can have the advantage of no scratchiness and a good number of attentuator steps (512 for instance). Of course you then need an actual rotary encoder or some such physical control and a microcontroller to drive the pot, and all the associated circuitry.
One trick you can play with stepped attentuators is to have a coarse one and a fine one, say 24 x 3dB steps for coarse and 12 x 1/4dB for fine adjustment, many ways to do it.
Why not, instead of fixed latches, have the bus carbon resist and use a wiper, combining the best of both?
I have used ALPS pots for more than 20 years, and I have pulled them apart and made one good one out of two broken ones. I have always measured them for best matching and they are never the same, obviously with a close tolerance. The good thing with them is they have a wide carbon track and also they have 5 fingers which makes contact as the wiper onto the carbon track. Five points of contact as opposed to one point of contact. I have had stepped attenuators with the surface mount resisters and they have failed too. One can never get stepped attenuators to go as quiet as a conventional pot.
If you have the time, please discuss Autoformer Volume Controls also known as Transformer Volume Controls. Thank you.
I think there are some designs that grounds the signal over the wiper, so the part of the signal that goes to the amplifier doesn’t go across the wiper. Hence you got less distortion from the volume control.
Excellent tutorial Mark. I actually like the feel of a good stepped attenuator but they can be expensive -- $200 +
I'm using one I got for free, but sometimes the switch on one channel doesn't make good contact so I think it is important to buy a good one. Maybe like the Goldpoints which I've been looking at.
Thanks
a typical volum potmeter is not linear?A good autenator has only one smd resistor pr step. They are pop free if pcb layout are done rigth.I use 21 step dact type copy sold by lazer collection on ebay.in my stax amp and benchmark dac.both have multi turn vr,s inside to adjust the channel balance.I use the one marked special hifi grade curve 10kohm witch is the same value as the pots a replaced.Also use 2 stereo on the inputs on my 4 channel amp to adjust all my amps down the db amount i need to let my dsp crossover run in unity gain after rommcorection and or speaker system is calibrated.The filters wil turn down midrange and tweeter section some db.To get the Best i turn it up again and turn down at the amp instead..It is a active speaker system.The 4 channel amp drive tweeter l/r.and midrange l/r. this amp is diy has no local or global feedback and they are quiet.No hiss.In a active system with high efficent thinfilm type midranges and amt type tweeter comersial amps is to noisy.You can hear the hiss in listening position.For the second time in my 46 years of hifi and diy i can honest say those this amp design is the best i have heard.It is famus to be linear.companies like bruel kjær use a verson of this amp design.They made or make messurement equipment.My woofers i use a big pa type power amp.C vega it say but it is a modified verson of a spanish brand.Dx1000.would use a autenator any day. Potmeters are crap and noisy to the sound signal. Sorry for my bad english
Left out resistor noise. Carbon resistors are noisier then metal resistors. Most pots are of the carbon type and most stepper attenuator are of the metal type.
Do you prefer linear or logarithmic steps?
Also , the speakers , sometime people change one box with different kind of speaker and they sound different.
I have stepped volume on my VTA SP-14 tube preamp and the only thing I don't like is you are stuck to the volume level of each step and can't choose a little louder or quieter than the step provides. I generally always play music at one preferred "step" but feel it's just a little too loud there. The step below is too low and the step above is too loud so I feel it's not "just right", kind of like the Goldilocks phenomenon....LOL I don't think precision is a factor, but a stepped attenuator feels nice.
Your videos are phenomenal! Thanks for all of the tips and knowledge that you share.
What about a stepped attenuator with a linear wiper between steps? Does anything like this exist? So you keep the feel and precision of a linear pot, but the perfect balance of a stepped attenuator?
Is there way to achieve volume sensitivity on gain POT on parametric EQ. I am wanting to make my EQ to from 1db increment to .5 db increment. Would that accomplished by putting resister on the middle pin? By the way POT on the EQ has center dented with boost to right and cut to left function. Thanks
Surprised you didn't go into the subject of how well the two pots "Track" with each other -or don't .
exactly which chinese blue alps have u had success with?
what about pots with an extra terminal ie 3 main terminals+1 extra were would you use them and what formany thanks sy
Why so many pins on the ALPS?
is for loudness (centertapped of the resistive track)
hi , do you think i can convert pot to att ?thanks.
I don't follow the part about 'what if your amplifier isn't balanced? The gain of an amplifier is normally set by the ratio of two resistors, not by the strength or weakness of a valve.
anyone knows what is the vr1 potentiometer on logitech z 533 pcb? it has a switch and 6 pins 3 back and 3 front. just can't find it anywhere, what a crazy component is this?
A slider ?
Where’s Rusty The Dog?
Wrong channel dude 😄
nothing to do with sound,,,, so much for Hi-Fi Audio
Exactly, just lost 15 mins
false
Why didn't you show wirewound potentiometers? they are the best. I would disagree that linear and logic are the same they're not the outcome is similar but the operation is different and the sound quality is different from both
Well, in my 30 years of working on audio gear, I've never once seen a wire wound resistor used for a volume pot. I wouldn't put them on my list of good, much less the best for this application. They are jumpy and don't provide a constant sweep at all times.
Blueglow Electronics I think it depends on the quality why don't you try it sometime
Not a match for a tube amp though - wirewould goes up to a few hundred ohms or so, tube volume pots are around 100k and up.
Mark Tillotson but you can run a high-power resistor of the end to make up the difference.
John sweda No you can't. All that does is reduce the effective range of the pot. A 500R pot after a 100K resistor will have only .05% effect on the output voltage.