no "to small to move" speaker drive level
voice coil motors are as linear, hysteresis free force sources as we have - and they are very, very good - have been used in interferometry, scanning atomic microscopy to control motion at fractions of a wave length of light
most speaker suspensions are flexures, rely on small linear bending of the material to move in response to the voice coil force at very small amplitude
suspensions and voice coil motors nonlinear behavior kicks in at high drive levels, large excursions, not small
dynamic loudspeakers respond linearly with electrical drive to way below audible threshold
unless your driver is broken (parts rubbing giving stick-slip dead band) then typical dynamic loudspeakers don't have a practical lower limit of linear motion - to far below practical electrical circuit thermal noise driving them
voice coil motors are as linear, hysteresis free force sources as we have - and they are very, very good - have been used in interferometry, scanning atomic microscopy to control motion at fractions of a wave length of light
most speaker suspensions are flexures, rely on small linear bending of the material to move in response to the voice coil force at very small amplitude
suspensions and voice coil motors nonlinear behavior kicks in at high drive levels, large excursions, not small
dynamic loudspeakers respond linearly with electrical drive to way below audible threshold
unless your driver is broken (parts rubbing giving stick-slip dead band) then typical dynamic loudspeakers don't have a practical lower limit of linear motion - to far below practical electrical circuit thermal noise driving them
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Quoted from the B1 Article
If you put a buffer in front of a volume control, the control’s low impedance
looks like high impedance. If you put a buffer after a volume control, it
makes the output impedance much lower. You can put buffers before and
after a volume control if you want
More contradictions ....
If you put a buffer in front of a volume control, the control’s low impedance
looks like high impedance. If you put a buffer after a volume control, it
makes the output impedance much lower. You can put buffers before and
after a volume control if you want
More contradictions ....
I will have to squeeze one answer from this one
Active stages gain stages too ( this according to post 94 also )
Why ?
there is your answer. same reasen that most active preamps has the volumpot before the gainstage.
the reason is the output impedance.
the reason is the output impedance.
so ...any stage that has lower output impedance will drive better the next stage
Are we done here ?
Are we done here ?
so the output impedance of a P37 is 200R
Can any one tell us what will be the output impedance of a RK 27K logger when set for example to 0.7 in a scale from 0-10 ?
Regards
Sakis
Can any one tell us what will be the output impedance of a RK 27K logger when set for example to 0.7 in a scale from 0-10 ?
Regards
Sakis
The reason is that it allow higher input levels but on a S/N basis it doesnt make sense.
I'm breaking my own rule again.
Read what that paragraph says.
It gives three operating options.
The reader can choose any one of the options.
option 1.)
place the Buffer before the vol pot.
option 2.)
place the Buffer after the vol pot.
option3.)
Place two Buffers in the circuit, one before the vol pot and one after the vol pot.
These are not contradictions!
They are all valid operating senarios, all will work.
No.
the source must have adequate current capability to drive the capacitance that follows.
Andrew thank you...
These are not contradictions!
They are all valid operating senarios, all will work.
Possibly yes one though should be familiar with
--principal of operation for every option
--Pros and cons of every configuration
Also in the specific thread where the target was very low listening power some things might work better than others ....so it will be good to know .
These are not contradictions!
They are all valid operating senarios, all will work.
Possibly yes one though should be familiar with
--principal of operation for every option
--Pros and cons of every configuration
Also in the specific thread where the target was very low listening power some things might work better than others ....so it will be good to know .
It seems that post 94 doesnt get any answers so i will refresh it to see how this is going...
Lets give another turn to the discussion .....
For the past few hours i checked every available schematic of CD players i could find that feature a fixed and a variable output .
Some of the CD players belonged to the past of the CDP era from Sony others newer , also some from sony and a few other brands that i could find ....Checked also Advance Acoustics ,Xindak, CAyin and Teac that we do authorized service for and have access to schematics .
In the Cd players of the past variable output takes place with a classic hand turn pot while in the newest feature electronic pots digitally controlled ( few also used motorized pots )
Now please explain to me why all of them use the pot behind the gain stage ????
If the behavior/presence of the pot doesn't effect anywhere the next stage to be driven OBVIOUSLY there should be some of the manufactures should place his pot mechanical or electronic directly in the output of the CD player .
If there is any manufacturer that does so please let me know ...
Answer this then you solve my problem too
Under the same logic what will be the reason to have a configuration= CD player goes to a B 1 then goes to a pot , then goes to power amp ...
If you are buffering for the input of the pot this is totally useless since the CD player already has an active stage in its output ...Why repeat a gain stage or a buffer once more
Now if you are buffering between the pot and the amp we are getting somewhere ....
Lets give another turn to the discussion .....
For the past few hours i checked every available schematic of CD players i could find that feature a fixed and a variable output .
Some of the CD players belonged to the past of the CDP era from Sony others newer , also some from sony and a few other brands that i could find ....Checked also Advance Acoustics ,Xindak, CAyin and Teac that we do authorized service for and have access to schematics .
In the Cd players of the past variable output takes place with a classic hand turn pot while in the newest feature electronic pots digitally controlled ( few also used motorized pots )
Now please explain to me why all of them use the pot behind the gain stage ????
If the behavior/presence of the pot doesn't effect anywhere the next stage to be driven OBVIOUSLY there should be some of the manufactures should place his pot mechanical or electronic directly in the output of the CD player .
If there is any manufacturer that does so please let me know ...
Answer this then you solve my problem too
Under the same logic what will be the reason to have a configuration= CD player goes to a B 1 then goes to a pot , then goes to power amp ...
If you are buffering for the input of the pot this is totally useless since the CD player already has an active stage in its output ...Why repeat a gain stage or a buffer once more
Now if you are buffering between the pot and the amp we are getting somewhere ....
Let me describe one more example ....
The structure of Sansui AU 717 in general is
--Phono stage to line level
--Line inputs and selector
--2*Tape monitor options
--Passive volume with a twist
-- Gain stage
--Localy buffered tone control so it can be excluded
--main amplifier .
The twist on the AU 717 is that the potentiometer has a DUAL function while the one will be a voltage divider in the input of the gain stage to attenuate incoming signals and the second gang of the pot is another divider obviously working in parallel to set the gain of the gain stage .
This is done before, some used a pot not as a volume control but as an actual gain control of the circuit but since the value of the pot was too big had tracking issues and failed to produce real 0 volume .
Now as we learned from audio sun to noise in the output of a gain stage is constant so in very low listening power there will be a danger of S/N ratio drop .
So from that we have to assume that the Sansui designer controls the the level of the source with the passive pot in the input of the gain stage while at the same controls the actual gain of the stage to reduce noise in the output .
Here is a very simple question:
Why any manufacturer should bother to ask Alps to construct for him a very sophisticated pot in the black line of Alps advanced beyond known standards involving a danger of tracking issues twice as much than any normal pot while instead he could simply use any quality pot of a standard value use it
On the output of the gain stage control the level of the next stage while preserving the highest available S/N ratio possible .
Answer this solve my problem too ....
The structure of Sansui AU 717 in general is
--Phono stage to line level
--Line inputs and selector
--2*Tape monitor options
--Passive volume with a twist
-- Gain stage
--Localy buffered tone control so it can be excluded
--main amplifier .
The twist on the AU 717 is that the potentiometer has a DUAL function while the one will be a voltage divider in the input of the gain stage to attenuate incoming signals and the second gang of the pot is another divider obviously working in parallel to set the gain of the gain stage .
This is done before, some used a pot not as a volume control but as an actual gain control of the circuit but since the value of the pot was too big had tracking issues and failed to produce real 0 volume .
Now as we learned from audio sun to noise in the output of a gain stage is constant so in very low listening power there will be a danger of S/N ratio drop .
So from that we have to assume that the Sansui designer controls the the level of the source with the passive pot in the input of the gain stage while at the same controls the actual gain of the stage to reduce noise in the output .
Here is a very simple question:
Why any manufacturer should bother to ask Alps to construct for him a very sophisticated pot in the black line of Alps advanced beyond known standards involving a danger of tracking issues twice as much than any normal pot while instead he could simply use any quality pot of a standard value use it
On the output of the gain stage control the level of the next stage while preserving the highest available S/N ratio possible .
Answer this solve my problem too ....
Weekend passed ...getting no answers.....
Am i Allowed to use democratic procedures here ??? I will presume yes ...
Since post 94 and post 155 fails to receive proper answers from forum members i will have to assume based on the facts given here :
A pot behind one main amplifier effects something .... to my estimation effects dynamics in very low listening level ...
having a pot always behind an active stage was a practice that :
Cd player manufactures did/doing it this way
Preamp manufacturers did/doing it this way
Integrated amplifier manufacturers did/doing it this way ..
All of them with the risk to have S/N ratio problems in the output of the gain stage .
Denon for example is doing it the other way around Luxman in some models also .
Now given as a fact what Andrew T as usually correct stated that both configurations are valid one has to investigate pros and cons of both ...
Now if there is a consideration about the use of a pot behind the amp either passive from the source or with any active stage behind that points in the direction of loss of dynamics in very low listening level I will also have to assume that either NP translated the message ""sucks the life out of my amplifier " the wrong way or Listeners described the situation of when passive in the wrong way or not enough information ....
Am i Allowed to use democratic procedures here ??? I will presume yes ...
Since post 94 and post 155 fails to receive proper answers from forum members i will have to assume based on the facts given here :
A pot behind one main amplifier effects something .... to my estimation effects dynamics in very low listening level ...
having a pot always behind an active stage was a practice that :
Cd player manufactures did/doing it this way
Preamp manufacturers did/doing it this way
Integrated amplifier manufacturers did/doing it this way ..
All of them with the risk to have S/N ratio problems in the output of the gain stage .
Denon for example is doing it the other way around Luxman in some models also .
Now given as a fact what Andrew T as usually correct stated that both configurations are valid one has to investigate pros and cons of both ...
Now if there is a consideration about the use of a pot behind the amp either passive from the source or with any active stage behind that points in the direction of loss of dynamics in very low listening level I will also have to assume that either NP translated the message ""sucks the life out of my amplifier " the wrong way or Listeners described the situation of when passive in the wrong way or not enough information ....
Setting up a test with intention to spectrum the output of the given amplifier , while a second test for spectrum the speaker in the same test is in order will take some time to arrange . ( still think that choice of speaker and threshold of starting will play major if not the only role in this when tests are made in such a low power )
So in between while continue to trust my ears also i did the test using things available in 5 minutes of working time
My configuration is source~passive pot~ gain stage ~ main amp
So what i did is to install a pot between the gain stage and the amp ( i actually had a passive thingy ( pot in the box ) in my hands so that was less than 2 minutes )
level set up was done by ears ...nothing to measure there ....
Result :
When the pot was behind my amp i had to increase the level of the previous stage to at least 3db to achieve the previous status and still it didn't sound 1000% right ...\
Kind regards
Sakis
So in between while continue to trust my ears also i did the test using things available in 5 minutes of working time
My configuration is source~passive pot~ gain stage ~ main amp
So what i did is to install a pot between the gain stage and the amp ( i actually had a passive thingy ( pot in the box ) in my hands so that was less than 2 minutes )
level set up was done by ears ...nothing to measure there ....
Result :
When the pot was behind my amp i had to increase the level of the previous stage to at least 3db to achieve the previous status and still it didn't sound 1000% right ...\
Kind regards
Sakis
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You have had answers, some of them correct. You have chosen to ignore them.east electronics said:
Democracy is permitted, but it is an astonishingly foolish and misleading way to attempt to answer a technical question.
Anyway, I am out of here. This thread was never an attempt to get at the truth, but just a way to gain mutual support for an error.
DF96
It is obvious that we don't agree in many issues .... It is obvious to me that your relation with real life procedures in audio is limited .
But just for the argument , both posts 94 and 155 is a simple description of a procedure that you continue to ignore and fail to answer ....
So do i have to take your word for it ?
Obviously NOT
It is obvious that we don't agree in many issues .... It is obvious to me that your relation with real life procedures in audio is limited .
But just for the argument , both posts 94 and 155 is a simple description of a procedure that you continue to ignore and fail to answer ....
So do i have to take your word for it ?
Obviously NOT
Any comments on that ?
Let me describe one more example ....
The structure of Sansui AU 717 in general is
--Phono stage to line level
--Line inputs and selector
--2*Tape monitor options
--Passive volume with a twist
-- Gain stage
--Localy buffered tone control so it can be excluded
--main amplifier .
The twist on the AU 717 is that the potentiometer has a DUAL function while the one will be a voltage divider in the input of the gain stage to attenuate incoming signals and the second gang of the pot is another divider obviously working in parallel to set the gain of the gain stage .
This is done before, some used a pot not as a volume control but as an actual gain control of the circuit but since the value of the pot was too big had tracking issues and failed to produce real 0 volume .
Now as we learned from audio sun to noise in the output of a gain stage is constant so in very low listening power there will be a danger of S/N ratio drop .
So from that we have to assume that the Sansui designer controls the the level of the source with the passive pot in the input of the gain stage while at the same controls the actual gain of the stage to reduce noise in the output .
Here is a very simple question:
Why any manufacturer should bother to ask Alps to construct for him a very sophisticated pot in the black line of Alps advanced beyond known standards involving a danger of tracking issues twice as much than any normal pot while instead he could simply use any quality pot of a standard value use it :
On the output of the gain stage control the level of the next stage while preserving the highest available S/N ratio possible .
Answer this solve my problem too ....
Let me describe one more example ....
The structure of Sansui AU 717 in general is
--Phono stage to line level
--Line inputs and selector
--2*Tape monitor options
--Passive volume with a twist
-- Gain stage
--Localy buffered tone control so it can be excluded
--main amplifier .
The twist on the AU 717 is that the potentiometer has a DUAL function while the one will be a voltage divider in the input of the gain stage to attenuate incoming signals and the second gang of the pot is another divider obviously working in parallel to set the gain of the gain stage .
This is done before, some used a pot not as a volume control but as an actual gain control of the circuit but since the value of the pot was too big had tracking issues and failed to produce real 0 volume .
Now as we learned from audio sun to noise in the output of a gain stage is constant so in very low listening power there will be a danger of S/N ratio drop .
So from that we have to assume that the Sansui designer controls the the level of the source with the passive pot in the input of the gain stage while at the same controls the actual gain of the stage to reduce noise in the output .
Here is a very simple question:
Why any manufacturer should bother to ask Alps to construct for him a very sophisticated pot in the black line of Alps advanced beyond known standards involving a danger of tracking issues twice as much than any normal pot while instead he could simply use any quality pot of a standard value use it :
On the output of the gain stage control the level of the next stage while preserving the highest available S/N ratio possible .
Answer this solve my problem too ....
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