When I was in highschool back in the 70's, my electronics shop class built el84 pp integrated amplifiers for our project. My shop teacher, Mr. Ballard stressed to each of us the importance of keeping the hookup wiring the same length for each channel so that there was no time smear distortion.
I continue to follow his rule, however I have always wondered how accurate his advise was. Any thoughts?
I continue to follow his rule, however I have always wondered how accurate his advise was. Any thoughts?
Well, considering the speed of electricity propagating thru a wire is some 90 % of the speed of light at 0.00000000000833 inches per second,????
I'd bet your instructor was mixing up audio frequencies propagating thru a wire OR was more concerned with changes in current capacities with longer wires...either of which is truly inconsequential.
------------------------------------------------------------------------------Rick...
I'd bet your instructor was mixing up audio frequencies propagating thru a wire OR was more concerned with changes in current capacities with longer wires...either of which is truly inconsequential.
------------------------------------------------------------------------------Rick...
I have to admit, my HS electronics shop teacher, Mr Connelly, was a great teacher.
Strict, yet somewhat forgiving, and open to reason.
One class project, a simple power supply provided by Graymark Kits, bored the hell out of me.
The thing was in a cheap plastic box and had a switch to select 6 or 9 volts, a center tapped transformer, bridge diodes (4) and a capacitor.
Dumb, I thought.
So I stopped by my local Allied Electroncs store and bought an aluminum chassis box, a 12 volt meter, 10V ac transformer, a 1P 8P rotary switch, diodes, filter caps, several WW resistors of same value, a neon panel indicator, toggle switch, binding posts, even a heyco strain relief and power cord.
At home, I pre-cut the meter opening, and other holes, and took it to class.
Connelly gave me looks, and insisted that I had to give a full explanation to the class of how my contraption worked.
I remember him saying that "I was getting way ahead of the rest of the class".
Well, this power supply outputted 1.5 to 12 volts depending on the selector switch, and the meter monitored the output.
Basically a voltage divider type supply.
Yeah, I had to explain the how and why of it in front of the class, but I got an A+ for that project, and dirty looks from some classmates.
Screw 'em.
Wiseoldtech, do you still have the power supply?
I made my first power supply o/p 1.2 to 30V at 1 amp.
Built from from scratch, sheet metal case to PCB layout & front panel photo sketching. Had to replace the Dick Smith capacitors as they dried out after 40 years. I expected it to be bulletproof after all these years.
In the same class, the fella in front of me, he wired the 20A toggle switch to one side of the green mains lead and the next thing I saw, a mighty bang to green continuing flashing explosions and the shadow of his head on the high ceiling and the fluro lights started dimming. The teacher ran over to cut out the safety mains by the wall. The poor fella could only see green for the rest of the class and all the students looked over in awe of the what's left of the heavy duty switch on his power supply.
I made my first power supply o/p 1.2 to 30V at 1 amp.
Built from from scratch, sheet metal case to PCB layout & front panel photo sketching. Had to replace the Dick Smith capacitors as they dried out after 40 years. I expected it to be bulletproof after all these years.
In the same class, the fella in front of me, he wired the 20A toggle switch to one side of the green mains lead and the next thing I saw, a mighty bang to green continuing flashing explosions and the shadow of his head on the high ceiling and the fluro lights started dimming. The teacher ran over to cut out the safety mains by the wall. The poor fella could only see green for the rest of the class and all the students looked over in awe of the what's left of the heavy duty switch on his power supply.
Well in a valve amp stray capacitance can be significant at audio frequencies due to the high signal impedances (100's of kilohms). 1pF stray capacitance is 8M ohms, 4pF stray is 2M, all at 20kHz frequency.
So varying wire lengths could lead to small subtle differences in high frequency response (unlikely to be audible though).
But apart from this its a false precaution.
What can be important is to follow the same layout as documented for stability reasons - and if you build two channels with the same layout, the wire lengths will be the same of course. Picking your own layout without regard to unintended capacitive feedback is a possible pitfall.
For an A+ you are supposed to deliver 97 - 100%. You were supposed to build a Graymark kit power supply but didn't.
Congratulations on (successfully??) slipping and sliding through life like that.
I agree with his teaching. You're trying to build a stereo amplifier, so you'd want to keep any 'constructional' parasitic capacitance and resistance the same on each channel. Obviously you're still going to try to minimise it by design.
I also think keeping the wires on the DC power supply to each channel as short as possible and the same length is also important. Otherwise each channel sees a different power supply impedance, particularly at high currents.
I'm not necessarily saying anybody could hear the difference, it's just good electrical engineering practice, so why wouldn't you want to do it?
No thinking outside of box I guess was the message here. He took a chance based on his knowledge level and skill level and was rewarded. That is not slip sliding through life.
Where would we be if no one took a chance or risk?
A while back, I added schiirrn to my ignore list, but thanks JMFahey and WntrMute2 for posting his comment and showing me my past choice to ignore was wise.
But yes, I was naturally "ahead" of my classmates back then.
Part of it was due to always reading electronics magazines and dabbling on projects in the basement at home.
I just had the strong urge to learn learn learn.
So I became "armed" with more knowledge than the class, and chose to move ahead and excersize my self-taught experience.
My reasoning back then at the tender age of 16-17 was that "why should I limit myself and hold back?"
But yes, I was naturally "ahead" of my classmates back then.
Part of it was due to always reading electronics magazines and dabbling on projects in the basement at home.
I just had the strong urge to learn learn learn.
So I became "armed" with more knowledge than the class, and chose to move ahead and excersize my self-taught experience.
My reasoning back then at the tender age of 16-17 was that "why should I limit myself and hold back?"
your teacher was completely right..
I never had a teacher for this it's all DIY, but, longer cable more distance to cover even if it's only a micros second..
the best to show the difference if you draw a layout for some amplifier board..with a good software you will be able to see how much current will pass the copper, when the pcb has been done.
May it's not that relevant, but using wires of same length, between left and right channel is a good idea, at least there will not be a difference.
I do so too. Also all my speaker Cables are the same length.. even one side might would use less or shorter than the other...Can someone hear it?
I'm positive that there are people who can hear, no everyone maybe, but there are some.. especially when cable getting longer than 1 meter.
For me electricity passing cables is like Water passing a Waterpipe.
Take a 1 meter 1Inch in diameter pipe and a compartment 100lt Water with a certain pressure
Take a 5 meter in length and also 1 Inch in diameter pipe, also a compartment with say 100lt. Water and also a certain pressure which of course must be the same as the one from that 1 Meter Compartment..
Supposedly there are two Water Valves which open simultanousely and also passing exactly the same amount of water through the Valve and then floating out that pipes. Which one will be emptied faster?
Just try it..
If signals do not arrive the same time as these supposed to be, then we have delay which under circumstances can be very annoying. and then these signals are out of synchronisation.
When Internet streaming or video streaming was in it's childhoods, it happend many times that Picture and sound were out of synchronisation, even Picture used more bytes than Sound, sound was lagging behind, because it had to pass sound chips, which were slower than the processors for the Video..Also the sound had to take the "Longer way to the sound amplifier" compare with the VIDEO Signals. And this can be measured..
Have seen this manytimes, it's exactly the same. If you may go to a Concert where mixing console is in the middle of the HALL, then note that the cables which are run to the Stage Speakers are the same lenght, because of delay..
If this is not enough then there is a test>
Use the same song from two different points played at the same time from equal Systems and then stand in the midlle of the signal, then find out the differences of that song.. move to left or right and then you will find yourself hearing the same song with delay or echo either from the one or other side..so the length of Cables take influence of the sound produced in the speaker of Amplifier. I do not call this distortion but time shift.
Sound is moving in one second only 300Meter as far I remember,
"speed of sound in dry air at 20 °C =
343 m / s"
Speed of electricity In copper at 60 Hz,
At least that's what I have seen also many time..
Take a 1 meter 1Inch in diameter pipe and a compartment 100lt Water with a certain pressure
Take a 5 meter in length and also 1 Inch in diameter pipe, also a compartment with say 100lt. Water and also a certain pressure which of course must be the same as the one from that 1 Meter Compartment..
Supposedly there are two Water Valves which open simultanousely and also passing exactly the same amount of water through the Valve and then floating out that pipes. Which one will be emptied faster?
Just try it..
If signals do not arrive the same time as these supposed to be, then we have delay which under circumstances can be very annoying. and then these signals are out of synchronisation.
When Internet streaming or video streaming was in it's childhoods, it happend many times that Picture and sound were out of synchronisation, even Picture used more bytes than Sound, sound was lagging behind, because it had to pass sound chips, which were slower than the processors for the Video..Also the sound had to take the "Longer way to the sound amplifier" compare with the VIDEO Signals. And this can be measured..
Have seen this manytimes, it's exactly the same. If you may go to a Concert where mixing console is in the middle of the HALL, then note that the cables which are run to the Stage Speakers are the same lenght, because of delay..
If this is not enough then there is a test>
Use the same song from two different points played at the same time from equal Systems and then stand in the midlle of the signal, then find out the differences of that song.. move to left or right and then you will find yourself hearing the same song with delay or echo either from the one or other side..so the length of Cables take influence of the sound produced in the speaker of Amplifier. I do not call this distortion but time shift.
Sound is moving in one second only 300Meter as far I remember,
"speed of sound in dry air at 20 °C =
343 m / s"
Speed of electricity In copper at 60 Hz,
An externally hosted image should be here but it was not working when we last tested it.
3.2 m/s. this is what wikipedia tells me..it goes faster with rising frequencyAt least that's what I have seen also many time..
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You need to ask Fahey about this, as he felt it was necessary to start with Nazi comparisons.
Yes of course it is, no doubt.
But, the speed depends on so many factors, that we can say if we take Silver or Gold wiring, then we may to some extend could change length of wires in a system if this is nonimportant to quality of whatever that signal does or is used for.
But I doubt that in Audio many will use Silver Wires nor Gold, because it's expensive and sometimes not even wanted because Silver wires are adding sound to high frequencies, I'm not sure about Gold.
But as long Aluminum and Copper are used then length of wires in amps on interconnections between Devices used in Audio System, and for Speakers, matters. It is measurable and also hearable..
My two cents..
But, the speed depends on so many factors, that we can say if we take Silver or Gold wiring, then we may to some extend could change length of wires in a system if this is nonimportant to quality of whatever that signal does or is used for.
But I doubt that in Audio many will use Silver Wires nor Gold, because it's expensive and sometimes not even wanted because Silver wires are adding sound to high frequencies, I'm not sure about Gold.
But as long Aluminum and Copper are used then length of wires in amps on interconnections between Devices used in Audio System, and for Speakers, matters. It is measurable and also hearable..
My two cents..