Home Theater Forum - View Single Post - Digital in the signal path is bad? Really? A look at something that happened.

Chu Gai · 07-08-2003, 09:48 AM

I'll confine my reply to things like resistors, capacitors, inductors.

I think it's entirely possible to replace one component with another and change the nature of the sound. Whether this is good or bad is difficult to answer but one must factor in something called 'builder's ear' which is the tendency for people to be enormously satisfied with something they've created. If you recall the wonderful movie, Unforgiven you'll see an example of that in the house that Gene Hackman built.

When people replace things there are a couple of things that often aren't done.
1) They don't measure the component that's being replaced to determine what it's value was. Nor do they measure the value of the component being put in its place. Not all components are stable for an infinite amount of time. Sometimes their values change in but a few years and being that human auditory memory is not a rock, we don't even notice it happening until one day something just isn't right. Depending upon the environment the component is in such as the temperature and even vibration (think about the insides of a speaker cabinet) this deterioration can be accelerated. Also a particular manufacturer, say Motorola for instance, occasionally comes out with a batch of whatever that doesn't age gracefully. As Elvis Costello said, Accidents will happen, it's only hit and run.
Electrolytic capacitors are a known culprit here because they can dry out and it's entirely possible to find that the capacitance has dropped by a factor of 10 or 100. Plus or minus 5% is one thing. Minus 100% or 1000% and you can be pretty sure there's a profound difference in what you bought and what you now have. You just might've lost the top end of your speaker response or lost the low end on your CD player. Of course, in the latter case, you could always fall back to the digital.
So if one knows what type of components are likely to age unfavorably, where they're located, and has some skill and chutzpah to delve inside with snips and a soldering iron, they can often restore a component like a CD player to meet it's original specs. Confirmation that there may be a problem can always be done by burning test tones on a CDR and playing it while measureing the output voltage. Of course this takes the fun out of upgrading and putting a new look on our equipment that now looks a bit dated.

2) When one looks in an electronic parts catalog like Mouser, one finds a ton of different flavors of a particular component. Resistors for example differ in things like rated power, maximum working voltage, operating temperature, etc. They also can have other electrical properties that cause them to differ. Inductance for example. A wire wound resistor has a non-significant amount of that and were you to replace a resistor with neglible inductance with a wire-wound one, you would be changing what that circuit was designed to do.

It is a strange thing that compels people to replace good components with other good and even more expensive components. Most though would not tolerate this sort of behavior from their auto mechanic. Golly gee Mr. Good Wrench, thanks for taking my brake pads out that had 30,000 miles left on them and putting in these Raybestos ones. Yeah, that chick that advertises them sure looks hot on TV. $450 for the job...thanks!!! Can I have a calendar too?

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07-08-2003, 09:48 AM	#5 of 12
Chu Gai Join Date: Jun 2001 Local Time: 03:01 AM Local Date: 12-05-2008 Posts: 7,403	I'll confine my reply to things like resistors, capacitors, inductors. I think it's entirely possible to replace one component with another and change the nature of the sound. Whether this is good or bad is difficult to answer but one must factor in something called 'builder's ear' which is the tendency for people to be enormously satisfied with something they've created. If you recall the wonderful movie, Unforgiven you'll see an example of that in the house that Gene Hackman built. When people replace things there are a couple of things that often aren't done. 1) They don't measure the component that's being replaced to determine what it's value was. Nor do they measure the value of the component being put in its place. Not all components are stable for an infinite amount of time. Sometimes their values change in but a few years and being that human auditory memory is not a rock, we don't even notice it happening until one day something just isn't right. Depending upon the environment the component is in such as the temperature and even vibration (think about the insides of a speaker cabinet) this deterioration can be accelerated. Also a particular manufacturer, say Motorola for instance, occasionally comes out with a batch of whatever that doesn't age gracefully. As Elvis Costello said, Accidents will happen, it's only hit and run. Electrolytic capacitors are a known culprit here because they can dry out and it's entirely possible to find that the capacitance has dropped by a factor of 10 or 100. Plus or minus 5% is one thing. Minus 100% or 1000% and you can be pretty sure there's a profound difference in what you bought and what you now have. You just might've lost the top end of your speaker response or lost the low end on your CD player. Of course, in the latter case, you could always fall back to the digital. So if one knows what type of components are likely to age unfavorably, where they're located, and has some skill and chutzpah to delve inside with snips and a soldering iron, they can often restore a component like a CD player to meet it's original specs. Confirmation that there may be a problem can always be done by burning test tones on a CDR and playing it while measureing the output voltage. Of course this takes the fun out of upgrading and putting a new look on our equipment that now looks a bit dated. 2) When one looks in an electronic parts catalog like Mouser, one finds a ton of different flavors of a particular component. Resistors for example differ in things like rated power, maximum working voltage, operating temperature, etc. They also can have other electrical properties that cause them to differ. Inductance for example. A wire wound resistor has a non-significant amount of that and were you to replace a resistor with neglible inductance with a wire-wound one, you would be changing what that circuit was designed to do. It is a strange thing that compels people to replace good components with other good and even more expensive components. Most though would not tolerate this sort of behavior from their auto mechanic. Golly gee Mr. Good Wrench, thanks for taking my brake pads out that had 30,000 miles left on them and putting in these Raybestos ones. Yeah, that chick that advertises them sure looks hot on TV. $450 for the job...thanks!!! Can I have a calendar too?