AllOut,

> How many guitar players do you know, that have changed the caps in a Marshall!! tell me does it make a deference!!!!!!

I was talking about pro audio gear, not guitar amplifiers! Further, I made the point "If a mixer or mike preamp is already audibly transparent..."

I don't think anyone would argue that a guitar amp is supposed to be "transparent." Apples and oranges.

--Ethan

Originally posted by AllOut:
Myth: Replacing the resistors and capacitors in preamps and power amps with higher quality units can improve the sound of a system.

In my experience, unless it's a relatively new peice of gear it absolutely will benefit from capacitor upgrades.

Fact: Unless your capacitors are defective (they allow DC current to pass through them), or have changed their value over time due to heat and other environmental factors, you are not likely to improve anything by replacing them.

Ethan, many pieces of gear are designed with 85 degree C caps which most are rated for 1000 hours of life. How long does it take to put 1000 hours of "on" time on a piece of equipment in a studio. The answer, less than a year. So if you use your rational and my real world figures that would mean that most gear can benefit from capacitor replacement after about a year of use. Of course we know that lots of equipment gets way beyond a year of use before someone does anything to it and even then it's only to fix what broke.

Many older designs such as the Ampex ATR102 that I just recapped use Tantalum capacitors in the signal path. This was done way back in 1976 because these caps were generally small for their ratings/values and electrolytics of the same values were physically too big to fit into the circuit board.

The same goes for replacement metal film resistors. It's true that metal film resistors have lower noise than other types, but that makes a difference only in certain critical circuits, such as the input stage of a high-gain mike preamp.

I don't know, my RCA BA6A compressor seems to have benefited from metal film resistors not only in overall noise but in sound. I've also found that replacing carbon resistors in my mix bus and signal amplifiers made a difference in terms of the transparency and noise level of the mix bus.

It's also true that different types of capacitors are more or less suitable for different types of circuits. But if you think the designers of your amplifier or mixer are too stupid to have used appropriate components in the first place, why would the rest of the design be good enough to warrant the cost of improved parts?

See my response above. In many cases designers design to a price point and for component availability, that's the real world. But that means that there's real improvements that can be made. Also capacitors have come along way in the last 10 years with low impedance high frequency designs being widely available. It made a large difference in the ATR102 when I replaced the tantalum signal path caps with some nice Panasonic HF low impedance caps.

We're not taking subtle folks.

In fairness, extremely old gear often employs carbon composition resistors, and replacing them can make a difference in many audio circuits. But anything manufactured in the past 20 years or so will use carbon film resistors and decent capacitors.

This has not been my experience.

Listen, components have come along way in the last 10 years or so. Why not go in a try some things to see if you can improve something or make it into something that you really like. It's relatively inexpensive to do it yourself if you have some basic schematic reading skills and can handle a soldering iron. If I can learn to do this stuff anyone can.

The bottom line is don't rely on anyone to tell you what's right for you. Go on, get your hands dirty already!

Ethan- Electrolytic capacitors have a life span of about 5 years. You will find these in Neve modules made in the 70's.

If, and when, you recap and recal an old Neve module it sounds better.

Basically, if it's an 'electrolytic' cap change them every 5 years if its an 85 degree Centigrade cap, 7-10 years for a 105 degree C. cap.

How come is it why that this thread is so wide it doesn't fit on my screen? Quite a pain in the ass...

Mark,

> How long does it take to put 1000 hours of "on" time on a piece of equipment in a studio.

I won't dispute that components can deteriorate or fail completely over time. But that's not really what I was talking about. I was addressing whether the audio quality is improved by replacing working components with other working components.

> Many older designs such as the Ampex ATR102 that I just recapped use Tantalum ... my RCA BA6A compressor seems to have benefited from metal film resistors ...

Yes, and that's why I specifically excluded old gear in my statement.

> I've also found that replacing carbon resistors in my mix bus and signal amplifiers made a difference in terms of the transparency and noise level of the mix bus.

And again, that's why I mentioned carbon film as being superior to carbon composition. I can see how better resistors can affect a circuit's noise floor, but how will a new resistor improve "transparency?" What specifically is affected?

> Why not go in a try some things ... if you have some basic schematic reading skills and can handle a soldering iron. If I can learn to do this stuff anyone can.

I've been an electronics engineer since the 1970s, so I have no problem with schematics and a soldering iron! :)

--Ethan

Fletcher,

> Electrolytic capacitors have a life span of about 5 years. You will find these in Neve modules made in the 70's.

That's certainly a valid point. But as I said to Mark, I am addressing audio components that are currently working to spec.

--Ethan