I'm a newbee when it comes to circuit tweaking, but I recognize the importance of low noise resistors in critical positions like input stages. As I said above, the folks at Audio Asylum steered me toward carbon comps. I took their advice and used them in a position that connects the coupling caps of my amp's input stage to the power stage. This is obviously in the signal path. For those that like details, here's the
circuit diagram and resistors in question: R18, R19, R20, R21.
After reading the article:
Resistor Types - Does It Matter?, and hearing what others have said, I realize these are the worst possible resistors I could be using... especially with a 1/2 watt power rating.
The article states:
Contact noise is dependent on both average DC current and resistor material/size. The most significant contributor to noise in guitar amplifiers is the use of low-wattage carbon composition resistors. Since the noise is proportional to resistor size, the use of 2W carbon comp resistors will improve the performance over that of 1/2W resistors. Studies have shown a factor of 3 difference between a 1/2W and a 2W carbon comp resistor operating at the same conditions.
Another interesting quote:
Wirewound resistors are the quietest, having only thermal noise, followed by metal film, metal oxide, carbon film, and lastly, carbon composition.
So I want to replace the carbon comps. My question is whether TX2575 or TX2352 are overkill for this situation. They aren't cheap at $10 and $7 a piece. I need a total of eight. Would Mills MRA-5 wirewound be a decent option? They're less than half the cost.