Best resistor to use?

[dmusic101]

Is there a general reccomendation as to the best resistors to use for audio cirduits? Metal Film? Metal Oxide? 1% ? 5% ?
Does is really matter?

Thanks

 

[gary o]

what does anyone think about the old carbon comp resistors, meant to add sweetening but also noise.

Cheers Gary O

 

[Mbira]

Here's a link about that:
http://www.groupdiy.com/index.php?topic=4998&highlight=free+resistors
Joel

 

[gary o]

Thanks Mbira that was a interesting read, Im still very curious about the possible sound sweetening capabillities of the old carbon comps,I was thinking I could use the carbon comps in the high voltage parts of the circuit & metal films else where in the circuit to make up for the extra noise from the CCs, best of both then perhaps.

Cheers Gary O.

 

[Family Hoof]

I thought the magic of carbon comps (old ones, not the refined stuff available today) was that they drift so much, adding more randomness to the circuit? And this is why tube guitar amp builders like them for emulating the classics. Correct me if I'm wrong. I haven't done any listening tests but the concept of noisier, unreliable resistors adding any amount of humanly detectable "sweetness" to a circuit seems like ******** - especially considering how much more dramatic of an effect the seleciton of other components makes. Will you hear this sweetness over the increased noise floor? Will it be different everytime (or based on temperature) because of looser tolerances?

I was taught that resistor noise is negligible regardless of what type and that it's better to go for reliability, longetivity, and tolerance instead. My thought process so far has been to go for 1% metal film where I need higher tolerance (i.e. switches and lower value bias), and hand pick some %5 carbon film for everything else. Haven't paid much attention to brands yet - just whatever Digikey sells me (usually Yageo).
Being the sucker that I am, however, I've been meaning to start a thread about name brand and 'special' resistors. For starters, what are those dark red colored ones I see in 70s gear like N*ve cards?

 

[EZ81]

http://geofex.com/Article_Folders/carbon_comp/carboncomp.htm

 

[gyraf]

dmusic101,

You may want to reduce the size of your (quite nice) avatar, to comply with the 60x60 pixels max. size.

The large graphics spoils the page layout for people with small screens. (and there are quite a few of us here - remember this is a low-tech forum!)

Best,

Jakob E.

 

[mcs]

[quote author="Family Hoof"]For starters, what are those dark red colored ones I see in 70s gear like N*ve cards?[/quote]
These ones?

http://stiftsbogtrykkeriet.dk/~mcs/Resistors.jpg

They are Beyschlag resistors "VacuumVoodoo" told me some days ago...

Best regards,

Mikkel C. Simonsen

 

[Family Hoof]

[quote author="mcs"][quote author="Family Hoof"]For starters, what are those dark red colored ones I see in 70s gear like N*ve cards?[/quote]
These ones?

http://stiftsbogtrykkeriet.dk/~mcs/Resistors.jpg

They are Beyschlag resistors "VacuumVoodoo" told me some days ago...

Best regards,

Mikkel C. Simonsen[/quote]
Yes! A google search just told me that they were a popular line of metal films in Europe for many decades. That means N*VE used metal films in the you know whats. I wonder what tolerance? Hmm... Thanks Mikkel :guinness: !

 

[BladeSG]

Sorry to hijack.... Does anyone know if there are any noise isssues when soldering resistors in series and parallell to make up values that are not so common?

Thanks,

Steve.

 

[mcs]

[quote author="Family Hoof"]I wonder what tolerance?[/quote]
I have only seen them in 5%. But so far I have never found one that was more than 1% off...

Best regards,

Mikkel C. Simonsen

 

[dmusic101]

As always when I post something I get some useful insight. Thanks you guys!

 

[Guest]

[quote author="BladeSG"]Sorry to hijack.... Does anyone know if there are any noise isssues when soldering resistors in series and parallell to make up values that are not so common?
[/quote]
If you solder resistors (of the some technology) to series,
you can improve flicker noise performance.
But significant improvement you do with nearly equal values.
If you do series combination of hardly unequal values, you make
too small improvement.

With paralel resistor (of the some technology and equal values),
you can decrease noise performance.
But with hardly unequal values, decrease wil be very small.

Theory of flicker noise is not simple and straight, this is part of
implications, which can be useful somewhere,
but in audio flicker noises are much tolerated via Fletcher-Munson curves.

xvlk

 

[BladeSG]

Thanks xvlk. So if I understand this correctly it's better to have resistors in series than parallel for noise reasons?

Parallel a 47K + 4.7K = 4.27K

Series a 3K + 1.2K = 4.2K

which of these combinations gives lower noise when the value I need is 4.22K?

Thanks,

Steve.

 

[Guest]

[quote author="BladeSG"]
which of these combinations gives lower noise when the value I need is 4.22K?[/quote]
Answer is:
in the white noise they are absolutely identical. White noise is
under thermodynamic law and if any combination of devices
(at the some) temperature have lower or higher
noise, we build perpetuum mobile.

Noise power is universal function of frequency and temperature
(van der Ziel)

Problem is, that in some circuit we are not in thermodynamical
equilibrium. Example of it is resistor with DC curent feeded trough.

This current can generate other noise, called flicker or current etc.
Amount of this noise is greater with greater freedom of motion
of electrons. If you put two resistors in paralel, electron can
vote if he pass first or second resistor.
If you put two resistor in series, electron can not "vote" and you
then will have lower flicker noise.

If you have DC current trough resistor, series combination may
be preferred.
If you have no DC current, you have not problem with flicker
noise and you have the some results if you use carbon or metal or
wirewound resistors in paralel or series connection. That was thermodynamics.
If someone say, that some resistors have big noise at zero DC current,
he is adept to Nobel prize: Use good resistor as generator,
bad resistor (at the some temperature) as load, and he have
dirrected energy flow, and he can produce energy at zero cost.
Hip, hip, hurrey.

xvlk

 

[BladeSG]

Thanks again xvlk.