CF vs MF plate resistors.

[leadfootdriver]

Did anyone ever compare the 2 and hear a difference? What was you experience?

[Bruce / Mission Amps]

I don't think anyone has ever experimented with CF and MF resistors. Gak.

Do you mean difference in tone or noise?

[Austin]

On a similar thought how does a tube configured as a resistor sound as the plate load compared to resistors and ccs?

[Bruce / Mission Amps]

Ha ha ha... good one.

[Chuck H]

From another thread:

The best point in all this (IMHO) has been to question the construction of complicated and condition specific devices, as Austin seems to like doing. It's his time! If he digs the geek end of it so much as to do whay he can, because he can, instead of just doing what he should because it's proven...
But just because something can be done doesn't mean it should. I can go down the street to the store. I can also leave my house, make a right and two lefts to get to the same store. Just sayin'.

I consider thinking outside the box a positive attribute. Most of the time. For me it needs to be in pursuit of of some worthy goal or to simplify an otherwise complicated issue. Complicating issues that don't need to be complicated doesn't count. "Simplicity is the ultimate sophistication." (Leonardo da Vinci)

[Austin]

How is this for "outside the box", a little vial of salt water for a plate load resistor. You would need gold or at least gold plated electrodes but the resistance could be adjusted by either adjusting the spacing between two metal electrodes or changing the amount of salt in the water. My thought is that the water would be less linear than a normal resistor and might sound neat for guitar... It could be made into a pedal.

[Chuck H]

I like it. But probably only because I don't know the pitfalls. What is the nature of the non linearity? What kind of lifespan would such a part have? Electrolysis could be an issue. What about the size of the part? What about safety? Is it even possible to build an electronic device to code that has a saline containing vessel in it? Could chemical salts be obtained and implemented in the construction in such a way as to prevent impurities from scaling and infiltrating nucleation sites on the surface causing fractures at temperature? Plus a host of other issues I'm sure I can't even concieve. I'm simply not willing to undertake the resolution of such issues when I can simply use a resistor.

How about a car tire with magnets in it that are angled in such a way as to draw toward the gravitational pull of the earths core? That's off the top of my head. And immediately I know that the returns are so tiny that the expense and complication outweigh any advantages.

All this aside... Don't let me discourage you. Honestly. Cynicism is probably what keeps most smarter than average people from innovation. But I'm reminded of something a friend of mine use to say when I would tell him about some whacky idea I wanted to develop. Invariably he would say "Great, but will you actually do it?" His point being that I should recognise what was actually worth pursuing in short enough order so as to avoid wasting time blathering about things that are most likely NOT worth the effort. I probably come up with two ideas a week that get a little consideration in my own personal head. I junk about a hundred ideas a year. In my own personal head. The other four ideas might get discussed here. If they're amp related. Otherwise I try to insulate people from the random musings in my own personal head. It seems to have improved my social life.

[tubeswell]

Did anyone ever compare the 2 and hear a difference? What was you experience?

Metal film resistors are typically quite a bit less hissy than carbon film - all other things being equal - in any of the AC load applications (Ra, Rg, etc), especially where the power ratings of the resistors are smaller (1/2 watt etc). (And yes, I've done several direct comparisons of locally available types). If in doubt, grab some assorted ones of each type and try them for yourself.

[Austin]

I like it. But probably only because I don't know the pitfalls. What is the nature of the non linearity? What kind of lifespan would such a part have? Electrolysis could be an issue. What about the size of the part? What about safety? Is it even possible to build an electronic device to code that has a saline containing vessel in it? Could chemical salts be obtained and implemented in the construction in such a way as to prevent impurities from scaling and infiltrating nucleation sites on the surface causing fractures at temperature? Plus a host of other issues I'm sure I can't even concieve. I'm simply not willing to undertake the resolution of such issues when I can simply use a resistor.

How about a car tire with magnets in it that are angled in such a way as to draw toward the gravitational pull of the earths core? That's off the top of my head. And immediately I know that the returns are so tiny that the expense and complication outweigh any advantages.

All this aside... Don't let me discourage you. Honestly. Cynicism is probably what keeps most smarter than average people from innovation. But I'm reminded of something a friend of mine use to say when I would tell him about some whacky idea I wanted to develop. Invariably he would say "Great, but will you actually do it?" His point being that I should recognise what was actually worth pursuing in short enough order so as to avoid wasting time blathering about things that are most likely NOT worth the effort. I probably come up with two ideas a week that get a little consideration in my own personal head. I junk about a hundred ideas a year. In my own personal head. The other four ideas might get discussed here. If they're amp related. Otherwise I try to insulate people from the random musings in my own personal head. It seems to have improved my social life.

Thanks Chuck, yeah theres alot of problems with the water resistor in a vial, the first couple that come to mind are having to have it vented for the hydrogen and oxygen gasses and still not leak all over high voltage power supply and then theres the when electricity flows through water it heats it up a little bit just like any resistor but "when water get warmer it conducts more" problem.. So really you could just have a glass of water or even a beer or whatever "outside the box" that was your pedal enclosure. Who knows maybe chocolate milk or iced coffee would give you the most killerest tone... The plate resistance value on something like this wouldn't need to be very exact value to work so anything over 10k ohms up to 1meg would probably still function. You wouldn't need any salt with tap water at least not where I live, stick your ohm meter leads down in some and see.. I have always wanted to try it, and who knows maybe water is just as linear as a normal resistor I have never tried to test it. But in that case it would be pointless I spose..

Here is another idea, using a broken 100 watt trigger type soldering iron coil as a choke to load the plate of a tube instead of a resistor. Broken because it got dropped off the workbench rather than overheated that is..

[Chuck H]

Thanks
Here is another idea, using a broken 100 watt trigger type soldering iron coil as a choke to load the plate of a tube instead of a resistor. Broken because it got dropped off the workbench rather than overheated that is..

Probably prone to thermal noise (johnson noise?) Guys here have been using stove top elements for dummy loads. I haven't checked for myself but have read that they're about 8 ohms. How much different when hot??? Dunno. But one solution has been to stick them in a tub of water. A pair like this would be a cheap 3000W dummy load! Nice if you need to test things like giant PA systems and giant transmitter amps.

EDIT: Why not Google "saline resistor" and see what you find. Info is out there. Speculating here without doing ANY preliminary research is about as relevant as openly wondering if you left the iron on at home or how much an average human head weighs.

[Austin]

Probably prone to thermal noise (johnson noise?) Guys here have been using stove top elements for dummy loads. I haven't checked for myself but have read that they're about 8 ohms. How much different when hot??? Dunno. But one solution has been to stick them in a tub of water. A pair like this would be a cheap 3000W dummy load! Nice if you need to test things like giant PA systems and giant transmitter amps.

EDIT: Why not Google "saline resistor" and see what you find. Info is out there. Speculating here without doing ANY preliminary research is about as relevant as openly wondering if you left the iron on at home or how much an average human head weighs.

The thermal noise isn't going to be a factor when the current is low, a 12ax7 at one milliamp isn't much heat.. One of my soldering irones fell on the floor last summer and broke open, there is a huge amount of wire in there, I think it might work for a choke or at least as a filter choke. I like the idea of using the stove burners as the transformer load tho. I didn't find any info of the performance of water as a resistor when used as a plate load resistor in an audio circuit.. That's why I threw it out there, maybe next time somebody googles it this post will get a hit. I like the idea of using a tube as a resistor for a plate load though, and wonder how it would sound compared to a normal resistor. I would guess a small signal tube diode could even be used but there would be no way to adjust its value.

[Alan0354]

saline is too hard to control, you might have to spend way to much effort just to keep it going and it evaporate on you and change everything. I don't know the construction of stove heater element, they might be very inductive if it is a coil inside. I don't think it is a simple resistive element. My tenant called me one time the stove element was arcing from a crack of the element and we had to go and change it.

in the late 70s, I used a big wire wound resistor with taps as a power break. It did not sound as good as the THD hot plate, but it was acceptable as an attenuator. Sometimes, it's good to be creative, but you always have to keep the common sense in mind on how practical the idea is.

[Alan0354]

saline is too hard to control, you might have to spend way to much effort just to keep it going and it evaporate on you and change everything. I don't know the construction of stove heater element, they might be very inductive if it is a coil inside. I don't think it is a simple resistive element. My tenant called me one time the stove element was arcing from a crack of the element and we had to go and change it.

in the late 70s, I used a big wire wound resistor with taps as a power break. It did not sound as good as the THD hot plate, but it was acceptable as an attenuator as that predated the real attenuators by years, no account on matching the impedance of a speaker or anything. I am sure you can find some cheap ones on ebay, those are the Ohmite old stuff. You can easily get a 12" long resistor with screw taps for adjustment. I doubted that few turns on the resistor will affect much particular for testing only. If you want one for performance, get the THD. I consider that is one of my best investment.

Sometimes, it's good to be creative, but you always have to keep the common sense in mind on how practical the idea is.

[lowell]

Dare i chime in? haha... liked reading about saline resistors though.

Once all other "tonal" factors are considered I find resistor types (noise aside) quite far down the totem pole. After musician, pickups, speaker, circuitry, tube types and on and on... then resistor types... maybe. IMO.

[Austin]

Any one ever use tantalum resistors?