So long as that 200V doesn't cause the resistor to exceed its wattage rating. I'd still prefer to a bit more gentle with the power and rate the resistor a bit over that spec for a non mass produced item. The extra MTBF (Mean Time Between Failures) would be worth it.
A strange observation, perhaps on the coast of the Adriatic only?
Please describe the 'metal sound' for us. THX
Carbon film resistors can work for plate loads, but metal film or wirewound resistors are generally better due to lower noise and better stability. If you're aiming for a warmer tone with some vintage character, carbon film can be a good choice. What’s your specific application?
I have tried 5W Kiwame carbon film to replace the the plate load resistor that originally has metal film 1/2W there. It sounds much more musical!!
Egellings,
You could as an alternative use an RN60-sized metal film part, which has a higher wattage rating. If you ae short on space you can always stand up the parts for closer spacing.
You could as an alternative use an RN60-sized metal film part, which has a higher wattage rating. If you ae short on space you can always stand up the parts for closer spacing.
Much noise on DIY related to resister noise of various kinds.
Has anyone done comparative measurements, and how the results
relate to the signal level likely at that place in the circuit?
Probably orders of magnitude, most home grown amps on DIY
are 2-stage things. Intended for a 2V input signal.
In the distant past we had to deal with mV sources.
How did we ever do that with CC resisters?? 😀
Yeah, I have seen classic tube amplifiers and receivers loaded with carbon composition resistors below decks - I'm currently working on a classic Scott receiver that has tons of the beasties. Why the RIAA section doesn't hiss like an angry snake is beyond me, especially as there are 12AX7s involved, and not the low-noise variety, either. I may just throw up my hands and replace the carbon comps with metal film parts. I think the RIAA preamp also has feedback EQ, so I would not swear on a stack of Bibles that the RIAA accuracy is anything to write home about...
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Resistors make two different kinds of noise. Thermal / Johnson / Nyquist noise depends on resistance value and temperature (only) and is the same for all constructions. Other noises, called "excess" noise, vary with construction and with current flow. So, a resistor in a location with no current through itself, like a grid stop for example, will make the same amount of noise independent of construction, but a plate load will vary.
The lowest excess noise comes from wirewound constructions, then metal film, and the highest comes from bulk (composite) carbon.
All good fortune,
Chris
The lowest excess noise comes from wirewound constructions, then metal film, and the highest comes from bulk (composite) carbon.
All good fortune,
Chris
is not strange, take one guitar amp lets say pcb made to avoid lead dress effects in repeatable build, populate all positions with all carbon film resistors and then the same pcb populate with metal film resistors.. give at the end you observation.
noise- hm. what noise have to do with the overall sound? one question, how many amps did you built in your life?"Less noisy than I'm used to"
what are you speaking about.. noise is 60-90 dB below actual signal.. and character is there not in the noise... minor masking maybe is possible but can be ignored.
put all carbon resistors in anodes and after that install metal films, various types.. if there is many cumulative preamp stages like in guitar amp, differences will be more clear.
No resistor is perfect.
The disadvantages of CF have been described in detail, so what are the advantages of CF? CF has excellent moisture resistance because they are only graphite. Although most of your food and your board are carbohydrates, it is obviously difficult to achieve this in resistor-carbon is very inert to water (but pay special attention to the fact that loose carbon may migrate when there is enough water，space and voltage), which is very beneficial to storage in humid environment.
The Ni-Cr alloy film of metal film resistor is not excellent in moisture resistance, and they will be effectively eroded by water and transformed into other unwanted substances, which will cause reliability problems for the resistor. In the early days, when a diamond knife was used to cut a huge volume resistor to form an vintage nickel-chromium film resistor which was described by modern people as a large number of inductors (fat, low power density), the film was thickly that wet corrosion problem not particularly serious. Modern metal films, on the other hand, are extremely thin film to control the resistance-which greatly reduces cost, inductor, and the moisture strability. Although metal film resistor manufacturers have come up with many methods, such as making a black inert layer on the surface of metal film, using high-strength epoxy resin packaging to reduce the possibility of moisture intrusion, etc. But remember: the metal film is not perfect, at least in terms of chemical storage stability.
In view of these extremely harsh (very humid) requirements, people have developed TAN resistor, which is also called tantalum nitride resistor. Precision, low noise, resistive film is inert to moisture. It's really good except, until your wallet become empty. and it temperature coefficient can't be made very low. Tantalum resistors used in audio are notoriously expensive.
CC resistor is still in production, but the previous sintering agent is clay and now it is replaced by alumina. Compared with the previous CC, the current CC is much more stable, at least they can keep within the tolerance range of 10% for a long time. CC's valuable property lies in its overall conductivity, so it has a large heat capacity. When you need instantaneous high-power discharge (for example, the large capacitor of switching power supply or electron tube equipment is discharged quickly), other resistances are calculated in watts, while the resistance of CC is calculated in Joules-which makes the discharge process quick, easy and concise. Obviously, this process is not only so easy, but also used in AED or non-automatic electric shock defibrillators in hospitals-to absorb and control the energy counted in Joules.
In addition, the excessive noise of CC resistor come from its strong DC current-the signal-to-noise ratio of CC resistor can be guaranteed to be 100 ~ 120 dB, and even some brand-new products that are not destroyed by water vapor crystallization and heating vapor pressure can achieve 140dB. The premise is not to pass through any DC bias. If you connect a few millivolts audio to a CC resistor that passes through tens of volts DC, obviously the signal-to-noise ratio will be very poor. The signal-to-noise ratio of modern CF resistor can reach 150 ~ 160 dB, MF160dB and foil resistance 162dB. If you don't pass DC, the signal-to-noise ratio of CC resistor is enough for general audio-of course, this doesn't mean that using CC in this way is fidelity, because there will be the influence of VCR, absorption and slow polarization effect. Moreover, CC will absorb water (because there is something called montmorillonite desiccant in minerals, and the traditional CC resistor is like a desiccant, haha). In the process of forming ice crystals and steam (sudden high-temperature use and incorrect drying), all it will destroy the fired structure, causing various damages and micropowder inside, making the resistance performance worse and worse, and the test resistance value generally drifts to a higher resistance. (However, it should be noted that the micro-damage caused by these resistors may still be turned on under high pressure, so the VCR has become extremely bad.)
But this is the historical fact-the CC of “cheaply garbage” has instead formed the memory of the sound of the times, which satisfies two characteristics of the luxury goods of the ancient tomb school: the popularity of the masses and the scarcity caused by the poor quality in the later period. metal film invented old than WWII，but not used in vintage personal consume instruments because expensive. I am opposed to rejecting or pursuing CC without knowing its performance clearly. When you know its performance clearly, you can use it whatever you want.
The disadvantages of CF have been described in detail, so what are the advantages of CF? CF has excellent moisture resistance because they are only graphite. Although most of your food and your board are carbohydrates, it is obviously difficult to achieve this in resistor-carbon is very inert to water (but pay special attention to the fact that loose carbon may migrate when there is enough water，space and voltage), which is very beneficial to storage in humid environment.
The Ni-Cr alloy film of metal film resistor is not excellent in moisture resistance, and they will be effectively eroded by water and transformed into other unwanted substances, which will cause reliability problems for the resistor. In the early days, when a diamond knife was used to cut a huge volume resistor to form an vintage nickel-chromium film resistor which was described by modern people as a large number of inductors (fat, low power density), the film was thickly that wet corrosion problem not particularly serious. Modern metal films, on the other hand, are extremely thin film to control the resistance-which greatly reduces cost, inductor, and the moisture strability. Although metal film resistor manufacturers have come up with many methods, such as making a black inert layer on the surface of metal film, using high-strength epoxy resin packaging to reduce the possibility of moisture intrusion, etc. But remember: the metal film is not perfect, at least in terms of chemical storage stability.
In view of these extremely harsh (very humid) requirements, people have developed TAN resistor, which is also called tantalum nitride resistor. Precision, low noise, resistive film is inert to moisture. It's really good except, until your wallet become empty. and it temperature coefficient can't be made very low. Tantalum resistors used in audio are notoriously expensive.
CC resistor is still in production, but the previous sintering agent is clay and now it is replaced by alumina. Compared with the previous CC, the current CC is much more stable, at least they can keep within the tolerance range of 10% for a long time. CC's valuable property lies in its overall conductivity, so it has a large heat capacity. When you need instantaneous high-power discharge (for example, the large capacitor of switching power supply or electron tube equipment is discharged quickly), other resistances are calculated in watts, while the resistance of CC is calculated in Joules-which makes the discharge process quick, easy and concise. Obviously, this process is not only so easy, but also used in AED or non-automatic electric shock defibrillators in hospitals-to absorb and control the energy counted in Joules.
In addition, the excessive noise of CC resistor come from its strong DC current-the signal-to-noise ratio of CC resistor can be guaranteed to be 100 ~ 120 dB, and even some brand-new products that are not destroyed by water vapor crystallization and heating vapor pressure can achieve 140dB. The premise is not to pass through any DC bias. If you connect a few millivolts audio to a CC resistor that passes through tens of volts DC, obviously the signal-to-noise ratio will be very poor. The signal-to-noise ratio of modern CF resistor can reach 150 ~ 160 dB, MF160dB and foil resistance 162dB. If you don't pass DC, the signal-to-noise ratio of CC resistor is enough for general audio-of course, this doesn't mean that using CC in this way is fidelity, because there will be the influence of VCR, absorption and slow polarization effect. Moreover, CC will absorb water (because there is something called montmorillonite desiccant in minerals, and the traditional CC resistor is like a desiccant, haha). In the process of forming ice crystals and steam (sudden high-temperature use and incorrect drying), all it will destroy the fired structure, causing various damages and micropowder inside, making the resistance performance worse and worse, and the test resistance value generally drifts to a higher resistance. (However, it should be noted that the micro-damage caused by these resistors may still be turned on under high pressure, so the VCR has become extremely bad.)
But this is the historical fact-the CC of “cheaply garbage” has instead formed the memory of the sound of the times, which satisfies two characteristics of the luxury goods of the ancient tomb school: the popularity of the masses and the scarcity caused by the poor quality in the later period. metal film invented old than WWII，but not used in vintage personal consume instruments because expensive. I am opposed to rejecting or pursuing CC without knowing its performance clearly. When you know its performance clearly, you can use it whatever you want.
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