Well, I voted that I don't like voting! And I'm pleased to see I am not the only idiot. 😀
Tube rectifiers are MUCH preferred by six-string and bass guitarists (not so much by pedal steel guitarists) due to the "SAG" factor---when played hard, the tube rectifiers will "sag" (drop voltage) and provide a very nice compression that is classic and not successfully imitated by compressor effects devices. This sound is evident on almost all of the classic Fender amplifiers, which are the Holy Grail of guitar amplification.
No, there are two reasons why new people ask silly questions:SY said:
1. they want to know the answer, and can't be bothered to look (lazy)
2. they want to stir up an argument, for some peculiar reason - maybe so everyone else knows they have arrived? (noisy)
I have no way of knowing whether the OP is lazy or noisy.
4. The last thread(s) devolved into a shouting match over which posters had incurred greater hearing loss while listening to their poorly implemented amplifiers.
5. After name calling stagnated the technobabble game of words ensued rendering the thread into a useless string of nearly incomprehensible theoretical gibberish.
5.a. Many threads use 5. as a default starting point.
5.b. Many technical articles use 5. as a default starting point in the interest of sounding smart. That is a HUGE contributing factor to the level of BS online. In particular I'm thinking of one in particular who's pages are all yellow and swears that wires are directional. It took a lot of reading to figure out he was completely full of it.
6. Item 5.b. can be extremely hard to detect without a firm grasp of the concepts involved and considerable time might be wasted chasing geese and learning lies.
7. (mostly likely scenario) The answers are hard to find, harder yet if you don't know what to search for. What REASONABLE person would expect me to snatch from the ether "Morgan Jones" as a search term. (meditating)
"hummm hummm hummm hummm hmmmor hmmmmorgan hmmmMORGAN JONES ! "
My experiences with diodes would be things like alternators, LED (been using CREE since 2001) Schottky on some solar chargers and such, etc.
The only ones that ever made a sound were on a malfunctioning alternator (bridge rectifier which you can hear the whine change) or one I exploded LOL.
Audio is just a whole different kind of circuit.
Also, some of us were blessed to be born in the age of silicon. I've NEVER even SEEN a tube powered TV, let alone scrapping parts from them.
Tube rectifiers? You mean like a tire patch? 😀
5. After name calling stagnated the technobabble game of words ensued rendering the thread into a useless string of nearly incomprehensible theoretical gibberish.
5.a. Many threads use 5. as a default starting point.
5.b. Many technical articles use 5. as a default starting point in the interest of sounding smart. That is a HUGE contributing factor to the level of BS online. In particular I'm thinking of one in particular who's pages are all yellow and swears that wires are directional. It took a lot of reading to figure out he was completely full of it.
6. Item 5.b. can be extremely hard to detect without a firm grasp of the concepts involved and considerable time might be wasted chasing geese and learning lies.
7. (mostly likely scenario) The answers are hard to find, harder yet if you don't know what to search for. What REASONABLE person would expect me to snatch from the ether "Morgan Jones" as a search term. (meditating)
"hummm hummm hummm hummm hmmmor hmmmmorgan hmmmMORGAN JONES ! "
My experiences with diodes would be things like alternators, LED (been using CREE since 2001) Schottky on some solar chargers and such, etc.
The only ones that ever made a sound were on a malfunctioning alternator (bridge rectifier which you can hear the whine change) or one I exploded LOL.
Audio is just a whole different kind of circuit.
Also, some of us were blessed to be born in the age of silicon. I've NEVER even SEEN a tube powered TV, let alone scrapping parts from them.
Tube rectifiers? You mean like a tire patch? 😀
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Lazy? Yeah that's definitely why I'm trying to learn new things. Total win there bud....
Every member should resent your characterization of my questions as "silly" and it can only discourage people from asking the very things they came here to learn about.
Why a thread?
The internet has become so crowded that search terms are highly diluted and wheat must be separated from chaff.
After some reading a few posters will rise to the top of the relevancy and intelligence scale.
Advanced searching can then commence around their posts as the top 5% of contributors. (keep in mind that many super-contributors are highly prolific and might have 10k-25k posts, no small search either)
In other words UTFS doesn't work when your terms are " I don't know"
Next....
I've never been to a technology based site where the mods actively trolled.
Did you become a mod to violate rules 1 & 2 ?
Your behavior encourages other posters to behave in a contentious manner (as quoted in #43), degrades the prestige of this forum and is likely to CAUSE trolls.
This site is the best one I could find. That is why I'm here.
Ban me now or please leave me alone.
Or better yet contribute, why else are you here? You are both obviously capable of contributing.
Every member should resent your characterization of my questions as "silly" and it can only discourage people from asking the very things they came here to learn about.
Why a thread?
The internet has become so crowded that search terms are highly diluted and wheat must be separated from chaff.
After some reading a few posters will rise to the top of the relevancy and intelligence scale.
Advanced searching can then commence around their posts as the top 5% of contributors. (keep in mind that many super-contributors are highly prolific and might have 10k-25k posts, no small search either)
In other words UTFS doesn't work when your terms are " I don't know"
Next....
I've never been to a technology based site where the mods actively trolled.
Did you become a mod to violate rules 1 & 2 ?
Your behavior encourages other posters to behave in a contentious manner (as quoted in #43), degrades the prestige of this forum and is likely to CAUSE trolls.
This site is the best one I could find. That is why I'm here.
Ban me now or please leave me alone.
Or better yet contribute, why else are you here? You are both obviously capable of contributing.
See? Something for everyone! "Not only am I a member, I'm the President!" 😀
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Maybe people asking question wanted to see others' views.
Maybe people want to socialise via forum on common hobby.
Maybe people want to see extra tube on their amp.
Maybe ...
Maybe people want to socialise via forum on common hobby.
Maybe people want to see extra tube on their amp.
Maybe ...
I think all of the supposed qualities of valve rectifiers can be achieved by adding a resistor after a good SS diode. I would challenge anyone to tell the difference even in a classic bass guitar amp.
Shoog
Shoog
Tube rectifiers worsen power supply regulation, so voltage drops with load.
Small filter caps worsen power supply regulation, and voltage gets heavily modulated by audio envelope.
Decreased supply voltage decreases headroom in all amps, if driven to clipping you can hear audio being modulated, specially mids/highs being modulated by Bass frequencies; some people like that.
Also some people like to eat dogs, sharks buried in sand for months or fermented fish , proving people's taste varies enormously, who am I to argue with them?
Small filter caps worsen power supply regulation, and voltage gets heavily modulated by audio envelope.
Decreased supply voltage decreases headroom in all amps, if driven to clipping you can hear audio being modulated, specially mids/highs being modulated by Bass frequencies; some people like that.
Also some people like to eat dogs, sharks buried in sand for months or fermented fish , proving people's taste varies enormously, who am I to argue with them?
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I would have thought more like 100-200R.
If you are looking for a 50V drop to compare to a 5R4 say and you are drawing 200mA you would shoot for (50V/0.2A) 250R.
Look at the spec sheet to see the effective plate resistance of your chosen valve rectifier.
Also, I would put a ceramic snubber across the combination as well. Both the resistance and snubber will severely limit your charging and recovery spikes and damp resonances. Hence you have a virtual valve rectifier.
Shoog
So if the impedance of a tube rectifier varies with load, then it adds something to the music like the carbon resistors, carbon plates etc do.
Just a thought.
Just a thought.
Take the good knowledge that you find, try to double and triple check it elsewhere and by all means start getting some hard factual knowledge from books like RCA tube manual, Radio Amateurs Handbook, etc. Remember take everything you read or see online with a grain of salt and a sprinkle of skepticism. There are other forums like Audio Asylum, Audio Karma, many more, and each is run by their own band of Merry Men wreaking havoc on unwary travelers. I guess every audio forum has their share of ?x*1#**! And sometimes mob mentality rules. It is an unfortunate side effect of giving everyone an anonymous soap box to stand on. Good luck.
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In additive synthesizers the low frequency oscillator can be used to cause a tremelo or vibrato effect by laying a low frequency wave over whatever else is being played.
Is this similar to the perceived effect you are describing?
Notice I said perceived effect, not asking if a synth = tube amp.
If yes then this would be the best explanation I've seen for them being some sort of "special sauce" not that special is siempre synonymous with desirable. Even if I have it wrong, thank you for that piece of puzzle.
BTW, you might add this to your list of delicacies https://en.wikipedia.org/wiki/Virgin_boy_egg
Thank you also to Shoog for his suggestion.
I see such things prefabricated on the proper tube base available for a very reasonable cost.
There are two things going on here:In additive synthesizers the low frequency oscillator can be used to cause a tremelo or vibrato effect by laying a low frequency wave over whatever else is being played.
Is this similar to the perceived effect you are describing?
Notice I said perceived effect, not asking if a synth = tube amp.
If yes then this would be the best explanation I've seen for them being some sort of "special sauce" not that special is siempre synonymous with desirable. Even if I have it wrong, thank you for that piece of puzzle.
BTW, you might add this to your list of delicacies https://en.wikipedia.org/wiki/Virgin_boy_egg
Thank you also to Shoog for his suggestion.
I see such things prefabricated on the proper tube base available for a very reasonable cost.
-the operating conditions of each valve are changing in response to the changing voltage of the B+. this will mean that their distortion profile will change and their actual amplification will change.
-as the B+ sags the amplified signal will be at it maximum so as it rises up the B+ falls down in response. This is likely to cause clipping of the top of the waveform which will dramatically increase the second and third harmonic distortion components.
I suppose if you get it right it can sound "good" in a instrument amplifier, but I can think of absolutely no situation where it would improve a HIFI amplifier.
Shoog
Tube rectifiers are completely obsolete for any project, unless you like looking at them (art object).
They make less Rf noise at the zero crossing (turning on and off), than a SS diode, but that's easily dealt with by adding .01uF 3kV ceramic caps across them, or just across the secondary winding of the power tranny, and across the large electrolytic caps. If grounding is done right, and these .01uF caps are there, Rf is highly unlikely to be a problem.
The "sag" that many guitarists think is great, can be created by a simple strategically sized RC on the output of the power supply. There's no reason why a tube rectifier series resistance is any better than a regular resistor. It's the discharge of the final filter cap feeding the output stage of the amp that creates the sag in either case.
I consider chokes obsolete too. I use two RC filters after the rectifier diodes using larger cap sizes, throwing away maybe 30 volts across the resistors, then a strategic RC with maybe a 50 ohm resistor feeding a "vintage" sized cap, maybe 20uF, if I want sag.
A rectifier tube takes up significant space, makes the thermal situation worse, and wastes significant power on another filament. Chokes are from the days when the biggest electrolytic cap you could get was 20uF. I use two 100uF caps with R's feeding them, before any sag RC.
Chokes take up significant space and add a few pounds to an amp that we all wish was lighter weight. The only issue to keep in mind is that you want to choose a power tranny that will give you maybe 40 volts more than you want for B+, so you can throw that voltage away across the resistors feeding the large electrolytic caps. Chokes drop a lot less voltage, per unit of effectiveness. These series resistors will likely need to be 10 watt rated, and roughly 50 ohms each, depending on the wattage of the poweramp. Do the math, and go with bigger wattage ratings (maybe 4 times higher) so heat is less of an issue. Pushing any R to it's power limit will make it very hot.
They make less Rf noise at the zero crossing (turning on and off), than a SS diode, but that's easily dealt with by adding .01uF 3kV ceramic caps across them, or just across the secondary winding of the power tranny, and across the large electrolytic caps. If grounding is done right, and these .01uF caps are there, Rf is highly unlikely to be a problem.
The "sag" that many guitarists think is great, can be created by a simple strategically sized RC on the output of the power supply. There's no reason why a tube rectifier series resistance is any better than a regular resistor. It's the discharge of the final filter cap feeding the output stage of the amp that creates the sag in either case.
I consider chokes obsolete too. I use two RC filters after the rectifier diodes using larger cap sizes, throwing away maybe 30 volts across the resistors, then a strategic RC with maybe a 50 ohm resistor feeding a "vintage" sized cap, maybe 20uF, if I want sag.
A rectifier tube takes up significant space, makes the thermal situation worse, and wastes significant power on another filament. Chokes are from the days when the biggest electrolytic cap you could get was 20uF. I use two 100uF caps with R's feeding them, before any sag RC.
Chokes take up significant space and add a few pounds to an amp that we all wish was lighter weight. The only issue to keep in mind is that you want to choose a power tranny that will give you maybe 40 volts more than you want for B+, so you can throw that voltage away across the resistors feeding the large electrolytic caps. Chokes drop a lot less voltage, per unit of effectiveness. These series resistors will likely need to be 10 watt rated, and roughly 50 ohms each, depending on the wattage of the poweramp. Do the math, and go with bigger wattage ratings (maybe 4 times higher) so heat is less of an issue. Pushing any R to it's power limit will make it very hot.
famousmockingbird takes the prize: "The tube rectifier along with a limited energy reserve adds some very nice compression. It's a feel thing too, guitar players don't just hear their amps, they feel them."
Vacuum tube rectifiers also provide a natural "soft start" that was often designed to allow power tubes to get up to operating temperature first before gently applying the B+. The down side is the large voltage drop of a vacuum rectifier, and subsequent heat and aging issues.
Vacuum tube rectifiers also provide a natural "soft start" that was often designed to allow power tubes to get up to operating temperature first before gently applying the B+. The down side is the large voltage drop of a vacuum rectifier, and subsequent heat and aging issues.
From a design point of view are there REAL advantages to rectifier tubes vs more modern tech?
The only advantage from tube rect are best SQ, otherwise its a expensive solution:
-need the supply at the power transformer,
-made alot of heat,
-heat the chassis and near transformers by radiation,
-need socket and wiring,
-and need the tube rect itself.
OTOH SS rect usually has better bass.
Does lowering the rail voltage of a tube amp reduce its voltage gain or is it the same as a SS amp where lower rails just cause clipping at a lower output voltage? If there the same, rail droop doesn't compress anything, just lowers the clipping point. (Which increases distortion at high levels.
In a fixed bias pentode amp then lowering B+ will just cause more clipping. In just about every other practical valve amp it will effect the gain and general behaviour of the amp as well.
Shoog
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