Valves
Join Our Community Subscribe to Paul's PostsWe’re all familiar with the terms amplifiers and valves. We use electronic valves like vacuum tubes and transistors to amplify audio signals. Yet, even writing those words makes me a bit nervous because I can see how they might be misunderstood.
When we talk of amplifying the input signal it sounds like we are taking a small signal and somehow boosting it. Maybe a good analogy can be found in an airport and its moving sidewalk. You’re walking along at your pace and then step onto the moving conveyor belt, boosting your speed. That’s amplifying your walking.
That’s not what’s happening in an amplifier.
In fact, the input signal never reaches the output. It does its work and then is discarded, never to be seen or heard again.
We don’t amplify the input signal in the same way a moving sidewalk amplifies our forward motion. Instead, the input signal turns a virtual valve up or down to release more or less voltage and current from the power supply. What gets passed on to our speakers and headphones is not the input signal, but voltage and current straight from the power supply.
It’s more than semantics.
Our input signals are but instigators.
Once they do their work they are gone forever.
Dr. Goodears has just replied to me why you need 47 or 48 people to make up an American Football team. It sounds frightfully complicated and from what he says 48 seems a bit thin on the ground. The reason being its a complicated game with a lot of things to do and also a bit physical. Well, there’s a game called Rugby Union that is positively brutal and you don’t get to wear a helmet. 15 guys and 7 or 8 substitutes. Two types of player, forwards (the big slow guys) and backs (the little fast guys). Cricket keeps it to 11 players and an extra (called, appropriately, the 12th man, even if a woman), who’s main job is to bring on drinks every once in a while. That’s the only simple thing about cricket, the rest is a complete mystery to everyone except the 2 billion people who love the game.
The point being, like audio (and it’s always like audio), there are very big cultural differences in this world, most of which are unfathomable to people from other cultures. One is the need to 150 watts, let alone 600 watts, or a room full of boxes to play music, or speakers with more than 3 or 4 drivers. It doesn’t make any one culture better than the other, and they can cross boundaries occasionally. The NFL plays a match or two in London, 100,000 people get very excited and the rest scratch their heads. It’s also rumoured that North Americans have attempted to play football, calling it soccer, a game that basically has only one rule (the offside rule) that most people don’t understand.
Cultural differences are there to be respected, if not understood.
Jack bowled well but comes away with a golden duck.
Let’s see what Capt. Joe can do tomorrow.
Can the English team also ‘drop like flies’? 🙂
Steven, I used to recall this NZ fellow called Jonah Lomu. He played wing an ran over Catts. He was not small. The only small international winger today is a South African named Kolbe. There are some other small ones. Most play scrum half, not with the rest of the backs.
In football, you can’t whack the other player or touch the ball with the hands. Unless you are Maradona.
CtA,
With regard to your Feb 15th, 3:14pm reply on yesterday’s ‘Brain Fog’ topic.
Please show me, & everyone else here, exactly where I typed that I’m a quitter; as you have stated that I said so in my own words.
You are nothing more than an inept liar; which you have now proved, to all who read these posts, to be.
You said you were 60 years old and having nothing to do but email your friends and listen to music on Mondays. You said you don’t read or not interested in new knowledge. Basically, you are a mediocre quitter. A loser. A simple mid fi salesman that bullies people around. A nobody. Your only topics of conversation are naming audio brands or cricket. Nothing else. Zippo. Nada. You even call yourself “fat”. With your words, why do you need mine to describe you?
CtA,
So because I take Mondays off to contact friends & to listen to music you assume that I don’t do anything or busy myself in any other ways during the rest of the week?
You’re a bona fide idiot; a complete loser.
‘Fat Rat’ is a moniker that my wife made up as a joke, you poor simple fool.
You still haven’t shown me where I said that I’m a quitter ‘in my own words’, nor did I say that I don’t read.
You should change your moniker to ‘Brain Fog’; that would be far more appropriate for you.
She is not joking. This is what she thinks of you. Poor soul your wife. At least she is honest in how she named you.
My wife does not use names like this for me.
CtA,
OMG, you have a wife?!!
Poor soul, she!
You have no idea what humour is, do you?
You sad, sad little amoeba.
If assumptions & lies are all that you can come up with, no wonder you are clueless when it comes to audio & it’s subjective nature.
Humor? Yep, humor has sarcasm and some truth to it. Some weeks ago you disclosed here how you don’t take care of your body.
So, to her you are a Fat Rat. The shoe fits. That is probably an “objective” observation of you from her.
I don’t lie. I said you are uninteresting and mediocre. So far, you are showing me to be correct.
You remind me of Alan Jones. All bluster and bullying. Get your talk show. At least, he was a good coach.
CtA,
(Brain Fog)
And you still haven’t shown where I said ‘in my own words’ that I’m a quitter; therefore you are still a liar who makes unfounded assumptions.
I take well enough care of myself without you needing to concern yourself.
Your filibustering should come to an end before you embarrass yourself even more.
I have asked you now three times to prove your claim that I stated ‘in my own words’ that I’m a quitter & you have not been able to do so.
All you have done is avoid the question & blather on with your unrelated & extraneous thoughts.
Are you hurting that someone tells you the truth? I’m not sorry. Your bullying and insults are tiring. Grow up, behave. It is time you discover yourself. The end.
Of course American Football was influenced from Rugby just as some aspects of Baseball are drawn from Cricket. Since the beginning of time, advanced cultures have inspired future culture. You know, the whole taxation without representation rap.
Europe provided the world with the sheet music of Bach, Mozart and Beethoven. The US brought forth Little Richard, Chuck Berry and Elvis Presley to the world via magnetic tape recording technology, radio broadcasting and phonograph records influencing The Beatles and Rolling Stones. These artists and technologies are the reason we’re here.
Football and Baseball are simply more three dimensional games when compared to their classic British counterpart match. As previously written, the game of Soccer is total chaos imho, though the most popular spectator sport in the world.
A friend of mine famously stated, “if a dog can play with a ball, what challenge is it for a man? therefore the only true sport is mountain climbing!”. 🙂
Here’s a loose analogy,
Let’s think of Paul as the signal or as he puts it, the ‘instigator’.
Now how many replies will stay on subject and amplify the thoughts of the day. (Signal replica’s). And how many will veer off the path and head in another direction. (Distortion of the signal, and lots of times that distortion gets dissipated as heat)
Will the end user (reader) come away with an accurate, or at least enjoyable, replica of the instigation?
Mike, to be completely honest and political I think the distortion began with the argument that the trail itself was unconstitutional.
I’m confused Bret. Honest and political don’t typically go together. Neither have anything to do with instigating a power supply 🙂
Mike,
I thought that Trump was the instigator & the ‘death squad rioters’ were the power supply 😉
I need an eye roll emoji …
Ditto
Audiophiles can learn from the Impeachment process. It’s called “Doing a Mitch”. You listen, learn, carefully consider, reach a full understanding of the relevant facts, which leads you down only one possible path … and go in the complete opposite direction.
Well somewhere along the path Mitch lost his cojones (power supply)
Y’all are f’n killing me 😀
I must admit it was priceless entertainment, that lawyer, Vincent von Doom, all the senators were laughing at him for some reason. I was complaining to the wife last night about who got to empty the dishwasher that there was an appalling lack of due process, to which she said if I want dinner tonight I can make it myself. The beauty of marriage is that it preserves First Amendment rights, you say whatever you like whenever you like, just don’t expect anyone to listen.
The funny part was when I wrote my comment this AM I wasn’t even thinking about all the bone heads in Washington.
As far as marriage goes I’ve learned that it’s only a democracy in theory. Much closer to an authoritarian style when push comes to shove. 🙂 Did you go hungry last night, or order out ? Or are you still trying to get the dishes into their proper storage area? 😀
We haven’t got that far. I’m demanding witnesses.
I’m happy to live in a country where a political elite play at running the country and everyone else ignores them. One of the true joys of Covid-19 is that the level of political discourse is now reduced to arguments and rebuttals over whether we order Indian or Chinese.
What I find really upsetting about the whole thing is that Trump gets to play golf and I don’t, because here the golf clubs are all closed.
While this country on this side of the pond may seem run by a bunch of political hacks, Most golf clubs are open (weather permitting). So since I travel all over the country, I spend at least 2 weekends a month in a golf haven state. (mostly to get out of domestic chores 🙂 ) One of the perks of still working….
Hear, hear Steven!
Bret,
If at first you don’t succeed; file a civil suit 🙂
Well put! Perhaps we should call this Pail’s Posts and Soccer scores.
good one Stimpy 2
Although I believe lately it’s been cricket matches. 😉
Mike,
“As far as marriage goes…”
I do like the way that ‘hawkaudio’ calls his 2nd marriage, “a second administration”…it does have that ‘authoritarian’ feel about it.
40+ years of the same administration here. I believe the ballot box is being rigged.
At this point does it really matter Mike. Check out the latest ANA[DIA]LOG Channel. His post is wonderful and nobody goes off topic. Paul I’m gonna send you the link.
No it really doesn’t matter stimpy2 🙂
I guess this a ‘big picture’ posting area. Not a place for individual’s specifics. Fun to read and participate in, but for specifics I guess that’s the forums side.
I’m not much of a you tuber at this point in my life since I’m still a working slob. So I read here, research when needed , and try to be pragmatic. Lately tweaks concerning isolation and coupling have had major influences on my systems sound.
Mike,
I’m kinda curious to find out whether tennis balls, cut in half & positioned under equipment platforms, are successful at absorbing any major vibrations.
Now I gotta find somebody with a band-saw….
If curious, then worth looking around to find someone with a saw. I’ve seen them used as crutch tips on walkers…. 😉
Mike,
Wtf?
“…crutch tips on walkers…”
How thick are the legs on those walkers??
😉
I don’t know, but maybe they are superior at reducing vibrations into the metal frames….. 😀
Hmm…probably useless for people with Parkinson’s disease (Emoji with rolling eyes)
The analogy is perfect. The quality of the output is no better than that of the power supply AND the accuracy of how the input is read by the valve and how well the valve (be it a tube or transistor) is able to translate the input. But the input’s job is done upon delivering the message.
Not to be political, think of last week’s impeachment activities in DC. The case managers from the house were the input. The vote of the senators was the output. The power supply was the constitution. Had the 100 senators voted guilty, the distortion would have been immeasurable. Since 57 of 100 voted guilty, the distortion level was 43%. Or, expressing the analogy as gain, there were four main presenters from the house so that potential gain could have been 14 dB. Required gain was 12.2 dB. But, the actual gain was 11.5 dB.
In any case, the input signal, regardless of quality or accuracy was lost and all that counted was the output.
Yes fully agree – where else could the energy to drive the speaker(s) come from other then the power supply.
Too much bias current applied to the output affecting the required gain.
Amplifier describes its function, not its mechanism of working.
The term power amplifier is a misnomer. It’s actually a voltage amplifier able to deliver a lot of current.
The proof is to watch the output meters swinging back and forth with no speakers connected. They are volt meters calibrated in watts that would be delivered into an 8 ohm resistor. With no speakers connected the power output is zero regardless of what the meters tell you. If your speakers are not the electrical equivalent of an 8 ohm resistor, then the meters are merely decorations and have no value except to tell you there is output voltage.
Teddy Pardo PSU does it for me.
Off topic. I thought this might be interesting. It’s about the first stereophonic phonographs
https://www.youtube.com/watch?v=5vP1GSTxKoM
The vinyl phonograph record was made possible by the Westrex 45/45 cutter developed in 1957 by Bell Labs and Western Electric, two divisions of AT&T. The First stereophonic records came from a small company Audio Fidelity in late 1957.
What has changed since? We have different signal storage formats and methods. We also have transistors as well as tubes. Except for refinement little else. Because of its obvious superiority over monophonic sound and because it was affordable to most people stereophonic sound took off on the market like a rocket.
I still have a few of those Audio Fidelity records.
I love the Dukes of Dixieland. Sorry I didn’t buy more of their recordings when I could.
Before I comment about to today’s post could someone please tell me what “ASR” is in yesterday’s post?
I think Paul’s analogy is very good and I think he is right in assuming that many people think that the amp boasts the input signal to make it the output signal, when in fact, the components in the amp use the input signal to create the output signal. Another common mistake that many people make is that electrons actually flow through the wires, circuits and components in our audio systems because we all talk about current flow in our systems. Most do not understand that current flow is just a mathematical description used to understand the flow of electrical energy through our systems, however, there is no matter ( electrons or any other matter ) that flows through our systems. The only place in some of our systems were electrons actually “flow” from one place to another is if you have actual vacuum tubes in your system and the electrons do not flow out of the vacuum tube.
Tony
I believe the reference was to audiosciencereview (website name).
Mike, Thank you.
By far, this is one of Paul’s most succinct and informative posts, perhaps for the some of us uninformed. Thank you.
…”In fact, the input signal never reaches the output. It does its work and then is discarded, never to be seen or heard again.”
….” What gets passed on to our speakers and headphones is not the input signal, but voltage and current straight from the power supply.”
Today’s post is fraught with inaccuracies, to say the least.
The loudspeakers only work with alternating currents, the input signal in the amplifiers is alternating voltage, while the output voltage of the source is continuous. The input voltage (small) in the amplifiers, although its amplitude (gain) is varied, remains alternate and does not disappear as such, in the amplification process until it reaches the speakers, as has been stated.
Subscribers to this forum not so young, can remember the unpleasant sound of the CD players of the first time, mainly its occurrence in the mass of strings, if this input signal had disappeared, as it is claimed today, we would not have heard this detestable anomaly, the same one that has gradually been improved, now for the new converters, now for the new formats (DSD) whose proof is in the claim of the manufacturer Sony, referring to the SACDs in the sense that they have a more analog sound .
The input signal maintains its characteristics whatever these are (including distortion) until it reaches the speakers. It is considered a virtue in amplifiers, that they are “neutral” enough not to pervert this signal, although this signal is perverted in the end when passive Xovers are used on the speakers.
The controversy attended by the manufacturer Linn, in the sense that it advocated that the quality of the sound in the loudspeakers was given by the “accuracy” and fidelity of the source (in this case the LP-12 turntable) while its opponents said that this was given by the sound of the speakers, it is well known.
Here the saying: Garbage in, garbage out, it is fulfilled.
Going beyond semantics, falls into the realm of fiction.
I have no idea what Audiomono is trying to suggest here but he’s just plain wrong.
Let’s take a pure voltage amplifier like a vacuum tube as an example. When the incoming signal voltage (AC) from the source is applied to the vacuum tube’s input (called the Grid), that causes current to flow between the plate and cathode. The greater the voltage on the Grid, the greater the current passing through the Plate to Cathode.
The input AC signal is turning on and off in varying degrees, the current from the power supply. The input AC signal from the source, never makes it past the input.
The output of the tube is 100% from the power supply of the vacuum tube.
I understand what you are saying Paul. What might be fun is to come up with a number of how many times the signal is replicated (amplified) in the typical process from the microphone , then mastering mixing, and finally to home set up delivery through the speakers or headphones. I can’t hazard a guess, but I’m guessing the number is very large, especially for studio recordings that use many channels or tracks when recording.
@PMG
The matter is very simple, you say that the input signal disappears when it reaches the speakers.
This never disappears, otherwise we would not be hearing the weak signal produced by a moving coil cartridge or a microphone.
The input signal (AC) coexists with the voltage of the power supply (DC) until both reach the speaker in the form of AC, through the ingenious resource of joining these two voltages of different amplitude, in any case, if something disappears it is the DC, as such, since, if you have only DC in the output and your amplifier is SS, this has to be repaired.
Don’t argue with Paul when he is right. The time to disagree with him is when he’s wrong. That’s my job 🙂 BTW I do this pro bono. I’m doing it for you guys (and gals if there are any reading or posting here) to help you understand. How do you get something with very little energy to perform work on something that requires a lot of energy? The answer is to use the small energy to control progressively more energetic sources until you have enough to drive loudspeakers or headphones. That is what Paul is saying. Now go read a book on elementary electronics and it will explain it very clearly. Before electronic amplification we had wind up phonographs with big horns driven directly by mechanical energy and crystal radios that used the energy of the radio waves themselves to drive an earphone. You could barely hear it. Here it is. No batteries, no power supply, no nothin’. I think I built one when I was about five or six years old.
https://www.electronics-notes.com/articles/history/radio-receivers/crystal-radio-set-circuits.php
Well put Paul. Until I started reading your posts and others that talk about the output of the amplifier to the speakers is nothing more than the modulation of the power supply of the input signal I never really gave much thought about it. Now you have presented a new analogy. You’re attacking the topic from several directions and perhaps that’s necessary so that everyone gets a full understanding of the subject.
Perhaps you could explain how an OTL Amp works without a power supply to regulate. Maybe this is another topic. Keep your great posts coming!
This why the power supply is more important than is mostly understood. It is the amplifier. The rest of the complicated amp is a power supply modulater.
When I was in graduate school working on my Ph.D. in physics there was a professor who would always show up when someone was defending their dissertation if it was an experimentalist ( as opposed to a theorist ) who was defending. He would almost always ask if the defendant had they checked to be sure their gear was working properly. He would ask if there something that you could do to the gear to change the results? I swore that if he asked me that question I was going to answer “Yes, I can unplug the damn thing and the results will change.” For whatever reason he did not ask me that question at my defense.
not sure I get your point
The power supply is always important.
Periodic recalibration of scientific test equipment is necessary to assure that the measurements are within the accuracy of the equipment’s specifications. Scientific instruments always have more than adequate power supplies or they wouldn’t be of any value to scientists. Well regulated and well filtered power supplies are a must. The component parts should also be top notch for accuracy, stability, and long life. When was the last time the measuring instruments used in the magazine test results had their calibration checked and adjusted? For a scientist this is not a trick question, it’s a fundamental requirement because if unmet the results are invalid.
Agreed but I was referring to audio gear where skimping a bit on power supply which is expensive hardly affects standard specs but does affect what we hear.
I think you spelled out what’s going on here very well Mike.
How much voltage do most amplifiers need from the preamplifier to reach the amplifiers full output? Is more voltage from the preamplifier good even if it’s much more than the amplifier needs to reach it’s full output?
2 volts or less—mostly less. The BHKs max out at 1.3 volts input for full output.
Too many volts on the input and the amp’s output will clip. Most amps have between 27dB and 30dB of gain. With 30dB of gain the voltage amplification factor is easy to remember because it’s the same as the dB. 30.
So, for 2 volts on the input and a gain of 30 you get 60 volts out.
Thanks Paul. I was aware of the possibility of clipping with too much preamplifier gain which is why some active preamplifiers allow for 3, 6, and 9db of gain adjustments, I guess it would depend on the source components output on which one you would choose. I do have one of those for my older Creek integrated and if it fits I don’t see why it wouldn’t work and sound good, it’s one model grade down. With most CD players and other source components having 2db and higher I find the use of the passive stage in my Creek amplifier suitable for most of the source units I own. My Creek model has the option to install an active gain card inside and set it to the desired level but that card is impossible to find even from the manufacturer plus you need to take the cover off every time you want to switch from one to another. The later models had them built in with a switch on the outside of the unit. With some active preamplifiers set too high like you said it would be easier to clip the amplifier which is why some manufacturers with high set preamplifier outputs would warn against turning the volume much past the 12 O’clock position to avoid that problem. My Creek integrated in it’s passive stage allows me to turn it to the 3 O’clock position or higher before I begin to detect the amplifier is running out of clean power. I love the sound, it’s as if there is no preamplifier in the signal path. I just have to make sure the volume control, speaker selector switch and source switches are clean which I just did using Deoxit and wow what a difference in the sound stage.
Got to watch for the amplifier input too as well as the preamplifiers output which you did explain. I imagine ohms play a role there.
If the signal is discarded at the beginning then how does it show up at the speakers. If what the post says is true then if the frontend is switched off in the middle of play the music should continue to come out of the speakers but that is not so. The signal it seems is never discarded. It rides on the voltage and the amount of voltage is controlled by the variable resister called a volume control. No signal no sound. Try playing music without the frontend switched on and the volume control at the maximum and see what comes out of the speakers. Regards.
It is a game of Chinese Whispers. The input whispers to the pre-amp which talks to the amp which shouts at the speakers. If all goes well the message is the same throughout.
I love this analogy of the Chinese whispering game.
Wow, the analogy about what is perfect? I’ve never been on a moving airport walkway that was even close to the speed of my normal leisurely pace, certainly not the many in Denver’s huge airport. Ever notice how many people walk on those faster than it’s moving? It’s not all out of hurry, although there are plenty of those, but because the typical moving walkway is so damn slow (probably for low common denominator safety). Another case where the blog end doesn’t follow from the starting point…