Talk:Amplifier figures of merit

message: Perhaps Thomas Edison?  The Carbon microphone is an amplifier.  Edison even built amplifiers for long distance phone lines by connecting a loudspeaker to a carbon microphone and battery.  But I don't know if there were earlier amps before this.  See: 
--Wjbeaty 05:43, Mar 31, 2005 (UTC)
:  Microphones are really transducers, which convert energy in one form (mechanical air pressure) into another form (electrical signals).
Generally they are, but the carbon mic is different in that it does amplify.
Tabby (talk) 11:16, 7 June 2010 (UTC)
thread_title:  who invented the amplifier 

message: Should we create an article for the different types of transistor amplifiers?  We already have common base, common collector, differential amplifier, long-tailed pair, cascode and so on.  Would be helpful to tie them all together.  — Omegatron 18:07, 24 October 2005 (UTC)
replies: text: I was thinking a nav box type thing would be handy. Three columns: FET, BJT, tube; three 'common-'s per column; and topologies along the bottom. Such a box could become bloated, though. - mako 07:27, 25 October 2005 (UTC)
replies: text:  Oh.  I made it the other day.  See Common_base#See_also. — Omegatron 12:27, 26 September 2006 (UTC)
thread_title:  [[transistor amplifier]] 

message: While it may not be written clearly it looks OK in terms of electronics design. I would suggest that as a external definative reference you use the first few chapters of the radio communication handbook published by the RSGB. This book is aimed at the radio electronics community but the ideas apply to audio equipment. I think that this page should be rewritten as an audio amp page, as it concentrates on audio equipment very much with the exclusion of things such as radio amps.
You may wish to read the page at Electronic amplifier which I suspect has been created and worked on by a different group of people who have not had much to do with this page.
Cadmium 16:41, 28 December 2005 (UTC)
thread_title: Class of amp

message: This entry should be merged with electronic amplifier.  In particular, the discussion of amplifier classes and efficiency is not clear on this page.  This could be eliminated from this page, since there is a good discussion of amplifier classes under the electronic amplifier entry.
:Agree about the new classes section.  There should just be a paragraph about electronic amplifiers in here with a  link to electronic amplifier. — Omegatron 22:48, 11 January 2006 (UTC)
thread_title:  Merge with electronic amplifier 

message: I personally feel that the quality of the article is very poor......i vote to rewrite the article...... and there is no need to merge the classification of amplifiers with electronic amplifiers...
Jayant, 17 Years, India|(Talk) 05:51, 16 January 2006 (UTC)
thread_title:  Rewrite..... 

message: I intend to make this into a hub page with all different sorts of amplifer being breifly described then linked to their own main pages.--Light current 01:23, 29 January 2006 (UTC)
replies: text: LC, the discussion is a bit too audio-centric. The audio amplifier page could use some content. - mako 02:31, 30 January 2006 (UTC)
thread_title:  Hub Page 

message: Harmonic distortion is fairly easy to measure. The amplifier output is connected to a  spectrum analyzer (a device which graphs frequency against amplitude). A pure tone -- typically a sinusoidal signal at 1 kHz -- is then applied to the amplifier input.  The largest signal on your analyzer should be the input signal at 1 kHz. You will sometimes see humps at even intervals along the graph at multiples of that base signal. These are the harmonics. The total harmonic distortion (THD) is the sum of these components relative to the signal.
--Light current 11:48, 23 May 2006 (UTC)
thread_title:  Cut from page 

message: I added information about the continuing advantages of microwave high power valve over semiconductor in the Valve amplifier section. I also added a Reference section and cleaned up the See also secton.Gerry Ashton 18:59, 4 June 2006 (UTC)
replies: text: Thats good. 8-) But have you considered adding the info to Valve amplifier instead or in addition? PS dont forget to sign your posts!--Light current 18:26, 4 June 2006 (UTC)
thread_title: Information about high power microwave valves

message: The last paragraph there? I don't even know where to begin.
KjellElec means:
Linearity as such is easily defined, see Wiki.
But this statement from the article is a horror and needs to be dealt with in detail or removed:
"Because tubes are significantly more linear than transistors, tube amplifiers do not need as much global negative feedback to achieve acceptable linearity."
Does he compare triodes, tetrodes or pentodes to bipolar, Jfet or Mosfet transistors, and are they  low-power types or not? Does he compare components or practical circuits?
Tube audio power amps must normally use output transformers, whose wild phase excursions at high frequencies forbid hard overall global feedback in order to stay stable. Thus tube power amps are _forced_ to use a limited amount of global feedback.
End of KjellElec meaning
fwiw there are many tube amps with no global feedback, and some with no feedback whatever  —Preceding unsigned comment added by 82.31.207.100 (talk) 20:00, 30 January 2011 (UTC)
thread_title:  Someone clean "linearity" up please 

message: http://en.wikipedia.org/w/index.php?title=Carbon_microphone&action=edit§ion=2 --Light current 19:23, 31 December 2006 (UTC)
thread_title:  Carbon mic amplifiers 

message: I removed the following text from the article for the reason that it is mostly unsubstantiated opinion:
In the earlier years of audio, vacuum tubes filled the active device role. Valve amplifiers are widely, but not always correctly, associated with the valve sound. Some claim this sound has more to do with the circuit topology and circuit design of the amplifier, than to the use of valves rather than transistors as the active gain devices. However, this reasoning is not entirely correct. Because tubes are significantly more linear than transistors, tube amplifiers do not need as much global negative feedback to achieve acceptable linearity. While large amounts of global negative feedback are effective for reducing total harmonic distortion (THD) at low frequencies, feedback has downsides such as reduced stability, reduced slew rate, reduced bandwidth, increased high-order distortion, and artifacts such as asymmetrical slewing. In most commercial designs, little attention is paid to these problems, and designers simply attempt to achieve the lowest possible THD.
Alfred Centauri 17:56, 24 April 2007 (UTC)
thread_title:  Removed text 

message: I accept the reason given for the removal of the reference to the BBC article on Metadyne but is this a reason for removing the words Metadyne, Magnicon and Magnavolt as well?  If so, shouldn't we remove Rototrol too? Biscuittin 11:28, 18 May 2007 (UTC)
replies: text: If you have a reliable source for Metadyne, Magnicon and Magnavolt, go ahead and add them back (but trademarks might not be important enough to include, if they are trademarks). As for Rototrol, from looking at http://siris-libraries.si.edu/ipac20/ipac.jsp?uri=full=3100001~!219875!0#focus it seems to be a trademark of Westinghouse; perhaps it should be removed. --Gerry Ashton 15:06, 18 May 2007 (UTC)
thread_title:   Metadyne, Magnicon and Magnavolt 

message: The current definition of amplifier from this article is:
any device that uses a small amount of energy to control a larger amount of energy.
I think "amount of energy" should be replaced by "signal" to be more general.
Also the definition of "gain" in this article should be similarly generalized. Any comments about this? Roger 15:47, 24 May 2007 (UTC)
replies: text: I think "power" is better than "signal". Some people may feel "signal" implies communications, and amplifiers are not confined to communication applications. Also, "power" is closer to the physical phenomena that occur in an amplifier than "signal". Finally, gain is usually defined as the ratio of the output power to the input power, so sticking with power will allow a more concise definition of gain. --Gerry Ashton 17:03, 24 May 2007 (UTC)
replies: text: But the output power can be smaller than the input power (like in a voltage amplifier), so it may not be a small power controlling a larger one. Also there are different types of power gain (transducer, available, etc.) that would need to be mentioned, so it may not be more concise. I think signal is better, because it can mean an energy, power, voltage or current signal. Roger 17:14, 24 May 2007 (UTC)
replies: text: This article is not confined to electrical amplifiers, so the input and output could be even more general than the examples mentioned by Roger: light, fluid flow or pressure come to mind. A power gain could be computed for any of these. An advantage of using the word "power" would be to eliminate certain quantities that, strictly speaking, cannot serve as input to an amplifier (energy, for example). --Gerry Ashton 17:33, 24 May 2007 (UTC)
replies: text: Thats true, but a voltage amplifier, for example, could have a power gain of zero or infinity, so it may not always be best to think in terms of power gain. Usually "amplifier" means "electronic amplifier" so I still think signal is a better word. Other non-electrical amplifiers could also be mentioned. Roger 17:58, 24 May 2007 (UTC)
replies: text: A transformer can increase voltage, but not power, so it is not an amplifier. Also there is nothing wrong with an amplifier having a power gain less than one. No real device has infinite power gain, which is another argument in favor of using the word "power"; it is intuitively obvious that no device can output infintite power. --Gerry Ashton 18:52, 24 May 2007 (UTC)
replies: text: My point is its misleading to ONLY think in terms of power gain. A voltage amplifier and a simple resistive divider can both have the same power gain, but obviously they are different. And yes, real devices won't have infinite gain , but a MOSFET CS amplifier can have an enormous power gain, but very little voltage gain for example. Roger 19:02, 24 May 2007 (UTC)
replies: text: I don't have any more arguments to make; I just want to say that I still think "power" is a better word than "signal" and if I don't make any further posts, it means I maintain my opposition to changing the word. --Gerry Ashton 20:08, 24 May 2007 (UTC)
thread_title:  Definition of amplifier and gain 

message: I think these could do with their own article. There are bits of info on carbon amps dotted about in different categories, but no carbon amp article. Alas no time today.
Tabby 16:42, 3 December 2007 (UTC)
thread_title:  Carbon amps 

message: A Rototrol isn't an amplifier..
It's a motor-driven power regulator for balancing currents in 3-phase systems. It belongs to the family of big adjustable inductive components used in power distribution. So I removed Rototrol from the amplifier article.  --John Nagle (talk) 17:30, 15 December 2007 (UTC)
replies: text: It looks like the term "Rototrol" has been used for two different devices.  The reference above to an adjustable inductive regulator is from a 1994 publication. But , "Rototrol scheme", from 1949 shows a field-modulated generator like a Ward Leonard control. This is probably too much information for the Amplifier article; it belongs somewhere else, under "obsolete rotating electrical machinery" or something like that.  I've been putting in a few lines on each obscure amplifier type, but avoiding too much detail.  --John Nagle (talk) 18:34, 20 December 2007 (UTC)
thread_title:  Rototrol 

message: There is massive identity crisis here: this article should be restricted to discussion of ampifliers in general, and properties common to all amplifiers, and not contain undue detail about e.g. power amplifiers. Its scope should be ALL amplifiers. Brews ohare (talk) 17:55, 9 January 2008 (UTC)
replies: text: I have moved the Power Amp Classes to "Electronic Amplifiers" and combined it with the already existing extensive discussion there. However, it would be desirable to put it all into a Power Amp article. Brews ohare (talk) 18:37, 9 January 2008 (UTC)

text: Moved classification scheme to discussion of that name in "Electronic amplifiers" Brews ohare (talk) 19:09, 9 January 2008 (UTC)

text: This entire article contains so many weak sections that it makes one weep. Brews ohare (talk) 00:22, 10 January 2008 (UTC)
thread_title: This article should be distinguished clearly from "Electronic Amplifiers"

message: definitely lacks in this category.  I would like to see amplifier class, types of connectors, RMS ratings, number of channels, etc.  It only briefly touches on "Efficiency" and never stating why it is more efficient or what each class does and how it works.
12.215.147.98 (talk) 04:41, 21 January 2008 (UTC)
replies: text: For class definition, have a look on Electronic amplifier. Yves-Laurent (talk) 07:08, 21 January 2008 (UTC)
thread_title:  this article lacks car audio/home entertainment information 

message: Right now the article looks like a wall of text. Some pics would really help to break the monotony.  —Preceding unsigned comment added by 72.186.242.122 (talk) 03:47, 5 June 2008 (UTC)
replies: text: I agree to that. A link at the bottom of the article, to a page with images for each type of the most types of amplifiers, mentioned below, was taken down by extreme causes.  —Preceding unsigned comment added by 83.248.161.207 (talk) 10:06, 4 November 2008 (UTC)
thread_title:  Could use some pics 

message: I was hoping to find info in this article in regard to software that is capable of increasing the intensity or audio of recorded sound files. I am no "expert" in this regard but it seems to me that the way to do it is to increase the intensity of the sound waves. I am also looking for software that is capable of removing background noice such as the hum generated by a recorder or the hum over an audio system when recording audio played over an audio system such as inside an audiotorim.  —Preceding unsigned comment added by 99.56.160.53 (talk) 21:03, 28 February 2010 (UTC)
thread_title:  Software Audio Amplifier of Sound Files 

message: "The glow from four "Electro Harmonix KT88" brand power tubes lights up the inside of a Traynor YBA-200 guitar amplifier"
having played with KT output valves, that piccy looks nothing at all like valve glow. Looks like someone put some lightbulbs under them.
Tabby (talk) 12:10, 7 June 2010 (UTC)
thread_title:  Valve Glow 

message: Deleted "The efficiency of the amplifier limits the amount of total power output that is usefully available" as I dont really see how that can be true, except in unrealistically extreme cases.
Tabby (talk) 15:05, 7 June 2010 (UTC)
thread_title:  deletion 

message: Someone makes a blatant claim in the article, that class B amplifiers are not acceptable for audio due to crossover distortion.  This idea is discussed in Douglas Self's book on amplifier design where he suggests class B if preferable to class AB, but there seems to be some divergence in the exact use of class B vs class AB.  Self mentions that no bias at all, should probably called class C.
I built a little audio amplifier somewhere around 2000 that ran as class B. It sounded great - there are ways to handle the crossover issue in class B.
82.31.207.100 (talk) 20:09, 30 January 2011 (UTC)
thread_title:  Class AB vs Class B 

message: Says in the lead, "The defining property of any amplifier is that it has a gain greater than one." This is uncited. By this definition, a transformer could qualify as an amplifier. --Kvng (talk) 14:20, 20 December 2010 (UTC)
replies: text: Linear amplifier and Electronic Amplifier us an increase in power as the defining property. I believe this is correct and have made the change. --Kvng (talk) 15:07, 20 December 2010 (UTC)
replies: text: Good catch. Thanks! Binksternet (talk) 16:54, 20 December 2010 (UTC)
thread_title:  Defining property 

message: It seems a major figure of merit haas been totally omitted from this article, the Output Power rating, and all of its various incarnations, eg., Peak Power, RMS Power, Music Power. An explanation of these basic parameters should be included in this article on amplifiers.  — Preceding unsigned comment added by 99.2.69.235 (talk) 06:24, 7 September 2012 (UTC)
thread_title:  Output Power Ratings 

message: The effort to make this the Main article for the Amplifier topic has not fully succeeded. This article and Electronic amplifier are struggling for that role. I have improved Amplifier (disambiguation) to map out coverage of this topic. I propose next to split out some of the non-electronic amplifiers into their own articles (e.g. Mechanical amplifier, Pneumatic amplifier) and the figures of into it's own article (i.e. Amplifier figures of merit). At that point, we could move Amplifier (disambiguation) in place of this article. -—Kvng 17:35, 26 January 2013 (UTC)
replies: text: Amplifiers are such a mixed bag that the main page should not go too much into details. Amplifier will better serve as a connecting hub for the other articles than a less often accessed explicit disambiguation page. However, I do think it could be edited to be more verbose than just a list. Olli Niemitalo (talk) 08:54, 27 January 2013 (UTC)
replies: text: There are limitations as to what we can do if we make this page a disambiguation as I propose. Can't make it more than a list. See MOS:DAB. -—Kvng 14:57, 27 January 2013 (UTC)
replies: text: Okay, I see. I think it is important that it is said to the effect of: "An amplifier is generally a device for increasing the power of a signal by use of an external energy source". If Amplifier becomes a disambiguation page then we can't keep that there. I like the idea of stripping stuff away from Amplifier, though. Olli Niemitalo (talk) 17:56, 27 January 2013 (UTC)

text: I appreciate the desire to organize the different kinds of amplifiers and agree that some kinds of amplifiers, such as mechanical amplifiers, deserve their own article. But this is considered a top importance article by two different Wikiprojects; before radical surgery or conversion to a DAB, it may be prudent to consult with them, say with an RfC. Mark viking (talk) 17:18, 27 January 2013 (UTC)
replies: text: Earlier I posted notices to the talk pages at WP:ELECTRONICS and WP:PSP. -—Kvng 00:54, 28 January 2013 (UTC)

text: That would actually solve a lot of problems. In today's world it comes more naturally to explain amplifier figures of merits in terms of electronic amplifiers. The more general concept of an amplifier could still be briefly explained in the lead paragraph as a significant minority definition, and wikilinks to non-electronic amplifier type articles could be given in a separate section. Also, in the hatnote, in addition to the disambiguation page, there could be links to Audio power amplifier and Guitar amplifier which from a Google image search seem to be very popular things understood as "amplifiers". Olli Niemitalo (talk) 22:57, 27 January 2013 (UTC)
replies: text: If I'm not mistaken, the only difference between my proposal and Spinningspark's is the final names for the articles. In either proposal we don't really have a place to say An amplifier is a device for increasing the power of a signal by use of an external energy source. Not much of a loss in my personal opinion but something that Olli indicated was important to have. -—Kvng 00:54, 28 January 2013 (UTC)
replies: text: In my comment I interpreted Spinningspark's proposal as Amplifier becoming an article about electronic amplifiers, not a disambiguation page. Olli Niemitalo (talk) 08:11, 28 January 2013 (UTC)
replies: text: Yes, that's my interpretation too. The next question is what happens to this article when we rename Electronic amplifier over the top of it. Since there was no new name given, I assumed it would cease to exist just like in my proposal (but with titles reversed). -—Kvng 14:48, 28 January 2013 (UTC)
replies: text: Yes, would cease to exist because everything in it would be covered elsewhere. Amplifier (disambiguation) would remain the disambiguation page and Figures of merit would either go into its own article or be merged (if someone has the guts for the task) into the article about electronic amplifiers that replaces this article. Olli Niemitalo (talk) 15:21, 28 January 2013 (UTC)

text: Here is a quick draft of that for your consideration. Olli Niemitalo (talk) 09:57, 28 January 2013 (UTC)
replies: text: What title do you propose for this draft? I see you propose to create Non-electronic amplifier. I don't think this is necessary. Any non-electronic amplifier worth covering should be able to establish its own notability and have its own article. -—Kvng 14:48, 28 January 2013 (UTC)
replies: text: The title would be "Amplifier". Okay I'll remove Non-electronic amplifier from the draft. Olli Niemitalo (talk) 14:58, 28 January 2013 (UTC)

text: The way you've stated it is a bit confusing but I gather we end up with two articles, Amplifier and Amplifier figures of merit. Presumably we leave Amplifier (disambiguation) pretty much as it is and Electronic amplifier becomes a redirect to Amplifier. I assume were going to salvage some of the other topics (e.g. Mechanical amplifier) in Amplifier as separate articles. All of this I accept as it is basically my proposal with names swapped for Amplifier and Amplifier (disambiguation). Can you tell me what is the difference between your User:Olli Niemitalo/Amplifier and the current Electronic amplifier? I see changes in the lead and a new first section. Is there anything else? -—Kvng 13:33, 30 January 2013 (UTC)
replies: text: Sorry that it is confusing; I tried to state an unambiguous procedure that also preserves most of the flow of revision histories and talk pages. The effect is as you describe. Here's a diff between User:Olli Niemitalo/Amplifier and Electronic amplifier. Olli Niemitalo (talk) 13:51, 30 January 2013 (UTC)

text: And yes some more stuff about mechanical amplifiers etc. can probably be salvaged from the current Amplifier into separate articles. We can do it after the big moves, right? Olli Niemitalo (talk) 13:59, 30 January 2013 (UTC)
replies: text: Thanks for the diff. By including the Other amplifier types section, I fear we are on our way back to where we are now. I think other amplifier types should be handled by a hatnote pointing to Amplifier (disambiguation). I'm also open to other suggestions. -—Kvng 15:56, 30 January 2013 (UTC)
replies: text: Would you care to elaborate on what your fear is and how it might materialize? I'm a bit lost in which way to work to resolve this. Olli Niemitalo (talk) 18:39, 30 January 2013 (UTC)
replies: text: I think some of the "other amplifiers" would legitimately belong in an article scope-limited to electric amps.  The carbon-mic acoustic amp, for instance, is used to amplify electric signals (it was used on telephone lines prior to active electronic devices becoming available).  Anything that is electric in and electric out is an electric amp from a black box perspective regardless of whatever is going on inside.  In just the same way a filter consisting of mechanical resonators is still considered an electric filter when used in an electronic circuit. SpinningSpark 19:00, 30 January 2013 (UTC)
replies: text: There are three terminals on a general amplifier: signal input, power input and output. How many of these need to be electrical for an amplifier to be considered electronic? Clearly it is somewhere between 1 and 3 inclusive. A carbon mic is 2. -—Kvng 19:37, 30 January 2013 (UTC)
replies: text: Perhaps you don't understand how a carbon mic amp works.  It is electric in and electric out and electric powered so, of necessity, has (at least) three terminals.  The carbon mic is an acoustic transducer to convert the sound wave into an electric signal.  This is the acoustic receiver.  However, since we require electric in, there must also be an acoustic transmitter transducer - which can also be a carbon mic used in reverse. See this page for instance - although note that the Tx and Rx labels are reversed from my description since they mean electric rather than acoustic Tx and Rx. SpinningSpark 21:15, 30 January 2013 (UTC)
replies: text: What's happened here is that you're talking about carbon mic amp (electrical in and out) and I'm talking about a plain carbon mic (acoustic in, elctric out). -—Kvng 21:37, 30 January 2013 (UTC)

text: Spinningspark suggested that Electronic amplifier is the primary topic for Amplifier and that sounds reasonable to me. Under that suggestion, the Amplifier article should be about Electronic amplifiers. Olli's proposed Amplifier article, with the addition of the Other amplifiers sections starts to become about amplifiers in general which is what Amplifier is about right now. Therefore Olli's proposal brings us at least part way back to where we are now (and I fear future edits will bring us all the way back). If that's where we want to go, we're already there and don't need to bother doing the work. -—Kvng 19:37, 30 January 2013 (UTC)
replies: text: How about removing the paragraph in the lead and the corresponding section and writing the hatnote to imply the same thing: "This article is about the electronic amplifier. For other types of amplifier and for other uses of the term, see Amplifier (disambiguation)." Is this OK or does it conflict with the purpose of a disambiguation page? Olli Niemitalo (talk) 20:46, 30 January 2013 (UTC)
replies: text: This is good. This is what I've been proposing all along. There is only a problem if you want to put significant content, not just links, on the disambiguation page. -—Kvng 21:37, 30 January 2013 (UTC)
replies: text: I know, I just wasn't at first able to imagine a satisfactory wording. I have altered the draft accordingly. Olli Niemitalo (talk) 21:51, 30 January 2013 (UTC)

text: @Kvng.  I am suggesting that electric amp is the primary topic which means a somewhat broader scope can be encompassed than electronic amp.  Some would argue that "electronic refers only to active electron control devices such as transistors and valves. SpinningSpark 21:15, 30 January 2013 (UTC)
replies: text: Oh well, I had misread your suggestion as "electronic amplifier", which is more popular and better focused pedagogically. I prefer that as the main scope. Olli Niemitalo (talk) 21:30, 30 January 2013 (UTC)

text: I also apologize for not reading more carefully. Do you have any references for these definitions: Electric amplifier, Electronic amplifier. Electric amplifier is not a term I'm familiar with. -—Kvng 21:35, 30 January 2013 (UTC)
replies: text: I'm not suggesting a definition of terms, or that a formal distinction between electric and electronic even exists.  But I don't think we need references to accept that many people have a narrow conception of electronic.  Google books certainly believes that electric amplifier is a term.  You might also want to consider electric guitar amplifier (1,140 hits) against electronic guitar amplifier (8 hits) although that term should perhaps be taken as electric-guitar amplifier.  In any case, it really doesn't matter since the proposed article title is simply "Amplifier". SpinningSpark 22:01, 30 January 2013 (UTC)

text: I salvaged text about pneumatic amplifiers to Compressed air gramophone and redirected Pneumatic amplifier there, and redirected Mechanical amplifier to Torque amplifier. Olli Niemitalo (talk) 11:42, 31 January 2013 (UTC)
thread_title: Amplifier topic organization