Teardown of a valve guitar amplifier - Page 1
Forum section: electronics / general

author: mjbmikeb
author_rank: Contributor
timestamp: August 19, 2011, 11:07:40 am
content: Is the 'valve sound' all about marketing?

author: Unknown
author_rank: Unknown
timestamp: August 19, 2011, 11:16:19 am
content: Yes 'valve sound' is a marketing buzzworldword.You can not hear nor measure a difference between a valve amp and a semiconductor amp unless one of them has a serious flaw.Edit: And where is the teardown may I ask?

author: Deepak
author_rank: Regular Contributor
timestamp: December 29, 2011, 07:12:05 pm
content: I know this is a pretty old thread, but it's new to me.This doesn't sound right at all. While there's no difference between solid-state and tube in your living room (when you have a lot of headroom available), the situation is entirely different when an amp is connected to an instrument. Well designed solid-state amps are generally better at sound reproduction, so they will not do anything to your signal until they're pushed into clipping, whereas tube amps will compress and distort the signal prior to clipping. Effects pedals, or DSP can be used to recreate the tube sound, but apples-to-apples tubes sound different than transistors.

author: im_a_human
author_rank: Regular Contributor
timestamp: December 31, 2011, 08:33:00 pm
content: I agree valves do sound different because they create extra harmonics that transistor amps dont. You cant beat the sound of blues guitar playing through a valve amp, you get those clean single notes then you play some harder chords and double stops and thats enough to bring out that over driven valve sound. THE effect just isnt as nice on a solid state amp.

author: slateraptor
author_rank: Frequent Contributor
timestamp: January 02, 2012, 02:17:32 am
content: Quote from: Deepak on December 29, 2011, 07:12:05 pmQuite the contradictory statement don't you think?Quote from: im_a_human on December 31, 2011, 08:33:00 pmIf by "extra harmonics" you mean non-linear distortion, then sure; transistor amps are designed to function as close to ideal as possible.It really is funny how an unwanted design limitation has gained so much nostalgic demand amongst consumers.

author: PStevenson
author_rank: Regular Contributor
timestamp: January 02, 2012, 10:19:12 am
content: for guitar it's okay to colour the sound like valves do however I prefer Transistor Guitar amps because when I'm recording I constantly have to filter out the fizz they have and EQ out the "warmth" so it sits in a mix without sounding crap.I'm actually thinking of building a transistor amp with glowing valves attached to it to trick guitarists into just recording throughthe transistor one.I agree with Slateraptors sentiment that an output signal should be as close to the input signal as possible (amplified of course)valves in hifis are just a horrible idea and should have been banned many years ago - however I don't actually think it can be called a "hifi" if it has a valve in it.no no no no bloody no! -http://mos.futurenet.com/techradar/Review%20images/Hi-Fi%20Choice/HFC%20341/HFC341.ikon.cdx1_tech-420-90.jpg

author: slateraptor
author_rank: Frequent Contributor
timestamp: January 02, 2012, 02:49:16 pm
content: Quote from: PStevenson on January 02, 2012, 10:19:12 amYES! LOL!!

author: don.r
author_rank: Frequent Contributor
timestamp: January 02, 2012, 06:09:56 pm
content: Quote from: PStevenson on January 02, 2012, 10:19:12 amI have found that, on occasion, the extra distortion afforded by a near-clipping tube is beneficial to some poorly encoded MP3s. Maybe it simply drowns out the unpleasing distortion generated by the poor encoding but it seems to work. We are talking 128kbps or less here. This is, of course, a decreasing issue going forward as most digital music has been sufficiently encoded these days. The tubes do need to be driven close to saturation so I use a tube buffer on my stereo and a tube headphone amp with the input tubes driven hard for my headphones. There is also something romantic (or is it nostalgic?) about the glow of tubes. Its akin to the amount of work and effort required to play a record. The physical contact, the preparation, the attention required, they all combine to draw the listener into the experience. Of course, the audio itself is shite...

author: PStevenson
author_rank: Regular Contributor
timestamp: January 02, 2012, 07:22:26 pm
content: @don.r honestly if it's personal preference no one can decry you for that at all.I think people (like me) get annoyed when claims are made that "old is better" and "digital is sterile" and we get retaliative to it. I do like the glow of a tube and the smell of really old electronics stuff,opening up a UHER tape recorder from the 70s shows you a work of art but I just don't believe it's ever better on a technical standpoint.but again if you like the sound a valve gives out thats cool! I do like the bugera valve amp I have for example (I do use a filter on it to get rid of the fizz though) I just prefer transistor ones and I would never record with a valve amp if I could help it! when working with bands I record their amp sound but I made a little secret buffered line splitter so I record a signal straight from the guitar without their knowledge and every time I've shown them 2 mixes, they chose the one with my Carlsboro tranny amp in place of their stupid A-Class valve thing hahaI feel like everyone has been short changed here so I'll put a few pictures of inside my Bugera amp for you.

author: Deepak
author_rank: Regular Contributor
timestamp: January 04, 2012, 07:22:44 pm
content: Quote from: slateraptor on January 02, 2012, 02:17:32 amTerse more than anything - I mean just prior to clipping. When there's a few dbs of headroom available it's impossible to tell the two technologies apart in a double blind test.Nice pics PStevenson. I'll try to tear apart my solid-state setup on here soon.

author: jackbob
author_rank: Regular Contributor
timestamp: January 05, 2012, 05:39:11 am
content: A valve amp teardown would be great! I learned vacuum tube amps before i started with solid state (probably wasn't a good idea at 13 with 700 volt transformers but i never got hurt). I have several organ amplifiers from the 50's that i rigged up to play modern electronic devices. They both use tube rectification and one runs two 6l6 the other two kt88. Anyone who mixes solid state with tubes (unless its a tube preamp solid state amplifier) should be ashamed.

author: slateraptor
author_rank: Frequent Contributor
timestamp: January 05, 2012, 05:46:28 am
content: Quote from: jackbob on January 05, 2012, 05:39:11 am

author: don.r
author_rank: Frequent Contributor
timestamp: January 05, 2012, 05:56:49 am
content: Quote from: PStevenson on January 02, 2012, 07:22:26 pmNo argument there. I believe most tubes are microphonic to a certain extent so there will always be some oddities in the sound from that alone not to mention their ability to pick up RF signals. The sound will never be as clean as a transistor.

author: slateraptor
author_rank: Frequent Contributor
timestamp: January 05, 2012, 07:36:03 am
content: The glamor behind tubes was largely voodoo mysticism to me until I attend a seminar hosted by an industry audio engineer turned professor. He went over everything from history; triode, tetrode, and pentode operation; relevant field equations and small-signal analysis; schematically analyzing a few Fender amps, a Lafayette phono amp, and the Heathkit W5M; and concluded w/ a discussion on tube sound and why it may or may not be appealing from a musical perspective.After that, I was wholly convinced that the characteristics that people where really after are in fact inherent limitations of the tubes themselves coupled with marketing, nostalgia, association, and other psychological, unquantifiable factors.To be sure, the extra harmonics that im_a_human alluded to was noted by the good professor as non-linear distortion producing lower-order harmonics, in particular, the 2nd, being an octave and contributing to musical warmth. Combined with little negative feedback and the soft field-induced clipping nature (which allows operation with relatively little headroom) of tubes and it makes complete sense why people might find tube sound pleasant. So what you're really getting isan amp with built-in DSP effects, so to speak, not superior amplification.Conversely, audiofools hating on transistor-based amps isn't completely unjustified (although the differences are rather subtle and I suspect the overwhelming majority couldn't progress beyond monkey-see-monkey-do).One part is a consequence of the fact that transistor amps depend on lots of negative feedback and thus requiring lots of head room, which becomes problematic when musicheads feel the need to crank the volume up to some deafening magnitude.Then there's clipping...the hard clipping exhibited by current-driven transistors. If you remember your Fourier analysis, you'll recall that a hard clip produces a waveform not unlike a square wave and is littered with lots of higher-order harmonics of significant energy. As it turns out, music theory has identified higher-order harmonics to be quite dissonant.Another part has to do with the odd symmetry of musical waveforms being amplified, producing odd harmonics and attenuating that coveted 2nd harmonic attributed to musical warmth.Then there's that seemingly always forgotten slew rate parameter, which guys likethisbriefly mention and completely fail to emphasize its importance in minimizing distortion; after all, if your device is incapable of tracking the waveform on an amplified scale, what good is it?But I digress.

author: slateraptor
author_rank: Frequent Contributor
timestamp: January 05, 2012, 07:44:13 am
content: Quote from: don.r on January 05, 2012, 05:56:49 amTransistors are just as susceptible to RF coupling...which reminded me of a class AB amp that I built from discretes a while back; with the inputs left floating, it was amplifying an AM station in town. Op-amp based amps, on the other hand, are less susceptible due to relatively high input CMRR.

author: don.r
author_rank: Frequent Contributor
timestamp: January 05, 2012, 02:38:06 pm
content: Quote from: slateraptor on January 05, 2012, 07:44:13 amRF coupling on the line maybe but tubes make much better RF antennas than transistors simply due to their physical size and the fact that many of them sit outside of the shielding. Many amp manufacturers want to "show off" the tube and the result is poorly shielded tubes.

author: Kozmyk
author_rank: Regular Contributor
timestamp: January 05, 2012, 06:20:15 pm
content: There are some rather definitive statements on here which only serve to illustrate the poster's ignorance of the subject of guitar amplification.While it may be possible, under certain circumstances, to set up an A/B test to fool a guitarist that he's using a valve amp when it is in fact a solid state amp; to think that that there is no difference is ridiculous.I can only think that the "recording engineer" above is some sort of amateur given his comments.Valve amps give guitars sounds rich in even harmonics whereas transistor amps introduce odd harmonics.Once the amp is overdriven, the characteristics of the valve enhance the sound whereas transistor distortion is harsh and over bright.Modern digital processing modelling effects units have done much to emulate the "valve sound" in solid state circuitry but this is a long way from being a transistor amp sound.The bottom line is that valve technology is much more than a marketing gimmick.If you get to work in the music industry for real you will come to know this.P.S.Regarding line splitters/DI boxes.The top UK studios use passive transformer based devices from Sowter in Ipswich.Check em out.http://www.sowter.co.uk/

author: slateraptor
author_rank: Frequent Contributor
timestamp: January 05, 2012, 08:04:25 pm
content: http://www.sowter.co.uk/dacs.phpDAC transformers?? Because 50 quid is sure to remedy a noise coupling issue that couldn't be assessed by proper EMC board layout techniques at no additional cost?http://www.sowter.co.uk/eqinductors.phpEQ inductors?? Because exotic mu-metal shielding negates any susceptibility that the other bandpass components might incur?http://www.sowter.co.uk/occ.phpOCC wire?? Yes, we can't forget the wire.Marketing methodology:1)Up play + liability offload: "claimed by our manufacturerto be 99.999 % pure"2)Down play: "We have always resisted the idea because we dont want to make exagerated claims which we cannot justify."3)Up play + liability offload: "His ['highly respected customer'] conclusionwas that there was an unmistakable improvement in the sound from the amplifiers using the OCC wire."4)Down play: "We do not consider this single result to be significant evidence..."Then why bother mentioning?5)Up play + liability offload: "However we feel sure thatother customers will wishto make their own experiments..."6)The sales pitch: "...and we are delighted to be able to offer versions of some of our standard products made using OCC wire."7)Fair warning (aka Fool's warning): "The wire is of course, much more expensive..."Say it ain't so....and the trap is set.Oh man, give it a break.Dear tube amps,Please stay clear of my dissonant, LFO-adulterated sawtooth wobbles.With love,slateraptor

author: PStevenson
author_rank: Regular Contributor
timestamp: January 05, 2012, 08:17:52 pm
content: Quote from: Kozmyk on January 05, 2012, 06:20:15 pmI wouldn't really say I'm an amateur, you can talk about harmonics till you're blue in the face but it all get's Eq'ed, compressed, effected and so on before it will sit in a mix properly.no one said valves don't sound different to transistors, I certainly didn't anyway. I said that they are a pain in the arse to record in comparison to SS or Transistor amps because you have to piss about eq'ing the "warmth" out of them so it doesn't turn into a muddy pile of shite, you have to have them turned up really loud so that the power valves are functioning properly which presents various acoustic issues, not to mention having to isolate the amplifiers to stop rumble travelling into the microphone, then you have to filter out the high end because it is fizzy as hell, mic positioning is a lot harder to do because if the amp is blowing your head off even when you're wearing noise cancelling headphones you end up with a bad sound. and ultimately if the source is bad it will never sound good .as for the line splitter, I don't want it to be passive because you lose signal integrity which is why I made one based on a INA217 inst. amp IC (not cause of it's sonic qualities, just cause I had one there.this is one of the songs I have recorded"recording engineer" is the name of my job it's certainly not anything I define myself as and the moment I can get a job in electronics I'll be out of there.

author: PStevenson
author_rank: Regular Contributor
timestamp: January 05, 2012, 08:21:29 pm
content: Quote from: slateraptor on January 05, 2012, 08:04:25 pmhaha but they will make your saws warmer!I stay away from anything that has Rupert Neves name on it, he was good in his day but technology is so much better now it doesn't drift after 10 minutes of a room full of sweaty hippies grooving away, I doubt very much he works on his stuff these days and I'm pretty sure he's not kept up to date with DSP etc.

author: slateraptor
author_rank: Frequent Contributor
timestamp: January 05, 2012, 09:55:10 pm
content: Quote from: PStevenson on January 05, 2012, 08:17:52 pmAll that effort put into attaining super-sonic golden ear orgasmic nirvana only to receive the golden finger known as lossy digital FLV compression. It's a shame, really. Sounds good to me. hehe

author: PStevenson
author_rank: Regular Contributor
timestamp: January 05, 2012, 10:04:22 pm
content: I love the sound of vintage flv compression, adds warmth to it

author: Kozmyk
author_rank: Regular Contributor
timestamp: January 06, 2012, 02:04:14 pm
content: WRT the OP - A tear down sounds like a fun idea to me. But I'm biased, negatively ;^).My earlier comments were aimed at more than one recipient ...but:Quote from: PStevenson on January 05, 2012, 08:17:52 pmNice. Very "clean", vocal a bit disconnected. All your own work?This is funTech Geek Punk - excellent.QuoteSomeone did. And they were wrong. 2nd postSure there's some noise to deal with from valves but muddiness is usually down to over compression.I was thinking less old Neve desks and morehttp://www.recordproduction.com/sarm_west_studio_video.htmhaving seen what was in the walls.Active DI/Splitters have their place, especially when you need a bit of gain but tell me they have less noise than a transformer.They may ring a little but it's a sweet way to lose "signal integrity".PStevensonCorrection - slateraptor, you are so right and the UK recording industry and the BBC are so wrong ..EQ'ing "fizz" out of a track before sitting it in the mix is a waste of good tone/signal content.Recording is much more the art of capturing a performance as the techie details of perfect fidelity, s/n ratios etc.Perspective - most of the best sounding guitar recordings in rock history employed valves.Case in point - psychoacoustic enhancersReplacing the "fizz" that over-processing has lost.

author: PStevenson
author_rank: Regular Contributor
timestamp: January 06, 2012, 03:33:36 pm
content: you know, that song about Dave and youtube people took me about an hour to do on a home computer, I didn't even think he'd play it. so judging my capability on it is a bit weak.the UK recording industry and the BBC are mostly digital based they talk about how they use all these passive things and NEVE desks etc. from the 70's but in the background it's all being shredded through high end ADC/DACs and mostly kept in a digital environment, I know this because I work in the UK recording industry, I've never worked at the BBC but when watching episodes of Doctor Who I never hear anything 70's correct.exciters don't put "fizz" back into, they add high order harmonic distortion which gives extra clarity to a mix without having to add treble to it.you can't really say the best sounding guitar tracks were captured using valves they may have been but you weren't there, you don't know what processing went on during/afterwards.the art of recording is more to do with making the people recording sound better than they can perform at least from our point of view - which is why we make a singer for example record 400 takes and then pump it into Melodyne anyway, focusing only on the "performance" is something amateurs do, and you may aswell just record a band in a concert if you just want performance recording.anyone in the recording industry worth their salt has moved on from the beatles and the dark side of the moon.I get into arguments like this all the time and it never gets resolved, if you can provide some kind of evidence of something you have recorded, that you know exactly what went into the engineering of it then I will be willing to concede but claiming that arguing with you on the subject is directly contradicting the BBC and the whole UK recording industry is just incorrect.

author: Kozmyk
author_rank: Regular Contributor
timestamp: January 06, 2012, 04:15:23 pm
content: Quote from: PStevenson on January 06, 2012, 03:33:36 pmWell, for one, I was commenting on the mix of that particular track not your abilities in general, but whatever.There Was actually a hint of a compliment intended there as well.QuoteThe recording/editing medium is mostly digital these days. Agreed. Your point is? ...Poor old Rupert Neve is getting a bit of an undeserved bashing here isn't he? One of the masters, some say.QuoteThey create the "illusion" of clarity.QuoteBut you know it's true.And there's plenty of documentary evidence out there.QuoteDontcha just love Auto-tune? ... pukeQuoteI still think of a guitar solo as a performance.QuoteIsn't it all so much better now ...QuoteOn the subject of DI boxes and splitters, YesErr, oops I may have directed the "BBC and the whole UK recording industry" bit to PStevenson earlier when it was a response to slateraptor's ridiculing of Sowters transformers.Sorry for the confusion.

author: PStevenson
author_rank: Regular Contributor
timestamp: January 06, 2012, 04:28:38 pm
content: well despite our disagreements we are all friends here.I don't want to it to get heated, the problem with sound is that it's subjective a lot of the timebut just for your edification (heard that word a few months ago and I have been looking for a place to use it) Melodyne is a different thing to autotune, it's not auto for a start! but yes, it is used to tune and quantize stuff, I personally use it very mildly when there was a case of "fatigue error" (when a performer has done a billion takes and fucks up the same thing over and over because the mistake has etched itself into their head)

author: im_a_human
author_rank: Regular Contributor
timestamp: January 08, 2012, 05:18:26 pm
content: http://www.tlaudio.co.uk/docs/products/VTC.shtmlAt the college i work at we have one of these and they sound loads better than any of the digial desks we use.

author: don.r
author_rank: Frequent Contributor
timestamp: January 08, 2012, 05:22:34 pm
content: Quote from: im_a_human on January 08, 2012, 05:18:26 pmQuantify "better". Would it have sounded "better" if you did not know it was valve-based and came in a rusty metal case?

author: im_a_human
author_rank: Regular Contributor
timestamp: January 08, 2012, 06:05:23 pm
content: I dont know. All i know is that digital desks just dont sound as nice as analogue ones. Harsh and brittle is the words i was looking for to describe a digital desk.

author: IanB
author_rank: Super Contributor
timestamp: January 08, 2012, 06:39:21 pm
content: Quote from: im_a_human on January 08, 2012, 06:05:23 pmThat's possibly true. But "accurate" could also be applicable. In the audio world nice sound does not always correlate with accurate reproduction.

author: Rufus
author_rank: Super Contributor
timestamp: January 08, 2012, 07:03:17 pm
content: Quote from: im_a_human on January 08, 2012, 06:05:23 pmSo difficult when our language doesn't have the words to describe how audio sounds, must be a reason for that.

author: PStevenson
author_rank: Regular Contributor
timestamp: January 08, 2012, 07:06:36 pm
content: Quote from: IanB on January 08, 2012, 06:39:21 pmif what you're getting out of the digital desk is harsh and brittle then what you're putting into it is equally as harsh and brittle.analogue stuff, valves in particular colour the sound and add what should be unwanted artefacts - this should not be celebrated !I really wish digital stuff had come first then there wouldn't be so much wankery out there

author: im_a_human
author_rank: Regular Contributor
timestamp: January 08, 2012, 07:24:01 pm
content: Mixing is never going to be accurate because nobody would ever ditch EQ, compression, and effects and just have the raw sound from the mics coming in. Mics dont have true flat frequency responce either. Also you never put your ear within 4 to 6 inches of an instrument or a persons mouth when you want to hear them sing. Technically if you wanted a voice or any instrument to sound accurate you would place the mics 10 feet or so away near the listening crowd. Then you would consider binomial recording to replicate the way humans hear things too.... Sorry i got carried away.

author: Flavour Flave
author_rank: Regular Contributor
timestamp: January 08, 2012, 07:35:15 pm
content: I think this article from soundonsound magazine will clear a lot things up about why people still like analogue recording equipment(I'm talking top recording engineers and producers).http://www.soundonsound.com/sos/feb10/articles/analoguewarmth.htm

author: PStevenson
author_rank: Regular Contributor
timestamp: January 08, 2012, 08:15:26 pm
content: I know exactly why people prefer valves and analogue stuff, it's not because they prefer the sound, not really. it's because it's all 70's endorsed, everytime I get SOS it's full of people bitching about "autotune" and hating on digital because they didn't like digital effects in the 80speople hear Dark Side Of The Moon and they assume subconsciously that it all needs to be analogue because that's how Pink Floyd did it or The Beatles, those bands went to the very latest stuff they could find at the time, if the Beatles were around now they would be loving the Digital environments, even Brian May used a transistor amp on most of his recordings."warmth" is not a sound, it's something you use to describe a vague condition of temperatureas for mixing, that is the human part of the recording process which is made better when the source material is accurate

author: Flavour Flave
author_rank: Regular Contributor
timestamp: January 08, 2012, 08:49:42 pm
content: They bitch about autotune because it has enabled a lot of talentless people to release records.Quote from: PStevenson on January 08, 2012, 08:15:26 pm

author: PStevenson
author_rank: Regular Contributor
timestamp: January 08, 2012, 09:27:23 pm
content: Quote from: Flavour Flave on January 08, 2012, 08:49:42 pmwhores have been around since the dawn of humanity just because they can now sing doesn't make the technology that enables them to do it a bad thing, it also helps people with legitimate talent who find it hard to sing with headphones which is very hard to do when you're focusing on performing and pitching.I do have a subscription to SOS but I do think a lot of it is written by idiots, some of it is worth the money though so I forgive it.

author: Bored@Work
author_rank: Super Contributor
timestamp: January 08, 2012, 09:38:44 pm
content: Quote from: Flavour Flave on January 08, 2012, 08:49:42 pmThere was surely no lack of records from talentless people before autotune. Going through old record collections at garages sales proves this.Analogue warmth is just a pitiful attempt to declare random distortions an inherent part of the art. Just like "artists" throw random buckets of paint on a canvas and declare the result a masterpiece painting.Generations of engineers worked hard to reproduce sound as accurate as possible. And then come the warmth people and shit on it. Because this is how it was in the past. Yeah sure, in the past. Why not go back to the concert pitches of the 18th century? I can already here the bitching of these warmth guys how the music is out of tune. Bad luck, just because their acquired taste doesn't match the historic taste of the 18th century or the modern taste it means they are right.

author: Flavour Flave
author_rank: Regular Contributor
timestamp: January 08, 2012, 10:11:28 pm
content: Well its funny how people on this forum recommend you getting an analogue scope as well as a digital one for the same reasons. One is better than the other at certain things.

author: Flavour Flave
author_rank: Regular Contributor
timestamp: January 08, 2012, 10:27:06 pm
content: But least they could could sing in tune. Or at least after 50 takes and a lot of time in the studio and tape splicing and that is very expensive. So there was a lot less of them "fevered egos, tainting our collective subconscious" as Bill Hicks said, getting record deals.Quote from: BoredAtWork on January 08, 2012, 09:38:44 pm

author: Flavour Flave
author_rank: Regular Contributor
timestamp: January 08, 2012, 10:32:17 pm
content: Well the proper quote is here after the short guitar intro

author: PStevenson
author_rank: Regular Contributor
timestamp: January 08, 2012, 11:27:58 pm
content: Quote from: Flavour Flave on January 08, 2012, 10:11:28 pmthis is an entirely different thing, there is no mystic "warmth" in an analogue scope, the main reason people say you should get a analogue scope is because you learn more as a beginner where as with a DSO you can just press an AUTO button and it sets it up for you,there are many legitimate reasons to get a analogue scope as well as a DSO but with audio gear it seems to be either/or.maybe we should go back to travelling by horse and cart cause the shit smells more organic and warm than car exhaust

author: Flavour Flave
author_rank: Regular Contributor
timestamp: January 08, 2012, 11:39:21 pm
content: No, it is not about Auto button, you obviously didn't take in what was said about analogue scope versus digital scope. If you don't understand what is meant by analogue Warmth and your want to be a sound engineer well......I rest my case............................It is an adjective...............................Quote from: PStevenson on January 08, 2012, 11:27:58 pm

author: Flavour Flave
author_rank: Regular Contributor
timestamp: January 09, 2012, 12:16:58 am
content: "Warmth in an analogue scope" Classic strawmanhttp://en.wikipedia.org/wiki/Straw_manQuote from: PStevenson on January 08, 2012, 11:27:58 pm

author: PStevenson
author_rank: Regular Contributor
timestamp: January 09, 2012, 12:18:12 am
content: as I've said, I don't want to be a sound engineer, I am one, I have been credited as such on various releases that is neither here nor there, everytime something comes in saying "I want it to sound warm" I ask them to elaborate as to what they mean and they don't know.so you're obviously the master, quantify what the audio version of warmth is.I know what you are getting at with the oscilloscope analogy, what I was saying is that it doesn't work because there are actual explainable reasons as to why it's beneficial to have both a analogue and a digital scope - Dave has even done Vblogs as to what those reasons are.I know exactly what this perceived warmth is, it is a boost in the 64hz range and a reduction in the 8K range - even shitty iTunes can do that.

author: Flavour Flave
author_rank: Regular Contributor
timestamp: January 09, 2012, 12:34:53 am
content: Well they are laymen and couldn't say "I would like some of that musically pleasing to the ear, you know, that intermodulation distortion that they somehow can't recreate in digital allthough they are having more success now.And I'm hoping you are not so ignorant an engineer to not know what I am going on about? Or are you one of those arrogant types". sort of thingQuote from: PStevenson on January 09, 2012, 12:18:12 am

author: Flavour Flave
author_rank: Regular Contributor
timestamp: January 09, 2012, 12:45:37 am
content: Look tallk to Dave Berners who designed the powersupply for the cassini mission. He was bored of that and took another phd. He now is chief algorithmic designer for UAD soundcards, maybe you will listen to him, cos it is very likely he was better or is at electronics than you will ever be. So maybe you will listen to him and get off your youthful arrogant high horse.https://ccrma.stanford.edu/~dpberner/work.htmlhttp://www.uaudio.com/webzine/2004/july/text/content2.htmlYour honour I rest my case

author: slateraptor
author_rank: Frequent Contributor
timestamp: January 09, 2012, 01:54:10 am
content: Wow. This thread sure blew up.Quote from: Flavour Flave on January 08, 2012, 10:11:28 pmCitation needed."people on this forum"?? Quite the strategic use of agentless prose."for the same reasons"?? Please, do illuminate these reasons.Quote from: Flavour Flave on January 08, 2012, 07:35:15 pmComplete pseudo-scientific crap...typical material from the audiofoolery industry.Quote from: Flavour Flave on January 09, 2012, 12:45:37 amBesides being of no relevance to the discussion, classic appeal to authority.http://en.wikipedia.org/wiki/Appeal_to_authorityAnd while we're on the topic of fallacious arguments...Quote from: Flavour Flave on January 08, 2012, 10:11:28 pm...which happens to be a classicred herringwithin the context of the discussion, which in turn prompted PStevenson's sound response, rendering this comment de facto irrelevant.Quote from: Flavour Flave on January 09, 2012, 12:16:58 am

author: EEVblog
author_rank: Unknown
timestamp: January 09, 2012, 02:38:55 am
content: Flavour Fave won't be backDave.

author: PStevenson
author_rank: Regular Contributor
timestamp: January 09, 2012, 10:29:55 am
content: it seems you can't have a rational discussion these days without it resorting to personal insults!

author: Unknown
author_rank: Unknown
timestamp: January 09, 2012, 12:36:43 pm
content: Seeing as unpleasantness has left the building we can resume some semblance of rational discussion.Quote from: PStevenson on January 02, 2012, 10:19:12 amCouldn't agree more, any preference to tube amps is for their softer entry into distortion and overload. Hundred of dodgy transistor pedals tried and failed to reproduce the sound distortion of a driven valve amp, but this was often more because they were battery powered promises in a box. In a quiet environment Marshall amps and their ilk ARE a nighmare of hum and buzz and poor top end response. I haven't been involved for a decade or two but I knew more than a few good players who could make a miked up pignose or Roland Combo sound like a wall of Valve driven quad boxes.I understand why guys love their old valve amps but anywhere other than a noisy gig they are a pain in the posterior. And given they sound like mud until theyare driven to 11 they are a pain at most of our nanny state noise regulated gigs too.QuoteI think more than a few dubious Asian manufacturers have beaten you to the punch on this. Mind you mounting it in a Marshall or Orange enclosure would soon have the handjob cowboys hearing all kinds of otherwise inaudible goodness.QuoteYep no place in HiFi, (do kids today even know what HiFi is) (do they know what valves are), no place in PA or sound reinforcement or anything to do with reproduction.QuoteThat thing is too funny. A CD player with built in room heating.

author: PStevenson
author_rank: Regular Contributor
timestamp: January 09, 2012, 03:00:31 pm
content: I think the asians use starved plate valves but sadly keep it in the signal chain, though if they do have "just for show" valves in their stuff then good for them.you are spot on with the hum issues, I've got a marshall JCM2000 DSL thing which is stuck in a corner for that very reason, that and the build quality is questionable at best, and as you said it sounds turd until it's turned at least upto 6 which you can't do cause there's some dick stood at the back shaking his head with his little decibel meter in handI really don't understand the valve in a CD-player thing, of all things a CD player!! mind you I've seen valves turn up on computer motherboards, that made me feel sick for a week (see attached picture!)I cannot see ANY purpose in that, old guitar amps are one thing but on a PC motherboard not only is it pointless, but as you mentioned earlier in regards to the CD player, it presents massive thermal issues - I just feel like electronics have been shot in the face.

author: IanB
author_rank: Super Contributor
timestamp: January 09, 2012, 03:10:03 pm
content: OK, so I'm looking into this and I read what I always thought, that valves can have excellent linearity. Wouldn't that enable them to make very accurate amplifiers?It appears that it's not the valves themselves that are the problem so much as the required interfaces and support circuitry to make them practically useful. But if you have a low power device like a pre-amp, why can't a class A valve amp produce accurate reproduction? I know there are questions of size and complexity and power requirements and heat generation and so on, and maybe semiconductor circuits can do the job just as well, but to what extent is a well designed valve amplifier actually bad at reproduction?

author: PStevenson
author_rank: Regular Contributor
timestamp: January 09, 2012, 03:38:26 pm
content: Quote from: IanB on January 09, 2012, 03:10:03 pmI'm not really sure, but people seem to use valves as a means to add "warmth" which is the problem, they want to add the artefacts to the reproduction so I don't think people spend any time trying to perfect the support circuitrythe A-class amp is very inefficient anyway because it's always pumping out power even if there's nothing to amplify which gives you noise issues.even if there were a way to iron out the creases of valve orientated design the question that would be asked is that, if you're trying to make it linear then why not just use a transistor/solid state based design - it's just so much easier to get a true representation of the input signal from thatI do concede it might be an interesting hobby project to try and get a valve amplifier to act like a solid state device just to see if it can be done but it would never have any real world applications in this day and age, they cost too much when they burn out for a start, and I have been electrocuted by valve amps in the past and it's no laughing matter!I am building up 2 amps. one that has a valve that you can see glowing but does nothing and is transistor based and one that you can't see the valve on but does do something and then get a group of musicians to tell me which they prefer the sound of.

author: ejeffrey
author_rank: Super Contributor
timestamp: January 09, 2012, 08:40:09 pm
content: Quote from: IanB on January 09, 2012, 03:10:03 pmNo, valves are not particularly linear. Neither are transistors or MOSFETs, really. The difference is that transistors in particular have much higher transconductance (gain) than valves. This enables them to be used with much more negative feedback. The large amount of negative feedback is what allows unprecedented linearity and gain flatness. Also, transistors are cheap and small enough to use dozens of transistors in an amplifier, rather than being limited to only a few valves. Again, this translates to more gain, more feedback, and better performance.QuoteIt is certainly possible to make a valve amplifier with good performance. You won't get the practically unmeasurable THD+N figures you see in transistor amps, but you can get good enough for audio. Remember that in the end you are going to play this back through speakers which don't have perfect flatness or linearity either. There just isn't really any point since transistors are better in every way that counts.Instrument amplifiers are a different beast. It is acceptable and desirable for them to 'change' the sound. There is no objective standard for a good instrument amplifier, all that matters is whether you like the sound that comes out -- whether that is done with a valve amplifier, a distortion peddle, DSP, or whatever.

author: Unknown
author_rank: Unknown
timestamp: January 09, 2012, 09:42:25 pm
content: Quote from: ejeffrey on January 09, 2012, 08:40:09 pmAudio perhaps but NOT HiFi, despite any theoretical possibility you cannot practically come within coo-ee of the transparency of a good transistor amp.QuoteIt wasn't possible or practical in the 70's and although performance of available semiconductor devices have improved greatly since that time the only development in vacuum tubes has been in the form of marketing.It's akin to meeting modern emission standards with a carburettor, possible in theory but why would you waste your time trying to attempt such a feat.QuoteI nearly barfed my wheeties reading this, and was about to call bull#@!% until I awoke sufficiently to realise you were talking "musical" instrument amplifiers. As mentioned previously such amplifiers do contribute to the tone/sound/racket created, all too often with added noises and racket.QuoteTrue, there is however issues of practicality, reliability etc, that make that ancient amplifier more of a PITA every year. What was state of the art in the era of woodstock is almost certainly not the only way to achieve "that" sound any more, and it is certainly not the most practical or luggable way to do so.Modern recording has improved by orders of degree, noisy humming amplifiers and ancient creaking drum pedals should be, or should have been retired by now. It's 2012.

author: ejeffrey
author_rank: Super Contributor
timestamp: January 09, 2012, 11:12:34 pm
content: Quote from: Uncle Vernon on January 09, 2012, 09:42:25 pmActually, on average valve based amplifiers (not the tubes themselves) seem to have gotten worse since the 70s. Everyone who cared about performance, cost, power, weight, or heat jumped ship for transistors long ago. Those who are left think that a single ended triode is the last word in amplifiers. That was obsolete for everything but the cheapest, lowest performance amplifiers for decades before transistors took over.

author: slateraptor
author_rank: Frequent Contributor
timestamp: January 09, 2012, 11:54:37 pm
content: Quote from: ejeffrey on January 09, 2012, 08:40:09 pmNot to be confused with instrumentation amplifiers.I can already foresee some poor, unknowing chap hopping on DigiKey to purchase a few ofthesefor his next DIY audio project.

author: BravoV
author_rank: Super Contributor
timestamp: January 10, 2012, 05:48:45 am
content: Quote from: slateraptor on January 09, 2012, 11:54:37 pmI'm guessing those chap is aiming for bling factor rather that it's true electrical performance, with that shiny golden metal on top when buffed to very shiny, it might looks really cool especially inside an enclosure with transparent window, and some poor chap might perceive and want to believe it will make the circuit sounds better compared to using latest generation op-amp than that museum part.Audio phoolery is all about perception, not sound actually.Looks !!! It has gold on it, it must creates "golden" sound.LOL

author: PStevenson
author_rank: Regular Contributor
timestamp: January 10, 2012, 08:35:07 am
content: I've got these babies for my next teeth project, I plan to replace mine with them hahaI figure it will make my voice sound better

author: BravoV
author_rank: Super Contributor
timestamp: January 10, 2012, 08:41:43 am
content: Trust me, you want to buff them right till it shines, otherwise you won't get the "majestic golden" sound.

author: PStevenson
author_rank: Regular Contributor
timestamp: January 10, 2012, 08:55:56 am
content: of course, I'm going to take the brasso to them right now

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: January 10, 2012, 05:27:28 pm
content: I must admit, the audio industry is a strange animal, especially as far as audio gear pricing is concerned. I really cant think of any field in the electronics industry where customers are milked to the extent that musicians are. For example, synth and FX modules costing 400+ euros each, which generally constructed from a fistful of op-amps and perhaps some digital components, totalling up to maybe $100 all up. It's nuts.

author: Deepak
author_rank: Regular Contributor
timestamp: January 10, 2012, 05:52:24 pm
content: Quote from: AntiProtonBoy on January 10, 2012, 05:27:28 pmAt least those, and the tube amps dosomething.The real money is in the cables

author: slateraptor
author_rank: Frequent Contributor
timestamp: January 10, 2012, 06:55:40 pm
content: Quote from: AntiProtonBoy on January 10, 2012, 05:27:28 pmSoftware-based synth modules sell for so much less and afford the user orders of magnitude more flexibility and control. I feel that those are legit investments.Some of the midi-based interface devices are worth the money too, in particular, the street-priced Akai APC40--interfaced with Ableton Live, it's a simple yet elegant solution...well constructed to boot and very hackable in the right hands.

author: im_a_human
author_rank: Regular Contributor
timestamp: January 12, 2012, 12:05:33 am
content: If like me, you could build your own synths and save a packet

author: slateraptor
author_rank: Frequent Contributor
timestamp: January 12, 2012, 04:28:00 am
content: Quote from: im_a_human on January 12, 2012, 12:05:33 amYou'd be hard pressed to build on as sexy as the APC40.

author: tekfan
author_rank: Frequent Contributor
timestamp: January 18, 2012, 10:39:29 pm
content: Speaking of tube amps. Anyone recognize where this is from?

author: Unknown
author_rank: Unknown
timestamp: January 18, 2012, 10:51:31 pm
content: Quote from: tekfan on January 18, 2012, 10:39:29 pmThe Skip bin?

author: PStevenson
author_rank: Regular Contributor
timestamp: January 19, 2012, 12:00:27 am
content: Quote from: Uncle Vernon on January 18, 2012, 10:51:31 pmDam I was going to say that!it looks like some kind of radio receiver, maybe even a transmitter

author: tekfan
author_rank: Frequent Contributor
timestamp: January 19, 2012, 04:56:08 am
content: Quote from: PStevenson on January 19, 2012, 12:00:27 amWell almost from the skip bin. It's actually out of a Hammond C2 organ from the late 40's and dare I say it: ''It sounds great!''The outside looks awful but the electronics are rebuilt and working perfectly. No more leaky capacitor noise coming out of this thing.Inside small the metal box is a air variable capacitor that is used as a volume control. They probably used it instead of a normal potentiometer to elliminate crackles.

author: Unknown
author_rank: Unknown
timestamp: January 19, 2012, 05:03:32 am
content: Quote from: tekfan on January 19, 2012, 04:56:08 amI was going to say from a Leslie speaker, but though I'd better not in case i might date myself. Was in the ballpark but still way off. Does anyone born after the 70's know what a Hammond Organ is/was?

author: baljemmett
author_rank: Unknown
timestamp: January 19, 2012, 01:11:02 pm
content: Quote from: Uncle Vernon on January 19, 2012, 05:03:32 amYo! But that should come as no surprise, surely.

author: Unknown
author_rank: Unknown
timestamp: January 19, 2012, 02:49:31 pm
content: Quote from: baljemmett on January 19, 2012, 01:11:02 pmYeah but you should know about even the lowly pump organ, if you wish to retain cred.

author: baljemmett
author_rank: Unknown
timestamp: January 19, 2012, 02:58:52 pm
content: Quote from: Uncle Vernon on January 19, 2012, 02:49:31 pmEverybodyknowsthe best instrument is the discarded chest of drawers you find behind the studio and just bash the hell out of, anyway!

author: SeanB
author_rank: Super Contributor
timestamp: March 04, 2012, 03:29:19 pm
content: I have some Siemens valved preamps that i used as audio line amplifiers. They came with the equipment, so were used. Only good thing about them is the overload level, around 15VAC.When I upgraded the equipment I got a set of plug in amplifiers ( Opamp Labs units, in an octal can) that was used for both video and audio. One died so I unpotted it with a grinder, and replaced the output transistors ( it had a 2N3904/5 power stage with a 709 opamp driving it) with some 2N2219/2N2905 and used heatsinks on them ( they were running a little hot in near class A and I wanted it working quick) and it is still working.Valve and transistor audio are the same, it is the design that is important.