-
Why is that?
Originally Posted by Christian Miller
-
03-05-2022 01:36 PM
-
I think it's more complex than he makes it sound (pun intended). Output stage distortion and preamp distortion are totally different animals in both form and sound, corrresponding to the 3 illustrations below: Originally Posted by Gitterbug
- The classic sound of an ordinary low gain tube amp pushed to its limits is that of power tube saturation. As I suspect you know, Markku, power tubes can only conduct so much current before reaching their maximum output. When that happens, they tend to "clip" the wave form softly. The peaks can't get any higher, but the signal components below peak will continue to increase in amplitude - the waves get squooshed, for lack of a better term, and are blunted but still without sharp amplitude transitions. The harmonic distortion this causes (in moderate doses) is largely even order and not grossly harsh or unpleasant to many. Think "tube warmth".
- Low powered amps like a Champ do this at relatively low volume levels. High powered amps without gain stage controls can be made to do this at low volume levels by adding an attenuator to the power output terminals to dissipate most of the output power as heat while maintaining the required output impedance.
- Output stage distortion of a different kind happens because the power supply can't keep up with the output stage's demand for electrons. Power supply "sag" is the phenomenon of voltage drop from a power supply unable to sustain the power demands of the output stage(s). This is the so-called "brown sound" beloved by so many, and it's often eliminated by a solid state rectifier instead of the classic 5Y3 or 5AR4. When voltage drops, the peaks are reduced but the waveform is less affected below peak - this causes the kind of compression that old blues guys loved.
- Traditional solid state output circuitry handles output clipping by simply chopping off the top of the waveform, which turns its formerly sinusoidal components into square waves near the peaks. This generates harsh odd order harmonics (known as a spectral splash) that cause that harsh sound we all hated.
Most guitar pickups do not put out enough voltage to overload most amplifier input stages. We cause preamp stage distortion by artificially overloading it with an additional preamp stage that generates more voltage than the amp's input stage can handle - this is truly overdriving it. If that input stage is a tube preamp, it will clip softly as above and sound smooth (in a different way from power tube saturation) until the tubes are hit so hard that the waveforms start to resemble square waves and sound harsh. If it's an old fashioned SS circuit, it will chop off the waveform tops in a distinctly un-jazzy fashion and sound harsh as soon a sthat begins to happen.
The added gain stage(s) can be external in pedals or other effects devices. But they can also be internal in the form of multiple cascaded gain stages (as Mesa started to call them almost 50 years ago). Multiple preamp gain stages are the backbone of most amps with a single "lead" or "boost" switch. A gain control on the preamp stage and a volume control between the preamp and amp stages is another way of increasing the voltage coming from the preamp stage(s) to the power amp. And these approaches are combined into amps with multiple stages, channels, and gain settings to balance the desired distortion among the various preamp (i.e. voltage gain) and power amp (i.e. current gain) stages.
The bottom line today is that the above phenomena can all be duplicated pretty well in solid state devices of various kinds. Even 20 years ago, solid state preamplification stages (e.g. J-FETs) and power amp stages (e.g. MOSFETs) were advanced enough to do more tube-like things with less SS harshness. Digital simulation can incorporate whatever transfer functions we want between the input jack and the speaker, so we can have the sounds of preamp overdrive, power amp tube saturation, voltage sag, and anything else we like from Bonamassa's Bassman to Bootsie's Boogie. These sounds are all valuable to artists in different genres, and being able to get them from simulation software and modeling amps is fantastic!
Anything can be used as a marketing gimmick, but the sounds and the way they affect our playing are not gimmicks - they're useful tools for musicians, producers, engineers etc. The gimmicks are the marginal implementations done on the cheap solely to pry a buyer away from competition. I think hybrid amps are valid ways to implement the above. But digital simulation seems to me to be on the verge of replacing tubes for all but the most diehard (and gargantuan) musicians.
- The classic sound of an ordinary low gain tube amp pushed to its limits is that of power tube saturation. As I suspect you know, Markku, power tubes can only conduct so much current before reaching their maximum output. When that happens, they tend to "clip" the wave form softly. The peaks can't get any higher, but the signal components below peak will continue to increase in amplitude - the waves get squooshed, for lack of a better term, and are blunted but still without sharp amplitude transitions. The harmonic distortion this causes (in moderate doses) is largely even order and not grossly harsh or unpleasant to many. Think "tube warmth".
-
Thanks, David! This is probably the techiest posting I recall on these pages. It hovers well above my dandruff (to quote a Finnish saying) but I'll pass it on to Mikko. Anyway, you seem to be confident about new technology catching up with the pleasurable shortcomings of the old. I think that, for practical purposes and with ubquitous digital signal processing, we're already there.
-
I think the sole remaining hurdle is the emotional bond so many still have to the past. Technology is already there, but some of us are not Originally Posted by Gitterbug
-
I prefer not to be in a world of simulation, where everything is run by algorithms. I like my valve amp for the sounds it was designed to make (and some that are accidental). It is not trying to copy the sounds of other amps. It does not include a menu of sounds, designed in the lab to provide the owner with a fauxthentic experience of playing like his guitar heroes did back then, on their valve amps. It is just an amp.
-
Not many years ago GP had a serious review of a special power cable, designed to go from wall socket to amp. The sales pitch was something to the effect that it provided better conditioned power, in some way. The reviewer skillfully avoided taking a position on whether it actually made the amp sound better.
Seems absurd -- somewhere there's a power plant which generates the electricity, sends it over miles of the power company's network into the wiring of your house -- and then, somehow, the last 6 feet of wire (the product) makes a big improvement.
And, apparently, some people say they can hear the difference.
Well, if they can hear that, tubes will be with us forever.
Disclosure: Two of the best guitar sounds I ever heard -- one was tubes (Twin Reverb), the other was SS. Both archtop guitars.
-
Just like Harley Davidson are now producing bikes with water cooled and even electric engines (out of necessity) the big inevitable guitar amp brands will know how to replace their tube-based products with ones containing solid-state and/or digital logic. And they won't have menus either ... how else are they going to continue to sell amps that have the same internals but a different sound?
The question is, will those replacements have fake tubes for nostalgia's sake?
-
whilst post #153 is a very good summary
of valve vs SS distortion
I think there’s more going on than that ,
other stuff that we can hear and feel
but we can’t yet quantify
I don’t know what that is either ....
but it ain’t nothing
If you turn up for a session and
there’s a top modelling rig there
and there’s a Twin or delux sitting there
What would you do ?
-
I’d try them both and use the one I like better. If there’s no clear difference, I’d use the one with the more accessible knobs and jacks. And if that’s also a toss-up, I’d use the one closest to me. Originally Posted by pingu
Originally Posted by rpjazzguitar
Originally Posted by rpjazzguitar
This is gospel to many audiophiles, and I think it’s pure nonsense. Eric Johnson says he can hear the difference between brands of battery in an effects pedal. I keep asking for blinded testing when people tell me these things…….and no one has ever agreed to do it.
FWIW, I do put my money where my mouth is. I correctly identified a 6’10” Steinway against the big one in 3 blinded tests using commercial recordings engineered by one of the regulars on audiophilestyle.com - I write a column for that forum called The Value Proposition in Audio. But I can’t hear a difference in power cords.Last edited by nevershouldhavesoldit; 03-05-2022 at 05:47 PM.
-
Ok. So, somebody else has carried the Twin. So, I won't include back injury as a factor <g>. Originally Posted by pingu
I wouldn't pick the modeling rig because I wouldn't know how to use it. I had trouble with a Boss GT-1. A full modeling rig without having read the manual and fiddled with it for hours?
If I had to pick one without first trying them all, I wouldn't pick the Twin because I've had some trouble with too much bass before. I'd probably pick the Deluxe because I've had good experiences with. A Hot Rod Deluxe is one of the best amps I've heard.
OTOH, one of my top two all time guitar tones was generated with a Twin, but by somebody else. I had a silver face with JBLs many years ago. It was too punchy -- that is, it reproduced the transient of the pick attack better than I wanted it to. Probably the JBLs. A gig up a flight of stairs made me want to quit music.
-
I don't need, nor want, a modeling amp. I just want it to reproduce the sound of the guitar. I don't want soft distortion, I want to be able to turn up to 11 without any distortion at all (not that I would ever want that much volume, but I don't want distortion at low volume either). Tubes have been obsolete for close to half a century. The original computers used vacuum tubes, but they moved on quickly. But I don't need a computer in my amp either. For me, the DV Mark Little Jazz does everything I need, and does it well. It's small, light, and sounds very good. I have a Fender tube amp, because I bought it used about 30 years ago for a great price, because I was playing in a group that included the manager of a pawn shop. I rarely turn that beast on, but now and then I get curious and want to hear how it sounds. Every time, it sounds worse than my Little Jazz, and I have to fiddle with the tone knobs to get an acceptable sound. With the LJ, I just set it all flat and forget it. I've had idle thoughts about getting one of the new Quilter Superblocks, but I won't, for several reasons. It costs money I could use for other things, I've never played a Quilter that I liked, and it requires a cabinet, which is just more stuff to carry. I like tech, and buy things with new technology all too often, but my current amp needs are met with the current technology. I haven't considered for even a millisecond buying a tube amp since I got the one I have, and I never would. I wouldn't consider buying an audio amp that used tubes. Some swear that the tube distortion, slight as it is, sounds better, but I'm entirely unconvinced.
-
Some great discourse here!
could I note that most guitar preamp pedals are trying to emulate/replicate preamp tube saturation & compression?
Some are their own thing (benson, Hudson etc) and other are more MAIAB type - Eg: revival drive.
This is distinct from Overdrives-(Nobel ODR, Fulltone OCD, Tubescreamers etc)
these preamps are all solid state devices. Yes you can buy all tube preamp pedals too- Kingsley Constable is a Marshall front end, the whole Victory V4 series)
you can feed them into the return of your fx loop and theoretically have a different amp tone available.
all break up in different ways. Diode clipping , op amps or tube saturation. JHS did a great video on the different methods. Worth a watch.
I would say that tubes in preamps are a gimmick if you cannot control their saturation gain.
running too low you may as well not have them. An op amp will be just as good. Plenty of examples of these around.
running too hot and you no longer have clean channel. There is a place for these too. But not for me.
but the total harmonic distortion you get from a tube gain stage exists on any tube. So does it’s compression characteristic. In the right circuit you can get access to all of this and you can tune it to your pickups output as well.
To me at least this is what solid state preamps are trying to duplicate.
Now if that signal is pumped into a compressing distorted output state or a speaker collapsing under load then you will probably never hear that preamp tube and any tube preamp is a gimmick then.
If though you pump that harmonically rich signal into a high headroom clean stage and a speaker cab combo up to the task then there is no where to hide and everything come out of that preamp.
I think it is this point which defines good preamps and bad ones? I think it in this space that quilter has made a performance stepchange in the generation of even order harmonics in the preamp stage and the feedback is speaking for itself.
Strymon iridium is apparently very good as well as a preamp to a FOH or powered FRFR speaker cab.
Modellers are probably just as good too- but personally I see them as an answer to an immediate need with far too many additional features I don’t envisage needing but would have to pay for. I view them as an option in specific circumstances but not a replacement for any circumstance.
But a shortened opinion- yes I too think tube preamps are a gimmick but not if they used or applied in the right circuit.
cheers all
EM
-
Thank you for this! Originally Posted by nevershouldhavesoldit
I think it's more complex than he makes it sound (pun intended). Output stage distortion and preamp distortion are totally different animals in both form and sound, corrresponding to the 3 illustrations below:
- The classic sound of an ordinary low gain tube amp pushed to its limits is that of power tube saturation. As I suspect you know, Markku, power tubes can only conduct so much current before reaching their maximum output. When that happens, they tend to "clip" the wave form softly. The peaks can't get any higher, but the signal components below peak will continue to increase in amplitude - the waves get squooshed, for lack of a better term, and are blunted but still without sharp amplitude transitions. The harmonic distortion this causes (in moderate doses) is largely even order and not grossly harsh or unpleasant to many. Think "tube warmth".
- Low powered amps like a Champ do this at relatively low volume levels. High powered amps without gain stage controls can be made to do this at low volume levels by adding an attenuator to the power output terminals to dissipate most of the output power as heat while maintaining the required output impedance.
- Output stage distortion of a different kind happens because the power supply can't keep up with the output stage's demand for electrons. Power supply "sag" is the phenomenon of voltage drop from a power supply unable to sustain the power demands of the output stage(s). This is the so-called "brown sound" beloved by so many, and it's often eliminated by a solid state rectifier instead of the classic 5Y3 or 5AR4. When voltage drops, the peaks are reduced but the waveform is less affected below peak - this causes the kind of compression that old blues guys loved.
- Traditional solid state output circuitry handles output clipping by simply chopping off the top of the waveform, which turns its formerly sinusoidal components into square waves near the peaks. This generates harsh odd order harmonics (known as a spectral splash) that cause that harsh sound we all hated.
Most guitar pickups do not put out enough voltage to overload most amplifier input stages. We cause preamp stage distortion by artificially overloading it with an additional preamp stage that generates more voltage than the amp's input stage can handle - this is truly overdriving it. If that input stage is a tube preamp, it will clip softly as above and sound smooth (in a different way from power tube saturation) until the tubes are hit so hard that the waveforms start to resemble square waves and sound harsh. If it's an old fashioned SS circuit, it will chop off the waveform tops in a distinctly un-jazzy fashion and sound harsh as soon a sthat begins to happen.
The added gain stage(s) can be external in pedals or other effects devices. But they can also be internal in the form of multiple cascaded gain stages (as Mesa started to call them almost 50 years ago). Multiple preamp gain stages are the backbone of most amps with a single "lead" or "boost" switch. A gain control on the preamp stage and a volume control between the preamp and amp stages is another way of increasing the voltage coming from the preamp stage(s) to the power amp. And these approaches are combined into amps with multiple stages, channels, and gain settings to balance the desired distortion among the various preamp (i.e. voltage gain) and power amp (i.e. current gain) stages.
The bottom line today is that the above phenomena can all be duplicated pretty well in solid state devices of various kinds. Even 20 years ago, solid state preamplification stages (e.g. J-FETs) and power amp stages (e.g. MOSFETs) were advanced enough to do more tube-like things with less SS harshness. Digital simulation can incorporate whatever transfer functions we want between the input jack and the speaker, so we can have the sounds of preamp overdrive, power amp tube saturation, voltage sag, and anything else we like from Bonamassa's Bassman to Bootsie's Boogie. These sounds are all valuable to artists in different genres, and being able to get them from simulation software and modeling amps is fantastic!
Anything can be used as a marketing gimmick, but the sounds and the way they affect our playing are not gimmicks - they're useful tools for musicians, producers, engineers etc. The gimmicks are the marginal implementations done on the cheap solely to pry a buyer away from competition. I think hybrid amps are valid ways to implement the above. But digital simulation seems to me to be on the verge of replacing tubes for all but the most diehard (and gargantuan) musicians.
- The classic sound of an ordinary low gain tube amp pushed to its limits is that of power tube saturation. As I suspect you know, Markku, power tubes can only conduct so much current before reaching their maximum output. When that happens, they tend to "clip" the wave form softly. The peaks can't get any higher, but the signal components below peak will continue to increase in amplitude - the waves get squooshed, for lack of a better term, and are blunted but still without sharp amplitude transitions. The harmonic distortion this causes (in moderate doses) is largely even order and not grossly harsh or unpleasant to many. Think "tube warmth".
-
At first glance this seems like a paradox; People cherish vintage guitars but look for futuristic amplification solutions...
I see a number of possible explanations;
1, Failure to accept the fact that an acoustic guitar is too feeble to hold its own when played together with other traditional (acoustic) jazz instruments. The introduction of the electric guitar was a complete game changer that eventually gave birth to rock 'n roll that put an end to the era of jazz as pop music. Some of you prefer the sound of your acoustic guitars and think that the amp is a (necessary) evil you would rather live without. (Some even play solid body electrics unplugged exclusively, because the amp is just too freaking loud and somebody could hear you
).
2, Failure to accept the fact that the sound of an electric guitar comes from a loudspeaker. -How are you supposed to hear the exclusive tone wood when the acoustics are overwhelmed by a loudspeaker that has a sound of its own? A tube amp is archaic and difficult to control and it got tonal artifacts and imperfections (noise) that disturb your acoustic experience.
3, Failure to accept the fact that Jazz belongs to history. And failure to recognize that the electric guitar is history. "A modern Jazzer" is an oxymoron. There are no modern guitar players, because the guitar, with its silly legacy design, is archaic and belongs to history. This is what we love, this is the legacy we honor when we acknowledge that the amp is part of the instrument. If I would go modern I would play the computer like everybody else these days. You, the good people of the Jazz guitar forum, are among the few that still can play. Thanks to you the electric guitar and the amp that makes the guitar electric, remain relevant. When you want vintage tone you look for vintage amplification, simple as that. -Why emulate the sound of a tube amp when you can have the real deal?
PS: Piezo technology is different. It was developed post the Jazz era but can obviously be used in jazz applications. Traditional tube amps are good for magnetic pickups, but I see no value add when using piezo pickups.
-
Some interesting points, but I do not agree that you cannot "play modern" on legacy instruments. You can do very modern things with old equipment, and some of those things may be hard if not impossible to do on modern equipment.
Sure, you can model a tube; generally that will be an ideal, new or just broken in (if that's a thing) representative of the model you're interested in. But you're modelling analog behaviour in a discrete system, and that approach has pitfalls and limitations. Your model may (and in fact has to) cut corners, meaning it may not behave exactly the same as the modelled system in certain conditions. You're simulating the model with an imperfect system but even a super computer would have limited numerical precision which can (and will) lead to discrete behaviour or numerical instability. And tubes age - even if that is captured in your model that will still not account for the fact that every tube ages differently. As far as I know that ageing also leads to failure more or less gracefully.
Many of these shortcomings are going to be smoothed out by the analog stages after the model, but if I look at this from the perspective of an acoustic player I am concerned about the loss of individual sounds this can cause.
EDIT: if you combine different simulated systems in series, where some take the input from other you might actually end up more easily in those corner conditions where the model isn't at its best.
A couple of years ago I went to a small local rockabilly festival. Had some fun, and heard a French group (The Capitols) I liked enough to buy one of their CDs, a tribute to (IIRC) Gene Vincent. Turns out this was recorded in a studio (somewhere in the French south-west) which is equipped entirely with vintage equipment (though presumably with a digital recorder somewhere at the end). The result lacks the brilliance and precision I have come to expect from high-end recordings of acoustic instruments but it still sounds great and probably more appropriate for the kind of music being played.
-
One thing you can never change, is the speaker.
Not sure if any solid state bout circuit can be made to interact with the guitar’s pickups like a 12AX7 (or a 6SJ7) does.
Jazz guitar is not dead, it’s like haute cuisine, for connoisseurs more than just a pleasure; it’s a pursuit. Like classic music. That sales are made to the under 12 year olds by semi pornographic videos doesn’t give it more value than a mars bar compared to Le Tour Carnet (or any other top or even just good restaurant).
We buy our amps for character, but what character has an amp that can do everything?
One thing has me flummoxed though. Many greats talk about the amp sound being essential or else the guitar would sound shite. I’m gonna look up the files I took of a Gibson Blueshawk into an MXR amp and straight to ‘tape’ as it sounded quite good.
Sent from my iPhone using Tapatalk
-
if you want clean , fine ...
SS will do that well already
eg sgosnell is happy with his LJazz
I want and need a bit of controllable dirt
sometimes that plays like a good valve
amp
but I want it super light and compact
The holy grail ?
-
confused Originally Posted by EastwoodMike
so does a high voltage valve preamp
into a SS clean poweramp make
sense to you ?
im thinking of one of these maybe
-
How much longer do you think we'll be able to even find "the real deal", let alone afford it? Where will we get the replacement parts and technical ability to maintain it? How will young jazz musicians be able to build careers and develop as players if they're taught that they have to use "the real deal" to get the best sound quality and presentation? Originally Posted by JCat
Sound quality is sound quality, and it's independent of the tools used to produce it - the sound is the "real deal", not the device used to make it. We only had one way to get it for many decades, and that was a tube amp. If modern technology can produce the same sound quality using devices we can easily afford, find, and carry, we should embrace them. I'm ecstatic about being able to carry a great sounding 250W amp and excellent speaker cab in one 20 pound bag with one hand.
-
Let's also forget the "emulation" fallacy. Solid state guitar amps have existed for half a century. Their purpose from the start was to provide a good-sounding tubeless alternative, just as solid state was conquering the HiFi market. Polytones have gained a cult status on their own merits. A few years ago, I went through a dozen amps at a well-stocked store. A lowly Fender Frontman 50 sounded by far the best for straight-ahead jazz. A speaker upgrade would have widened the gap further. The modeling stuff is recent and nobody's is force-feeding it to anybody. Quilter (brighter) and DV-Mark (darker) offer great Class D heads and combos that aren't too cluttered with menus, downloads and plug-ins. For a simpleton like me, development could well stop here. And two gens ahead they would be coveted vintage.
-
yes. Makes perfect sense to me. But with controllable (not fixed) gain Originally Posted by pingu
EM
-
It’s strange that I can never get
demos of the ‘touch-sensitivity’
of the various amps ....
like
when I pick medium strength it sounds like this
when I dig-in and it breaks up like this
(i thought maybe High Voltage tube
pre-amps were the way to go)
when they model tube amps ,
at how many different input levels
(strengths of picking)
do they sample I wonder ?
Brian May can go from totally clean to
super sat and everything in-between
with the same amp setting
(guitar , preset amount of clean boost into AC30)
I’ve seen him do this just on the
guitar volume control
amazing
-
A tube amp is not necessarily that expensive. In perspective, when considering what people pay for guitars, amps are affordable. Some guys own 10 electrics or more, but no amp...(because they plug into the computer, using headphones). Originally Posted by nevershouldhavesoldit
My best advice to any beginner would be to invest in a good sounding amp from day one. Don't overspend on guitars and think you can escape the amp, because sooner or later you'll find yourself in a situation where people would like to hear you play.
The rumor of the death of the tube amp started 50 years ago and I think we can now safely conclude it was exaggerated.
-
I’ve got a really punchy nice Blues junior tweed mk1 ....
but it’s too heavy for me now at 32lbs
Im old ok , there I said it ....
-
In case anyone is interested, I know of a Fender Blues JR LA Vice for sale in France.
Reply With Quote
“Shearing style”
Today, 05:26 PM in Comping, Chords & Chord Progressions