Amp Emulations

[Mark Hammer]

The sound quality is not "built in" to the technology.  Rather it depends on how the technology is used.

If I use a 320 x 200 screen, EVERYTHING will look jagged no matter how good an artist I am.  If my screen was 3200 x 2000 pixels, the image would be *potentially* less jagged and more realistic, but I would still have to be a good artist to make it *look* that way.

Current generation DSP is capable of doing a high quality job but several things have to be in place:
1) You can't ask the technology to take on too many tasks at once (e.g., reverb, compression AND distortion) and still expect quality in real time.  The things that DSP handles well with ease are the simple tasks like delay-based effects, EQ, compression, etc. because their relationship to inpu amplitude is relatively simple and straightforward.  Distortion properties are several orders of magnitude more complex.
2) You have to have an articulate detailed model and understanding of the phenomenon you are trying to emulate.  There are many things we understand pretty thoroughly/flawlessly about different types of effects, but a complete description of what happens in a tube context in response to variations in input signal still awaits us. 

And as always in science if you can't describe it, you can't predict it or control or replicate it.

[petemoore]

  Power Supply
 Tube output section
 Iron
 Whatever else is 'mojo' in there...
 These items are co-dependantly interactive in a tube amp, capturing even the elemental ones necessary to make a fair replication necessitates complex algorythms, it is my belief that any processor will introduce some latency, the more complex the greater the number of calculations = the greater amount of time to perform them.
 For recording purposes the timing can be compensated for and synchronized.
 If time is of any consequence, simply processing to achieve 'x' tone cuts time big time...getting a tube amp/guitar/effects to sound cool/be low noise is expensive and time consuming, as is the Mic/Pre/and any effects you want added...alot of figuring out...by the time all that got done you could have accomplished Alot of recording as opposed to gathering up batches of hardware items and working with them.
 As far as stage sound goes, [I'll stick with my opinionated self, based on experience...I've seen and used ALOT of tube and tube-like amps]...and say it depends exactly on how your hardware and or software solutions are working for you, the way you're applying them.

[petemoore]

Distortion properties are several orders of magnitude more complex.
  I would like to add that the rate at which these complex algorythms occur is 'quite fast'.
 

[Mark Hammer]

Distortion properties are several orders of magnitude more complex.
  I would like to add that the rate at which these complex algorythms occur is 'quite fast'.

Correct.  Which is why if you are attempting to "simultaneously" do compression, distortion, EQ, phasing, delay, and noise gating all in the same DSP-based floor or rack unit, there is a good chance that the algorithms for the distortion will be wanting.  Dedicated DSPs are more likely to be successful in doing what needs to be done for real-time authenticity - in all its complexity - than DSPs asked to multi-task.  Same reason why console game-machines were always so much faster and smoother in their graphics than multi-tasking desktop PCs running at even faster speeds.

But we've had this discussion before....many times.

[modsquad]

I have a digitech unit that uses 2 12AX7s in preamp distortion section that gives loads of flexibility as far as distortion along with the digital distortion.  The main issue is that things that are time based like reverb, echo, flanger take up a ton of memory.  I used to use the unit a lot, but found it a bit artificial sounding a couple of years ago and quit using it.  I am now looking at using the effects loop for echo and reverb.  The amp emulation is pretty decent but I find these units like a swiss army knife, they do a lot of things decently but nothing really outstanding.

Stan

[Gus]

The output tube(s) to the transformer is going to be hard to model

I build and mod condensers microphones for fun In my learning I have relammed and bought a number of different >20 transformers to use in tube and solid state microphones.  Amorphous core, 49% Ni Mu, 80%Ni  Mu, Mixed Mu Co Fe lams, China alloy lams don't know what it is.    Besides the inductance change and winding method and size the alloy type(s) make a difference.  They all sound different.  I friend of mine that has a studio and DIYed alot of it  can often tell the transformer brand by ear.   Look at the distortion curves of the transfomer vs level; and other parameters(look around cinemags site at some PDFs)

Take M6 M29 etc used in guitar transformers.  The same stuff does not work well at microphone output levels but if it gets a big enought signal  it works well.  Then you have the BH curves and inductance that change with level.  Who know whats going on in the pentode(s) when the amp is clipping. 

The overdriven output stage seems to matter a lot.

[Ge_Whiz]

It's about sounding/feeling a way to inspire me when I'm playing.

Good point! If your tone sounds bad to you it will affect your performance, but a happy camper plays better. Which of course affects the audience perception of your performance.

Point made. You see, not only do our perceptions of the sound differ, we're not even playing to the same purpose. Fun, but ultimately pointless, discussion. Personally, I make a point never to play with 'bad tone', and what inspires me is the music I'm playing, not my perception of my own 'rock-godness'. No offense meant.

[puretube]

I want "TZD" : towards zero distortion.
now - not after processing
no latency... 

[Ge_Whiz]

I want "TZD" : towards zero distortion.

So, no use having a valve amp, then? 

[puretube]

that`s a "zero" in the time-domain: instantly - not after having waited for the "processor" to have completed its calculations...

(zero latency)

[Ge_Whiz]

Acoustic guitar?

[Doug_H]

Personally, I make a point never to play with 'bad tone', and what inspires me is the music I'm playing, not my perception of my own 'rock-godness'. No offense meant.

For me, a lot of different things inspire me: The music I'm playing as well as my sound/performance, the sound/interaction/performance of the band as a whole, etc, etc. My main motive when playing is to touch the people we're playing for. If any of those things are "off" or if I'm uninspired or bored with what I'm doing it can distract from that.  Yes I do care about the audience, so I need what I'm hearing to feed back into my playing so they will get a good performance.

Is that more clear?

[Meanderthal]

 

For me, a lot of different things inspire me: The music I'm playing as well as my sound/performance, the sound/interaction/performance of the band as a whole, etc, etc. My main motive when playing is to touch the people we're playing for. If any of those things are "off" or if I'm uninspired or bored with what I'm doing it can distract from that.  Yes I do care about the audience, so I need what I'm hearing to feed back into my playing so they will get a good performance.

Ditto.

And if a jfet emulator/whatever gets me there, fine by me. Not at the moment(no tubes at all or emulators in my current live rig), but I'm eyeing up the Flipster...

[Doug_H]

And if a jfet emulator/whatever gets me there, fine by me.

I agree 100%. So why call it an "emulator" when we are not trying to imitate something "better"- it's a very good sound in its own right.

[Rafa]

IMHO we can call them amp ``X´´ adapted as a stompbox, or amp ``X´´ stompbox adaptation
In an shorter way, ie: Vox Ac30 SA
I dont think its neccessary to clarify that the tubes have been changed for transistors as most stompboxes dont have tubes.
Cheers
Rafa

[A.S.P.]

more "professional"
Tube Amp FAT Emus
and Tube Leds 

[Aharon]

Rafa,don't sweat it ...........listen,I have built at least 20 tube amps,anything from a trainwreck to a firefly with everything in between..............I havent heard a single amp that can do everything from clean to full out distortion the way I would like it......how can we expect a little box full of chips to do that convincingly?(at least at the point the technology is right now,remember that also the box has to cost less than the famous  50 thousand dollar hammer for NASA).

Like you I have a Princeton SS (Princeton Chorus 212) that I like for cleans,I like the distortion on my SLO,crunch is cool too...maybe too agressive......see what I mean?..............endless tweaking,but in order to be "happy" I have to cary a truckload of sh*t to the gig.

I recently upgraded my digital stompbox to the latest model..........the presets (70) sound like "crap" if you ask me and I almost returned the box for a credit bit I started fiddling with the individual effects and I was floored!!,nevermind that the tuner alone pays for the box but the wah simulations are some of the best wahs I've heard,reverbs are lush,chorus is great.......the problem is that people put a string of 20 efects on the chain and expect the thing to sound like what?.it would sound like crap with 20 analog effects too.
Then they plug into a crappy SS amp with an 8" speaker and want 412 "emulation"?.

Distortion is another problem,like MArk says.............but I even that,I've run a  distrotion emulation through an HO amp on "clean" setting and the the resulting distrotion was the best ZZtop emulation of BGs guitar I've yet to hear but then it won't do cleans well if you know what I mean.

I have a friend that's a professional guitarrist for more than 30 years.
He either owns or has owned every amp ever,he's got tweeds,bassmans I've played through them,some sound like crap to me some are really nice....one thing for sure,he can almost make them all sound most excellent..........you know what I'm getting at...........

If you ever go to a tube amp forum you will see people argue about what tubes sound better,what brands and if that is not enough ............what year or batch number..................

I say get some decent gear that you like and can afford and play your heart out..............in the end once you get your perfect sound in the bedroom you still have to filter all that through the noise in the bar,beer goggles and that chick in the corner that is making faces at you and makes you forget what song you are playing.
This is rock and roll after all...........come to think of it the players I admire the most played through whatever loaner they could find and a tele with no effects.....but thats me.
I'm sure technology will get there sometime in the near future...............did I mention I don't like samplers?

Aharon

[Rafa]

What a long and great response Aharon
Clearly youre much more expirenced than me, lately Ive been very busy with university, (I havent been around much), so I havent had much time to finish my projects. But one of my projects I want to finish soon Is a small champ, Which I already have all the tubes except from the rectifier which Im going to use diodes. I must admitt that what motivated me to build the amp was this long and endless discussion between SS and tubes. As I said before SS distortions never called my attention but on the other hand I havent palyed thorugh many tube amps in my life, so building my own seemed the best idea. I agree with you maybe I worry too much about equipment,
Cheers
Rafa

[Aharon]

Good luck with the Champ..

Did you ever go to the Ax84 forum?..............there's a couple of amps that could be made with the same parts as the champ (give or take a few) that may be better suited to what you are looking for.
Have you looked into the HotBox,if what you want is tube preamp distortion maybe it's a good alternative....true,it does not include power tubes or output transformer but it's "simpler" to build and less expensive and you can plug it into your SS amp.
PM me if you need anything.
Aharon