Conference napalm::guitar

    The solid state power amp that everyone is raving about is the Lee
    Jackson-Metaltronix SP1000. It fits into one rack space and delivers 
    125wpc. I've heard that it has a warm tube-like tone.  
    
    Couple this to a tube preamp, and you've got the basis for a great
    rack system, in a lightweight package. Then, the only tubes you have
    to contend with are the 12AX7 preamp tubes, which are much cheaper 
    than power tubes, and do not have to be matched/biased.
    
    As far as transistors are concerned there are two types:  Bipolar and
    FET (Field Effect Transistors). There are some good amps out there with 
    both bipolar and FET transistors. These include Gallien-Krueger, Peavey, 
    Pierce, Carvin, Fender, Roland, Ampeg, etc. Roland jazz-chorus amps are 
    among the best selling, but really only provide a clean sound. Fender has 
    a new solid-state combo (covered in  grey Ozite carpeting) which is 
    suppossed to be so hot, the stores can't get them in fast enough. The old 
    LAB amps sold through Norlin had a great sound for solid state amps. Paul 
    Reed Smith just introduced a new line of solid state amplifiers. These are
    definately worth checking out. 
    
    There is a discussion going on in the general bs note about this same
    subject.
    
    Mark
    

    BTW, the Carvin FET400 and FET1000 amps you mentioned in .0 are
    stereo power amplifiers intended for sound-reinforcement appli-
    cations (ie. PA systems). There's no law that says you can't use
    them for electric guitar provided you use a preamp, but I don't
    think they offer the special voicing you normally associate with
    guitar amps.
    
    The Marshall MOSFET amps have been around for years. I can't say
    for sure, but I haven't heard too many good endorsements for them.
    
    Mark
    

    The HOT new power amp out on the market is the MOSvalve.  I believe
    it's made by Tube Works, but can't be sure.  Rumor has it it blows the
    SP1000 away in warmth.  FWIW, it's 2 rack spaces high, has volume and
    presence controls for each channel, costs a little more than the
    SP1000, and is BUTT UGLY! (bright yellow knobs and lettering on black)

My reaction to the SP-1000 when I tried one with my not_yet_smoked testerossa
was wow, somebody finally made a decent sounding solid state power amp.

The store owner was saying things about a BB King sound, when I went into 
crunch mode...

dbii

    
    I love these "amplifier" discussions...
    
    I dont know of any specific amplifiers that you can go check out.
    The things I do know something about are specific engineering reasons
    why something sounds the way it does. In my opinion, some fraction
    above 50% of the "Fet's sound like tubes" claim is marketing hype!
    
    Yes, an F-E-T works like a tube does in theory; you can engineering
    model them both the same way in a circuit simulation. Practically,
    they have very different capabilities and applications. As much
    as one would like to believe, there is no way to plug a FET into
    a tube socket for a 6L6 and make a FET amplifier.
    
    The FET wouldnt survive long in a 6L6 circuit topology, even if
    it had a 1000 volt Vds rating.
    
    Which brings me to my point - it's more a factor of a particular
    circuit topology - how it's implemented - that it is the kind of
    elements used as building blocks. You can do circuits with tubes
    that you *just cant do* with transistors of any kind, and vice versa.
    
    How many guitar amplifiers have you seen using transistors that
    have an output transformer; how many amps do you know use tubes
    without one? The existance of an output transformer in the circuit
    - it's particular physical characteristics - has some say in how
    it sounds. Unless this is specifically accounted for in a transistor
    design somehow, it just wont ever sound that way.
    
    How many transistor amps have tubes in the power supply? According
    to what I read about some vintage Marshall designs, the power supply
    tubes just happen to - by virtue of what they are - provide a very
    desirable compression effect characteristic of vintage Marshall
    amps. Marshall figured this out and deliberately left the circuit
    design the same, instead of giving it this "beefed up" power supply
    in their vintage re-issues.
    
    A LAB amplifier is one solid state that has a compression control,
    which simulates this effect in transistors. While it makes the amp
    work better than without, it's still not the same as the effect
    that happens in the original tube circuit.
    
    By now, I believe that any attribute you want is available in an
    amplifier, be it solid state or tube or some combination thereof.
    You have to know what you want however and know how it's done in
    the particular circuit design of the amplifier - or at least be
    aware that *the design* is done intending to do "something good"
    for you. Just cause it says "FET" does not mean "will sound like
    a twin, cranked" necessarily.
    
    Joe

    re .-1
    
    I'm glad somebody brought up the point about circuit design, because I
    think it's a relevent point.  If not, it's at least interesting. 
    Usually the designers of solid state amps try to emulate the "tube"
    sound to some degree.  If you look at the resulting circuit, it will be
    much more complex than the "equivalent" tube-based circuit.  Just like
    Joe said in the previous note, tubes and transisters are like apples
    and oranges, or, more to the point, screwdrivers and pliers:  To make
    one work like the other takes a lot of gyrations.
    
    My preference is for simplicity always.  When I look at how simple the
    circuit is for a fine tube amp, I find myself wanting that because the
    sound I want just natually is produced via the tube's physical
    properties.  I am uncomfortable with using a complex design (using
    transisters) to do what a simple one (with tubes) will accomplish.
    
    Now having said that, I do realize that there are financial realities,
    and reliability issues as well.  Under different circumstances, I could
    see opting for solid state.
    
    (I'm just glad I don't have to! ;^) )
    
    Boogies, Marshalls, Fenders, Hiwatts forever!
    
    Will

    Re: MOSValve
    
    It is all black with yellow (or some goldish color) text.  I've seen
    one and wouldn't call it BUTT UGLY ;-).  I hear it uses MOSFET
    technology.
    
    I'll post the manufacturer's info in the appropriate note.  It is made
    by Tube Works in Denver.
    
    Mike

    
    
    Transistors, FETs, MOSvalve and whatall, are getting much better. But it
    just so happens the other day while I was sittin on the thone lookin
    over some old guitar player mags, I came across an article written back
    in '75 about the "new" Gallien and Krueger" Transistor amp. I'll post
    an excerpt from it witch purports that they had significantly closed
    the gap between transistor and tube sounds. Here it is, damn near '91
    and we're still bsing about it.
    
    Just a few weeks ago I bought a Fender M-80 amp with 1-12. I took it
    to rehearsal and tried a side by side comparison with my "twin". Well,
    you can tell the difference, especially in the overdrive channels. Now 
    this is interesting because the difference is negligible for the clean
    channels. It isn't a scientific test, but it impressed me that the
    original Fender sound can now be duplicated using new transistor
    technology. I would have thought that the overdrives, with all the
    distortion harmonics would have mucked up the signal so that it'd
    sound more the same than the clean channels. Not so. I guess a buzz 
    is not just a buzz.
    
    So like everything else, I guess it depends what you're gonna do with
    it (the amp) whether you like the sound of it to begin with (and this
    why I can't get by the Marshall sound in the music store), and the $$$.
    My "twin" is one hell of an amp as I've written ad nauseum. But it cost
    several hundred more than the M-80. Worth it? For me, only time will
    tell as I'm in a state of uncertain future insofar as my guitar playing
    is concerned these days. (How's that for a song title - "State of the
    Uncertain Future")
    
    "sakman" 

    By the way, Carvin *does* make a transistor amp that goes for about
    $500 that is supposed to provide good tube emulation. I don't know the
    model offhand, and I've never heard one. 
    
    	- Ram

    
    Blind test???   ;^)

    I think the reason the distortion is hard to reproduce is because
    that's where the device (tube or transister) comes into effect the
    strongest.
    
    To a very large degree, any amp that's built to give the same EQ'd
    sound as another will sound the same regardless of the technology. 
    It's when you push the device into overdrive and clipping that it
    sounds way different.  When you abuse the device to make it distort,
    the different technologies sound different.
    
    It's like taking a fast car and a fast train around a tight corner.  As
    long as you don't go too fast, and the tires stick and the train's
    wheels stay on the rails they feel the same if you didn't know which
    one you're on.  But, if you push it to where the car's tires slide on
    the pavement and the train's wheels pop off the rails, then you would
    immediately know which one you're riding in.  One will gently slide and
    the other will violently crash.
    
    Tubes act more like the slow break away of the tires.  Transisters act
    more like the violent break away of the train.  That's why tubes have
    that certain sound that most people like better.  Intrinsically, that
    is.  The designers are getting better at making the one sound like the
    other, and indeed, I think are now quite close.
    
    Will

    
    My father has been repairing TV's, radios, and etc for years starting
    in the old days of tubes.  When I brought my Boogie home, I flinched
    when I saw him peering thru the back side, thinking he'd think it was 
    outdated technology.  To my surprise, he said, "Oh, tubes!  This should
    sound a lot better and warmer than a transistor amp!"  
    
    And he doesn't know a thing about the resonating of the filaments in
    the tubes to create "distortion", either, but he soon found out!!!
    
    ;^)
    
    J.

    
    	Re .12 -
    
    	Yes, that "resonating" is an example of something that *cant*
    happen using a solid state circuit. Some part of the way a cranked
    powerful tube amp combo sounds is because the speaker vibrations are 
    actually shaking those grids and the resulting physical displacement 
    modulates the signal the tube is amplifying.
    
    	This dont happen in a "rack" system ;') Of course, the effect
    could be simulated by mods, a special circuit or maybe the new "hot
    setup" would be to bolt a small speaker onto your ADA rackmount
    preamp, to shake up that 12AX7 in there a bit ;')
    
    	As I said before, the output transformer is a biggie, because
    it's a nonlinear device, which means it has it's own "breakaway"
    characteristics when driven hard in that total sound mix too. So,
    lots of stuff is going on when a pair of 6L6's are winging away
    into this coil of wire wrapped around a hunk of iron.
    
    	My official guess is that you could use Mosfet's driving
    transformers for a couple of stages in the circuit topology, and
    get damn close to the mystical "warm" sound. I'd find it interesting
    to see the circuit of that lastest and greatest, to see what they
    do -
    
    	Joe

    RE: Mike
    
    For a free demo of a tube preamped, Metaltronix SP1000 powered
    stereo rig, come back to Colorado and check out my rig.
    
    jc
    

    I received my MOSValve propaganda over the weekend.  They also have a
    dealer in Phoenix!   Tube Works is even coming out with combos and
    heads based on the Real Tube II preamp and MOSValve amp.
    
    Maybe I should start a new note...
    
    Mike

    The truth is, nothing sounds like a tube.  Ya can make solid state
    sound like a tube, but it's all BS in the longrun. This is because
    of the voltages and headroom involved in tubes, and the reactions
    of the gases and glass, output transformer, etc.  Ask Jim Marshall.
    
    Power amps with tube drivers and mosfet outputs stages are as
    close as ya can get.  If you want a great schematic of a true
    tube/mosfet power amp, e-mail me.
    
    Jay Tashjian
    

    I'm willing to bet it's only a matter of time before DSPs are built
    right into amplifiers to emulate different technologies. Not only will
    it compensate for the tube effect, but will precompensate to make the
    speaker sound like anything you want. The user end of the DSP market is
    still incredibly crude. They toss you a few algorithms for reverb,
    compression, etc. The front panel of your amp will be an
    
    	       	AMPLIFIER CONSTRUCTION KIT
    
    and it will all be done in software. For a few extra bucks, you can buy
    a sampler that reconstructs any guitar sound you want.
    
    The only limit is s/n.
    
    							John.

    re -1
    
    yeah? so 'scuse my ignorance...but ah what is a "DSP"?
    
    does s/n mean signal to noise?
    
    "sakman" 

    DSP = Digital Signal Processor...And S/N is the ratio of signal to
    noise... FYI

    Not only that but you can have at the push of a button:
    
    Satriani's Marshall
    Vai's Marshall
    Vaughn's Fender
    
    Etc, etc, etc, ad infinitum. Believe it or not, the prices are crossing
    the threshold where it will be cheaper to emulate many excellent amps
    than it will be to own just one.
    							John.

    
    
    	Vaughan's Fender.... Naaaawww! If I could find a zister amp that
    would sound like that, I'd buy... ummmmm... 
    
    
    
    	Ten or twelve of em'
    
    
    Steve

    Yo Grevie-dude,
    
    I got Vaughans Fender amp tone in my little 1 rack space Mp1.
    check out the preset swap note.  It might not be "perfect"
    but it's DAMN close.  I can get a similar tone on my Quattro
    too.
    
    jc

    re: .-1
    
    I didn't really think it sounded very much like SRV.  It's a cool sound
    though.  
    
    Greg

    Well, I don't much about his tone...  ;0
    
    It just didn't sound "clean and processed" as much, ya know ?
    
    Kinda raunchy.

    Just 'cuz thats's what the preset's named, ain't always what it is ! 8^)
    
    My GP-8 has several "heavy metal" patches .... nope ... but I certainly
    built a few !
    
    Scary ...

    
    	Only SRV had SRV's tone...  Sheesh Coop.

    Gotta remember - he played a Strat, so who in their right mind would
    want his tone anyway ....   8^)
    
    Scary 

    pull the pin, lob it in, and wait for the explosion, eh ?
    
    Mark 
    
    I'm not touching this one.

    
    How about a word from SRV himself on his tone?
    
    from December, 1990 GUITAR WORLD, p. 89
    
    "I record guitars in a way that is real unorthodox.  A lot of people
     just play thorugh a single amp.  That's not how I play as a rule.
     Sometimes I'll have a Super Reverb, and a Roland Jazz Chorus
     three feet away from it.
    
     I tend to use different amps for different things.  For example, 
     on some things I used a Groove Tube preamp, and in a way, it
     sounded neat by itself.  But the Groove Tube sounds better if it's
     mixed in with the Roland that sounds real clean and a Bassman and
     a Marshall. 
    
     Sometimes I used two Tube Screamers tied together.  You usually
     don't use a distortion unit to drive a distortion unit to drive an
     amp, but I'll try anything."
    
      ________________________________________________________________
    
    Of course, there's only several thousand dollars of equipment
    referenced here.  Have your roadies bring it in for you...
    
    Brian
    

re: transister amps sounding "close"

Right.  That's about it -- close.

I don't put out that kind of money for "close."

Will