>On 4/8/12 3:18 PM, HardySpicer wrote: >> >> The beauty of guitar amps is that the more distortion the better! > >i don't think it's as simple as that. > >Marshall put out some solid-state amps in the 70s and 80s that sounded >like canine feces. > >because it has been difficult to emulate exactly what the various tubes >are doing (and other parts, like output transformers with hysteresis), >it has been difficult to get the kinda soft distortion morphing into the >wonderful power chord distortion that we could get from tube amps from >Marshall or other manufacturers (like the Fender Twin Reverb or the Mesa >Boogie). > >it gets very complicated when the distortion is applied to chords with >non-harmonic notes, because then the intermodulation distortion gets >messy. play a nicely tuned major chord and it comes out okay, but play >a minor chord and it comes out muddy. > >even when distortion is what you're looking for, not all distortions are >equal and it's such a multi-dimensional problem (with both non-linear >and non-memoryless components; Volterra series anyone?) that it's hard >to get something good without experimentation, alchemy, and luck.Most of the DSP amp modellers seem addicted to blindly modelling every little aspect of what famous tube amps do, like the sag on loud notes due to the relatively high impedance of a tube rectifier. I'm surprised there isn't at least one modelling developer who has tried to take the best of what tubes do, and avoid the bad stuff - like using 6 sensors for the 6 strings, and separately processing the notes, so any chord with any amount of distortion comes out right. It would make an electric as polyphonic as an acoustic instrument. Steve
RIP Jim Marshall
Started by ●April 5, 2012
Reply by ●April 8, 20122012-04-08
Reply by ●April 8, 20122012-04-08
robert bristow-johnson wrote:> On 4/8/12 3:18 PM, HardySpicer wrote: >> >> The beauty of guitar amps is that the more distortion the better! > > i don't think it's as simple as that. > > Marshall put out some solid-state amps in the 70s and 80s that sounded > like canine feces. >... and some that didn't. Broadly, the MOSFET Marshalls weren't bad. As in all things, it depends on how they are used.> because it has been difficult to emulate exactly what the various tubes > are doing (and other parts, like output transformers with hysteresis), > it has been difficult to get the kinda soft distortion morphing into the > wonderful power chord distortion that we could get from tube amps from > Marshall or other manufacturers (like the Fender Twin Reverb or the Mesa > Boogie). >A Twin driven into distortion would sterilize lab animals...> it gets very complicated when the distortion is applied to chords with > non-harmonic notes, because then the intermodulation distortion gets > messy. play a nicely tuned major chord and it comes out okay, but play a > minor chord and it comes out muddy. > > even when distortion is what you're looking for, not all distortions are > equal and it's such a multi-dimensional problem (with both non-linear > and non-memoryless components; Volterra series anyone?) that it's hard > to get something good without experimentation, alchemy, and luck. > >-- Les Cargill
Reply by ●April 8, 20122012-04-08
steveu wrote:>> On 4/8/12 3:18 PM, HardySpicer wrote: >>> >>> The beauty of guitar amps is that the more distortion the better! >> >> i don't think it's as simple as that. >> >> Marshall put out some solid-state amps in the 70s and 80s that sounded >> like canine feces. >> >> because it has been difficult to emulate exactly what the various tubes >> are doing (and other parts, like output transformers with hysteresis), >> it has been difficult to get the kinda soft distortion morphing into the >> wonderful power chord distortion that we could get from tube amps from >> Marshall or other manufacturers (like the Fender Twin Reverb or the Mesa >> Boogie). >> >> it gets very complicated when the distortion is applied to chords with >> non-harmonic notes, because then the intermodulation distortion gets >> messy. play a nicely tuned major chord and it comes out okay, but play >> a minor chord and it comes out muddy. >> >> even when distortion is what you're looking for, not all distortions are >> equal and it's such a multi-dimensional problem (with both non-linear >> and non-memoryless components; Volterra series anyone?) that it's hard >> to get something good without experimentation, alchemy, and luck. > > Most of the DSP amp modellers seem addicted to blindly modelling every > little aspect of what famous tube amps do, like the sag on loud notes due > to the relatively high impedance of a tube rectifier. I'm surprised there > isn't at least one modelling developer who has tried to take the best of > what tubes do, and avoid the bad stuff - like using 6 sensors for the 6 > strings, and separately processing the notes, so any chord with any amount > of distortion comes out right. It would make an electric as polyphonic as > an acoustic instrument. > > Steve >Some modellers are better than others. I've been quite happy with the fender Super Champ XD, which has fairly modest models and uses a pair of 6V6 as a filter... Guitar Rig Pro is serious stuff... -- Les Cargill
Reply by ●April 8, 20122012-04-08
By the way, I've always wondered how Marshall came up with his wattage rating system. Matt's Marshall was a "Marshall 50" or 50 watts, but that's the loudest 50 watts I ever heard. ---RY Randy Yates <yates@digitalsignallabs.com> writes:> Jerry Avins <jya@ieee.org> writes: > >> http://www.sfgate.com/cgi-bin/article.cgi?f=/n/a/2012/04/05/international/i060752D77.DTL&tsp=1 > > Thanks for the news, Jerry - I hadn't heard. > > "Marshall was proud that he resisted suggestions that he shift all > production outside of England to save costs." > > Excellent! Seems like he was one of Britain's finest! > > By the way, my old high-school rock band guitarist Matt Dillon (now CEO > of Dillon Production out of Atlanta, > > http://www.dillofnproduction.com/aboutus.html > > used one at the time. I had a Leslie 910 with a combined output of 100 > watts. He (and the rest of the band) played so loud at times that I > could be completely saturating (overdriving) that Leslie and not even be > heard!-- Randy Yates DSP/Firmware Engineer 919-577-9882 (H) 919-720-2916 (C)
Reply by ●April 8, 20122012-04-08
On Sun, 08 Apr 2012 18:50:35 -0500, Randy Yates <yates@digitalsignallabs.com> wrote:>By the way, I've always wondered how Marshall came up with his wattage >rating system. Matt's Marshall was a "Marshall 50" or 50 watts, but >that's the loudest 50 watts I ever heard. > >---RYI suspect that a saturating amplifier will sound louder than a linear amplifier because of the higher average power. With the peak power in each the same a saturated signal will have a higher average power than one held in the linear region of the amp. It's the same reason commercials appear "louder" on TV than other content, even though the regulated "peak power" is the same.> >Randy Yates <yates@digitalsignallabs.com> writes: > >> Jerry Avins <jya@ieee.org> writes: >> >>> http://www.sfgate.com/cgi-bin/article.cgi?f=/n/a/2012/04/05/international/i060752D77.DTL&tsp=1 >> >> Thanks for the news, Jerry - I hadn't heard. >> >> "Marshall was proud that he resisted suggestions that he shift all >> production outside of England to save costs." >> >> Excellent! Seems like he was one of Britain's finest! >> >> By the way, my old high-school rock band guitarist Matt Dillon (now CEO >> of Dillon Production out of Atlanta, >> >> http://www.dillofnproduction.com/aboutus.html >> >> used one at the time. I had a Leslie 910 with a combined output of 100 >> watts. He (and the rest of the band) played so loud at times that I >> could be completely saturating (overdriving) that Leslie and not even be >> heard! > >-- >Randy Yates >DSP/Firmware Engineer >919-577-9882 (H) >919-720-2916 (C)Eric Jacobsen Anchor Hill Communications www.anchorhill.com
Reply by ●April 8, 20122012-04-08
eric.jacobsen@ieee.org (Eric Jacobsen) writes:> On Sun, 08 Apr 2012 18:50:35 -0500, Randy Yates > <yates@digitalsignallabs.com> wrote: > >>By the way, I've always wondered how Marshall came up with his wattage >>rating system. Matt's Marshall was a "Marshall 50" or 50 watts, but >>that's the loudest 50 watts I ever heard. >> >>---RY > > I suspect that a saturating amplifier will sound louder than a linear > amplifier because of the higher average power. With the peak power in > each the same a saturated signal will have a higher average power than > one held in the linear region of the amp.Yeah, but you can create a saturated signal by simply overdriving the amplifier, whether it is rated 50 watts or 100 watts or whatever. That is, I would think a 50 watt Fender driven into saturation would sound just as loud as a 50 watt Marshall, but that didn't seem to be the case. Perhaps the reason is that the Marshall power amplifiers had a lower output resistance and so adding more cabinets (in parallel) actually did result in more power. I'm pretty sure the Marshall PAs could be configured with either one or two speaker cabinets, and I think I remember something about the power increasing with the number of cabinets even though the head (PA) didn't change. -- Randy Yates DSP/Firmware Engineer 919-577-9882 (H) 919-720-2916 (C)
Reply by ●April 9, 20122012-04-09
On 4/8/12 4:45 PM, steveu wrote:> > Most of the DSP amp modellers seem addicted to blindly modelling every > little aspect of what famous tube amps do, like the sag on loud notes due > to the relatively high impedance of a tube rectifier.it's an effect. why not model it.> I'm surprised there > isn't at least one modelling developer who has tried to take the best of > what tubes do, and avoid the bad stuff - like using 6 sensors for the 6 > strings, and separately processing the notes,we call that a "hex pickup" guitar. and they be doing that, both for guitar synthesis control ( http://www.graphtech.com/products.html?CategoryID=2 , http://www.youtube.com/watch?v=VbFIpRNnqSI and the AXON and Roland synths), but those pickups are meant to go into pitch-to-MIDI converters, not so much to be listened to. this guy ( http://www.ubertar.com/hexaphonic/ ) makes hex pickups that are hot and meant to be listened to. i dunno how good his separation is, but i want to find out pretty soon.> so any chord with any amount of distortion comes out right.but sometimes you *want* some intermodulation distortion from the mix. you want to be able to control it.> It would make an electric as polyphonic as > an acoustic instrument.well, they sorta are anyway. aren't they? -- r b-j rbj@audioimagination.com "Imagination is more important than knowledge."
Reply by ●April 9, 20122012-04-09
>On 4/8/12 4:45 PM, steveu wrote: >> >> Most of the DSP amp modellers seem addicted to blindly modelling every >> little aspect of what famous tube amps do, like the sag on loud notesdue>> to the relatively high impedance of a tube rectifier. > >it's an effect. why not model it.Sure, but why not go in a more interesting direction if you are going to put that much effort in.>> I'm surprised there >> isn't at least one modelling developer who has tried to take the bestof>> what tubes do, and avoid the bad stuff - like using 6 sensors for the 6 >> strings, and separately processing the notes, > >we call that a "hex pickup" guitar. and they be doing that, both for >guitar synthesis control ( >http://www.graphtech.com/products.html?CategoryID=2 , >http://www.youtube.com/watch?v=VbFIpRNnqSI and the AXON and Roland >synths), but those pickups are meant to go into pitch-to-MIDI >converters, not so much to be listened to.Right. The necessary pickups are widely available, but normally just for driving a synth.>this guy ( http://www.ubertar.com/hexaphonic/ ) makes hex pickups that >are hot and meant to be listened to. i dunno how good his separation >is, but i want to find out pretty soon.I hadn't heard of those people. They sound interesting. There's still a lack of 6/7 channel signal processing to feed such a pickup into, though.>> so any chord with any amount of distortion comes out right. > >but sometimes you *want* some intermodulation distortion from the mix. >you want to be able to control it.If you start out with clean signal you can always add control intermods. Today you have no control.>> It would make an electric as polyphonic as >> an acoustic instrument. > >well, they sorta are anyway. aren't they?Not really. The last 50 years of development of electric guitar soloing technique has been of making sure things are played one note at a time. As you move from string to string, you heavily mute the old string, so the decay of the old note doesn't intermod with the new note. Wouldn't it be great to free the instrument from that constraint? playing shouldn't be governed by the clunkiness of the equipment, when that clunkiness is completely avoidable. Regards, Steve
Reply by ●April 9, 20122012-04-09
On 4/9/12 12:38 AM, steveu wrote:>...>> this guy ( http://www.ubertar.com/hexaphonic/ ) makes hex pickups that >> are hot and meant to be listened to. i dunno how good his separation >> is, but i want to find out pretty soon. > > I hadn't heard of those people.pretty much a single person named Paul.> They sound interesting. There's still a > lack of 6/7 channel signal processing to feed such a pickup into, though. >check out http://stringport.com/ but i wanna make something more self-contained.>>> so any chord with any amount of distortion comes out right. >> >> but sometimes you *want* some intermodulation distortion from the mix. >> you want to be able to control it. > > If you start out with clean signal you can always add control intermods. > Today you have no control. > >>> It would make an electric as polyphonic as >>> an acoustic instrument. >> >> well, they sorta are anyway. aren't they? > > Not really.well, they *are*, but there is some form of grunge that comes along with it.> The last 50 years of development of electric guitar soloing > technique has been of making sure things are played one note at a time. As > you move from string to string, you heavily mute the old string, so the > decay of the old note doesn't intermod with the new note. Wouldn't it be > great to free the instrument from that constraint? playing shouldn't be > governed by the clunkiness of the equipment, when that clunkiness is > completely avoidable.preaching to the choir, Steve. -- r b-j rbj@audioimagination.com "Imagination is more important than knowledge."
Reply by ●April 10, 20122012-04-10
On 4/6/2012 1:57 AM, Randy Yates wrote:> Jerry Avins<jya@ieee.org> writes: > >> http://www.sfgate.com/cgi-bin/article.cgi?f=/n/a/2012/04/05/international/i060752D77.DTL&tsp=1 > > Thanks for the news, Jerry - I hadn't heard. > > "Marshall was proud that he resisted suggestions that he shift all > production outside of England to save costs." > > Excellent! Seems like he was one of Britain's finest! > > By the way, my old high-school rock band guitarist Matt Dillon (now CEO > of Dillon Production out of Atlanta, > > http://www.dillofnproduction.com/aboutus.html > > used one at the time. I had a Leslie 910 with a combined output of 100 > watts. He (and the rest of the band) played so loud at times that I > could be completely saturating (overdriving) that Leslie and not even be > heard!Hi, Randy. In i952, I had a home-built Ultralinear Williamson rated at 20 watts. That rating was for 0.1% THD. I carried it to work one day in order to compare it with a friend's amp after work. When I got to the Port Authority Terminal (less than half the size it is now) there were people running around with megaphones making anouncements. Their PA amplifier had died. I lent the Williamson to the Info Desk, and it ran the whole terminal. Later I used it to modulate a 100W AM transmitter and got 100% modulation. I can't tell you what the distortion was at those levels were, but my ear suggested no more than 10%. To prove a point, I built an amplifier that clips at 12 volts when driving a 4- to 16-ohm load. It recovers from clipping in about half a microsecond, and the every-day equipment at RCA Labs couldn't measure any distortion at all below clipping. Using a good speaker (15-inch Tannoy), I could play music that would have had 20V peaks if the amplifier had allowed it, but even so, clipping was rarely audible. (It was clearly audible with a two-tone test signal, but not with symphonic program.) Hi-fi nuts used high power because any overload would "stun" the amplifier by upsetting the charges on the coupling capacitors, with a long settling time before sufficient recovery to get back to linear operation. My little demo amp (which I ended up using at home until I went stereo) was DC coupled to avoid all that. I wouldn't blink at the news that the Fender 50 could put out 150 or 200 watt peaks if distortion was no issue, and Lord knows, they were used with plenty of distortion. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
