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Basically, treat them like the lamp in a projector, or in fact any tungsten light bulb...
Originally Posted by Little Jay
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03-15-2022 08:26 AM
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I don't think so. Originally Posted by pingu
This is correct, like for example the iconic Fender 5E3 Deluxe. Originally Posted by EastwoodMike
The concept of the "negative feedback loop" (NFB) can be summarized as follows:
- A portion of the output to speaker signal is inverted (phase reversed) and sent back to the power amp input. When the inverted feedback signal blends with the power amp input signal it cancels/attenuates the corresponding frequencies. The affected/canceled frequency range is defined by a RC filter (Resistor, Capacitor). NFB is typically implemented to attenuate mids and lows for the purpose of reducing distortion and noise. It's a mandatory feature in a Hi-Fi stereo amplifier. When implemented in an instrument amplifier we get the mid scooped sound generally referred to as the "Blackface sound".
- NFB amps are perceived having more head room, because they won't distort until the volume knob is near max. Non-NFB amps tend to be louder, looser (more bass and lower mids) and with a smooth transition of distortion.
- NFB enables "Presence control". Presence on 12 means that lower mids are fully scooped out, producing a trebly "ice pick sound" (you need ear protection). Contrary to popular belief; Presence on 0 does not mean that the NFB loop is bypassed. A portion of the lows will always be scooped out when NFB is implemented with or without a presence knob and regardless of presence setting. Hence NFB amps are inherently bright in comparison.
- Reverb (an invention by Les Paul) has nothing to do with NFB, but at the time Fender first implemented reverb, all Fender amps had NFB. Meaning that any original Fender circuit with reverb is a black- or silver face amp. Many guys have preferred blackface amps for no other reason they just wanted reverb.
- The BMT (Bass, Middle, Treble) tonestack is notorious for scooping out mids, meaning that when the signal hits the power amp, it's bright already. Then NFB does its thing, removing whatever is left of your original guitar signal. The result: A crystal clean, spanky, twangy chicken picking country tone (Yee haw!), or; a dripping wet and shimmering surf sound ala 60th guitar pop. With a little luck and some serious tweaking sometimes one can get a descent Jazz tone as well
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Is the negative feedback (NFB) loop in a tube amp the same as the negative current feedback circuit in a SS amp? Don’t think so?
I read SS amps need NFB to function. Tube amps do not, they just use it to keep noise levels lower but function perfectly well without it (arguably better say some).
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ok I accept that Neg FB isn’t
part of the elusive tube magic
because many good and desirable
tube amps designs don’t have it
(I'm learning here not preaching)
So what is the magic ?
not the transfer function of the tube itself ,
because that can and has been copied
faithfully by amp modelers etc
and yet tubes appear still have
something else going on ....
any ideas ?
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Negative feedback is part of the elusive magic of black face amps, but I will tell you what is quite useful is to have a negative feedback control. This lets you go from BF tone to a more open and raw tone with more mids. My Fat Jimmy amp has this and it's great.
In terms of the magic, I don't know, it is probably a sum of the different gain stages and the transformer and its relationship to the speaker. I do know that the quality of the OP transformer is crucial, if you post an OP in a vintage amp and replace with new, the sound is much different.
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Dont forget as well power supply sag and the impact of solid state vs valve rectifier recovery… Originally Posted by bluejaybill
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but all those things are easy to
model and have been modelled
many times
and still we seem to prefer
the actual tube amps
i’ve lost count of the number of times
in interviews I’ve heard something like
“oh yes I use the Kemper (or whatever modeller ) and it works ok/fine for the show but I’d rather have my amp on stage”
then there’s Jack’s experiences to
that effect too
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There is no magic, just woo.
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I’m not convinced that this is true. The only way to know is to build a pair of identical-appearing amps, one with a tube chassis inside and one with a modeler, and to let players who don’t know which is which play their guitars through both. Then see if they can consistently identify which one has tubes. Originally Posted by pingu
This is an age old dilemma. Can Eric Johnson really tell the brand of battery in an effects pedal? Can an audiophile consistently identify a $500 power cord or speaker cable against zip cord? Most “experts” avoid the issue by claiming that blinded testing is invalid. I don’t see how or why it would be, if properly done. I strongly suspect that’s just an excuse to avoid being put to the test.
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I'm repeating myself. Solid state amps have existed for decades before digital signal processing became commonplace. A Fender solid state combo has been the starting point for thousands and thousands of players. Let's forget modeling amps for a while and take today's "plain" solid state amps as they come: Quilter, DV Mark, Milkman, BluGuitar, H&K, AI, Raezer's Edge, Seymour Duncan... It's obvious that the designs have graduated from entry-level cheapos into pros' gigging tools of choice. Many but not all are based on the ICEPower power source/power amp module. A self-respecting pro still goes sound first, but logistics, cost and reliability also factor in. Cork-sniffing less or not at all. My admittedly pedestrian guitarist "career" started in the mid-'60s and I've had only four tube amps for brief periods, Peavey Classic 30 and Fender's HRDL, Excelsior and SCXD. I can't say I miss any of them. Last night I tested a pair of TOOB 12Rs headed for Hungary. Powered by a DV Mark Micro 50M (i.e. 60W @ 4 ohm), they sounded absolutely huge on jazz humbucker, single-coil and electric 12-string. My ears are still ringing. No need for "magic", "mojo" or "vintage" there.
Last edited by Gitterbug; 03-16-2022 at 05:26 PM.
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For clean sounds , I totally agree
that the current SS technology is totally
there ....
but for dirt on Solid State amps
How would Brian May sound ?
Angus
Jimi ?
How about a roaring B3 ?
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None of my business.
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But most O/D and distortion effects are solid state and most name players whose sounds are distortion-driven use them. Far more metalheads and rockers praise "germanium transistor" distortion than tubes, and the biggest selling effects of all time are Tube Screamers and clones. Cobain usually used a SS Randall head. When he used a Twin, he drove it with a Boss DS-1. Jimi used a Fuzzface, which was the in-demand germanium device of its kind and is in "reissue" mode today. Originally Posted by pingu
As for the B3, most of today's Leslie cabs have SS amplifiers in them, and nobody notices or cares because they sound fabulous and have a "drive" knob that's simply a SS effect control. Even their flagship model (the 3300), which is what I use, has a hybrid amplifier with a tube input stage and a 300W power amp. A few of the current models have full SS amplification, and only one or two still use a small tube amplifier like the ones in the originals (today rated at 50W). The Leslies of the '40s and '50s had very low power amplifiers by today's standards. I think the first ones were about 10 watts, although they were well designed and well integrated with the speakers - so they were amazingly loud for their power rating. Still, they distorted naturally because you couldn't make a Leslie scream without pushing it to its limits and those limits were established by the power amp's limitations.
The roaring B3 to which you refer offers a double blinded test of sorts. Many players and most listeners think they're hearing an all tube amplifier when they hear a B3 through a Leslie. If you ask them, they'll tell you that they far prefer tubes and point to the B3 / Leslie setup as an example. They're wrong on both counts - they don't actually know what they prefer and they don't know to what they're listening. Further, modern Hammonds and Leslies like my XK5 Pro and 3300 are far more reliable than the originals. I played keys for Larry Garner at the Hudson River Park Blues Festival some years ago, and they rented a B3 and a huge Leslie from New York's premier source. As we were warming up, the organ went silent on me. Before I could even get my blood pressure up too high, a guy runs across the stage and starts taking off the back. I said "Who are you?" and he responded that original B3s and Leslies are fragile and prone to failure even when perfectly restored and maintained (which this one was) - so the rental company sends a tech with every one they put on stage. He fixed it in about 3 minutes, and it was one cool show - but we'd all have been happier and better off with a new XK5, for a lot less money.
Here I am, nursing the recovering patient through a great set on a blisteringly hot day -
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ok I’ll take that on
The transistor based pedals that
the rock and metal guys use are
almost always driving a tube amp into
distortion ....
I didn’t know that about Kurt Cobain
sound being SS
(he’s an outlier then)
are you saying the modern Hammonds
with SS Lesley cabs can roar and scream like the old tube ones ?
if so can you post an example ?
I genuinely haven’t heard that
But If the chorus of ‘smells like team spirit’
was SS then I think you win this debate !
A huge massive Sound ....
ps
I was walking through the TOTPs studio
when I first heard that tune coming over the PA and I remember thinking
”well that blows everything else clean
out of the boat”
Rock + Punk energy
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Are you mixing op amps with SS amps? Originally Posted by Little Jay
Transistor amps can be made without NFB (I'm not sure if it is common though?), but op amps need NFB to function as signal amplifiers.
Conceptually/theoretically it is the same thing. (but maybe not from a guitar perspective in the way that you can take a valve amp and add a NFB switch or pot to it and it will give you usable sounds both with and without feedback).Is the negative feedback (NFB) loop in a tube amp the same as the negative current feedback circuit in a SS amp? Don’t think so?
In both cases it reduces gain, but improves bandwidth and linearity.
For guitarists gain often means distortion/dirt/etc but in this context it is the amount of amplification. Increased bandwith and linearity means that the amp is more even across the frequency and dynamic spectrum.
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Hi, Pingu!
Those tube amps simply amplify - cleanly - the distortion added to the input signal and stage. It’s not power tube clipping. And you’re hearing modern Hammonds and Leslies all over the place - you just don’t recognize them because they sound so good. Even the B3 patches in my Roland guitar synth are decent. I once played a blues gig at a nice club called the Bubba Mack Shack (now sadly closed) where there was (unexpectedly) an old B3 and Leslie on stage. When I fired it up and checked it out, the band told me to use my guitar and synth because it sounded better to them than the organ.
Here's Roger Smith with Tower of Power last Sunday night.
I'm pretty sure that's the same Hammond XK5 Pro that I play at our club. His Leslie was behind him so I couldn't see it clearly - but from the size and character, I think it's a 3300. I don't think they made the PortaB in a wood case - but even if that's what it is, it's not a mechanical device any more. It's digital and it's great! Here's Hammond's own capsule description of what you get today:
I do bristle a bit at the use of the word "authentic" in refence to a digital Leslie.Last edited by nevershouldhavesoldit; 03-16-2022 at 12:47 PM.
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If I may venture an opinion, based on nothing more than experience:
The "magic' and the "mojo" are the result entirely of, as Pierre was wont to say, "Time on the Instrument" - with "instrument" understood as the Guitar/Amp/Human melding. The living sensorium of the player takes in all inputs and makes such adjustments as are necessary to achieve the desired result in real time -actual knob twisting and switch flicking being only the most general manifestations, and accounting merely for ballpark effects, with by far the greater precision in the realm of actual physical manipulation of the vibratory apparatus.
TL,DR: Tone is in the hands, in a manner of speaking.
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@ nevershouldhavesolidit - your remark about metal guys using clean amps with distortion coming only from a pedal is certainly not always true. The Mesa series of amps is very popular with tock and metal players (eg Metallica). They began as modified Fenders, with extra tubes added at the pre-amp stage. So yeah, the distortion doesn't come from power amp clipping, but rather from pre-amp distortion, with several gain stages employed. Some folk will add a boost pedal or tube screamer to the front to further increase the gain. But I understand (and, full disclosure, this is from seeing how folks on the Axe FX forum set up their virtual rigs) that the tube screamer is commonly used without adding any distortion of its own but as both a clean boost and an EQ.
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I agree - it's not always true. But it's true more often than not, and I'm always amazed to find out that a cheap pedal was used on a major recording. Stevie Ray used a Boss SD-1 to record Pride and Joy. Prince used a Boss Blues Driver on Purple Rain. The list is endless, and most studio recordings are not made with Marshall stacks on 11. Originally Posted by CliffR
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At band rehearsal last night I got the best on-stage jazz guitar sound I have ever gotten. I plugged my Ibanez GB10 into a SansAmp Para Driver DI into the mixing board and from there to a QSC FRFR powered speaker. Boom. Even without reverb, it sounded fantastic. Tweaking the EQ was trivial and the whole process was so stupidly simple to get up and running that even I could do it, despite knowing almost next to nothing about mixers and sound reinforcement. The difference was amazing compared to the Line6 modeling amp provided in the rehearsal space (Walker West Academy in St. Paul MN, for those familiar). Dispersion compared to the beamy tendencies of a guitar amp was also amazing.
I may never use an amp on-stage again if there is a PA that I can try plugging into directly. The SansAmp is a great tool.
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I think the reverb was done by the room. Volume is an extremely influential thing. But I’m quite stoked to hear this and I feel quite stupid for selling of my sansamp blonde 5 years ago. Originally Posted by Cunamara
Sent from my iPhone using Tapatalk
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Interesting and very helpful - thanks! At tomorrow night's show by my jazz trio, I'm going to try running my archtop through my ART preamp DI to the house board. We have a killer triamped house system with 18" bass bins and serious QSC mids and tweeter arrays: Originally Posted by Cunamara
Now that we all wear IEMs, it should be great. I'll report back!
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Our late longtime organist used a chop B3 and two 122 Leslies for yrs he got in trade w Joey D for Herbie Nix's old ebony B3 and Leslie that had been soaking in water when Winston's in Camden NJ burned down (Joey restored it and it's one of his favorites) Originally Posted by nevershouldhavesoldit
But most O/D and distortion effects are solid state and most name players whose sounds are distortion-driven use them. Far more metalheads and rockers praise "germanium transistor" distortion than tubes, and the biggest selling effects of all time are Tube Screamers and clones. Cobain usually used a SS Randall head. When he used a Twin, he drove it with a Boss DS-1. Jimi used a Fuzzface, which was the in-demand germanium device of its kind and is in "reissue" mode today.
As for the B3, most of today's Leslie cabs have SS amplifiers in them, and nobody notices or cares because they sound fabulous and have a "drive" knob that's simply a SS effect control. Even their flagship model (the 3300), which is what I use, has a hybrid amplifier with a tube input stage and a 300W power amp. A few of the current models have full SS amplification, and only one or two still use a small tube amplifier like the ones in the originals (today rated at 50W). The Leslies of the '40s and '50s had very low power amplifiers by today's standards. I think the first ones were about 10 watts, although they were well designed and well integrated with the speakers - so they were amazingly loud for their power rating. Still, they distorted naturally because you couldn't make a Leslie scream without pushing it to its limits and those limits were established by the power amp's limitations.
The roaring B3 to which you refer offers a double blinded test of sorts. Many players and most listeners think they're hearing an all tube amplifier when they hear a B3 through a Leslie. If you ask them, they'll tell you that they far prefer tubes and point to the B3 / Leslie setup as an example. They're wrong on both counts - they don't actually know what they prefer and they don't know to what they're listening. Further, modern Hammonds and Leslies like my XK5 Pro and 3300 are far more reliable than the originals. I played keys for Larry Garner at the Hudson River Park Blues Festival some years ago, and they rented a B3 and a huge Leslie from New York's premier source. As we were warming up, the organ went silent on me. Before I could even get my blood pressure up too high, a guy runs across the stage and starts taking off the back. I said "Who are you?" and he responded that original B3s and Leslies are fragile and prone to failure even when perfectly restored and maintained (which this one was) - so the rental company sends a tech with every one they put on stage. He fixed it in about 3 minutes, and it was one cool show - but we'd all have been happier and better off with a new XK5, for a lot less money.
Here I am, nursing the recovering patient through a great set on a blisteringly hot day -
That chop sounded spectacular, it was a parts organ, manual from an A100, guts from a B3 etc.
He eventually switched to an XK3-C and 3300 Leslie for the last 10 yrs of his life. A great sounding rig for sure and much more portable of course but not as good sounding as his old one.
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Dave, imo Jamey should take some of that stuff off the stage so you guys can move around, it isn't Woodstock in there
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Looks like we have some Quilter (Sound Company) fans here :-)
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