Why don't you send me your V-Bass and I'll do some lengthy test on that. This way you have got all the time you need to concentrate on your great speaker designs...
Deal ?
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Tech21 VT-Bass - where's the magic ?
- Thread starter OldogNewTrick
- Start date
Why don't you send me your V-Bass and I'll do some lengthy test on that. This way you have got all the time you need to concentrate on your great speaker designs...
Deal ?
Not really. I think it's the way of counting the harmonics.
500Hz Fundamental - 1000Hz. 1st harmonic, odd - 1.500Hz 2nd harmonic, even - 2.000Hz. 3rd harmonic, odd - 2.500Hz 4th harmonic even... and so on...
So in the Fat Tube setting you see the even harmonics heavily emphasized.
As you crank the Drive control you see them even out ant the odd harmonics take over past 12 o'clock into the overdrive
Any tube driven into saturation will "soft clip" the signal, thereby causing it to compress a bit. I find the VT-Bass is simulating this effect quite nicely.
The Carl Martin is really a different animal altogether. It add basically nothing. Its a flexible semi-parametric 3 band EQ with a post EQ gain stage.
the 0 dB green line is the sound system calibration result. the brown -10 dB line is the pedal on bypass.
the 300Hz sine wave in purple is on bypass, the yellow is the preamp engaged. Nothing added at all.
The 50Hz spike is an AC hum (Europe, remember 50Hz AC) the harmonics at 600 and 900Hz, no idea where they are from... might be the AD converter or my soundcard... anyhow, its at-85dB, which is pretty decent overall....
here some more plots of the "clean channel"
Mids adjustments range
1st is the fundamental 500hz
2nd is 1000hz
http://en.wikipedia.org/wiki/Harmonic
So in the Fat Tube setting the odd harmonics are heavily emphasized.
You are absolutely right, this is the current convention and correct. However back then from where the sentiment of tube amps emphasize the even harmonics, SS the odd harmonics stem from, you did not count the fundamental as 1st harmonic. The fundamental was just that, the harmonics sat on top.... we meant overtones and said harmonics... Hence my reference to the way of counting....
Those odd harmonics as shown in your charts and as described on wikipedia will when added together form a square wave. They really are "odd harmonics" that are being emphasized by the big "tube" sound of the VTbass. They have always been called odd harmonics. The original odd/even statement refers to low powered class-A amplifiers. It never refered to big power amps.
Ya. I've heard that before, but I'm telling you my SVT is the cleanest amp I've ever played. If it's distortion, it's distortion that makes it sound very clean.
Compared with the preamp in my modded Eden (with the latest high performance op amps), the SVP-Pro has a certain roundness and dynamic "give" to it. Thinking I might sell it after the VT Bass arrives. My guess is that what sounds to some as subjectively clean may not actually be low in distortion.
I might be able to buy that explanation, but don't mistake the SVP Pro for an all-tube Ampeg. Whole different world when you add in power tubes.
- Dec 18, 2000
- 13,201
- 340
- Disclosures
- greenboy designs: fEARful, bassic, dually, crazy88 etc
The terms harmonic, partial, overtone, all get mixed and the idea then becomes mangled. I often type a few extra words just to avoid that confusion, like "the overtone one octave above" when it aids the text. Unfortunately when discussing even-order and odd-order it still is tough to make sure people know exactly what is being referred to, further fogged by a lot of spew on the web.
But graphs themselves when you can actually see the reference points, make it a lot clearer. Showing some instrument preamps using tubes and some tube heads at various levels of signal input/drive and output gain would be illuminating.
Related thread with frequency response plots: http://www.talkbass.com/forum/showthread.php?p=7987232
after all my earlier theorizing, I guess I should also provide a mini review.
This pedal (and any other piece of gear) is a different thing to everybody. My review pertains only to my circumstances (see my profile), but I guess there might be a few people around here, who might relate to this perspective.
I have used the pedal now for a week, or so, in 2 basic setups.
Bass-> {(on true bypass) L6 BodXT ->} VT-Bass -> Carl Martin ParaEQ into either KME studio poweramp or into a Fender Dual Showman.
Tone goals:
Ever since my encounter with the GenzBenz Shuttle Max 12 I had this scenario in mind.
A switchable/blendable setup with a SS side as dry and fast as a Markbass F500 for slap / finger-funk and a tubey side for classic Ampeg sounds for rock and blues from warm, round to slightly overdriven with a bit of edge.
With the sqeaky clean KME studio poweramp. The combination of Carl Martin pre and VT-Bass works out out just as hoped for. The combination provides a huge amount of available sounds.
A different story with the Dual Showman. Just using the "Normal" channel I am already 85% there, but it is too clean. Adding just that bit of VT to it does it very nicely. That said, jumpering both channels brings out that edge as well. So the use of the VT is strictly speaking not essential to getting sufficiently close to my (tube) tone goals.
I have noticed a significant improvement when running through the L6 BodXT. Adding those harmonics from the VT-Bass, the dull and lifeless tone of the BodXt comes alive. I did not find any need / benefit using the amp & cab modeling. Between my clean CM Pre and tubey VT-Bass I have been able to dial up every tone that I wanted to achieve. However when I couldn't stand the effects modeling, now I find a number of effects quite acceptable and fun to use.
Lastly, my Clover XP15.5 loves the VT-Bass, it really improves the tone, providing with pickuzp combinations a number of great options. The Ibanez Rick benefits in the KME setup from the added harmonics, bringing out that ringing roundwound Rick tone in a very satisfying way. Not necessary at all with the Dual Showman, Rick and all tube amp is a great match.
My Human Base Daily5 fretless benefited the least from the VT, being happiest with the pure and clean sounds of the Carl Martin, maybe with just a touch of added harmonics from the VT.
To cut a long rant short, yes, me likes...
This pedal (and any other piece of gear) is a different thing to everybody. My review pertains only to my circumstances (see my profile), but I guess there might be a few people around here, who might relate to this perspective.
I have used the pedal now for a week, or so, in 2 basic setups.
Bass-> {(on true bypass) L6 BodXT ->} VT-Bass -> Carl Martin ParaEQ into either KME studio poweramp or into a Fender Dual Showman.
Tone goals:
Ever since my encounter with the GenzBenz Shuttle Max 12 I had this scenario in mind.
A switchable/blendable setup with a SS side as dry and fast as a Markbass F500 for slap / finger-funk and a tubey side for classic Ampeg sounds for rock and blues from warm, round to slightly overdriven with a bit of edge.
With the sqeaky clean KME studio poweramp. The combination of Carl Martin pre and VT-Bass works out out just as hoped for. The combination provides a huge amount of available sounds.
A different story with the Dual Showman. Just using the "Normal" channel I am already 85% there, but it is too clean. Adding just that bit of VT to it does it very nicely. That said, jumpering both channels brings out that edge as well. So the use of the VT is strictly speaking not essential to getting sufficiently close to my (tube) tone goals.
I have noticed a significant improvement when running through the L6 BodXT. Adding those harmonics from the VT-Bass, the dull and lifeless tone of the BodXt comes alive. I did not find any need / benefit using the amp & cab modeling. Between my clean CM Pre and tubey VT-Bass I have been able to dial up every tone that I wanted to achieve. However when I couldn't stand the effects modeling, now I find a number of effects quite acceptable and fun to use.
Lastly, my Clover XP15.5 loves the VT-Bass, it really improves the tone, providing with pickuzp combinations a number of great options. The Ibanez Rick benefits in the KME setup from the added harmonics, bringing out that ringing roundwound Rick tone in a very satisfying way. Not necessary at all with the Dual Showman, Rick and all tube amp is a great match.
My Human Base Daily5 fretless benefited the least from the VT, being happiest with the pure and clean sounds of the Carl Martin, maybe with just a touch of added harmonics from the VT.
To cut a long rant short, yes, me likes...
great thread !!
... i'm getting my first and only pedal for Christmas ,
and it's going to be the Tech21 VT-Bass !!
... i'm getting my first and only pedal for Christmas ,
and it's going to be the Tech21 VT-Bass !!
I've used the Tech 21 stuff for about the last 5 years in my bass rig after years of using various tube amps. From my observation the Tech 21(RBI) tends to sound more like a whole amp, pre and power section whereas something like the SVP Pro tended to sound more like a preamp.
I think where all this is important is that in most real amps the preamp tends to produce even order distortion because you're running a triode into clipping on one half of the wave and then you add gain between the stages and then clip the other side of the wave and asymmetrical clipping produces even order harmonics.
Power amps are usually push pull designs which when clipped tend to clip both sides of the waveform at the same time and in the same way which tends to produce odd order harmonics.
While even order harmonics tend to give the amp fullness too much can make it sound muddy and indistinct. Odd harmonics tend to make the sound seem hollowed out but also give it sharpness and edge and the ability to cut through a mix. The trick is to have some of BOTH types of distortion in about the right amounts in order to give what most folks tend to think of as a nice all around tonality.
I've looked around and found a couple of SansAmp schematics on the net and I think that most of their products revolve around very similar basic circuits which are then tuned up for various specific uses such as this pedal.
I think where all this is important is that in most real amps the preamp tends to produce even order distortion because you're running a triode into clipping on one half of the wave and then you add gain between the stages and then clip the other side of the wave and asymmetrical clipping produces even order harmonics.
Power amps are usually push pull designs which when clipped tend to clip both sides of the waveform at the same time and in the same way which tends to produce odd order harmonics.
While even order harmonics tend to give the amp fullness too much can make it sound muddy and indistinct. Odd harmonics tend to make the sound seem hollowed out but also give it sharpness and edge and the ability to cut through a mix. The trick is to have some of BOTH types of distortion in about the right amounts in order to give what most folks tend to think of as a nice all around tonality.
I've looked around and found a couple of SansAmp schematics on the net and I think that most of their products revolve around very similar basic circuits which are then tuned up for various specific uses such as this pedal.
All bass guitar waveforms I've seen are symmetric. These waveforms can be viewed in any sound editing software. Therefore when played through a clipping power amp will clip it asymmetrically.
All this talk on even versus odd harmonics is easy to measure these days. I hope to see more measurements as have been given here early in the thread.
wow! you guys have too much time on your hands.
I just set the right priorities... 
Planet Boulder
Hey, this is a private residence...man
- Nov 10, 2001
- 4,014
- 65
- Disclosures
- I once had impure thoughts. Oh, and I pluck my ear hair.
