VT pedal with my rack rig RTA observations

johnk_10 · #1 05-31-2010, 05:57 PM

since i finally broke down and bought a sansamp VT pedal, and have been experimenting with it with some of my rack rigs, i thought i'd run a few RTA tests on it to see exactly what it's doing to the frequency response before it hits the front end of my amp, since i really like the sound of this pedal.

here's the first RTA test, including bypassed, all controls set at 12:00 (with the exception of the drive control), and with the 'character' knob set at the minimum (fully CCW):

with all of the controls at 12:00, you can see that it has a large rise at around 3.8K and then rolls off very sharply. and with the character cut at its max, it places a large dip at around 800Hz, while also lowerring the high end but shifting its peak at little higher at 4.3Khz.

the next chart shows what happens when you set the character to its minimum but boost the mid knob to its maximum (orange line), and also boosting the bass control to its maximum (blue line):

This setting (blue line) shows the bass control's center frequency at around 80Hz and the mid control is now compensating for the mids cut by the character knob.

the last chart shows settings with the Bass and Treble set to the max (fully CW), the mid at noon, the green line with the character control at noon, and the violet line with the character fully CCW:

here you can see that things have shifted a little bit, where the bass control is now centered around 100Hz, the treble is around 3.8K to 4K, and the character knob having the most effect at around 750Hz.

i just though that i'd post this for anyone that would like to see a visual representation of what this pedal is doing before it hits the front end of your amp. for all of the tests, i did not use the drive control since it doesn't so much change the frequencies, but rather adds harmonic distortion to them.

if anyone has a setting that they use and would like to see it as an RTA plot, just let me know what your favorite settings are and i'll run it thru the RTA program.

bongomania · #2 05-31-2010, 06:13 PM

Cool! FWIW there was already a thread with RTA images of the VT... maybe this could be attached to that thread? Just so it's easier to find both sets when searching.

joeydavidson · #3 05-31-2010, 06:19 PM

I've been using the pedal for almost 2 years now (not knowing how flat or scooped it was) and I have just recently started setting it about flat with everything at noon after doing a bit of research here on TB (I have the treble on my amp rolled off slightly though so that would make it flatter than the already flat response in the first diagram) I do use the low on the pedal to adjust for the room however as my Jazz needs some lows to compensate for pick playing. These types of diagrams are very useful for EQing.

johnk_10 · #4 05-31-2010, 06:45 PM

Quote:

Originally Posted by bongomania

Cool! FWIW there was already a thread with RTA images of the VT... maybe this could be attached to that thread? Just so it's easier to find both sets when searching.

cool. i never saw that thread. i'll try to locate it.

RockBobby · #5 05-31-2010, 07:02 PM

Thanks John,
My settings are level=10:00, Mid 12:00, Char=11:00, Drive 8:30, Bass 1:00, Treb 12:30. I ab using a Jazz with DR Flats, Pick and Fender CS 60's jazz pups. Full neck, 80% bridge, tone 70%.

I am after (and getting close) a V4 sound.

boing · #6 05-31-2010, 07:09 PM

This is the other thread (unless there are more):

VT Bass frequency response plots

johnk_10 · #7 05-31-2010, 07:15 PM

Quote:

Originally Posted by RockBobby

My settings are level=10:00, Mid 12:00, Char=11:00, Drive 8:30, Bass 1:00, Treb 12:30.

Hi Bobby,
here's what the RTA of your settings looks like:

johnk_10 · #8 05-31-2010, 07:20 PM

by the way, i don't know if they used pink noise or a quick signal sweep on the results on the other thread (?), but i used the quick sweep method, since i find that it gives much more accurate results. plus, if it helps, i'm running my TrueRTA program at 1/24th of an octave from 10Hz to 20Khz.

johnk_10 · #9 05-31-2010, 07:21 PM

Quote:

Originally Posted by boing

This is the other thread (unless there are more):

VT Bass frequency response plots

thanks for the link!

BroKenSticKs · #10 05-31-2010, 07:26 PM

I find this stuff very interesting. I happen to own this pedal also so that helps. Thanks for taking the time to post this.

johnk_10 · #11 05-31-2010, 07:35 PM

you're most welcome.
BTW, here's the setting that i've been using going into the front end of my Avalon VT737SP:

JimmyM · #12 05-31-2010, 11:23 PM

cool stuff, john! what really strikes me wild is how flat the bypass is. considering it's buffered and not true bypass, i wasn't expecting that, especially when a handful of people in the effects thread say they thought it was noticeable when it was plugged in and bypassed. according to that it shouldn't be the least bit noticeable, which is the way i hear it.

ok, so here's what i do usually...except i put the drive to noon. but it's become sort of a universal setting for me no matter where the drive is.

lows: slightly above 12:00
mids: slightly below 12:00
highs: 10:00
character: 12:00

this is an ever-so-slightly modified version of the near-flat setting tb user dannybuoy came up with using fdeck's frequency analysis program. seems to work for me. mainly want the same sound as my amp with some od on it. it'll be real interesting to see what you come up with for it.

johnk_10 · #13 06-01-2010, 12:15 AM

yeah, i didn't look to see if it has a true bypass, but just assumed that it did since it's so flat when bypassed.

okay Jimmy, here's the RTA graph of your settings (in green) and the setting that gets it the most FLAT for mine (in violet):

and here's a pic of the actual unit when i got the 'flat' setting:

JimmyM · #14 06-01-2010, 12:34 AM

your flat settings are even flatter than danny's, i think, although they're very similar dial positions. yours may be dialed up just a little from his. i've cut back a little on my use of those upper mids since going back to the soloed p pickup a lot more often so that chart looks identical to how i hear it.

thanks bro!

johnk_10 · #15 06-01-2010, 12:47 AM

yeah, i too cut the mids a bit, and boost the bass because i'm using it with my ric 4003 with the bridge pickup only. it sounds fuller and fatter that way, since the bridge pickup on that bass can get a bit 'barky' when used by itself, but i'm diggin' how punchy it sounds with it. plus adding just a bit grit gives the sound a little more 'fluid'.

JimmyM · #16 06-01-2010, 12:56 AM

amazing what a hint of overdrive can do for your clean sound, eh? it's getting to be an always-on thing for me. i'm not quite there but i'm close.

johnk_10 · #17 06-01-2010, 01:15 AM

yeah. i think that i'll be using it at 50/50. the little bit of 'hair' on the notes just seems to 'glue' its tone together and makes it a bit more 'syrupy' / slightly compressed. i have to admit, these VT pedals are pretty amazing little gadgets. i actually like their tone better than my RPM, and the RBI that i had, and that's saying alot.

JimmyM · #18 06-01-2010, 01:18 AM

pedal of the future.

johnk_10 · #19 06-01-2010, 01:26 AM

"pedal of the future" (-that sounds like the past)

IMO, you probably should be getting a royalty for them by now.

'just tell 'em Jimmy sent 'ya'

12bass · #20 06-01-2010, 01:59 AM

Interesting that you've got the Drive at 12:00 for the "flat" setting. With my basses, that would make for a fairly overdriven sound. If I want clean, I keep the Drive below 9:00 or so, or else it starts to add some clipping on transients. I like that sound too.... when I'm after a bit of snarl/squishiness. BTW, I've modded mine to switch the speaker emulator out of the circuit. Really opens things up. Sounds more transparent.