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-   -   Tech 21 Vt bass deluxe issue/question (http://www.talkbass.com/forum/f36/tech-21-vt-bass-deluxe-issue-question-949186/)

Heath_eld 01-16-2013 04:53 AM

Tech 21 Vt bass deluxe issue/question
 
Hey there,

I recently brought a tech 21 vt bass deluxe and am initially very impressed. However I have an issue or question.

The manual describes the level control as just adjusting the overall output level. However I find on mine that when I turn it past about 12.00 the sound starts to distort. Like a real tube amp yes - but this is Different to what my bass driver DI does. By the time you turn it up all the way it is quite dirty.

Is it supposed to do this?

JimmyM 01-16-2013 06:56 AM

That all depends on what the rest of your settings are. However, when I'm doing just a basic clean sound with no drive or boosted-past-12:00 character settings, it won't overdrive.

cheapbasslovin 01-16-2013 07:42 AM

Are you overdriving the input of your amp? Making the distortion happen inside the amp rather than in the Sansamp pedal?

tech21nyc 01-16-2013 10:29 AM

Quote:

Originally Posted by Heath_eld (Post 13727232)
Hey there,

I recently brought a tech 21 vt bass deluxe and am initially very impressed. However I have an issue or question.

The manual describes the level control as just adjusting the overall output level. However I find on mine that when I turn it past about 12.00 the sound starts to distort. Like a real tube amp yes - but this is Different to what my bass driver DI does. By the time you turn it up all the way it is quite dirty.

Is it supposed to do this?

The level control shouldn't create distortion. It's possible that if your EQ settings are too high you could possibly overload the dig-pots.

If using the 1/4" output you should engage the boost switch if you find you have to turn the level control very high. There are no hard and fast rules as it all depends what you are plugging the pedal into. A mixer, front end of an amp, power amp etc.

Gain structuring is a very important step when using various units together. You will experience noise or possible unwanted distortion if not done properly.

Heath_eld 01-16-2013 12:01 PM

I tried all the variables - I was running it into a mixer and using my shure iems - and it was an actual sound - that is the unit was putting out a distorted sound - had all the other settings as they came in the manual... I tried engaging and disengaging the boost switch - that did what it should do, either increased or decreased the volume.

Thanks guys

Heath_eld 01-16-2013 02:49 PM

Ok - I've had a fair bit of email help from tech 21 - very helpful - looks like there might be an issue so I'm gonna head back to the store today and try out whether the standard vt does this (unfortunately they don't carry the deluxe in store)

tech21nyc 01-17-2013 08:07 AM

The settings in the manual are just to get you into the ballpark of a sound and will not always correlate with your bass, playing style etc.It would be helpful to know some specific settings. You have a number of variables. First the mixer. Which mixer? When going to the mixer are you using a line or 1/4" input or a mic XLR input. If going to a mic input is the mixers trim set properly. Are the IEM's being run with the mixers headphone output, into a headphone distribution unit or something like the Avion system?

The reason I ask all this is that many times when someone has an issue with our product it can come down to a number of factors. It's helpful to have an understanding of each piece of gear to make it all work optimally.

Is it possible to just try the VT Bass Deluxe into an amp with just your bass and nothing else?

Heath_eld 01-17-2013 02:24 PM

Hey,

I've tried both the xlr and 1/4 inch - and also with a bass amp. It is less obvious with the bass amp - because you don't hear the high frequencies as well, but it's very much there.

Settings are about 9-10 o clock drive, 9.00 character, bass and miss about 12.30 and highs about 12. Starts to clip when you take the volume past 1.00. Iems were plugged straight into the desk. I did an A B with my bass driver and all sounded fine.

I've tried a couple of basses - a 5 string stingray and a Mexican P.

alec 01-17-2013 04:44 PM

I can max out the volume of my VTD with no distortion if the drive is kept low.

Growly Lytes 01-17-2013 04:51 PM

Quote:

Originally Posted by cheapbasslovin (Post 13727680)
Are you overdriving the input of your amp? Making the distortion happen inside the amp rather than in the Sansamp pedal?

Hot basses send hot signals.Could be your overdriving the amp input or the settings arent properly set on the Sansamp.

Heath_eld 01-17-2013 05:28 PM

Quote:

Originally Posted by alec (Post 13736116)
I can max out the volume of my VTD with no distortion if the drive is kept low.

I guess what I'm really getting at is "should the level affect the amount of distortion at all".

I'd say I'm clipping the output on the VTD - I guess I'm wondering whether that is supposed to be possible.

SolarMan 01-17-2013 05:39 PM

Yes, depending on all other variables.

Heath_eld 01-19-2013 11:13 PM

Hey again,

Alright - So i took this thing into the shop and the problem was not obvious through a real bass amp in the shop. However i took it back home and it continued through my mixer - In ears.

Then the real issue for me - i took it down and plugged it into my real rig - so VT deluxe into a power amp driving an SWR Henry the 8x8. I will add - at lower volumes, it sounded hot - room shaking and exactly what i'm looking for (please understand - i am not dissing this product!). But it didnt drive the power amp to its full. And in the same way as with the mixer and IEMs,, when i went past approximately 1-2.00 on the level dial, it just broke up into a clipping sound that with that setup simply didnt sound usable.

So to be clear - if i set this thing up so that its sound is fat and clean, should the level control affect that sound in any way?

I seem to be getting told that it shouldnt - but not everyone agrees :)

Thanks

Heath

tech21nyc 01-22-2013 08:22 AM

Quote:

Here are some actual scientific figures that were arrived at with proper test equipment.

Instrument level is generally accepted to be -10dB. This will vary with the bass guitar, pickups and how hard the player is actually hitting the strings. We have measured our passive bass to put out 0 dB with aggressive playing. With a -10dB signal driving the VT Bass Deluxe with the 1/4" output boosted in bypass mode we get an output of 0dB which is line level. If we use 0dB at the input the output is +10 and just starts to clip the pedal and that is still bypass mode.

When the pedal is engaged with a -10dB signal feeding it and the drive set at 9 o'clock (that is a clean signal) and the Character, Low, Mid and High controls set at noon and the level cranked we get +8dB which is about 3 volts output which is double what the power amp needs to drive it.

If we use a -20dB signal in and everything else the same but the drive at 11 o'clock we get 9dB of output. With -30db signal in and the drive at noon we still get 9db of output. The signal is still clean at these settings. Everything will vary with how hard you play and how you have the pedal set up.
It is possible that you could be clipping the digi pots but I can't say for certain without being able to test that actual pedal. You should not have to run the VT Bass Deluxe at full level into a mixer channel. Your mixer can easily be driven with the average microphone. Microphone level is considered -30dB. Which mixer are you using and where are the input trims set at?

As for your power amp do you have the input gains turned all the way up? Which power amp and do you know the input sensitivity for the amp?

I'm not ruling out that something could be wrong but it sounds like a gain staging issue. Do you still have the Bass Driver pedal? The output should be similar but the Bass Driver has the "blend" function and that could possibly be why that seems cleaner depending upon the way it is set.

Even though the VT Bass Deluxe has more than ample output you should not have to run it full out. It's not an amplifier. If you have to turn it full up either the system is under powered or something is set incorrectly.


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