Input and Output specs of the VG-99

Started by rockguy66, May 14, 2014, 03:24:55 PM

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rockguy66

Hey guys,

I have been digging a lot into the VG and Mesa Boogie forums trying to solve an issue I am having with the insertion of my VG-99 into the Mark V Effects Loop. The Mark V sends Pro Level (+4dBu) and expects a return the same.

From what I can gather on the VG-99, the input is consumer level (-10dBu) and the guitar main outs are also consumer level (-10dBu). Many of the DI boxes and attenuators I have been looking at are listing consumer level as -10 dBV, not dBu. Could the specs listed in the VG manual have a typo? From all I have read dBu and dBV are not equal. I was pointed to this sweet little puppy:

http://www.sweetwater.com/store/detail/LLS2/ 
the Ebtech LLS-2 2-Channel Line Level Shifter. It converts Pro (4dBu) to Consumer(-10dBV), has two channels and you can convert into either direction, it seems like just the gem I need however the dBu to dBV difference concerns me, could the specs in the VG manual have a typo? I spent $100 on this thing and want to make sure it is the right item. It seems like it will work, and was suggested by a Mesa Boogie tech. Can anyone add to the discussion, and maybe clarify the specs of the VG?

Many thanks,

Barrett "rockguy66" Hamilton

Elantric

#1
The VG-99 Specs are indicated in the VG-99 Owners manual




QuoteMany of the DI boxes and attenuators I have been looking at are listing consumer level as -10 dBV,

http://www.sengpielaudio.com/calculator-db-volt.htm
The origin of the index of dBu comes from "u = unloaded" and dBV comes from "V = 1 volt". Some say:
The "u" in dBu implies that the load impedance is unspecified, unterminated, and is likely to be high.

What is dBu? A logarithmic voltage ratio with a reference voltage of V0 = 0.7746 volt ? 0 dBu
What is dBV? A logarithmic voltage ratio with a reference voltage of V0 = 1.0000 volt ? 0 dBV
The home recording level (consumer audio) of ?10 dBV means 0.3162 volts, that is ?7.78 dBu.
The studio recording level (pro audio) of +4 dBu means a voltage of 1.228 volts.
The maximum undistorted level of audio amplifiers is +18 dBu. In USA it is +24 dBu.
Domestic gear with a -10 dBV level is usually unbalanced. Studio gear with a +4 dBu level is always balanced. 0 VU = +4 dBu.




Having mentioned all the above - know that most folks have very poor results / lots of noise  inserting the VG-99 in the FX loop of ANY Guitar Amp  - not recommended!

rockguy66

Thanks Elantric,

Kind of weird how it wasn't specified to the industry standard, but I am new to this part of the equation so maybe there is no standard? I know that almost every site I went to, consumer line level was listed as -10dBV, not the -10 dBu the VG is listed at. Oh well.... Bet I am wrong on that though

I have thrown so much money at this so far, I just ordered a TC Electronics G Major 2. It seems the FC-300 is one of the suggested controllers. I just did not want to have to reprogram every patch
I had on the VG into a new processor, especially since the FC-300 was so easy to program via the VG-Editor. Now, I guess I have to relearn a new processor, with no editor software, and I am crap for any midi programming so I might just spend even more money and hire a programmer to take the headaches out of the loop for me.... LOL! I truly appreciate all of the help you have given me, and your patience. At least with the FC-300 I will still be able to switch between the 3 channels of my Mark V no problem.

That being said, anyone want to buy a VG-99? I already have the GR-55 for my Brian Moores....

Take care all!

Barrett "rockguy66" Hamilton