• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Double Bass GK MB200 Owner's manual messed up?

Chris204T

Chris204T

Feb 4, 2014
102
113
Dallas area
#1
Sorry if this should be posted in the thread about the GK MB200, but I'm new at this and didn't want to incorrectly reply to a message about something different. Please move it if it needs to be moved. Anyway, I bought a MB200 and I'm reading the owner's manual like a good boy. It mentions the "input volume control" and the "master volume" settings. This amp has neither of those knobs, only a knob marked "gain". I assume that has to be the volume control of course. The only other knobs are for EQ. So I guess they cut-and-pasted the manual from some other amp or whatever, but how can it be so wrong in the manual I got and on the GK website? This amp has been out for a while, you'd think they would at least correct the web site version of the manual. Anybody else notice this?
 
#3
I seem to remember from when I owned one that the manual was for the MB200 and MB500. The current one is for the MB200 alone so my guess is that when it was updated they missed some information that was relevant to the MB500 only.
 
#4
Thanks for the replies. I never seem to get many to my questions. I'm kind of wondering why the knob is marked "gain" instead of "volume". I'm new to the whole amp thing, hope my questions don't seem too stupid but a guy's got to learn somehow.
 
#5
Gain refers to how much an amplifier amplifies, and volume refers to how loud the result is. The knob on an amplifier adjusts the gain of the electronic circuit. So if you turn up the gain, you get more volume. As a result, people often interchange these terms. Usually, the preamp (input) gain knob is marked "gain" and the gain knob at a later stage in the amplifier is marked "master volume" or "volume" or "master". It looks like the MB200 has a "gain" knob which they also seem to call "Input Volume" in the manual. There is no "master" on the MB200, but there is a master on the MB500. I hope that helps some.
 
#7
Gain is the input volume control. On tube amplifiers this was the control for clean or overdriven sound (which needs to be compensated by the master volume control). Gain usually sits close to the input jack, master volume usually at the other end of the line of knobs.
Master volume controls the volume of the preamp output to line out or power amplifier. It is generally used for volume, since it does not alter the sound. Gain should be set to the highest position that still sounds clean and not distorted.

On older amps (Polytone), there is no gain control, the gain is fixed, so you either have a fitting instrument level, loose some volume possible or hope to have a volume control at the instrument to avoid distortion.

Using a good setting for gain and master volume can reduce hissing coming mostly from the preamp sound controls. So is is useful to gave both controls. An amp with only an input gain control must have a very quiet preamp or you have some constant at least partly avoidable hiss.
 
#8
DoubleMIDI said:
Gain is the input volume control. On tube amplifiers this was the control for clean or overdriven sound (which needs to be compensated by the master volume control). Gain usually sits close to the input jack, master volume usually at the other end of the line of knobs.
Master volume controls the volume of the preamp output to line out or power amplifier. It is generally used for volume, since it does not alter the sound. Gain should be set to the highest position that still sounds clean and not distorted.

On older amps (Polytone), there is no gain control, the gain is fixed, so you either have a fitting instrument level, loose some volume possible or hope to have a volume control at the instrument to avoid distortion.

Using a good setting for gain and master volume can reduce hissing coming mostly from the preamp sound controls. So is is useful to gave both controls. An amp with only an input gain control must have a very quiet preamp or you have some constant at least partly avoidable hiss.
Click to expand...

So in the case of the GK MB200, there is only a dial labeled "gain". So the true gain must be fixed (besides a -10 switch) and the "gain" dial is actually volume?
 
#11
The answers given above come close.:) The first distinction to make is between physical and psychological quantities. Gain is a physical quantity and refers to the amount by which the input signal is amplified. Volume is a psychological quantity that is actually not the same as the psychological quantity of "loudness." Rather, volume refers to the perceived "size" of a sound. The perception of volume is affected by physical quantities in addition to sound-pressure level. Again, it is not one-to-one with loudness.

Now, virtually everyone is aware that, all other things being equal, increasing the gain of an amplifier leads to an increase in perceived loudness and perceived volume. It became practice (somewhere beyond the 1950s, IIRC) to label the master gain knob with the psychological quantity "volume."

Let's get psychological quantities out of the way and consider each of the gain controls on a typical amplifier. The master gain control determines the gain across the power amp stage. The control at the input determines the gain between the input and the pre-amp stage and, as pointed out by DoubleMidi, typically retains the label "gain." Both controls-- the one between the input and the pre-amp and the one between the pre-amp and power-amp-- control gain. They both affect the overall gain of the amplifier. DoubleMidi discussed the reason why both controls exist. Their optimal use maximizes signal-to-noise ratio. The gain control at the input stage is typically adjusted for maximum gain before distortion and overload and then the master gain is used to make adjustments to achieve the desired loudness after that.

Some early hi-fi tube amps from the 1950s had a pair of controls, one labeled "gain" and the other labelled "loudness." Here's how they worked. With the loudness control set to 0 dB, one adjusted the gain control to achieve "concert level." Where the gain had to be set to achieve that depended on the loudspeaker one was using. After that setting was achieved, only the loudness control was used. As "loudness" was reduced, the appropriate amount of compensation (boost of low-frequency and high-frequency ends of the spectrum) was inserted to maintain, theoretically, a constant perceived overall tonal balance according to the Fletcher-Munson loudness curves.
 
Last edited:
  • Like
Reactions: Povl Carstensen

Latest posts

Top Bottom
Back