Jump to content
Why become a member? ×

Input gain versus master vol


scrumpymike
 Share

Recommended Posts

I've just taken delivery of an excellent Mesa Subway 800 purchased off this forum and decided to have a quick read of the user manual unexpectedly received with it.  Having generally bought used amps without any paperwork, I don't have much experience in these matters but I was surprised that Mesa's quick set-up guide reads: set the master to 1 o'clock and then increase the gain to achieve the required volume.  I've always first set the input level to the point where the overload indicator occasionally flickers on and off 'in extremis' (or more permanently for an overdriven sound), and then set the master to get the required volume.  Any ideas why Mesa advise the opposite approach - is it a class D thing?

Link to comment
Share on other sites

6 minutes ago, mep said:

I'm with you scrumpymike. I don't know about this amp. Does it noy have an input gain level light of some sort? What does it sound like and does it change much if you set the levels as you suggest? 

Yes, it has the usual warning light and, yes, the sounds are noticeably different for the two opposite methods - exactly in the way that anyone who understands the control functions would expect.  Adopting the Mesa approach and noodling around loud-ish at home through an 8ohm Barefaced SC (= 400 watts), the gain ends up around 10 o'clock and the sounds produced are sweet and clean.  Done the opposite 'traditional' way produces sounds that are less clean and more dynamic, according to how far you crank up the gain pot - again, just as expected.

OK, beats me why Mesa say do it their way.  I think this is just a non-topic!

Link to comment
Share on other sites

I'm not into the edgy, gritty, overdriven or vintage sound so I always go for whatever gives me the cleanest sound at the volume I need for a gig. Usually for me that means having the master as far open as I can without hiss, which on my QSC PLX 2402 that means fully open but not so with my walkabout head. Then I bring up the input gain of my pre-amp till I get the volume I need. That always gives me a clean powerful sound. 

Link to comment
Share on other sites

Oddly I watched a sound engineer (PA hire) set the desk master fader to '0' (ie max output), all of the channels in use to max and then started increasing the individual channel gains for voices/instruments (active PA cabs were at max).  I asked why he didn't set each channel using the input gain and corresponding PFL meter and he said that his way was easier... just saying.  ;)  

Link to comment
Share on other sites

Setting up a PA desk is different. The last thing you want is to have clipping at the input stage, so that procedure would be more or less correct, at least as far as the individual channels is concerned. However, a good desk would not have the 0dB setting the max, either on the individual channels or any of the outputs. 0dB would typically be at least 10dB below maximum. Also, you wouldn't start with both the desk outputs and the power amp attenuators at 0dB. Doing so might result in the input gains being too low for acceptable signal to noise ratio. A knowledgeable engineer uses the input LED readout to be sure that the applied gain puts the signal strength in the Goldilocks zone.  

  • Like 1
Link to comment
Share on other sites

  • 2 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...