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Author Topic: Channel Strip vs. Straight Preamp  (Read 3576 times)

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Roving Sign

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Channel Strip vs. Straight Preamp
« on: February 21, 2007, 08:33:32 PM »
I notice my mixer seems to have a bit of gain even when the knobs are all turned down...

Compared to my dbx preamp which I can turn all the way down...

Why the inherent gain on the mixer? Does that mean that mixers preamp sucks?

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Re: Channel Strip vs. Straight Preamp
« Reply #1 on: February 21, 2007, 08:56:58 PM »
I notice my mixer seems to have a bit of gain even when the knobs are all turned down...

Compared to my dbx preamp which I can turn all the way down...

Why the inherent gain on the mixer? Does that mean that mixers preamp sucks?

Its just because its hard to design a single preamp knob with 60 db of gain on it that goes from 00 to +60 db.  So some have there gain range set to -50 to +60. Some mixers have -50 to +60 + a 20db pad that subtracts 20db from the input giving you a range of -70 to +60 good enough for most things. You can however mod a board that does not have a pad and put one in so you can pad down the input. There is also another way to do it by using the mixers channel insert point and adding a 10k pot to it and connecting it to the send and return now you will be able to dial down the mixer by at least 20-30 db right after the gain control. Seems counter productive. The main thinking behind this design of a gain pot is what is the mixer most likely to be used for. For example on a professional mixer we have a -20 db pad because for a channel that is used for Kick drum we might have to pad the input down before it gets to the first gain stage inside the board. And then there is the snare drum pretty much always have to pad that channel down. But when its a small mixer they skip the extra wide gain control. Because your not likely to use for example a 4 channel board to mic a drum kit. So there are workarounds to your problem it all depends on how bad you want to fix it :) The other reason why they don't put in single pots that do from -70 to +60 is noise floor. Having a high value pot like that in the gain stage introduces noise into the front end of the preamp.

The DBX is a rack mount so you only have to deal with two channels its not as much of a big deal for noise floor because there is less electronics inside the preamp rack then there would be in a console. So they can design gain pots that have full travel its also cheaper then having to add a pad on the dbx preamp if it does not have one. The danger in this type of design is that the first stage can still be overloaded with out a pad to lower the input before it reaches the first gain stage. This is the whole delima with digital recording devices with digital attenuation the first stage can still be overloaded I wish more companies would put a simple resistor pad in the front end of there recorders then you would not have the overloading problem that is so prevalent today.

Chris Church




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Roving Sign

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Re: Channel Strip vs. Straight Preamp
« Reply #2 on: February 21, 2007, 09:33:02 PM »
The reason I ask is - the first time I tried to run an AKG 480 on my Yamaha mixer - I couldn't control the mic without the pad engaged...the peak light was flashing like crazy, even with the trimmer all the way down. Once the pad was on - no problem.

The part of the recording without the pad - suprisingly sounds undistorted for the most part...but a little "darker" than the padded passages...The padded part has a little more air, twinkle and a more musical sound.

I guess it makes me wonder if there are a lot of rigs/setups that are basically running the preamp a little harder than necessary - even though the sonic effects might not be that noticeable...???

(it was this thread that got me thinking about this..)
http://taperssection.com/index.php/topic,80064.0.html

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Re: Channel Strip vs. Straight Preamp
« Reply #3 on: February 21, 2007, 10:46:09 PM »
The reason I ask is - the first time I tried to run an AKG 480 on my Yamaha mixer - I couldn't control the mic without the pad engaged...the peak light was flashing like crazy, even with the trimmer all the way down. Once the pad was on - no problem.

The part of the recording without the pad - suprisingly sounds undistorted for the most part...but a little "darker" than the padded passages...The padded part has a little more air, twinkle and a more musical sound.

I guess it makes me wonder if there are a lot of rigs/setups that are basically running the preamp a little harder than necessary - even though the sonic effects might not be that noticeable...???

(it was this thread that got me thinking about this..)
http://taperssection.com/index.php/topic,80064.0.html

That's strange you found that with the pad you had more high end... what is the model Yamaha board, The really old ones all had transformers in them. Yamaha has always had a long standing issue with gain settings... Like on the PM1000/PM2000 there first large format console the input gains are detented. Not good for a live console to get levels where they need to be so you often ended up using the fader to control the level because the gain knob was not continuous. So you could not run the faders at the 0 line you had to run them -5 or -15 in some cases not cool if you bump into one in the middle of a show and bump it up 30 db or so... They have always has strange designs but even though Yamaha had strange designs there consoles with the exception of the pm3000 were very good sounding. If its a major issue build a pad for the XLR input. If the preamp is designed well you should be able to run it a little hotter with out distortion that being said its always nice to have at least 8-10 db of headroom on any Yamaha console. It could also be a case of bringing the fader down a bit on the channel if your board has faders. Some old yamaha mixers had knobs.. No faders.


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Re: Channel Strip vs. Straight Preamp
« Reply #4 on: February 21, 2007, 11:01:48 PM »
Not really more high end - just better detail from the high end that is there...almost like the preamp was more "comfortable"

This is just the little 99 dollar Yamaha MG10/2...it has all knobs - for some reason I dont like slide faders...particularly on portable gear - which is always at risk for a beer spill...faders are nice for mixing live - but not terribly great for 2 channel recording...IMO...

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Re: Channel Strip vs. Straight Preamp
« Reply #5 on: February 21, 2007, 11:06:55 PM »
Not really more high end - just better detail from the high end that is there...almost like the preamp was more "comfortable"

This is just the little 99 dollar Yamaha MG10/2...it has all knobs - for some reason I dont like slide faders...particularly on portable gear - which is always at risk for a beer spill...faders are nice for mixing live - but not terribly great for 2 channel recording...IMO...


Yep that makes sense. Its hard when its a small mixer to do any kind of mod because its all surface mount. But it can be done. Beer is not good. The first live gig I ever mixed was with this Punk band in Hamilton Ontatio Called the Forgotten Rebels. The soundboard was brand new some skin head thought it would be cool to empty his beer mug into it.. $1,000 later it was fixed and back up and running. And needless to say it pretty much ended the show.
Oh the fun days of punk rock!
for warranty returns email me at
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