Can you daisy-chain preamps?

SonicAlbert said:
The Brick gives you 55 dB of gain, which in most situations should be enough. I think only the quietest sources might need additional amping.

But if it does, then running line level out of the Brick into your other preamp should do the trick. I wasn't aware that the DMP3 had line level inputs. You're just adding another gain stage, and probably using little of it since the Brick will be handling most of the gain.

I personally would try to avoid that because I like to keep signal paths to a minimum, especially when recording. You'd just have to experiment with it.
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The DMP3 doesn't have line inputs.That's why I figured I couldn't do it.

And I've been told that an SM7 needs 60+ dB, so 55 might not cut it.

In a way, I'm glad that this is turning out to not have such an obvious answer. I don't feel quite as ignorant for asking.
 
Just for the record my SM7 into my brick works fine for vocals. The signal is a little weak going in but it's strong enough to work with.
 
You need to remember that sending the signal from the output of the Brick to the mic input of the DMP3 won't *necessarily* distort the signal. I sometimes run my mixes through a DAV BG-1 and using some care setting levels it is possible to get a clean undistorted signal. The BG-1 can handle a lot of level, but still, I'm sending a line level full mix through it!

So as Micter says, the SM7 to the Brick will work, as most likely will sending the line level signal from the Brick to the mic input of the DMP3. Especially if it is a little soft to begin with. You just have to be careful.

There are preamps that are designed for extra gain. Like Grace makes a version of the 101 that has 70 dB of gain, not the usual 60 on their standard model.
 
SonicAlbert said:
You need to remember that sending the signal from the output of the Brick to the mic input of the DMP3 won't *necessarily* distort the signal. I sometimes run my mixes through a DAV BG-1 and using some care setting levels it is possible to get a clean undistorted signal. The BG-1 can handle a lot of level, but still, I'm sending a line level full mix through it!
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I used to run my Soundcraft Ghost through an ART Dual MP to a DAT machine for mix down.

You certainly CAN run line level into a mic level input and still have quite clean sound! But the trick is, you would want your console to be producing most of the line level volume you will want!

That is what I meant in my original post. Once you put a line level output to a mic level input, the potential for noise being amplified is HUGE. You MUST optimize your signal to noise ratio BEFORE that last stage so that you are not amplifying noise. The less gain you have to use at the end the better!
 
Ford Van said:
I used to run my Soundcraft Ghost through an ART Dual MP to a DAT machine for mix down.

You certainly CAN run line level into a mic level input and still have quite clean sound! But the trick is, you would want your console to be producing most of the line level volume you will want!

That is what I meant in my original post. Once you put a line level output to a mic level input, the potential for noise being amplified is HUGE. You MUST optimize your signal to noise ratio BEFORE that last stage so that you are not amplifying noise. The less gain you have to use at the end the better!
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yup, well said
 
Ford Van said:
You certainly CAN run line level into a mic level input and still have quite clean sound! But the trick is, you would want your console to be producing most of the line level volume you will want!
Click to expand...

Yes, good post--that is the way I do it too. The preamp is more for color/cohesion than anything else, along with a little more gain.

I currently use a Speck X.Sum with a breakout box that allows me to bypass the final master volume control on the mixer. I use my DAV BG-1 preamp for that instead. Basically just substituting electronics, but I like the way it sounds a lot of the time (not always).
 
I think the most confusion surrounding this issue is the misconception that the gain pot on a preamp boosts the output of the amplifier. The gain of an amplifier chip is static... The gain pot is nothing but a variable attenuator... By turning it up you're actually decreasing the attenuation at the input to the preamp. The net result is that the output of the amp increases, but the amplifier doesn't provide additional amplification, it's just passing along what it sees on the input.

An amp has a noise floor... the lower the amplitude of a signal at the input, the closer the signal is to this natural noise floor... to keep this delta at it's maximum you have to keep your signal as hot as possible at the input. If it's too hot, now the amp distorts... but that's what gain staging is about... a careful balance between noise and distortion. You want to hit the input hard enough to keep the noise floor down... but not so hard as to create distortion...
 
I think there's a a couple of things here that are being taken as absolutes that aren't really. Saying that a preamp puts out line level is one. A preamp is a variable gain stage that we use to drive our signals approximately to +4 dBu (1.228V (RMS)) or -10 dBV (0.3162V (RMS)), but that's totally a function of how much of it's available gain we use and the signal level we start with. Secondly, input voltages don't always fall into "line level" or "instrument level" as absolutes.
The DMP3 can take a maximum input of +14.6dBU, which calculates to 12.38dBV, or 4.15V (RMS). So, it will have no trouble at all accepting the line level output of a previous preamp stage, which isn't even at line level or we wouldn't be discussing this. :D
The other consideration is input impedance. We usually talk about just high impedance and low impedance, but mid impedance should probably be in our lexicon. High impedance in this discussion would be around 1M - 3M ohm, typical for instrument inputs. Mid impedance might be around 10k - 20K ohm, typical for line inputs. Low impedance is usually in the 600 ohm range. I believe there is more to be gained by having a high impedance input for pickup based sources than there is to be lost by presenting a line level signal to a high impedance (instrument) input. Someone can correct me if I'm wrong, but I don't think this presents a problem.
 
Thanks guys

but the trouble is, now I gotta wait for someone to put a Brick up for sale again for a good price. And hope I have the $ when they do.

It's not all in the wrists, it's all in the timing.
 
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