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Question about "Clean Boost"

isher1992

isher1992

Nov 27, 2008
1,209
200
Little Rock, Arkansas
#1
Hello!

I have a question for the effect forum regarding "clean boost."

I used to feed all of my pedalboard into my SansAmp, and let that put out signal. But lately, I've started liking the overdrive to it and decided to put it before all my modulation effects. The only problem with this is, I have to reduce the signal by A LOT and now my power amp sounds like it's barely getting any signal.

If I record straight into my computer, it's actually too loud. But if I plug into the amp, the signal is too low.

I know there are some "Clean Boosters" that are really basic overdrives, like LPB-1. But is there a Clean Booster out there, that is truly a clean, signal boost? Or would a compressor benefit me more to boost my signal and keep all the dynamics level?
 
#2
isher1992 said:
Hello!

I have a question for the effect forum regarding "clean boost."

I used to feed all of my pedalboard into my SansAmp, and let that put out signal. But lately, I've started liking the overdrive to it and decided to put it before all my modulation effects. The only problem with this is, I have to reduce the signal by A LOT and now my power amp sounds like it's barely getting any signal.

If I record straight into my computer, it's actually too loud. But if I plug into the amp, the signal is too low.

I know there are some "Clean Boosters" that are really basic overdrives, like LPB-1. But is there a Clean Booster out there, that is truly a clean, signal boost? Or would a compressor benefit me more to boost my signal and keep all the dynamics level?
Click to expand...

Actually, the LPB-1 is a clean booster! Remarkably clean & flat response, there's only a little bit of treble roll off in the last 15% or so of the boost knobs travel. (I actually put it on a scope a while back- I was shocked at how flat it was with a pink noise test signal!) It was designed, of course, to overdrive an amps input stage - but in a configuration with headroom downstream, it could work perfectly for you.
 
#4
Since you're feeding a power amp, you need to find the spec of its input sensitivity, and whether that sensitivity is different for balanced and unbalanced inputs. Sometimes it will be given as two dB ratings (one for bal, one for unbal); sometimes only one rating will be given, but the manual will say there is a -6dB drop when using an unbalanced input. And in some cases there is no difference in how the amp handles bal/unbal inputs.

Find those specs, report them back here, and we'll give you an answer that actually means something useful.
 
#5
I'm using a DI box after pedalboard, so everything is a balanced signal, if that says anything.

I can't find anything for sensitivity in the manual or on the website. It does give the impedance.

Which is for balanced, 20K ohms and 10K ohms unbalanced. It does say that Input Level is +4dB.
 
#7
Grrr, thanks for linking a site that tried to set malware on my computer.

Couple of things: many DI's are not unity gain, i.e. if you send a +4 dBu signal in, you may get a much lower signal out. Depends on the DI. Passive DI's typically drop the signal about -12 to -20 dB! IOW that right there would be a source of a huge loss of volume (again, depending on the DI). Also, just to be clear, you mean you are sending the XLR output of the DI to the power amp, right?

That random +/- spec is out of context, it looks like they just copy-pasted some specs and did a sloppy job of it.

The difference in input impedance between balanced and unbalanced means an unbalanced signal may have to work a little bit harder to reach +4dBu at that input.

Not a huge deal, probably. But +4dBu is pretty high, higher than many clean-boost pedals can go. There are some that can do it, it's just a question of sorting them out from the others. For example I found the Creation Audio Mk4.23 wasn't quite up to the job, but their Holy Fire overdrive pedal had plenty of juice for driving any power amp.

The easiest problem-solver for this kind of situation is a small mic preamp. Many of them have a 1/4" instrument input, and they all have a line-level balanced output that very often has enough juice to drive a power amp. With mic preamps, the weak ones are the exception.

ART TubeMP is a great choice for low $$: ART Tube MP Studio Mic Preamp: Shop Pro Audio & Other Musical Instruments | Musician's Friend
 

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