Reamping box background noise

L

Laimon

New member
Hi, I am new to reamping and I wanted to ask your advise.
I own a passive reamping box (Radial ProRMP), and I wanted to reamp some direct signal I recorded some time ago. If I send the signal straight from my sound card to the amp it makes a lot of background noise, and I know that's expected since (as far as I understood) the output of the sound card is balanced. Then I tried using the Radial in between, and the background noise has got only so much better, the signal seems far from clean as it should be. I must maybe say that the direct signal was not recorded with a direct box (so I recorded it unbalanced), but I don't think that's the real issue, since the background noise is present at all times, not only when a track is playing.
Am I doing something wrong in the connection?
Thanks a lot!
 
The balanced, unbalanced thing has nothing to do with it really. There are both level and impedance differences between a line level and an instrument signal. That is what the reamp box is for. (and what a direct box is for also)

Without hearing the background noise, I can't tell you what is causing it. It could be a ground loop, it coyld have been noise recorded with the signal because you didnt use a direct box, it could just be the amp, etc...

If you could post a sample of the noise, that would be helpful.
 
I'm not at home now, but I could try recording a sample and posting it later.
By the way, as far as I understand a direct box converts unbalanced signal to balance, and a reamp box does the opposite. But can one be used as the other by just having audio flow the other direction? For example, if I put a cable between the (balanced) output of my sound card to the (balanced) output of my direct box, and then another from the (unbalanced) input of the direct box to the input of an amp, will it work as a reamp box?
 
A di box does a few things all at once. The direct box converts an unbalanced high impedance line level signal into a balanced, low impedance, mic level signal.

A reamp box converts a balanced, high impedance, line level signal into an unbalanced, high impedance, instrument level signal.

Yes, you can run a direct box backward and get an unbalanced signal, but it will also be even higher impedance and high signal level, which is not what you want.

Direct boxes and reamp boxes do a lot more than balance and unbalance the signal. The balancing is really the least important part of what they do.
 
Some DI boxes have attenuation settings though, so you can run it backwards and get a halfassed passable "instrument" signal. It's not as ideal as a reamp box, but it can work.
 
Well, I asked just out of curiosity, but I don't really need it, having the reamping box. I also read, in the meantime, that it can't be done with active DI boxes (which was also my intuition), and mine is active.
A more interesting question: if you want to record your unprocessed guitar signal to reamp at a later time, you should go throught the DI box anyway to have it balanced, right?
 
You should go through a di box to make it a mic signal that the mic preamp you are plugging into is expecting to see. Balancing the signal is not the important thing here.

If you have been just plugging your guitar into a line input, that input is not expecting an instrument signal and will load down the pickups on your guitar. That will take away some of the high end. The di box avoids that problem.
 
Ok, my bad, I did indeed have to push the ground loop.
So that issue is solved. Now I have another one: I tried recording the direct input with the DI box (active, no attenuation) and then reamp it with the reamp box...well, the recorded seems to be very weak. I don't mean strictly in the sense of "not loud enough", because even amplifying it it still seem to have way less gain than a similar track that I recorded playing directly through the amp and then to the sound card via direct box (20db attenuation).
Is this phenomenon normal? How does one fix that?
 
Laimon said:
Ok, my bad, I did indeed have to push the ground loop.
So that issue is solved. Now I have another one: I tried recording the direct input with the DI box (active, no attenuation) and then reamp it with the reamp box...well, the recorded seems to be very weak. I don't mean strictly in the sense of "not loud enough", because even amplifying it it still seem to have way less gain than a similar track that I recorded playing directly through the amp and then to the sound card via direct box (20db attenuation).
Is this phenomenon normal? How does one fix that?
Click to expand...

You're feeding the amp a weaker reamped signal. Somewhere in your chain you've dropped the output before the amp so that the amp is seeing a signal similar to something like rolling the volume off the guitar.
 
Greg_L said:
You're feeding the amp a weaker reamped signal. Somewhere in your chain you've dropped the output before the amp so that the amp is seeing a signal similar to something like rolling the volume off the guitar.
Click to expand...

Yeah, that should intuitively be it, and yet I did not attenuate the signal from the direct box in recording, I also made sure the track with the unprocessed signal was at the right level, and the reamp box has no attenuation option. If I were to guess something must have gone wrong in the recording, because even boosting the track when reamping would lead to a weaker result, in terms of gain.
 
Whatever it is, you need to do your best to make sure the amp sees a signal comparable to what a guitar would feed it. In a perfect world the amp will react exactly as if a guitar is plugged into it.
 
Normalize the track. some reamp boxes assume you are going to feed it a full scale signal.

Also, I have found that some amps just hate an active signal. If this were the case, it would happen when using pedals or emg pickups too.
 
Some stuff I have found reamping, I have a passive unit as well:

1. Cable from interface/soundcard has to be balanced, either TRS or XLR or a combination of the 2.

2. If there is a lot of noise? Hit the ground switch.

3. Guitar cable from reamp box to amp needs to be short. Shorter the better honestly, I use a 1' long instrument cable.

4. Output from soundcard should be zero'd, in other words if you don't have an extra output and are using an output with a gain control, DIME the gain. It should be full signal.

5. Onboard gain on the reamp should only be used to match the output to the guitar. Easy way to do this is plugin guitar to amp, play riff and then plug in reamp and adjust till it's AROUND the same.


Honestly, reamping is actually less noisy than plugging in the guitar to the amp for me. YMMV though.
 
I find it absurd that the conventional wisdom on reamping is to use a bunch of boxes to first attenuate the signal, then gain it up to louder than it was before, then attenuate it back down hopefully to where it started. Assuming you actually do get back to unity, all you've done is use shit poor gains staging and add noise to the signal. Why not just stay at unity gain all the way through and use straight wire wherever possible.

Your interface is unity gain from line in to line out unless you do something in the software. The line input is too low impedance for the guitar, so buffer it. Grab your favorite big name pedal. The line out is fine to drive the input of the amp. You might lose some level from "improperly" unbalancing the signal. It wont be anywhere near what you're dropping the other way. Make it up in software where it's cheap and clean and silent. In most cases this will not add enough noise to notice.

Now you've found that you have a ground loop. The first step to fix that is to plug the amp and computer/interface into wall power as close together as possible. Like the same power strip. If that doesn't work, then you need to isolate the other path between their chassis. A transformer (like in your reamp box) is one way to do this, but there are others.
 
Whooo! Some heated opinions and misconceptions here!

First the DI box. It must be balanced out and at mic level to qualify for the name as most folks understand it.
Balanced because the original idea was to send a middling level, middling source impedance guitar signal a long way. Out of a control room to a desk or off a stage to a desk for PA.

Mic level because they were all originally passive and thus you needed a 10:1 ish transformer. These days the sound guys still want everything coming down a snake to be at mic level. Grounds invariably needed lifting.

Re-amp "box": Don't strictly need one. All that is required is some form of control over the level because guitar amps want to see about neg 40, about 10mV otherwise it is hard to accurately set a level. Simplest R-A box is therefore a pot in a tin.

Ground lift is however almost always required and best done with a transformer. NB not a 10:1 "DI" traff but a 1:1 type pre the pot. But very often you can get away with just breaking the shield at one end, usually best done at source.

Note, the guitar amp does not give a flying ffffig for the source impedance. Even if said Zs was equal to the 1meg Ohm in of most amps the signal would only suffer 6dB of loss and given the gain of most guitar amps you would barely notice. It is however best practice to keep the source Z low, <1k as this avoids HF loss in the cable capacitance.

Dave.
 
Greg_L said:
But you'll happily use a bunch of boxes and shenanigans for your guitar tone without ever actually touching an amp? Absurd indeed!
Click to expand...
Nope. I just buffer and go into the line in on the interface. Then I use sims, so no need for anything fancy getting to the amp.
 
Greg_L said:
lol :facepalm:
Click to expand...

Ahah, my thoughts exactly :P
Ashcat_lt, I'll definitely give a shot at buffering the signal through some pedal on the line in...but I am still going to a real amp later on, not a fan of amp emulators ;-)
ecc83, thanks a lot for the thorough explanation! I admit I ignore quite a few of the things you mentioned, but I'll get some time later today to check out about them and get a decent grasp :)
 
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