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Re-amping via ART Cleanbox Pro vs Passive box?

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Re-amping via ART Cleanbox Pro vs Passive box?

Postby Elephone » Wed Feb 06, 2019 5:34 pm

Just read this article on Re-amping:

https://www.soundonsound.com/sound-advi ... -re-amping

"Re-amping is the process whereby the direct signal from a guitar, bass or keyboard is recorded — usually on a separate track alongside the signal captured simultaneously with a microphone from an amp — and later routed to an amp in a studio to be miked up and overdubbed."

"A passive DI box can often be used reasonably well in this role, although it is normally necessary to attenuate the line‑level input significantly, to avoid saturating the transformer and generating an excessive unbalanced output level."


"Alternatively, the kind of line-level balanced/unbalanced interface intended for connecting domestic equipment to professional systems can be used, and the original ART CleanBox is often recommended in this role. However, for only a slightly greater outlay, a dedicated re-amp box, such as the Radial ProRMP, is rather more convenient to use."

I'm confused because I was under the impression that the ART CleanBox Pro was unsuitable for this job because of potential ground loops. I've not had any noticeable problems using mine, but are there any other potential problems with using the CleanBox Pro, such as changes to the signal? I'd like it to be as identical to "plugging the guitar into my amp" as possible.

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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby Hugh Robjohns » Wed Feb 06, 2019 5:49 pm

There is a risk of ground-loop problems with the Cleanbox Pro because the output grounds are tied directly to the input grounds inside the box due to the nature of its active circuitry.

Consequently, the ground of the guitar amp will be tied solidly to the ground of the computer interface and, if in different rooms or powered from different sockets, you therefore stand a very good chance of suffering ground-loop hums and buzzes.

Dedicated Reamping boxes -- like the superb and very good value Orchid Amp interface -- or passive DIs (used backwards), separate the input and output grounds with a transformer, thus avoiding any possibility of a ground-loop under any circumstance.

https://www.soundonsound.com/reviews/orchid-electronics-amp-interface

Whatever you use, you're never going to replicate the exact interface characteristics of a guitar plugged into the amp, because a guitar's pickups are strongly reactive and the output of an active box like the Cleanbox Pro, or even a proper reamper, is much more linear... That means that some of the extreme subtleties of playing a guitar into an amp live may well be different when a pre-recorded track is reamped into the guitar amp... but That's not usually an issue (or even noticeable) for most people using this technique!

H
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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby Elephone » Wed Feb 06, 2019 6:08 pm

Would the main problems be avoided if I transfered my files to my Zoom H4n (battery powered), and reamped that with the Cleanbox? I could then just record it via my audio interface into the PC.

(Sorry, I'm clueless about electronics. I could do with finding a crash course in essentials.)

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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby Hugh Robjohns » Wed Feb 06, 2019 6:32 pm

You said in your first post that you don't have any problems with your current set up -- if it ain't broke, don't 'fix' it! :D
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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby Elephone » Wed Feb 06, 2019 6:39 pm

It was quite a while ago and I might have been lucky! :) Maybe a different combination of wall plugs would produce ground loops.

I do want to do some re-amping again soon. Isn't re-amping the battery-powered Zoom more closely in line with what the CleanBox was intended for?

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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby Wonks » Wed Feb 06, 2019 6:52 pm

It always helps to take a DI whilst playing into an amp with a similar sort of sound to the one you plant to re-amp with e.g. clean amp for clean, distorted amp for distorted. You'll then get a lot of the guitar/amp interaction captured correctly.
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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby Hugh Robjohns » Wed Feb 06, 2019 7:27 pm

Elephone wrote:Isn't re-amping the battery-powered Zoom more closely in line with what the CleanBox was intended for?

Not really, but if you use the (battery-powered) Zoom as the reamping source you're much less likely to suffer a ground-loop compared to using a mains-powered computer/interface as the source.
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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby ef37a » Wed Feb 06, 2019 7:50 pm

Hi Elephone,
I am not quite sure that the conventional passive DI box is at all suitable for re amping?

I assume the line level signal is sent to the XLR "mic" connector and an unbalanced signal from the jack fed to the guitar amplifier? Since DI boxes generally use a 10:1 transformer I can see that quite some attenuation is going to be needed to kludge the thing to work!

The idea of a "backwards DI" probably started from the use of two such boxes? One was in the control room with the guitarist and sent a mic level, balanced feed to a second box into its XLR. The resultant jack signal would be a fair copy of that from the guitar.

All that is really needed is a pot to take line level down to about 40mV for an amp . A means to break the SIGNAl earth is usually needed as well. As said. Mr Orchid has the very thing but better!

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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby Hugh Robjohns » Wed Feb 06, 2019 8:01 pm

ef37a wrote:I am not quite sure that the conventional passive DI box is at all suitable for re amping?

Depends on the specific box, but it is workable with a bit of care. A proper reamper is MUCH easier!

I assume the line level signal is sent to the XLR "mic" connector...

Yes, although it usually needs to be heavily attenuated to avoid saturating the transformer, either at the desk's output, or with an inline pad, or both!

... and an unbalanced signal from the jack fed to the guitar amplifier?

Unbalanced and (ground) isolated... Yes.

Since DI boxes generally use a 10:1 transformer I can see that quite some attenuation is going to be needed to kludge the thing to work!

Yep. Kludge indeed... But workable with care if necessary. There are better solutions!

The idea of a "backwards DI" probably started from the use of two such boxes? One was in the control room with the guitarist and sent a mic level, balanced feed to a second box into its XLR. The resultant jack signal would be a fair copy of that from the guitar.

While that would work, it's not reamping, just line-extending! But I don't think that's the origin of the 'backwards passive DI' as a reamper. I think this bastardised application of a passive DI was simply a classic studio-assistant's kludge that got a job done with minimal fuss! ;-)

All that is really needed is a pot to take line level down to about 40mV for an amp . A means to break the SIGNAl earth is usually needed as well. As said. Mr Orchid has the very thing but better!

A pot, a transformer, a box and some socketry! :-D
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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby The Elf » Wed Feb 06, 2019 10:48 pm

Wonks wrote:It always helps to take a DI whilst playing into an amp with a similar sort of sound to the one you plant to re-amp with e.g. clean amp for clean, distorted amp for distorted. You'll then get a lot of the guitar/amp interaction captured correctly.
Repeated for emphasis! :thumbup:
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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby Elephone » Thu Feb 07, 2019 3:57 pm

The Elf wrote:
Wonks wrote:It always helps to take a DI whilst playing into an amp with a similar sort of sound to the one you plant to re-amp with e.g. clean amp for clean, distorted amp for distorted. You'll then get a lot of the guitar/amp interaction captured correctly.
Repeated for emphasis! :thumbup:

I suppose a thorough approach would be to split the signal from live guitar playing (while noting amp settings) record DI and amped signal simultaneously, then compare recorded re-amped DI signal (same amp settings) with the recorded live-amped audio.

Thanks for the replies.
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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby The Elf » Thu Feb 07, 2019 4:02 pm

Elephone wrote:
The Elf wrote:
Wonks wrote:It always helps to take a DI whilst playing into an amp with a similar sort of sound to the one you plant to re-amp with e.g. clean amp for clean, distorted amp for distorted. You'll then get a lot of the guitar/amp interaction captured correctly.
Repeated for emphasis! :thumbup:
I suppose a thorough approach would be to split the signal from live guitar playing (while noting amp settings) record DI and amped signal simultaneously, then compare recorded re-amped DI signal (same amp settings) with the recorded live-amped audio.
That's exactly the way. A DI box will have a 'through' that you send to the amp and a mic output that you record as a dry pickup signal in order to be able to re-amp. There's so little cost in doing it this way I do it practically every time. Aside from re-amping it has other significant benefits for editing, since you have a much cleaner signal to spot transients.
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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby Elephone » Fri Jul 12, 2019 9:54 pm

Hugh Robjohns wrote: Whatever you use, you're never going to replicate the exact interface characteristics of a guitar plugged into the amp, because a guitar's pickups are strongly reactive and the output of an active box like the Cleanbox Pro, or even a proper reamper, is much more linear... That means that some of the extreme subtleties of playing a guitar into an amp live may well be different when a pre-recorded track is reamped into the guitar amp... but That's not usually an issue (or even noticeable) for most people using this technique!

H

Sorry for harping on about this but...

...if I record a guitar while playing directly in front of my amp, but split the signal to record the guitar pickups directly, then re-amp the dry recorded pickup signal back through the same guitar amp and recorded that (exactly the same way)... then there shouldn't be any discernible difference between the recordings?

I ask this question, not because that's what I want to do, but because I want to understand what influences what. For instance, I know you can record dry feedback, then play it back through an amp. So, all these "extreme subtleties of playing" may also be capturable if the dry signal includes them(?)

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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby Hugh Robjohns » Fri Jul 12, 2019 10:17 pm

Elephone wrote:...if I record my guitar while playing directly in front of my amp, but split the signal to record my guitar pickups directly, then re-amp the dry recorded pickup signal back through the same guitar amp and recorded that (exactly the same way)... then there shouldn't be any discernible difference between the recordings?

Exactly this technique is used quite extensively.

H
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Re: Re-amping via ART Cleanbox Pro vs Passive box?

Postby ef37a » Fri Jul 12, 2019 11:17 pm

There are guitars players who will say, "unless you record guitar,amp, player in real time you miss the "feedback/feel"...art if you will, " ?

I am sure they are right. A very knowledgeable reviewer might say "Glenn Gould was having an off day" on a particular CD but it WAS still Glenn Gould!

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