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Post by jamesgasson on Mar 12, 2018 19:10:58 GMT
As the title suggests, I'm wondering about the necessity of re-amp boxes... A band I know uses Native Instruments' Guitar Rig at their gigs. They plug a guitar into their interface, run it through a bank of software effects boxes, and then feed the physical output into an amplifier. I asked if they used a re-amp box before the amp to unbalance the signal and provide correct impedance, and their technician tells me that he doesn't bother and it's never been a problem. What is everyone else's opinion on this? Ethan... are re-amp boxes snake oil?  |
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Post by Hexspa on Mar 13, 2018 1:31:53 GMT
As the title suggests, I'm wondering about the necessity of re-amp boxes... A band I know uses Native Instruments' Guitar Rig at their gigs. They plug a guitar into their interface, run it through a bank of software effects boxes, and then feed the physical output into an amplifier. I asked if they used a re-amp box before the amp to unbalance the signal and provide correct impedance, and their technician tells me that he doesn't bother and it's never been a problem. What is everyone else's opinion on this? Ethan... are re-amp boxes snake oil? I don't really have an opinion because I don't have one nor have I used one. That being said, impedance does matter and can effect the sound. |
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Post by jamesgasson on Mar 13, 2018 11:26:51 GMT
You've never used one because you've never found it necessary? Or because you generally don't re-amp anything?
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Post by rock on Mar 13, 2018 13:11:29 GMT
I don't reamp so I don't know but here's an article: www.diyrecordingequipment.com/blogs/news/86235652-explain-like-im-5-why-do-i-need-a-reamp-boxWhat I HAVE done is to run line level signals into a hi-gain guitar amp like a Marshall 1987 (plexi). Two main Issues; 1) As far as the balanced issue goes, all electronically balanced circuits will operate unbalanced one way or another. Some are designed to so when you plug a TS plug into a TRS jack, the sleeve of the plug shorts the ring and sleeve of the jack and as a result you get and unbalanced signal. You can also use a in inline transformer, these are passive so they will work both ways. Here's and article on Bal/Unbal: www.presonus.com/learn/technical-articles/Balanced-Unbalanced2) Signal level. The line level signal is usually too hot for a hi-gain gtr amp. If you don't attenuate the signal, the input/gain knob (on the amp) is at or near zero and hard to adjust if you can do it at all. I built a little attenuator (passive) box with a 10K resistor and a 40K pot in an "L" pad configuration. I put a 1uF capacitor (not required but for "good luck") on the input to block any DC that might be on the signal line. (exact values not critical as long as you're in the ballpark) The impedance should not be an issue because you're going from a low Z out to a hi Z in. The other way around would be bad because you'd load down the wimpy hiZ output which is not what you're doing so you're OK. |
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Post by jamesgasson on Mar 13, 2018 13:37:30 GMT
Very interesting, thank you very much.
It does then rather beg the question why re-amp boxes are necessary. If the output of your interface is going to give you an unbalanced signal, if impedance isn't really worth worrying about (bar a few rare exceptions), and if you can sufficiently attenuate your signal by lowering the output level -- what are they really for??
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Post by rock on Mar 13, 2018 19:30:07 GMT
Well, I suppose they are not absolutely necessary but they will make life easier, especially if you're not handy with even simple DIY electronics.
I do think you need an inline attenuator instead of just lowering the output from inside your DAW. Reason is, when you lower the output level in your DAW only, you still have not lowered the noise level from the hardware in the computer out. OTOH, if you run the DAW at normal levels, and attenuate the line, you reduce the signal level AND the any inherent hardware noise at the same time.
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Post by Ethan Winer on Mar 15, 2018 13:53:26 GMT
I've never used a formal re-amp box either, but I can't see why that's any better than two resistors to drop your line level feed down to guitar amp level. I think a 20 dB pad is about right. Or you can be fancy and put a 10K potentiometer in a nice metal box with connectors to optimize the send level separate from the line level source volume. I'd put a 22K resistor in series first, so the maximum volume is 10 dB softer, then the pot won't be so sensitive at the bottom of its range. I'm not sure what else is in a "real" re-amp box. Maybe a transformer to avoid ground loops? A quick Google search returned this schematic from the Jensen Transformer company:  This is even fancier because it lets you change the source impedance the guitar amp sees. But really, a voltage divider (20 dB pad made from two resistors) is probably all you need. |
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