Guitar amp input impedance matching with line signal

You don't need to do anything to match impedances per se. But guitar levels are a little quieter than line level so you may need to reduce the output level of your interface ~6dB more than usual.

Thanks -
 
I've done a bit of reamping ITB with sims, and even some using the USB port and reamping features of the IRT Studio.  The latter is a real pain though because of ASIO single device limits in Windows ....
 
Thanks again.

Jeff gave some good places to look but forum user tlw will hopefully come by. He has been an endlessly useful resource on such matters for me and can only assume he's a guitar (and general stringed instrument) player who's been wrangling with this stuff for decades.
 
Based on his (and others) input I've learned there are lots of factors to take into consideration from output to the guitar > any DI type devices to go to either mixers/interfaces to bring up the output level of the guit (which is also dependent on the type of pickups involved) > into whatever recording platform (the DAW) and handling it there (like using the External Insert plugin in Sonar or other methods of routing back out and in again) > out from the DAW > into the device that's gonna give you your initial "reamp" signal (essentially taking the recorded track back down to an Instrument level signal to mimic the output of your guitar) > into the amp or guitar FX unit or guitar pedal(s) or whatever > back into the DAW via mics or amp line outputs or mixer or whatever (and whether you are doing it using an FX send/return/insert type setup or recording the results straight into a new track or whatever).
 
Brain bustin' shiz fo sho...
 
You have however said you want this...
 
E.Guitar -> to INST input on interface -> ITB effects -> Ext Insert -> guitar amp input -> guitar amp DI -> interface
 
I've added a bunch of crazy thoughts and notes based on all my chaotic pontifications on the matter. I have indeed spent a LOT of time thinking on this and have been enacted many of the actions I describe/allude to.
 
"E.Guitar (which I'm assuming means an electric guitar) ->
 
to INST input on interface (the Inst input on many interfaces ain't nearly as good for guitar as they claim to be... they do not have the input impedance a guitar preamp section does so you may want to consider that... especially if you are going to get some kind of guitar DI that can do reamping which may help at this stage as well)->
 
ITB effects (I would probably avoid going nuts on effects inside the DAW until AFTER you have reamped it... could you describe more what you intend to do at this stage)->
 
Ext Insert -> (This is where you need the "reamping" device to appear to bring the Line output level down to a regular guitar output level that can be properly process by a guitar amp)
 
guitar amp input -> guitar amp DI (okay... but if you have the guitar amp DI can I ask why you aren't using it to do your initial recording in the first place? You could use a splitter to send to your guitar amp AND the interface Inst input and get the best of both worlds in one shot... no reamping needed and you can always reamp the DI signal afterward anyway)->
 
interface (at this point your reamping device will probably be outputting a Line Level signal so disengage the Instrument/Hi Z stuff... or, and I would personally prefer this, send it through a mixer first so you can trim/pad/EQ the signal a bit before it hits the DAW).
 
 
What devices do you have currently available? Like what kind of amp do you have (and what cnnections does it have)? What interface? What (if any) kind of mixer do you have? Do you have any fancy pedals or pedalboards that can act as splitters?
 
I'm assuming you do not currently have a reamping device which will be the missing peice of the puzzle for i/o and the Radial stuff is definitely something to research (and there is lots of informational stuff online to help figure out the whole process as well... which may make you realize you don't actually NEED to reamp... like if you can acheive an input splitter type setup... for example like I can with my Boss TU-2 tuner pedal).
 
I have been personally looking at an ART Tube MP/C unit because it is capable of reamping but serves a bunch of other purposes like adding tube drive and external compression to mic, instrument and line input signals. It's a cheapo unit and there are much better options that are more specific (like the Radial stuff) for the various tasks but it depends on your needs and budget.
 
That's a big ole, unproofread dump of chaotic info to absorb but you're smart so hopefully it can help you do the same type of research I've been doing over the past couple years and come to the best conclusions for your own needs.
 
Cheers.
 
Edit: and batsbrew is here now too... who is actually the one who pointed me to the ART stuff and has a lot of knowledge on such things as well.

batsbrew

 
new, read about this in this month's TAPE OP
 
sounds very intriguing

Looks interesting.  Like the original Reamp box.  I'll check it out

Actually, most of the time the effects loop should do fine.  That's where the majority of the effects I normally use "belong".  The normal case goes like this:
 
E.Guitar -> AMP -> AMP/Send -> interface -> ||| [DAW effects] -> AMP/Return -> AMP/DI -> interface -> DAW
 
If the signal is recorded at |||, then reamping of effects/power section/cab/spkrs/mic can be done without sending the signal back out again.
 
Of course the ultimate flexibility is to go straight in and record a completely dry guitar signal ... but what led me here is trying to decide if I should be using my real amps instead of buying more sims.
 
So many toyz, so little time ...

Thanks for the tip.  Hopefully I'll get everything sorted so I can put whatever I wherever I want - that's the goal!
 
 

Beepster
Jeff gave some good places to look but forum user tlw will hopefully come by. He has been an endlessly useful resource on such matters for me and can only assume he's a guitar (and general stringed instrument) player who's been wrangling with this stuff for decades.

Well, thanks for the compliment Bit, but re-ampings something I claim little to no expertise in other than saying I think the big issue isn't impedance but volts and amps. Guitars are fussy about what impedance they're plugged into but amps generally don't mind so much what's plugged into them.

Guitars output what, millivolts. +4dBU levels can be a couple of volts or more, and -10dBU is still much hotter than a guitar. It's not that a +4dBU signal will destroy the amp input stage or anything (I hope), but it will totally and instantly saturate the amp circuit. Winding the line signal reaching the amp right down may or may not be low enough to get acceptable results. Hence re-amp boxes, and the most useful of all are the ones that let you split the signal so one output feeds your amp and another feeds the mixer/interface so a "bare" copy of the guitar or bass can be recorded at the same time.

Unless you want to use a fuzz face or similar basic fuzz or booster that reacts very strongly to the guitar tone and volume pots. They really do need an actual guitar plugged into them to work properly because the guitar becomes part of their circuit in a deep amd meaningful way (which is possibly why the emulations of them range between poor and hopeless).

Other than that I defer to Danny Danzi and people more likely to want to re-amp than I am.

I think (and seriously I don't know) that the risk of damage to equipment comes from the input that's expecting a low output from a guitar thus draws too much (or maybe sends too much) from the source device... thus potentially blowing the source device (not the input device/amp).
 
I have no idea though. I would just never hook up a line level output to a guitar amp/hiz input.
 
As for the experiment of hooking a guitar up to a line level input then through I DI if your pedal does have line out capability (a lot of Line6 stuff does) then you could just plug directly from the guitar into a line input on your interface, record it and then try it again through the Line6 (using the line level output).
 
Even easier though would just record the difference between the Line input and then any HiZ inputs on the interface.
 
Actually I just ran into an old problem of mine again where my bass, for some bizarre reason, ouputs WAY too hot for the HiZ input on my interface. If I switch to the Line input and crank up the trim I get a reasonably volume level BUT the sound is garbage.
 
This is all very odd because it's just a stock Squier P-Bass single coild bass pickup. I have no idea why it ouputs that hot. I eventually remembered that the best signal I can get (using the gear I have on hand) is to run the bass into my old Line6 Duoverb head and record the DI/Balanced line outputs.

Actually the impedance matching is necessary for the good performance of the Amplifier and the other related devices.
Can you please share your specifications for the Amplifier and the Cable interface you are using?
Also do you have any idea for the impedance from both side of your devices?