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I was trying out Kurt's suggestions about re-amping the guitar tracks to create layer of heavy sounding guitars. I threw a cables from the headphone output of my aadrvark q10 straight into the clean channel of my mesa boogie dual rectifier head. I hear the guitar allright but I aslo hear a pretty loud "hum" sound. I tried using the main outs from the Aardvar but same story. I even re routed the signal into my Mackie 24:8 mixer and tried all of the mackies output but still,I get a loud hum. Is this normal ? Any suggestions ?

Comments

KurtFoster Thu, 09/23/2004 - 13:36

If you recorded humm, it will be there in playback .. amplify that and you have more huuummmmm ...

Another issue is be sure the guitar amp and your Arrdvark is plugged into the same electrical circut. If it isn't, you may get what is known as a "ground loop", where there are 2 paths to the ground ... this makes anything huuuuuuuuummmmmmmmmmmmmmmmmmmmm

Do not use the headphone out to reamp or to go to any other type of amp .. you need a line level signal for this application. A phone output will work, but there is extra unneeded aplification in the path which will add extra noise and you run the risk of pushing too much voltage into the amp and blowing the inputs.

Take a line level channel out from the Aardvark ... there should be 8 analog outs. You need to route the track you want to reamp from your recording software to the output you choose on the Aarvark.

Big_D Thu, 09/23/2004 - 20:39

I am also using Kurt's suggestion of reamping so I can get the whole rhythm section in one take. (By the way Kurt, it works GREAT, much tighter.)

I read about this years ago in an article on Bob Rock. If you have more than 1 amp you can send your recorded guitar signal to your Boogie, then send your Boogies slave out to the other amps input, Mic both cabs (you may have to use a gobo between them to prevent too much bleed through) check phase and pan hard L/R for the sound of 2 guitars playing or both panned the same for more texture. I've used up to 3 amps at once and blended them together for a nice fat sound (Boogie, Marshall and Fender). In the BR interview he said he's done up to 6 at once on the Black Album. Just thought you might want to try it.

therecordingart Thu, 09/23/2004 - 22:17

I have my old band coming in to record soon. They have two guitar players and here is their amp list.....

Guitarist 1:
Bogner head/Marshall 4x12
Mesa Boogie Single Rect/Mesa Boogie 4x12
Marshall JCM 900/Marshall 4x12

Guitarist 2:
Marshall JCM800/Marshall 4x12
Crate Blue Voodoo/Blue Voodoo 4x12
Mesa Boogie Dual Rect/Mesa Boogie 4x12

They have tons of rack gear including the ADA MP-1 which everyone has used or still uses.

I was planning on recording each guitar player separate. I'd run the guitar into the board through a DI box and send the signal out of the board through two different outputs. From there I'd send the guitar signal to each amp, mic each with an SM57, and record. Then I'd have the guitar play double their part with a the remaining amp. I'd have each of them do this....in my head this will create the biggest sounding guitars ever, but things don't always work out the way you plan.

This is really great gear they are using, I'll be using a mic almost everyone uses to mic a cab, and my pre's are decent.

I've never done this before so I'm hoping for the best.

HMNP Fri, 09/24/2004 - 05:48

Kurt Foster wrote: If you recorded humm, it will be there in playback .. amplify that and you have more huuummmmm ...

Another issue is be sure the guitar amp and your Arrdvark is plugged into the same electrical circut. If it isn't, you may get what is known as a "ground loop", where there are 2 paths to the ground ... this makes anything huuuuuuuuummmmmmmmmmmmmmmmmmmmm

Do not use the headphone out to reamp or to go to any other type of amp .. you need a line level signal for this application. A phone output will work, but there is extra unneeded aplification in the path which will add extra noise and you run the risk of pushing too much voltage into the amp and blowing the inputs.

Take a line level channel out from the Aardvark ... there should be 8 analog outs. You need to route the track you want to reamp from your recording software to the output you choose on the Aarvark.

Hi Kurt..No I didnt record hum. I'll try the other outs on the Aardvark and re route the signal and lets see what happens.

Therecordingart I didnt know you could use a direct box into the the mixing console and re-route it to the amps. Ill definately try that. Thanks alot guys!!

anonymous Fri, 09/24/2004 - 10:18

HMNP wrote: I hear the guitar allright but I aslo hear a pretty loud "hum" sound. I tried using the main outs from the Aardvar but same story. Any suggestions ??

You're running into a ground loop hum do to impedance mismatch. You can't plug a line-level signal into a device that only accepts instrument level and expect everything to play nicely.
You will need a device to properly "step down" your signal. the one I use everyday is the Little Labs PCP box. It has a routeable line-level input to instrument-level output converter. http://www.littlelabs.com/pcp.html made just for that reason. If it's too expensive for you, there are a couple less expensive options... like the Rolls MB15 which seems to do an OK job.

KurtFoster Fri, 09/24/2004 - 18:50

dustbro wrote: You can't plug a line-level signal into a device that only accepts instrument level and expect everything to play nicely.

Keyboards have line level outputs (-10dB / -20dB) ... and people run them into guitar amps frequently. I re amp this way all the time off the tape, with no problems. It is necessary to keep the levels in check, making sure the send from the cosole is not so hot that it overload the inputs of the amp. Caution is in order or you can fry in input stage of your Marshall /Fender / Boogie (or whatever).

I use transformers if I am going to make a long run with the signal, like out to the "Live Room" through the wall box's or a snake but if the amp is relativley close to the mixer or patch bay, I have found plugging directly into the amp presents no problems.. I usually keep the amp head close to the patch bay and run a fat huge herkie 10 guage speaker cable to the speaker cab ..

Ground loops are caused by more that one path to ground, not impedance mis-matches .... a transformer (essentially what the Radial and the Littlelabs boxs are [btw, both are excellent and if you can affrod them work wonderfully!] ) lifts the ground and eliminates the hum.

Big_D Fri, 09/24/2004 - 19:50

Kurt, I have been sending my amps the tape signal straight from one of my Layla's outs. Is this wrong? Should I be sending it to my mixer first and then to the amp so I can control the levels? Is their a ceiling I should stay below to prevent damage. These amps ain't cheap and blowing out the input stage would make for a very bad day.

anonymous Sat, 09/25/2004 - 01:55

Kurt Foster wrote:
Ground loops are caused by more that one path to ground, not impedance mis-matches ....

Wherever there is an impedance mismatch, a portion of the signal is reflected back into the cable rather than being transmitted to the input. This will definitely cause an audible effect, such as a hum in this case.

KurtFoster Sat, 09/25/2004 - 11:34

The Radial box splits the signal as well ..

dustbro wrote: Wherever there is an impedance mismatch, a portion of the signal is reflected back into the cable rather than being transmitted to the input. This will definitely cause an audible effect, such as a hum in this case.

Thanks Dustbro for clearing that up .. I understand what you are speaking of now ... but this doesn't happen in every case .. and I have never had a problem with it .. Most guitar amps will handle a 10k ohm input just fine...

HMNP Sat, 09/25/2004 - 13:55

Kurt Foster wrote: HMNP
Did you manage to get rid of the hummmmmm???

Yes Kurt thanks a millions. I re-routed it thru the Aardvark Q10 assignable outputs like you said and its totally gone! Im trying out different stuff now. I have to think was is best, either to record a single channel of electric guitar and then re-amp it or when recording use a splitter and record using two different amps at the same time. Both ways Im getting great results. Im using a Bass POD to split my guitar signal, one goes intoa the Boogie the other into a Marshall and that things sounds TOO GOOD!! Thanks a million!!

anonymous Tue, 02/27/2007 - 08:31

Kurt Foster wrote: [quote=dustbro]You can't plug a line-level signal into a device that only accepts instrument level and expect everything to play nicely.

Keyboards have line level outputs (-10dB / -20dB) ... and people run them into guitar amps frequently.

If I see a keyboard running through a guitar amp, it's a rhodes or something similar, which has a guitar level output. If it's a digital based keyboard, it seems as though people typically run through those Roland keyboard amps, which have mic/line inputs.