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Helix Rackmount in 4CM - Volume Setting

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I am running the Helix Rack in 4CM with my tube amp.  I noticed the master volume on the front of the Helix still controls the overall volume output to my amp.  Is there a recommended setting I should set this at?  I'm attempted to match the volume as close as I can by ear.

 

Thanks!

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The "Volume" level controlled by the "BIG KNOB" occurs in the digital realm, before the final DA conversion. It has been demonstrated by geeky science types that lowering the level on the "BIG KNOB" affects tone. So, IDEALLY, you want to keep the "BIG KNOB" maxed. That setting is UNITY Gain - the (electrical) level IN = the (electrical) level OUT.

 

In REALITY, you gotta have much better ears than mine to tell the difference when using the "BIG KNOB" to control level.

The thing to do is to try it yourself. Set up a simple (NOT hi gain) preset. Start with the "BIG KNOB" maxed, and back it off a bit at a time. Be certain to compensate each time by raising the ACTUAL (what comes out of the speakers) volume level, to avoid having your ears tricked by the Fletcher-Munson effect (google it).

 

If you can honestly say that you hear a difference, leave the "BIG KNOB" maxed, or assign it to different Outputs (same thing - Unity Gain). If you CAN'T hear a difference, go ahead and use it to control Amp Level.

 

I leave it maxed (assigned to the active outputs). Not that I can hear a difference, it just works for me, as I have a Floor and set the output level on my PC112+ using an expression pedal and MIDI. If I was using a traditional MV tube amp and a Rack, I'd have to walk back to the amp/rack to adjust the level anyway, so I'd probably use the "BIG KNOB" so as to avoid changing the relationship between the pre and master sections of the amp.

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Not all amps work this way, but on some amps the master volume is pre the FX loop.  The 5150 III works this way.  I set all my volumes on my three channels so they are relatively the same volume.  Then I use the Helix volume as a master-master volume.  That way, if I need to turn up or down I only change one knob, not three and have to balance them out again.  

 

Generally speaking, if you max the volume on the Helix and you turn off the FX loop on your amp, which means the Helix volume will not work, then you should hear no difference.  You can set it up many different ways to achieve what you want.

 

In my opinion, changing the master volume on the Helix has little to no impact on "tone."  Another reason I keep the volumes constant on the amp is so the noise gate I have after the pre-amp does not need to be adjusted for volume changes.  I've done similar with my "analog" board by adding a JHS Little Black Amp Box Signal Converter which is a basically a master volume I can control in the fx loop of the amp.

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Sorry if I wasn't clear.  I didn't notice any change in tone, it was specifically a notable volume change.  When the volume is maxed on the Helix, the volume coming out of the amp is significantly higher than when its not plugged in.  

 

For the record, I am running a Mesa TC50, not sure if the master volume is before or after the effects loop.  For now, I've been doing my best to match the volume by using a decible reader without the Helix then using it again and changing the Helix's master volume to match accordingly.  Without any "suggested" settings, not sure if there is a better way.  Figured it was at least worth an ask! :)

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Mesas are a different animal.  They sometimes have parallel FX loops which causes problems. Most amps have series FX loops. 

http://www.diamondamplification.com/blog/2016/9/18/series-v-parallel-effects-loops

 

The other thing I would suggest is to make sure the FX loop you are using on the Helix is set to the correct level and matches your amp. Go to the Global Settings - Send/Return (FX loop #).  Normal setting for amps is Inst (instrument) but some amps will work better with Line level which is considerably louder and what yours may be set to.

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From the owner's manual, I thought this was interesting.

 

The Effects Loop is basically a circuit bridge from the end of the preamp to the Driver stage, with the SEND interrupting the signal at the preamp’s end and the RETURN feeding the power section just before the Driver tube. Using this patch point usually ensures the best sonic performance as well as signal to noise ratio with your outboard processors. That said, it is important to point out that this is a critical junction in the TRIPLE CROWN’s circuit path and whatever is inserted here can have an effect on the overall performance of the amplifier.

The Effects Loop is a Series Loop, meaning that the entire signal goes through it, unlike a Parallel Loop where a percentage of the unaffected pure signal is taken around the Loop. Therefore, the quality of the devices used in the Loop and their performance is critical to achieving the best sound and performance from your amplifier.

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I took a look at it and saw that the 1/4" output was set to Line, changing that to instrument was able to resolve that issue (since its going directly into the amp's effect return).  Everything was set to instrument already.

 

Thanks for the help everyone!  I love running the Helix in 4cm, especially since you can blend in amp sounds if needed too!

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I'm not suggesting that this works or is important to everybody running 4CM, but whenever anybody starts talking about levels I always like to point out that the difference between "line" level and "instrument" level has as much to do with impedance as it does with voltage. I don't know if the Line/Instrument options in Global Settings on the Helix change the impedance as well as the level. All I know is that back when I had a POD X3L (line level fx loop), I ended up having to use a reamp box, not only on the signal coming from the X3L fx send to the front panel of the amp, but also from the X3L live output to the effects return on the amp (the reamp box I have is 2-channel - https://artproaudio.com/product/dual-rdb/.) It wasn't enough to just turn down the fx loop send level and the output level of my X3L - the low-z signal coming from the X3L fx send made my preamp "screamy" (for lack of a better term) at any gain setting, and the low-z signal coming from the X3L output caused a weird ringing/pinging noise similar to microphonic tubes. Once I put the reamp box in there my preamp sounded just like plugging straight in and the ringing was gone. Yes, the output volume for a given Master Volume setting on my amp is a little lower than without it, but certainly not enough that I can't still rattle the tile off the floor when I need to (my Mesa Boogie .50 Caliber+ is too loud at 2...  plenty of headroom). So when I got my Helix I briefly checked out the Line/Instrument options but it didn't take long to realize that just leaving the levels at Line and using my reamp box was still the best option.

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