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Getting a unity gain line level output?


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Hi all!

So I'm enjoying my HD500 (yea i only just bought one in 2018 in great condition second hand) for use with something not generally thought of but for solo acoustic shows. I will also use it for electric gigs with a band (1% of gigs) in the same way but this question is about specifically getting a unity gain signal out of the 1/4" output for Acoustic gigs so venues that have an XLR to In-House can get neither a too quiet nor a too loud signal. These venues take this signal and plum it off to their amp and usually control their level from an iPad. If the signal is weak i guess i'll have to readjust my master output coz they'll not have enough level and if its too loud it could result in a lot of bleeding ears and equipment damage etc. 

I have a pedalboard with the unit and Roland kick trigger in it where everything, vocal mic, acoustic and kick trigger (into effects return) is setup. I have done 2 gigs so far and it already sounds good but just with my own equipment not into a venues in-house. My paths are as follows:


Path/Input #1: Guitar (with active pickup at max) > Vintage Pre > EQ > Tube comp (for boost) > AMP DISABLED > Both join at Mixer > Reverb > Effects Loop > Looper

Path/Input #2: Mic > Vintage Pre > EQ > AMP DISABLED > Both join at Mixer > Reverb > Effects Loop > Looper

Roland Kick: Effects loop return > Looper (this only seems to work when the Effects loop is disabled, why haha?)

(if there is some way to get the Looper to only record the guitar id love to know!)



Unit switches = Guitar in is at "Normal" and 1/4" output is at "Line"

I then use a mono 1/4' to XLR cable to my powered speaker, the XLR out of this speaker will go to the venues In-House.


So i did notice that when i disabled the effects on the guitar path it was a lot louder signal, and the mic had distortion and some signal noise so i should be able to fix that no worries... 

My real question is that without the HD500 having a sound meter or clipping meter how do i know where to set the guitar pickup level and whats the correct way to achieve this?

Is it at the mixer? Maybe its at the master output? 

Obviously on a real mixing desk you set the fader at 0 and bring up the gain pot so its kinda just in the orange.

Is there some software on the computer that emulates a mixing desk that i could hook up via USB and play into to test signal level? Can the HD500 Edit software do it?

Sorry for all the questions haha!


My thought is to start fresh with the 2 paths (no effects or amps), leave guitar pickup at max, adjust desired Mic volume output to match with the trim pot, then add effects preamps/eq's etc that are not boosting or cutting volume.


Would be great to hear everyones thoughts if that all makes sense,

Thanks :)!

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I keep on bypassing every block, to make sure it doesn't amplify too much or decrease the signal


Blank patch is great to find unity, in a tube amp i found 3/4 Master is the sweep spot, equivalent to guitar plugged directly in the amp

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Yes, the biggest oversight in the HD500 design was no signal level meter. The signal can get clipped after any of the FX blocks if you're not careful. But unless you're doing something extreme, and I doubt you are with an acoustic guitar, then you're probably fine.


I measured the clip levels of the HD500's various IO ports and reported my results here. For example, for Guitar Pad = Normal, the input ADC will clip at 8.3Vpp, which is HUGE. You're active preamp output is probably closer to 1Vpp. Also, note that the gain from Guitar (Normal) to 1/4" out (amp) is -4.9dB. That is, a blank patch lowers your signal by 4.9dB! However, switching the pad to "Line" adds 6.1dB of gain and will largely restore your signal gain back to it's normal level (actually giving you -4.9dB + 6.1dB = 1.2dB of signal gain).  All my data was taken with Master Volume = max. Reducing that will result in lowering your signal level (obviously).


I have also measured the gain thru a variety of FX and listed the results here. This way you can account for those gains/losses as well.


Finally, since you're using the Vintage Pre you may be interested in this thread, where I measured the frequency response of a variety of EQs. The Vintage EQ and gain & output level controls so you probably have to adjust both to get net gain = 0dB. In that set of data I used an input level of -20dBFS (to make sure I didn't clip anything) so for 0dB gain look for a -20dBFS output level. It looks like Gain = 50% and Output = 72% will do it.


Oh, one more thing - once you start adding compressors and EQ then the concept of "what's louder" gets really fuzzy. Frequency response effects and changes in dynamics can make something SOUND louder even tho it may measure lower. So, use my measurements only as guidelines and places to start from.

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  • 4 weeks later...

There are so many variables to changing the levels it can become so mindboggling, many just give up on the HDs.,

A level meter on the unit would of been good but there are other ways.

This one turns up your ears.

Shield your instruments pickups as best as can be. Anti feedback cover over sound hole etc.


Plug HD into a PA mixer with monitors attached and has metering ideally but best an external Interface to computer to check level into a Audio program and follow below. Set interface levels to +4db.

Ensure on the HD the output is set to line and use the pad for active pickups . These toggles are next to the expression pedal.

Turn the PA output down to accommodate the HD Master volume knob to the max. (Do not use the headphones on the HD itself)


The noise level will be heightened but for now put up with it and turn down the output on the mixer but don't adjust it, leave all faders, EQ etc. flat. Unity gain, and just enough input gain to register about -12 db or -14dbFS on peak meters. Still in the green. but keep it below clip. Let the ears listen.


The theory behind this method is you set up the HD at max and run the line outs into a mixer (ideally with metering) and turn it's output down to for listen/ tracking.


Now when it comes to setting levels within the HD itself you have ruled out one variable. Your ears will be attuned to what your unit is doing at max output. 
Adjust all FX, amps and both paths via the mixer block with this stable maximum.

Solve levels between FX etc this way within the HD and keep from going into the red and clipping your input level on your PA mixer. Always trust your ears over visual meters.


In reality, at a Gig or normal use you can turn the HD output level down to minimize noise but most importantly if you need to turn it up you are not turning up internal distortion not previously heard  Shielded electric guitars should be fine with little noise.


Resist the urge to lower the Master volume, even for noise and then making tweaks on the unit .  Make all tweaks at maximum HD output. If you need to change or tweak at a gig use the global EQ only unless you made a booboo.


Mostly in normal use you will back off the volume knob a quarter or so and a half or more for headphones directly plugged into the unit but not ideal for making patches that will be good for live work.


Hopefully, you can sketch this out and think with it.  Turn down your external monitoring; max out the HD volume knob, listen from there; Check the levels into an audio interface and adjust at the HD to keep from clipping. Before making huge changes make sure the output toggle is set to line level and the active pickups have a pad activated next to the expression pedal; make all level decisions between FX within the HD and only at max output knob volume.


If you are going into an amp or some other setup and need to make changes it is best to save these as a preset in a setlist under the name of the different monitoring method and naming it as such.







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I use to set levels on all my patches. It's only for PC.


I think you're going to want to find a base point on your pickup's volume and craft your patch levels around that mark. Ideally you don't want to accidentally bump the pickup volume because that could clip the rest of the signal down the path. That meter will let you know when you get into to clipping. Like the previous response said, I set the master on the pod at about 2 o'clock. I put tape on the pod and drew a mark at 2 o'clock to remind me.

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