GP-10- Question about H/P Jack use...

Started by MountainCraft, July 04, 2019, 09:30:46 AM

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MountainCraft

For some reason, I was under the impression that when something was plugged into the Headphone jack, the L (mono) and R 1/4" outputs were inactive (no sound)...

But I was looking into this in the manual and it says the following:

"PHONES jack
Connect a set of headphones (sold
separately) here.
* When you connect a stereo-mini plug
to this jack, the internal guitar amp
simulator will be automatically on so
that you can also enjoy the powerful
guitar sound with your
headphones. In this case,
the sound from OUTPUT
jacks will have the same
effect.


So to be sure, if I connect something to the H/P jack, there will still be an output from the normal L/R 1/4"  outputs, but they will be effected so as to simulate an amp like in the H/P jack?  If this is true, it makes things a lot easier..

Also (pretty sure of the answer to this, but want to make sure), If I intercept the humbucker pickup signal via the G/K cable (and then return it via same cable), then whatever I am inserting back into the GP-10 (via the GK jack), will 'always' be available to me at the Guitar out jack, right?

From the manual:

GUITAR OUT jack
Normal pickup signals of the guitar are output.


So, if I intercept the humbucker signal in the GK cable, and then send it through an effects loop and return it to the GP-10's GK jack, then whatever is input at the GP-10's GK jack, will show up unadulterated at the Guitar Out jack, and still be available to the GP-10 internally to use either the GK pickup, the regular pickup, or both as selected patch determines, Right?

Is there a 'levels' issue here?  Or can I just adjust patches as needed (or more specifically, output from the effects in the loop) and I'll be good to go? (don't want to damage the input circuitry of the GP-10 by feeding it a line level signal where it's expecting a pickup level signal).. I'm thinking that since many guitars have active pickup circuitry, and thus are a line level output, the GP-10 should be able to handle line level inputs from an effects loop (in this case, the output of my MS-3) at the GK jack?

Slowly getting issues worked out on the way to integrating everything how I want..

Thanks,
Mark

admin

#1
Yes both GP-10 Headphone out and L& R 1/4"  Output jacks deliver sound at same time

But the Output Mode for all will be forced to Line/Phones Output Mode (which when GP-10 DSP Amp /Speaker modeilng is on , Line /Phones mode  rolls off brittle high frequencies anytime the GP-10  Headphone out jack is occupied.

Goal of Line/Phones Output mode is to emulate a miced speaker cab EQ curve for going straight to PA/ recorder

MountainCraft

Quote from: admin on July 04, 2019, 09:37:37 AM
Yes both GP-10 Headphone out and L& R 1/4"  Output jacks deliver sound at same time

But the Output Mode for all will be forced to Line/Phones Output Mode (which when GP-10 DSP Amp /Speaker modeilng is on , Line /Phones mode  rolls off brittle high frequencies anytime the GP-10  Headphone out jack is occupied.

Goal of Line/Phones Output mode is to emulate a miced speaker cab EQ curve for going straight to PA/ recorder

This is good in my case, since I go direct into a mixer/PA...

What about line level from an effects loop going straight in on the normal p/u circuit at the GK jack?  Safe?

Thanks for the quick response... Have almost enough info to start making cables/jacks, etc.
Mark

admin

This GT-100 thread covers valuable info on Line/Phones Output Mode which also  applies to GP-10 and  many other Boss MFX pedals  (GT-001, GR-55l

https://www.vguitarforums.com/smf/index.php?topic=26010.msg189710#msg189710

admin

#4
Quote
What about line level from an effects loop going straight in on the normal p/u circuit at the GK jack?  Safe

Any signal hitting GP-10 Guitar Input  must be padded down to instrument level


don't forget the GP-10 internal stereo Line level  summing mixer input ( aka the 3.5mm TRS Aux Input - to add external stereo signals from FX, External Synth returns, etc

MountainCraft

Quote from: admin on July 04, 2019, 09:48:38 AM
This GT-100 thread covers valuable info on Line/Phones Output Mode which also  applies to GP-10 and  many other Boss MFX pedals  (GT-001, GR-55l

https://www.vguitarforums.com/smf/index.php?topic=26010.msg189710#msg189710

Gotcha, I think just the way it comes out of the box is what I need...

My only big question now, is if it's safe to put an effects loop in the normal guitar circuit of the 13 pin GK-3 cable going from the guitar to the GP-10..

IOW, if instead of using the provided short TS cable jumper from the guitar's normal pickup jack to the GK control on the guitar, I took a cable from the guitar p/u jack, ran it through a guitar processor or stompbox loop, and then plugged the output of the guitar processor/FX loop back into the GK control on the guitar, sending it through the 13 pin GK-3 cable to the GP-10  (in practice, I plan to intercept the signal inside the pedalboard just before it goes into the GP-10, but electrically, this describes what I want to do)..

Safe?

Thanks,
Mark

admin

#6
QuoteMy only big question now, is if it's safe to put an effects loop in the normal guitar circuit of the 13 pin GK-3 cable going from the guitar to the GP-10..

Been doing that for years

Back in 1996 with RMC Fanout Box
Then with a modified Roland US-20  GK A/B Switcher


https://www.vguitarforums.com/smf/index.php?topic=3664.0

But during recording anyone can accomplish similar by  feeding normal guitar jack out to external FX , then return into the GK-3 Guitar input

MountainCraft

Quote from: admin on July 04, 2019, 10:28:21 AM
Been doing that for years

Back in 1996 with RMC Fanout Box
Then with a modified Roland US-20  GK A/B Switcher


https://www.vguitarforums.com/smf/index.php?topic=3664.0

But during recording amyone can accomplish similar by  feeding normal guitar jack out to external FX , then return into the GK-3 Guitar input

There is no active circuitry (ie buffers/impedance matching) in the path at all? (not sure what all is going on inside the box)

Thanks,
Mark

admin

#8
Quote from: MountainCraft on July 04, 2019, 10:40:58 AM
There is no active circuitry (ie buffers/impedance matching) in the path at all? (not sure what all is going on inside the box)

Thanks,
Mark

Of course there are buffers

Break down the GK-3 signal path
we have schematics

https://www.vguitarforums.com/smf/index.php?topic=73.0

Impedance matching went out the window decades ago


There are guidelines

https://electronics.stackexchange.com/questions/169608/impedance-matching-for-a-guitar-pedal

There is already a HiZ input opamp buffer
inside every GK-3
any subsequent  FX pedal will have a low impedance signal after that GK-3 " normal guitar opamp buffer

And most "non true bypass " Boss FX also have always on FET buffers

MountainCraft

Quote from: admin on July 04, 2019, 10:45:05 AM
Of course there are buffers

Break down the GK-3 signal path
we have schematics

https://www.vguitarforums.com/smf/index.php?topic=73.0

Impedance matching went out the window decades ago


There are guidelines

https://electronics.stackexchange.com/questions/169608/impedance-matching-for-a-guitar-pedal

There is already a HiZ input opamp buffer
inside every GK-3

And most "non true bypass " Boss FX also have always on FET buffers

But the bottom line is that the input of the GP-10 at the 13 pin GK jack can safely handle the output of an FX loop, right?  I just don't want to fry anything at the GK input of the GP-10...  Beyond that I can 'experiment' as long as it is safe to do so...

Thanks,
Mark

admin

Quote
But the bottom line is that the input of the GP-10 at the 13 pin GK jack can safely handle the output of an FX loop, right

Yes, but must be instrument level ( avoid +4 dB levels)

MountainCraft

#11
Quote from: admin on July 04, 2019, 10:56:13 AM
Yes, but must be instrument level ( avoid +4 dB levels)

This is where I'm confused.. The difference between line level out of an active FX unit (hi Z), and the HiZ level of a Passive pickup...

I understand +4 to be line level balanced output from pro audio gear (like other mixers, DATs, etc.), and -10 to be line level HiZ output from things like pedals, RCA jacks on CD players, 1/8" TRS on cell phones, etc...

But what is the difference in signal strength between passive and line level HiZ signals?  Is it something I have to consider (other than adjusting gain within the given ranges of the FX devices in use and the GP-10)?

I'm pretty sure all is well in what I want to do, but I'm just checking, double checking, and triple checking..



Example signal flow of passive guitar pickup:

Guitar to GK cable >  input of TRIO+ > TRIO+ FX Send > Guitar input of MS-3 > L output (mono) of MS-3 > input at GK input at GP-10 > L output (mono) of GP-10> FX Return of TRIO+ > TRIO+ H/P out to Mixer & GP-10 H/P out to Mixer (MIDI to mute/unmute channels on Mixer as needed)

Considering other options, but as long as that chain will work, then all of the other options I'm considering will too..

Sounds like I'm safe to experiment, but just want to make triple/quadruple sure...  (stupid questions better than costly mistakes)  ;D

Thanks,
Mark

PS: That's a handy thread you linked me to.. Lots of info in there and answering other questions I had (ie, GK jack/cable pinout)

The GP-10 could have been made so much more powerful and customizable  by just including DIN MIDI ports and an FX loop...  Really missed the boat by leaving those two things out...


admin

No 5 PIN MIDI I/O on Rolands newest/Best Guitar to MIDI Processor (2015 Boss GP-10) is a total missed opportunity

The bean counters needed to save $2 cost

But they probanly saved $100k in support calls

Where's my paycheck? ;)

MountainCraft

Quote from: admin on July 04, 2019, 12:12:37 PM

Where's my paycheck? ;)

Right?

On the plus side, it opened up some opportunity for entrepreneurial problem solvers... 
Still would prefer plug and play functionality though..