ADA Depot - A Forum To Support Users of ADA Amplification Gear

Non ADA Gear => Rack Gear => Topic started by: El Chiguete on August 04, 2015, 05:52:55 AM

Title: line level to instrument level (with correct impedance)
Post by: El Chiguete on August 04, 2015, 05:52:55 AM
Ok so here is the deal,what do you recomend that will take a line level signal down to instrument level with the correct impedance of a guitar to have as close as the original guitar signal go in to a guitar amp (btw that amp will be our loved MP-1!)?

BTW, I only mention the impedance not because I'm sure that this is a problem for me now but that one time in another forum someone mentioned that it might be a problem.
Title: Re: line level to instrument level (with correct impedance)
Post by: MarshallJMP on August 04, 2015, 01:50:27 PM
Can you explain a bit more,how does he want to use it?
Title: Re: line level to instrument level (with correct impedance)
Post by: Peter H. Boer on August 05, 2015, 01:25:31 AM
http://www.soundonsound.com/sos/jun04/articles/qa0604-3.htm (http://www.soundonsound.com/sos/jun04/articles/qa0604-3.htm)

 :thumb-up:
Title: Re: line level to instrument level (with correct impedance)
Post by: rnolan on August 05, 2015, 07:28:26 AM
Hey El, easy way is what Peter posted. We did a few posts about this ages ago where I posted a simple circuit which uses 2 resistors to drop the voltage. I have a lead which I used to go from Rockman X100 headphone out to 2 mono jacks with resistors to drop the level so I could plug into 2 Marshalls. Search on my posts you should find it, but it was ages ago. In that thread MJMP also gave some good advice re impedance IIRC.
Title: Re: line level to instrument level (with correct impedance)
Post by: El Chiguete on August 05, 2015, 11:32:12 AM
I think the link Peter posted hists it in the head of the nail my problem:

"The other issue that you need to be aware of is impedance. Guitar amps are designed to accept a high-impedance input, and plugging in a low-impedance, line-level signal will result in an increase in amp hiss. This will be more of problem if you like to turn your amp up loud."

I believe there is some level differences but that I can adjust BUT even when I just place in the chain a VOLUME PEDAL on my Lexicon MPX G-2 I get that dredded hiss! So now I have to get a reamp box to test this out... Maybe easier said then done because here not many people use the gear I use and dont run in to problems that need the solutions I'm trying to sort, but I'll get it done eventually!
Title: Re: line level to instrument level (with correct impedance)
Post by: MarshallJMP on August 05, 2015, 12:28:36 PM
The impedance is not so much a problem (EMG's are also low impedance) but the level can,but you can sove this with a small pot or 2 resistors.

It's usually better to drive with a low impedance,this gives less noise.For instance,the output impedance of the mp-1 is 100 ohm and usually goes in a 10k input (amp).
Title: Re: line level to instrument level (with correct impedance)
Post by: Peter H. Boer on August 06, 2015, 04:13:47 AM
I believe there is some level differences but that I can adjust BUT even when I just place in the chain a VOLUME PEDAL on my Lexicon MPX G-2 I get that dredded hiss! So now I have to get a reamp box to test this out...
Or try out what the article also suggests.
Take a stompbox on bypass that does not have a hardwired bypass. Reduce the level from line to guitar before going to the stompbox.
That should convert your low impedance back to high impedance again.

Worth a shot to try out first O0
Title: Re: line level to instrument level (with correct impedance)
Post by: El Chiguete on August 12, 2015, 09:55:17 PM
No luck guys, I have a friend that build a pedal that he can turn on and off the buffer and I'm still getting the same hiss! Check it out http://adadepot.com/index.php?topic=79.new#newp (http://adadepot.com/index.php?topic=79.new#newp)
Title: Re: line level to instrument level (with correct impedance)
Post by: Peter H. Boer on August 15, 2015, 07:40:49 AM
So, to make this clear:

You go Guitar -> MPXG2 Guitar input
MPXG2 Insert send -> MP1 input
MP1 output -> MPXG2 Insert Return
MPXG2 Main output -> Poweramp and/or direct to computer soundcard

Right?
Title: Re: line level to instrument level (with correct impedance)
Post by: El Chiguete on August 15, 2015, 11:34:31 AM
Yes.
Title: Re: line level to instrument level (with correct impedance)
Post by: Peter H. Boer on August 16, 2015, 01:44:07 AM
OK.

You've restored factoy settings as per page 1-3 in the manual?
And you've set up the gain structure as explained in the manual on page 1-5 & 1-6 (preset 249, unity gain, etc.)?

And when you bypass the pre-gain path the hiss is gone, when you engage th pre-gain path the hiss is there eventhough you've originally set it up at unity gain?

Correct?
Title: Re: line level to instrument level (with correct impedance)
Post by: Systematic Chaos on August 16, 2015, 02:48:46 AM
Went last night through some hidden sub-settings (using G2 Editor software) together with EC in a intl VidChat/WhatsApp "conference" and sent him a complete dump of my G2 setup and patches...

There's some hidden global EQ'ing deep down in the Sys-Routing that might have been the cause for the strange EQ curves EC posted recently....
Those hidden sub setting include Peak, Shelf and further global eq related settings....

We'll gonna go through it all step by step and set it up like mine (which works and sounds flawless and awesome) l8r today....

The hiss when engaging the PedalVol coul be caused by placing the PedalVol in the FX1 or 2 block...PedalVol should normally (as per the manual) be placed in the EQ block so I guess the block structure/layout is different and tailored to the fx that should go in the respective blocks...

Keep your fingers crossed and may the force be with us :)
Title: Re: line level to instrument level (with correct impedance)
Post by: El Chiguete on August 16, 2015, 06:35:24 AM
Went last night through some hidden sub-settings (using G2 Editor software) together with EC in a intl VidChat/WhatsApp "conference" and sent him a complete dump of my G2 setup and patches...

There's some hidden global EQ'ing deep down in the Sys-Routing that might have been the cause for the strange EQ curves EC posted recently....
Those hidden sub setting include Peak, Shelf and further global eq related settings....

We'll gonna go through it all step by step and set it up like mine (which works and sounds flawless and awesome) l8r today....

The hiss when engaging the PedalVol coul be caused by placing the PedalVol in the FX1 or 2 block...PedalVol should normally (as per the manual) be placed in the EQ block so I guess the block structure/layout is different and tailored to the fx that should go in the respective blocks...

Keep your fingers crossed and may the force be with us :)

It was a LONG day for me for sure, I spend almost 12 hours messing aroung with everything (including having to run a Virtual Windows XP on my PC with W7 to be abble to upload the patch of SC to my Lexicon) but at around 2:45am I finally had it done!

As for the Pedal/Vol using the FX1 or FX2 I actually tested the Volume effect in all the blocks placed before the preamp and it made the same noise (including the EQ block)... actually its ANY effect that I place before, doesn't matter which one it makes the same noise.
Title: Re: line level to instrument level (with correct impedance)
Post by: El Chiguete on September 01, 2015, 07:43:03 PM
I think tomorow will be a busy day!
Title: Re: line level to instrument level (with correct impedance)
Post by: Peter H. Boer on September 01, 2015, 11:28:19 PM
I think tomorow will be a busy day!
Yup, enjoy :D