rogonzab
404 posts
Nov 04, 2013
5:06 AM
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Hi,
I have some extra cash and I want a Delay Pedal. I have two option, an used Behringer Vintage Delay, or a new (and more expensive) joyo analog delay (mxr carbon copy clon).
I guess that any of these two will work for me, but there is an internal difference:
VD Input = 500k ohms
Joyo Input = 1meg ohms
So, this differences in the input impedance is going to make a sonic diference when I plug my Hi-z mic (Shure CM 99b86 and Akai DM-13).
The inputs on most guitar amps is 1meg, whit a smaller input impedance is going to be a missmatch or something?
Thxs!!
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Greg Heumann
2444 posts
Nov 04, 2013
8:45 AM
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The input impedance of a pedal, when it is on, take's the amp's input impedance out of the circuit as there are active electronics in between. When off, it may or may not depending on design ("true bypass" means the pedal is out of the circuit and once again the amp's input impedance is what your mic sees.) Either way, anything ELSE in between the mic and that pedal, such as a volume control - is effectively another resistor in parallel - so total input impedance is less than the impedance value of the pedal OR the pot in the volume control. The formula is r1*r2/r1+r2. For example a 250K volume control and a 500K input impedance on the pedal brings the actual input impedance to 166K ohms. The same VC with a 1M pedal results in 200K.
The good news is that dynamic mics tend to be pretty happy until the input impedance drops to 50K or so. Crystals on the other hand are much more sensitive.
Note that all of the Lone Wolf harp pedals have an input impedance of 1M to keep everything as high as possible.
The tonal difference between these pedals should drive your choice - and probably is NOT due to their difference in input impedance.
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***************************************************
/Greg
BlowsMeAway Productions
See my Customer Mics album on Facebook
BlueState - my band
Bluestate on iTunes
Last Edited by Greg Heumann on Nov 04, 2013 8:48 AM
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rogonzab
406 posts
Nov 04, 2013
8:57 AM
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Thxs Greg!!
If I get it right, whit dynamic the input impedance is not as an important whit a pedal.
One question remains, whit the input of an amp is the same? is any differecne betwen a 1meg or 500k inputs in the amp?
thxs a lot!
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Greg Heumann
2445 posts
Nov 04, 2013
11:38 AM
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The amp's input does not matter if the pedal is active.
If the pedal is off and is a "true bypass" style pedal - then the input impedance the mic sees is now a function of the amp's input impedance (and volume control if present)
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***************************************************
/Greg
BlowsMeAway Productions
See my Customer Mics album on Facebook
BlueState - my band
Bluestate on iTunes
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HarpNinja
3580 posts
Nov 04, 2013
11:51 AM
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Related:
I noticed that when I run my Tech 21 Blonde into a LW V2 Delay into a LW Fat Cat, into a QSC K10 there is a huge volume drop from the FC.
Meaning, the Blonde and Delay give me a very strong signal. When I turn on the FC, the signal is cut and no amount of knob turning gets me back to unity gain.
This only happens with the K10. If I plug that board into my desktop interface, there is no volume drop. I am speculating there is an impedance issue with the FC and K10. Thoughts???
FWIW, the three pedals sounds awesome into my DAW. I'd like that sound through the K10.
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Mantra Customized Harmonicas
My Website
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rogonzab
407 posts
Nov 04, 2013
12:11 PM
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Greg,
Sorry to insist, but english is not my first language so sometimes I cant express myself right.
What I wanted to ask was this:
"whit the input of an amp is the same? is any differecne betwen a 1meg or 500k inputs in the amp "whitout any pedal, just the mic"?
Sorry for the lost time.
Thxs!!
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Greg Heumann
2446 posts
Nov 05, 2013
9:05 AM
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When you're playing straight into the amp, the input impedance does matter. The difference between 500K and 1M for a dynamic element is negligible. It would even be negligible for a crystal element, unless and until a volume control is added. The math is as above. A 500K input impedance and a 500K pot in the mic drops the impedance to 250K - kind of the lower limit for crystal elements.
----------
***************************************************
/Greg
BlowsMeAway Productions
See my Customer Mics album on Facebook
BlueState - my band
Bluestate on iTunes
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