"Auto" Impedance - 1st Active Block - Does an active Mixer Block Count?

sprint

sprint

Axe-Master
The Axe3 manual states that, when set to "Auto" the impedance will be set according to the 1st active block in the chain - does anyone know if an active Mixer block counts with regard to this behaviour (if impedance set to "Auto" and the 1st active block is a mixer and I place a Fuzz after it, will I get the lower impedance of the Fuzz seen by my guitar pickups?)
 
Ah! - I had investigated this before! - answer is Yes - mixer block does count for anyone else searching - also, the status of the impedance is updated in the Input 1 block info on front panel but not in AxeEdit.
 
I honestly am not sure my Impedance ever switches when it's on auto. When I first got the unit it seemed to switch but I have to manually switch it now for Fuzz pedals.

Does your input impedance switch for you? Interested to hear.
 
On "Auto", It does switch automatically to the impedance related to the 1st active block in the chain after the input block (Mixers, Volume Blocks, Send Blocks, +other active "utility" type blocks count wrt this (for some reason, an active looper block does not)). The change does not show in AxeEdit for me, but it does on the Axefx front panel in the Input1 block info. Not many blocks will, if positioned as 1st active block, change the impedance to something other than 1M - examples I noticed are the Treble Boost drive, Phaser on Classic Univibe, and some of the Fuzzes.

After a fair amount of auditioning yesterday I've concluded that I can't hear or feel the difference between 1M impedance and low impedance (maybe it's the guitar (sg)? or probably because I just have tin ears and hands). Just as well as I now won't be trying to get certain blocks to the front of the chain - pita depending on the patch requirements, if you just have to have your pickups seeing that 70k on univibe or whatever.
 
sprint said:
I've concluded that I can't hear or feel the difference between 1M impedance and low impedance
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Are you keeping the volume of your guitar wide open? You should notice a pretty big difference if you roll your guitar volume down. On the lower impedance settings your tone should clean up quicker and stay brighter as you roll your volume down.


thud_peterson said:
I have to manually switch it now for Fuzz pedals
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I’ve noticed that mine stays at 1M with a Fuzz Face first in the chain, which seems odd.
 
Of the fuzzes, looks like only Pi Fuzz changes impedance on Auto if first active in the chain (1M if not 1st Active). With PiFuzz (impedance switches to 22k from 1M), and Univibe (Impedance switches to 70k from 1M), I'm not noticing any difference at all in volume, tone, or feel with volume mid way on any guitar even with single coils. I should hear it if it's supposed to be significant (my hearing's not great but not that bad yet - I hope :anguished:) - strange. I love univibe so got into this investigation after reading somewhere about how much different it sounds 1st in the chain due to the impedance difference as opposed to after a buffer. I must be doing something wrong.
 
Found it - I was plugged into the rear input jack - when I plug into the front the differences are there.

Anyone know if it's supposed to be like this (impedance changes only appear on the front instrument input?) - I thought both front/back instrument inputs were the same on AxeIII - don't see anywhere in the manual where it indicates a difference.
 
Cool, I love it when Fractalites do their own investigation, answer their own questions and solve their "issues".

Plus I didn't know that. Thanks.
 
sprint said:
Found it - I was plugged into the rear input jack - when I plug into the front the differences are there.

Anyone know if it's supposed to be like this (impedance changes only appear on the front instrument input?) - I thought both front/back instrument inputs were the same on AxeIII - don't see anywhere in the manual where it indicates a difference.
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I'm with you, I thought the front and rear inputs were supposed to be the exact same.. I'll have to see how it works on my unit today!
 
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yyz67 said:
Hmm seems to work for me with rear input.
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Thanks for checking yyz67 - can I ask a couple of questions though?

Do you have Axe3 Mk1 or Mk2?

When you say it works for you, is it that you are seeing the value change on the front panel when plugged into the rear instrument input? or, are you actually hearing it change to a different sound when you play something plugged into the rear input at a low impedance compared to a high impedance also plugged into the rear input?

In my case I can see the value change as expected in Auto mode on the front panel when plugged into either front or back, but, when I'm plugged into the back, I do not hear a different sound when the impedance flips from 1M to 70k in "Auto" mode with a Treble booster changing from 1st active block (70k) to not first active block (1M - playing with guitar volume low to hear the difference clearly as suggested by Marshall2553 above). Even if I just leave the Treble Booster 1st in the chain after input, and switch the impedance back and forth between 1M to 70k, I can clearly hear a difference between these two when plugged into the front input, vs, no difference when plugged into the rear input with the same guitar and cable.

I supposed I might have a damaged unit, but I'm doubtful of that as my Axe3 was pristine on delivery and went straight into a rack with stable power and never moved since.
 
@sprint , you're right. No audible change with the rear input, whether Auto or manually set. Very clear using the front input with Pi Fuzz which is 22K.

I'm guessing it's by design to allow both behaviors?
 
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You can get around the "1st active block in the chain" thing if needed, by putting any blocks in front of the Drive(s) that you want ignored, one row above. The algorithm only looks at blocks to the right of the 'Input' block in the same row, or below... Not above. There are some other interesting things about how this is handled, but it would probably take a video to cover it all.

Example...
Impedence bypass.png
 
sprint said:
Found it - I was plugged into the rear input jack - when I plug into the front the differences are there.

Anyone know if it's supposed to be like this (impedance changes only appear on the front instrument input?) - I thought both front/back instrument inputs were the same on AxeIII - don't see anywhere in the manual where it indicates a difference.
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Thanks for uncovering that. I never understood why I couldn't hear any difference :).
 
Moke said:
You can get around the "1st active block in the chain" thing if needed, by putting any blocks in front of the Drive(s) that you want ignored, one row above. The algorithm only looks at blocks to the right of the 'Input' block in the same row, or below... Not above. There are some other interesting things about how this is handled, but it would probably take a video to cover it all.

Example...
View attachment 78304
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Wow! I was trying out all kinds of convoluted ways to do something like this to force the input to low impedance just for classic vibe without giving up other patch functions that I want positioned before phaser block - this is perfect! Awesome info! Thanks for Sharing!
 
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yyz67 said:
@sprint , you're right. No audible change with the rear input, whether Auto or manually set. Very clear using the front input with Pi Fuzz which is 22K.

I'm guessing it's by design to allow both behaviors?
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Thanks for testing on this - really appreciated. Phew, my Axe is not broken - will switch to front panel input to get the impedance switching and
have my classic vibe at funky 22k impedance.
 
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