Output Impedance is 600ohms?

So I am trying to get an understanding of impedance, and how it affects the audio chain.

Someone mentioned somewhere, that the Axe3 outputs are 600ohms. If that's the case, it made me wonder how that makes sense?

Usually the rule of thumb states, that you want the impedance load of what you connect your source into, to be at least 10 times higher than your source impedance. In the Axe3 case, that would then be > 6K ohms.

But considering that the Axe is basically built to connect to the mic-pres of a mixerboard or sound card, and these often "only" have a load impedance of 1,5K - 3K ohm (which is usually sufficient for microphones, as they are about 50 - 200ohms output impedance). My big analogue Amek console from 1993 for example, have a 1,5K ohms load, on the Mic-pre's.

I am sure there is a very good reason for these specifications, and that it all makes sense. But perhaps someone can chime in on, what I am overlooking here? 🤔🙂
 
I'm certainly no expert, but to my understanding it's an active vs passive thing.

The Axe III has active outputs, so it can supply enough current to keep the signal voltage from dropping excessively when feeding a lower input impedance.

In the case of a passive output like passive microphone or guitar pickup, it's a voltage source and can provide very little to no current, so a bad impedance match will cause excessive signal loss in that case.
 
The Axe-Fx III is NOT intended to be connected to microphone preamps. It is a LINE LEVEL device and is intended to be connected to a high impedance line-level input. Line level inputs typically have input impedances of 10K or more (usually much more - 100K - 1M).

Theoretically the "optimum" input impedance matches the output impedance of the source. This provides maximum POWER transfer and hence best SNR. For line-level devices, however, SNR is not a concern so the input impedance is typically designed to be quite high (10K+).
 
Thank you Cliff, I was hoping to hear your input on this. Well, then the 600ohms output obviously makes sense. 😊

I guess a passive D.I. should be inserted between the axe and the console then, to properly load down the signal for use with mic-preamps, to preserve especially the high end of the signal?
 
Thank you Cliff, I was hoping to hear your input on this. Well, then the 600ohms output obviously makes sense. 😊

I guess a passive D.I. should be inserted between the axe and the console then, to properly load down the signal for use with mic-preamps, to preserve especially the high end of the signal?
No. Doesn't your console have any line-level inputs?

Most high-end consoles have at least a few line-level inputs and/or some channel strips with switchable mic/line inputs.
 
No. Doesn't your console have any line-level inputs?

Most high-end consoles have at least a few line-level inputs and/or some channel strips with switchable mic/line inputs.
Indeed my studio-console has line-level inputs, with a 10K ohms load 👍

Also a quick google search, informs me that most digital desks today uses around 10K ohms inputs for balanced inputs, so they serve as dualfunction mic-pre's and line inputs at the same time, so no doubt it makes most sense with a line-level output in todays digital environment. :)
 
Thanks for the thread - buried in the spec pages of my interface's manual is that only 2 of it's 8 inputs are 10k - the rest are 5kohm. Just switched my Axe outs to the 10k interface inputs after 10 years - lol! 👍
 
Thanks for the thread - buried in the spec pages of my interface's manual is that only 2 of it's 8 inputs are 10k - the rest are 5kohm. Just switched my Axe outs to the 10k interface inputs after 10 years - lol! 👍
5k is common on some tascam stuff too
 
Was there a big difference in sound?
I could not hear a difference but maybe with some content I might hear it, and my ocd just likes having things optimized. Also, usually I'm using my Axe3+Axe2 thru spdif to interface (Guitar > Ax3 via Frontinput1 > Ax2 via Out1spdif > interface via Out1spdif) but sometimes I'll also run a 2nd L/R set of Ax outputs to the interface via analogue connection to drive a 2nd set of monitors / cabs with an altered output.
 
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