Low in impedance? You read the numbers correctly?

The pots in guitars range between 220k and 470k. You want to exchange them too? Lots of guitar amps have 470 kOhm as input impedance - mod them? So you think the difference between 500k (your value) and our 470k (30k less) is worth thinking about? And more than the difference in input capacitance will do? THIS is where the sound is made, not with the impedance. Oh, we did not list the capacitance? Yes, because it is too low. The sound will be changed by your guitar cable only, having more or less capacitance.

Yes, this is known as "BRIDGING law". Bridging is the most common circuit configuration when connecting audio devices. The objective is to maximize the Voltage Transfer between the source and the destination rather than the Power (as it was in the past with Vacuum Tubes).

That's why your guitar amps have a 1M Ohm Input... but for low impedance microphone <600 Ohm you'll need, in a similar way, an imput impedance approx. of 2000 Ohm in order to properly bridge the microphone. Don't try to connect a Low impedance source to your Guitar amp, it will most probably not work.

A low impedance microphone may always be connected to an input with a higher impedance. However, the microphone may not always be able to provide enough signal strength to properly drive the equipment's audio input. .

So an input impedance of 470K Ohm is a compromise solution to allow both Low impedance or Mid impedance sources to be used on the same input without trouble.

as an example with your 220k output the signal loss will be approx. of 1.7dB when connected to 1M Ohm input and be approx. of 3.33 dB to a 470K Ohm input. Twice as much but still acceptable. As a rule of thumb, a loss of 3.5 dB or less remains acceptable.

Anyway if you like you can also use an impedance matching adapter or a direct box.

Hope this helps.

That's the way to go :-)

My H&K Attax 200 Guitar Amp comes with 1 mOhm impedance as well and that seems to be a widespread value. I don't think it matters much for my humbucker equipped guitars though.  But yes, MC seems to be a bit sarcastic on that subject. And yes, capacitance makes the tone, but low level makes the noise!

I registered this forum just to reply this thread.

I had a babyface but sold it for this reason.

I connected my electric guitar(with passive PUs) direct to the “Hi-Z”input of babyface, and it sounded weak and muffled compared to other audio interfaces I own. Later I found that all the other interface‘s instrument input(Hi-Z input) impedance are 1M ohms, only RME’s are 470K. I don't know why you design it this way.

I find it quite surprising to read this BS. Arrogant and indifferent. That 470K are supposed to be high. It's not. It's mid.

Many amp-sim makers, such as Scuffham amps S-gear tells this in their requirements for using their software. Along with "Win/7 2,4 ghz cpu minimum..." and so on they say "sound interface with Hi-Z instrument input at 1 mOhm". You can read this for yourself on their site. On top of this, if you are using passive single coil pickups this difference is heard immediately and in a no subtle way. If you're using humbuckers, and active pickups, however, this doesn't matter, the difference is too subtle.

If you have active pickups such as EMG's these things doesn't matter. But I know several musicians who have looked elsewhere just because of this. 470 K is way too low.

I've tried a Radial JDV preamp before which has a drag control and goes up to 4 Ohm. Tried this with a RME babyface and there is a clear difference, especially in the transient attack, beginning of each note even if you pick hard or soft. Even without any amp sims. The clinical clear tone. Only above 1,5-2 mOhm no change is heard in any sound anywhere.

Since Fender tube amps has this for real, the guitar pickup becomes an integral part of the tube amp circuitry and acts accordingly. This is very hard to translate to digital world at all. You have this "limit" or "roof" that becomes the AD conversion anyway. Can only say that other makers has recognized this, and while 4 mOhm may be a bit of a stretch, this 1 mOhm is crucial in getting ANY amp-sim to translate what happens with a guitar signal. 470K isn't enough. Maybe 800K would be sufficient enough. The AD conversion hears this pick attack and high transients and the amp-sim converts this accordingly.

Otherwise you can bicker and whine about this to mr Scuffham himself, who was chief designer for Marshall amps in the 80s. I've just steered away a friend of mine from buying RME just because of this. I recommend him to search for sound interfaces that has listed their Hi-Z specs to a tee, and not only saying "Hi-Z" instrument input.

You may not hear any difference at all by just running a test sine wave into the input. Most people test just by doing that. Of course it sounds the same then. It's the start of each note that has high end transients. Before the actual note is produced, the percussive "thud" so to speak. Also when riding the volume knob on the guitar at the same time. You still get a lot of treble in the signal when turned halfway down, at 1 mOhm, but not so on 470K. I use M-audio Firewire to this day just because of it.
They have full 1 mOhm.

I find this very flippant, and loopy reply from the administrator. An input with 1 mOhm can do the same thing as anything with 470K in it. It's lower. But not the other way around, i e that a 470K input will be the same as a 1 mOhm input. Guitarists rides their volume pot on their guitars all of the time. You seem to make a false assumption that people are playing with it full out all of the time and leaves it at that.

I'll gladly attend a blind test any day. You guys pick the date and time! :-)

There's a difference here...

One manufacturer specifies it als "470 K on each leg". Those of us who know about impedance, might add that up, as it would be in series...

Of course, these resistors are not in series, as only one of them will be used, as the guitar output is unbalanced.

The only purpose of having two resistors is to make sure that you still get sound from the guitar if you go from unbalanced to balanced with a faulty cable. Of course, the guitar signal will have the wrong polarity, but hey, it works!

Some even "smarter" marketing departments might use this to show a 1 MOhm input impedance on paper. In marketing, more is always better. That's why they usually forget the minus sign when reporting S/R, for instance. After all, 67 dB is more than -67 dB, isn't it?

A real 1 MOhm input will only result in more noise and a far greater chance of picking up RFI. And that's far worse than a perceived difference in sound.

If you hear a difference, there's a fairly big capacitance in your chain. And that could even be a long, cheap guitar cable.

Even when some gear might show 1 MOhm input impedance for instrument input on paper, I'll take it with a grain of marketing salt till I can measure it.

I said that guitarists lower their volume knob sometimes to back off distortion, or going to have clearer sound. Then they want to keep the high treble spikey transients. Yes, noiser and more prone to pick up RF. But so is a real tube amp input too. But it's very effective and simple just to close and stop this thread, then. Alright. RME are not for guitarists then. Would be better to incorporate a rider like Radial did, so one can decide and adjust for oneself. At least on the higher end models, UFX, Fireface 800 and so on.

Make a collaboration deal with Lehle instead. Then why would such things need to exist then, like the Lehle Sunday Driver?

But close the thread, it seems that we've thread on someones sensitive toes, as the former MCs replies to it hints at a certain "not-now-again" and "oh-have-heard-it-thousand-times-before" stance. But still 470K is not high or "Hi-Z" by any means. And does not sound the same as 1 mOhm. Period. Just as much marketing campaign as 1 mOhm in that case. Anything above 600 K is high, though. But alright then, goodbye, roger over and out all drama queens.:-)

I think some pragmatism is required here.

The Instrument input is a compromise, which should not normally be a problem unless there is a significant amount of capacitance in the whole input loop that creates a filter that will create frequency dependencies, in which case, a hi-z buffer circuit is required.