RE: RME Fireface 400 and Guitar Hi-Z inputs

["Qua Veda" <qua@oregon.com>]

Hi Kris, 

Others may be able to explain it better than I , but the main issue with the instrument input is impedance, not gain.   I believe that instrument gain is somewhere between mic and line.  But a HiZ signal would be best served by a HiZ input so the impedance is matched.   I’ve used a Summit Audio TD-100 which is a really nice pre/DI for guitar or bass.  It has an adjustable input impedance.  So you can hear how the tone is affected as you adjust the impedance to match the instrument’s pickups.   An impedance mismatch can remove the highs and “air”.  Perhaps if you are going for a jazz tone it may not be as critical.   Same goes for using cables that are not of the proper impedance. 

 

I have an RME FF800, but actually haven’t tried using the hiZ input since my Stick has 2 outputs and I have a nice small preamp that is designed for the Stick.   But I’ll give it just to hear what it sounds like.

-Qua

 

From: Krispen Hartung [mailto:khartung@cableone.net]
Sent: Sunday, September 23, 2007 8:54 PM
To: Loopers-Delight@loopers-delight.com
Subject: RME Fireface 400 and Guitar Hi-Z inputs

 

I read an audio review that suggested the RME Fireface 400 wasn't ideal for guitar because it doesn't have a Hi-Z input for guitars and basses. The RME Fireface 800 does, however, have a separate hi-z input for guitar, which also has the speaker simulation, etc.

 

Can someone describe what is special about a Hi-Z input for guitars? It can be because it is the only type of input that will bring a guitar up to a decent level, because I can easily take any mixer board line input and adjust the trim so that the level is far above red line...so is there something about the quality or circuitry of a hi-z input that a line or mic input doesn't have?

 

When I read the literature for the Firewire 400, it leads me to believe that it will handle any type of input source, becaues of its sophositication in dealing with them.

 

From the RME website on the FW400:

 

"The Fireface 400's front panel features 2 balanced microphone inputs with a digitally controlled input stage, individually switchable 48V phantom power, and Neutrik Combo connectors for XLR and TRS. These can also be used as additional line inputs. A pre amplification of up to 65 dB, adjustable in steps of 1 dB over a range of 55 dB, exceptional EIN performance even at low pre-amplification settings, and extremely low THD+N let these preamps surpass those of other devices that cost several times the price of the Fireface 400. All level settings are 100% reproducible and can also be adjusted by software comfortably.

Inputs 3 and 4 are extremely flexible balanced universal inputs. Firstly, they operate exactly as inputs 5 to 8 on the rear and can be adjusted to accept standard studio input levels (+4 dBu, LoGain). Furthermore, the input impedance can be switched from Line (10 kOhm) to Instrument (470 kOhm). An additional analog input amplification of up to 18 dB (in steps of 0.5 dB) is also available. In short: There's no signal that these inputs can't deal with perfectly!"

 

So what will a hi-z give me that will make any audible difference, from the line input of the FW 400 adjusted to the correct level on my guitar?

Kris