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DIY Stompboxes => Building your own stompbox => Topic started by: ragtime8922 on February 10, 2005, 11:24:03 AM

Title: Guitar Level to Line Level
Post by: ragtime8922 on February 10, 2005, 11:24:03 AM
What has to be done to convert your guitar to line level?

Also, what are the actual levels for each?
Title: Guitar Level to Line Level
Post by: toneman on February 10, 2005, 11:55:03 AM
can U say "booster"?
can U say "preamp"?
there U go
Title: Guitar Level to Line Level
Post by: waldo041 on February 10, 2005, 12:36:52 PM
Jerry Garcia used something similar in his guitar. it does change the guitar signal(hiZ) to a line level(loZ).

cae sound unity gain buffer:

http://www.caesound.com/cgi-bin/cae/info?bufPreamp

hope this helps. peace, waldo
Title: Guitar Level to Line Level
Post by: R.G. on February 10, 2005, 01:29:24 PM
Line level is usually taken to be 0dbm, which is 0db relative to 1milliwatt in 600 ohms. This is 775millivolt RMS, or about 1V peak.

Guitar level is a misnomer. Guitar pickups put out signals from a few millivolts to over 2Vrms on peaks. "Typical" for single coils is about 70mVrms, 0.1V peak, although there is a range you can drive a truck through.

To do some serious level adjusting, see :"The Adjusticator" at GEO. It's intended to do such matching.
Title: Guitar Level to Line Level
Post by: Satch12879 on February 10, 2005, 02:47:54 PM
::Edited: REMOVED RANT::

Thanks, R.G. :mrgreen:! Say, would "instrument level" be more accurate?

rags, here you go; I'm not sure if this helps, but it'll get you started.  Sorry if there's dupe info, I finished composing after R.G. posted:

http://lp2cd.com/audio_terms/l/level.html

Level: Intensity of a continuous tone used for test purposes (measured in decibels by comparison with the standard reference level, or zero level, of 0775 volt rms, which is equivalent to a power of 1 milliwatt in a resistance of 600 ohms); colloquially, intensity of program output or of noise. Also the definition of dBm for voltage.

http://lp2cd.com/audio_terms/l/line_600.html

Line, 600 OHM: A transmission line with a characteristic impedance of 600 ohms. This was, in the past, the STANDARD for transmission lines, especially for telephone signals.  All outputs and inputs had to be 600 OHM.  You still see it today; Pete Cornish designs his DIs to 600 OHM floating (switchable ground lift) outputs.

http://lp2cd.com/audio_terms/l/line_level.html

Line level: A signal whose level is at or about, +4 dBm. AKA "Professional" gear.  "Consumer" or "Prosumer" gear typically puts out a signal of -10 dBm.  You'll see this on mixers, recorders, and other studio gear (there'll be a level control or "pad" switch).

http://lp2cd.com/audio_terms/d/decibel.html

Decibel: A unit of level equal to ten times the logarithm of the ratio of two powers. Depending on the reference level used, the decibel symbol will be immediately followed by a letter, as: dBA - An "A" weighted decibel level. dBB - A "B" weighted decibel level. DBC - A "C" weighted decibel level. dBm - A decibel level in which Pb represents one milliwatt of power dissipated in a 600 ohm line. Pa must a also be measured in a 600 ohm line. DBV A decibel voltage level, in which the reference, Vb, is 1.0 volt. A reference of 0.775 volts is also frequently used. The decibel was devised by EEs during the early days of telephone in order to a) easily facilitate the calculation of gains between amplifiers and b) minimize inaccuracy due to significant figures.
Title: Guitar Level to Line Level
Post by: ragtime8922 on February 10, 2005, 07:41:54 PM
Quote from: R.G.Line level is usually taken to be 0dbm, which is 0db relative to 1milliwatt in 600 ohms. This is 775millivolt RMS, or about 1V peak.

Guitar level is a misnomer. Guitar pickups put out signals from a few millivolts to over 2Vrms on peaks. "Typical" for single coils is about 70mVrms, 0.1V peak, although there is a range you can drive a truck through.

To do some serious level adjusting, see :"The Adjusticator" at GEO. It's intended to do such matching.

Thanks RG, guys. I got my degree in 1992 and until a few years ago I hadn't done any component level electronics. Then of course it was all FX and other small projects. It was all RF, cable stuff. I know dB and especially dB per milivolt but I never knew the related levels for instrument/guitar. Thanks.
Title: Guitar Level to Line Level
Post by: ragtime8922 on February 10, 2005, 07:56:45 PM
Quote from: tonemancan U say "booster"?
can U say "preamp"?
there U go

Thanks toneman, but I was thinking a tad more in depth like how and to what extent is the levels are amplified.

Question: "ah, can you tell me how to get to Fred's hardware store in the next town?"

Answer: "can U say 'drive'"?
            "there U go"

8)
Title: Guitar Level to Line Level
Post by: markr04 on February 24, 2005, 09:19:03 PM
Quote from: R.G.Line level is usually taken to be 0dbm, which is 0db relative to 1milliwatt in 600 ohms. This is 775millivolt RMS, or about 1V peak.

Guitar level is a misnomer. Guitar pickups put out signals from a few millivolts to over 2Vrms on peaks. "Typical" for single coils is about 70mVrms, 0.1V peak, although there is a range you can drive a truck through.

To do some serious level adjusting, see :"The Adjusticator" at GEO. It's intended to do such matching.

I'm interested in The Adjusticator at GEO. Unfortunately, I can't locate a PCB layout for it. Does one exist?
Title: Guitar Level to Line Level
Post by: R.G. on February 24, 2005, 09:28:07 PM
Sorry - that's one thing that never made it to the layout stage. It's not all that hard to perf wire, though.
Title: Guitar Level to Line Level
Post by: Paul Perry (Frostwave) on February 25, 2005, 05:12:51 AM
Quote from: R.G.Sorry - that's one thing that never made it to the layout stage. It's not all that hard to perf wire, though.
Maybe some kind person will make a stripboard version :wink:
Seriously, it would be a good beginner project.