embarrasingly nooby question: hi and lo inputs

McToot

What are they all about?

I may have been playing guitar for over 30 years but I've never had an amp with hi and low inputs.  But as of todfay I do.  What's the deal with them?

(It's the Cornford Carrera I got off Mrkj2000 by the way - full NAD thread to follow).   

menamestom

The Hi one is the one just above the Low one

McToot

menamestom said:

The Hi one is the one just above the Low one

Incorrect.  It's to the left.

octatonic

I usually use low input for humbuckers and high input for single coils.

Depends on the amp though.

the_twin

low and high gain

Drew_TNBD

Always assumed that high was for pickups with a fairly low output, and low was for pickups with a very high output.. essentially a way to choose between two different input sensitivities, and not much more than that.

ICBM

If it's the standard vintage arrangement where both are inputs to the same stage, then:

Hi - full signal level, high impedance. Brightest tone and most gain.

Lo - half signal level, lower impedance. Softer tone as well as quieter.

It's done with a couple of resistors which are connected in two different arrangements depending on which jack you plug into. You can do two other things as well:

Plug two instruments into both inputs at once - both are then effectively Hi inputs. Also useful if you have some sort of parallel effects path where you want to mix clean with effect.

Plug the guitar into the Hi input and daisy-chain the Lo input to another amp, or another channel on the same amp.

There are also some amps (Marshall JMP and JCM800 Master Volume amps, and a few others derived from the same basic circuit mostly) where the Lo input is a lot different and bypasses the first gain stage, giving a much cleaner tone.

The Carrera is the vintage type, assuming the unofficial schematic I found is correct.

Fusionista

Wisdom for that ;-) 

Check out Koss's Marshalls in this vid 

Personally I always use Hi, but I'll give Octatonic's idea a crack.

Fusionista

Oops wrong vid.  What's he done there Icey ?

chillidoggy

The high input is the 'normal' input. Check out the explanation here for the Hurricane, but I'm guessing it's the same for the Carrera.

 

http://cornfordamps.com/hurricane.htm

57Deluxe

The Hi and Lo inputs originated in the days when the guitar amp was also used for a microphone input and often (don't laugh) the very popular accordion!

ecc83

ICBM said:

If it's the standard vintage arrangement where both are inputs to the same stage, then:

Hi - full signal level, high impedance. Brightest tone and most gain.

Lo - half signal level, lower impedance. Softer tone as well as quieter.

It's done with a couple of resistors which are connected in two different arrangements depending on which jack you plug into. You can do two other things as well:

Plug two instruments into both inputs at once - both are then effectively Hi inputs. Also useful if you have some sort of parallel effects path where you want to mix clean with effect.

Plug the guitar into the Hi input and daisy-chain the Lo input to another amp, or another channel on the same amp.

There are also some amps (Marshall JMP and JCM800 Master Volume amps, and a few others derived from the same basic circuit mostly) where the Lo input is a lot different and bypasses the first gain stage, giving a much cleaner tone.

The Carrera is the vintage type, assuming the unofficial schematic I found is correct.

And then! There is the Artisan series that have four jacks, two per channel and you can feed one across to tother and use both channels for increased tonal effect. Or indeed as a sort of "poor man's FX loop.

Dave.

McToot

Thanks all.  I very rudely asked a question and then scarpered out to take my wife, mother in law and two daughters for tea (a sort of penance for having bought the Carrera).  No I am back and catching up on this and it all makes sense. 

chillidoggy

Don't forget the demo vid you promised, McToot!

stickyfiddle

Dibs, btw

McToot

stickyfiddle said:

Dibs, btw

Oxblood would look good with a desert backdrop...

McToot

chillidoggy said:

Don't forget the demo vid you promised, McToot!

PM'd