Hi and Lo inputs on amps- what's the actual difference

[Lord Sausage]

I was having a discussion about this last night with my drummer, also a guitarist and runs a recording studio. He knew the answer. Anyway out of interest i decided to look online. Came across this page!

Who is right?

http://music.stackexchange.com/questions/3473/difference-between-hi-and-low-on-amps

[Michael J]

[quote name='Lord Sausage' timestamp='1420037998' post='2645065']Who is right?[/quote]
Your drummer.

[Bill Fitzmaurice]

[quote name='Lord Sausage' timestamp='1420037998' post='2645065']
Who is right?
[/quote]Both and neither. Hi and low may refer to the output level of the instrument, usually active versus passive, but it also may refer to the gain applied to that input by the amp, hi gain for passives, low gain for actives. As a method of last resort, and at the risk of having your Man Card revoked, you might consider looking at your amp manual to find out which applies to your amp.

Nah...

[icastle]

Does anyone actually use the 'Lo' socket?

I think every amp I've owned over the last 35 years has had a 'lo' socket and I've never bothered with it.

[Lord Sausage]

[quote name='Bill Fitzmaurice' timestamp='1420039969' post='2645085']
Both and neither. Hi and low may refer to the output level of the instrument, usually active versus passive, but it also may refer to the gain applied to that input by the amp, hi gain for passives, low gain for actives. As a method of last resort, and at the risk of having your Man Card revoked, you might consider looking at your amp manual to find out which applies to your amp.

Nah...
[/quote]That's what i initially thought, the active and passive thing!

[Conan]

[quote name='icastle' timestamp='1420041048' post='2645098']
Does anyone actually use the 'Lo' socket?

I think every amp I've owned over the last 35 years has had a 'lo' socket and I've never bothered with it.
[/quote]

You've never owned a Spector, have you?

[Mornats]

My Ashdown Touring combo has a hi and lo input and the manual (not that I've read it of course... of course...) says to plug an active into the hi and a passive into the lo. It even says plug an active into the lo for an earlier breakup of the tone from the tubes.

[icastle]

[quote name='Conan' timestamp='1420142083' post='2646098']
You've never owned a Spector, have you?
[/quote]

No, but I've seen them getting beaten up by James Bond.

I presume they have a much hotter output than anything I've owned to date?

[Conan]

[quote name='icastle' timestamp='1420143919' post='2646130']
I presume they have a much hotter output than anything I've owned to date?
[/quote]

I certainly found that - as the Euro I owned did not have the trim control on the tonepump circuit. It managed to easily overdrive my Hartke LH500!

[Beer of the Bass]

A lot of amps (though not all) still use the same input jack wiring as the old Fender amps. I would expect that the LH500 does, as the preamp is derived from the Fender Showman/Alembic F2b design. In that case the high input is both high impedance and higher gain, while the low input has a lower impedance and is padded down. There's a good explanation of how the two inputs work here: [url="http://www.tdpri.com/forum/amp-central-station/287285-input-1-vs-input-2-blackface-amps.html#post3511035"]http://www.tdpri.com/forum/amp-central-station/287285-input-1-vs-input-2-blackface-amps.html#post3511035[/url]

So the low input is primarily used to prevent instruments with a hot output from overdriving the preamp, but will also have a different tone with a passive bass due to the lower impedance. On guitar amps I've sometimes found this useful to mellow out the high end from an overly bright instrument.

Edited January 3, 2015 by Beer of the Bass

[gadgie]

OP
What did your drummer say? Or am I missing something?

[Woodinblack]

It seems to depend on the amps themselves, it seems remarkably different how these things are labeled.

And one thing I have noticed is there is much of a confusion about actives / vs passive. an active shouldn't be louder than a passive, and if it is it is a bit of a poor design, it should be the same as passive level. However, what it should give you is low impedance, and the whole point of that is that the higher impedance in a cable the more easily noise will be injected into it. Obviously this only works if you are playing into a low impedance destination.

And if you plug a passive bass into a low impedance destination, its output will be reduced, but that is because it doesn't have the power to do it, not the volume. The active bass should provide the same volume (ie voltage) into both.

[Lord Sausage]

[quote name='gadgie' timestamp='1420282583' post='2647429']
OP
What did your drummer say? Or am I missing something?
[/quote]he said roughly same as on here. I just like getting as much info as poss. Plus i take a perverse delight in people disagreeing on the internet