what does the input trim do

I inaccurately tend to think of amp block input trim as a pre boost / cut, but from the manual:
"Input Trim – This control allows you to modify any model to have more or less gain than would be possible with the regular controls. This is different from the Input Drive in that it does NOT interact with the surrounding circuitry to change frequency response. In other words, use Input Trim to adjust gain without also changing tone."
 
mr_fender said:
Yep. Setting it to 0.5 simulates plugging into the low sensitivity input on most amps that are so equipped.
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And that makes perfect sense.

One would wonder, if in analog world, a resistor or some component would be involved that changed the signal in some way besides gain?

Not that I would EVER use less gain. :)
 
squealie said:
One would wonder, if in analog world, a resistor or some component would be involved that changed the signal in some way besides gain?
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Depends on the amp. For amps like Plexi's and vintage Fenders, the Low input uses a voltage divider with a pair of resistors to cut the signal level in half. That puts a lower resistance in parallel with the input gain stage, so the total input impedance of the amp is a bit lower when using the low sensitivity input. Depending on the pickups and cable used, that could possibly give you a little bit darker sound on the low input.

An exception to this would be something like a JCM800 2203 or 2204. The low input on those doesn't use a voltage divider, but rather bypasses the first tube gain stage in the preamp entirely to provide a lower input level.
 
All solid stuff

Another use:

Occasionally I will use it on a factory preset (to make the distortion match the intended target i.e. Rush).

Depends on the guitar (hb or sc) whether to add more or less; and I don’t mean by much usually (for me +/- 0.05 - 0.15)

Then, SAVE
 
With some amps like the Marshall Plexi the louder you have the gain the darker it gets. You can hear the tone get progressively darker as you turn up the gain past 5.

For example I might like the tone with the gain at 6, but want more gain. So I raise the input trim to 1.5 or higher, and keep the tone just add more gain.

For another example I might cut the input trim in half to 0.500 (or lower) if I want a really clean sound and the amp is not clean enough even with the gain set really low at 3 or 4, (or if my pickups are too hot).

I also use it with low output single coil pickups to bring the level up to a humbucker level sometimes.

It's a really useful tool.
 
sprint said:
I inaccurately tend to think of amp block input trim as a pre boost / cut, but from the manual:
"Input Trim – This control allows you to modify any model to have more or less gain than would be possible with the regular controls. This is different from the Input Drive in that it does NOT interact with the surrounding circuitry to change frequency response. In other words, use Input Trim to adjust gain without also changing tone."
Click to expand...
Mmm, alrighty then👍
 
sprint said:
Mmm, sorry - superfluous reference i guess - some forget about the manual.
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Oh no I wasn't referencing that...it was one of those times when you need the obvious pointed out to you. I'm also not really good when being faced with huge tracts of info...that highlight really was a lightbulb moment...thanks.
 
It’s one of the most useful controls on the Axe. I find it almost impossible to get a super clean tone with humbuckers without taking it down to .5 or less. It’s the beginning of setting up your whole amp gain structure which is the most important thing in a preset. Don’t be afraid to really turn it way down with humbuckers or up with single coils. It also helps get more clarity and less mush when driving an amp. Broadly speaking I take input trim down and push the gain a little more to achieve this. I’m into low-mid gain sounds and learning to use the trim really helps get where I want to go.
 
If the input trim is in the amp block, then hasn't the signal from a high output humbucker already gone through the input block's noise suppressor, the drive block, or anything else used pre amp-block, at too high a level, before hitting the trim..?
I don't understand why the input trim is not at the beginning of the chain - in the input block, as it is in the Boss GX-100 for example.
My input signal is hitting the red on the front panel.
Or is the input trim actually at the beginning of the chain, even though it's accessed via the amp block.?
 
NOGALOSH said:
If the input trim is in the amp block, then hasn't the signal from a high output humbucker already gone through the input block's noise suppressor, the drive block, or anything else used pre amp-block, at too high a level, before hitting the trim..?
I don't understand why the input trim is not at the beginning of the chain - in the input block, as it is in the Boss GX-100 for example.
My input signal is hitting the red on the front panel.
Or is the input trim actually at the beginning of the chain, even though it's accessed via the amp block.?
Click to expand...
It is an input trim for the input of the amp. So it’s in the amp. It’s a choice to use if you want to reduce the gain of an amp.

Nothing to do with how much signal your guitar is sending to the hardware.

You set your guitar input in Setup.
 
Ok, so I found the actual input trim setting, in the global menu, and had to set it at 17%.
Does this mean that I will have to go the the global menu, and reset it, if I change guitars.? For example from a HB equipped Les Paul to a SC equipped strat on a different preset.
Will I be unable to save the different input level settings per preset patch.?
Seems a bit illogical, don't you think Jim.?
We wouldn't have done it like this on the planet Vulcan.
The input trim would be in the input block. Fascinating.
 
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