Jcm900 4100 Volume Between Channels

rudeness

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Quick question: I have a Jcm900 4100 and with both channel preamp gain knobs maxed, should channel A be louder than channel B? When I am playing with drums I have to set the master for channel B around 5 or 6 (1 o clock) where channel A gets to drum volume at around 3 or 4 (around 10 o clock) on the master volume.

just seeing if this is normal or if there is something wrong with channel B. The preamp gain knob has a huge effect on the volume for channel A where channel B almost stays the same volume and just adds gain. Does this have something to do with the diode clipping on channel B that people mention?

Many thanks ahead of time for anyone able to provide info. I have searched the Internet for about a week but could not find any helpful info.
 

South Park

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The preamp is split at the start not the whole signal Chain . So both Chanel’s share most of the circuit. Most of the time all you are doing is bypassing the first tube that is the difference . You can look at the schematic and see this
 

tubes

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Quick question: I have a Jcm900 4100 and with both channel preamp gain knobs maxed, should channel A be louder than channel B? When I am playing with drums I have to set the master for channel B around 5 or 6 (1 o clock) where channel A gets to drum volume at around 3 or 4 (around 10 o clock) on the master volume.

just seeing if this is normal or if there is something wrong with channel B. The preamp gain knob has a huge effect on the volume for channel A where channel B almost stays the same volume and just adds gain. Does this have something to do with the diode clipping on channel B that people mention?

Many thanks ahead of time for anyone able to provide info. I have searched the Internet for about a week but could not find any helpful info.


Cheers rudeness.
Here is my first thought:

(I'm a happy 4100 user here.)

There is something about compression and perceived volume to take into account.

I can't explain it in terms of the circuit like South Park did.
but in terms of what the ear hears...

The more 'gainy' signal (on B) is more compressed.

> Does this have something to do with the diode clipping on channel B...

Well..., yes. Not so much because it's diodes but because it's clipping and compression.

I was impressed with the massive bottom end of the 4100 on clean settings.
It's almost too much.
Well, to be honest, it's way too much.

But I think I know why it's there.

It's because when a lot of gain and compression kicks in the output can seem more thin to the ear.

But a player might want gain AND lots of low end (and highs too).


So there NEEDS to be HEAPS of power.

To my simple mind these realities also answer a question that we frequently see on the forum:

"Why does anybody even need a 100 Watt amp these days?"
 

rudeness

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Cheers rudeness.
Here is my first thought:

(I'm a happy 4100 user here.)

There is something about compression and perceived volume to take into account.

I can't explain it in terms of the circuit like South Park did.
but in terms of what the ear hears...

The more 'gainy' signal (on B) is more compressed.

> Does this have something to do with the diode clipping on channel B...

Well..., yes. Not so much because it's diodes but because it's clipping and compression.

I was impressed with the massive bottom end of the 4100 on clean settings.
It's almost too much.
Well, to be honest, it's way too much.

But I think I know why it's there.

It's because when a lot of gain and compression kicks in the output can seem more thin to the ear.

But a player might want gain AND lots of low end (and highs too).


So there NEEDS to be HEAPS of power.

To my simple mind these realities also answer a question that we frequently see on the forum:

"Why does anybody even need a 100 Watt amp these days?"


Okay so it sounds like it is normal. The clean channel just seems to get a lot more powerful sonner than channel b. I guess I will just live with playing channel b with a higher master volume. Thank you for your response!!
 

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