RM20 Built-in Boost function

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usrname

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Hey guys, I've been fiddling around with the RM20's built-in boost function to drive the Brahma over the edge. I was just wondering what exactly is happening when I do this.

The boost has gain and level; Is it essentially just like putting a clean boost in front? How many db does it actually add? Do both gain and level drive the preamp? If this is true, does this mean the main level on the module is driving the power amp like a master?

Also, if I use this function correctly, do I really need a boost/od pedal to get those old rock tones, (ala Iron Maiden/Judas Priest), out of the Brahama? I've been going crazy trying to figure out which OD to get.

Sorry for so many questions, but I couldn't seem to find a manual for the RM20 anywhere. If someone has one, I'd sure appreciate a copy.

BTW, I'm using a PRS CE24 with HFS/Bass pups, in which the HFS bridge is pretty hot. Thanks in advance for any help!
 
It's pretty simple, set your brahma where you want it for rhythm, then add volume/gain to taste with the boost. db and stuff like that isn't going to really mean anything to you, so I wouldn't worry about it.

The volume boost on the RM20 is later in the preamp, it has to be because you can add so much volume. If it was in the front of the module then it wouldn't add volume - it's pretty much like a second master, really, with a gain boost. You don't need to know how it works to dial it in though - just set the amount of gain you want to add and then set the volume, super easy. You're making it harder than you need to.

BTW, did I mention I love my RM20s? :D

Pete
 
okstrat said:
It's pretty simple, set your brahma where you want it for rhythm, then add volume/gain to taste with the boost. db and stuff like that isn't going to really mean anything to you, so I wouldn't worry about it.

The volume boost on the RM20 is later in the preamp, it has to be because you can add so much volume. If it was in the front of the module then it wouldn't add volume - it's pretty much like a second master, really, with a gain boost. You don't need to know how it works to dial it in though - just set the amount of gain you want to add and then set the volume, super easy. You're making it harder than you need to.

BTW, did I mention I love my RM20s? :D

Pete

Thanks for the reply, but I wasn't asking for solo boost; I would like to get a heavier rhythm from the Brahma, but keep the same tone.

Wasn't trying to make it harder on myself, I was just asking if getting an additional boost/od is worth it or will the on-board boost work the same way. I know boost pedals usually state how much db or gain they add, so I was curious how the RM20's boost compares.

I'll probably just pick up an od pedal and compare, thanks.
 
usrname said:
okstrat said:
It's pretty simple, set your brahma where you want it for rhythm, then add volume/gain to taste with the boost. db and stuff like that isn't going to really mean anything to you, so I wouldn't worry about it.

The volume boost on the RM20 is later in the preamp, it has to be because you can add so much volume. If it was in the front of the module then it wouldn't add volume - it's pretty much like a second master, really, with a gain boost. You don't need to know how it works to dial it in though - just set the amount of gain you want to add and then set the volume, super easy. You're making it harder than you need to.

BTW, did I mention I love my RM20s? :D

Pete

Thanks for the reply, but I wasn't asking for solo boost; I would like to get a heavier rhythm from the Brahma, but keep the same tone.

Wasn't trying to make it harder on myself, I was just asking if getting an additional boost/od is worth it or will the on-board boost work the same way. I know boost pedals usually state how much db or gain they add, so I was curious how the RM20's boost compares.

I'll probably just pick up an od pedal and compare, thanks.

Then turn the gain up and see if you like it. I still think you're making it too complex... who cares if it's after the first triode, the second triode, before/after the tone stack, +3db or +30 - worry about how it *sounds* instead of specs.

My experience is that the built in gain boost is a lot quieter and more natural than most pedals I've used in the front of amps, but your mileage may vary.

Pete
 
I did not know the RM20 had a built in boost. I have the RM50 but it does not have that??
 
okstrat said:
Then turn the gain up and see if you like it. I still think you're making it too complex... who cares if it's after the first triode, the second triode, before/after the tone stack, +3db or +30 - worry about how it *sounds* instead of specs.

My experience is that the built in gain boost is a lot quieter and more natural than most pedals I've used in the front of amps, but your mileage may vary.

Pete

I see your point. Like I said, I'll probably pick up an od and see which *sounds* best to me. Thanks.
 
usrname said:
laflamme said:
I did not know the RM20 had a built in boost. I have the RM50 but it does not have that??

Nope. But you do have 2 channels and a master! :wink:
Plus an extra effects loop and reverb...
the RM20 has the recording XLR out too though.
It's nice to have both, but it would be awesome if they shared more of these features!
 
kojdogg said:
usrname said:
laflamme said:
I did not know the RM20 had a built in boost. I have the RM50 but it does not have that??

Nope. But you do have 2 channels and a master! :wink:
Plus an extra effects loop and reverb...
the RM20 has the recording XLR out too though.
It's nice to have both, but it would be awesome if they shared more of these features!

Yeah, a two channel RM20 w/ reverb would be awesome! I'll probably end up with a head later on. :?
 
laflamme said:
I did not know the RM20 had a built in boost. I have the RM50 but it does not have that??

Yes, the RM50 does have a footswitchable volume boost, just not a gain boost.

I wish the RM100 had it! :)

Pete
 
okstrat said:
...The volume boost on the RM20 is later in the preamp...

I don't think this is right. After looking at the schematic for the RM20, the boost function uses the second half of the first 12AX7 (V1) to provide a gain boost in the signal path after the first input stage (1st half of V1) but before the first gain stage of the module.

The boost level control then bleeds signal to ground after the module but before the power amp section.

Accordingly, it should be possible to tailor the type of "boost" response by modifying the boost stage's various components.
 
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