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PostPosted: Wed Dec 27, 2017 9:02 am 
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Bottle Rocket

Joined: Fri Sep 16, 2016 8:13 am
Posts: 17
Hi, I've a Nomad 100 head. I've done mud mod + reverb mod.
I wanted to know if it's possible to mod the Channel 3 to have more gain.
I wanted to have the same gain that I have when I push it with my Ts Mini (but without using Ts Mini).
I've red in web that you can change a resistor near V3 to have more gain in CH2 and CH3 but not which resistor change.

Can You help me? Thanks :)


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PostPosted: Thu Dec 28, 2017 12:57 am 
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Mark IV
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Joined: Tue Oct 07, 2008 11:26 am
Posts: 870
Location: So Cal
You could try a 270 pf cap across the 100k resistor after V3a (between the .1u cap and ry4b on schematic). Did this with a friend's Nomad 55 and he loves the result. Of course it affects ch2 as well, but really helped ch3, giving it more 'bite' as well as volume.

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Stiletto Ace head
Triaxis/50-50
4x12 and 1x12 cabs
Studio Cal 22+
Various Hamer, G&L, Jackson

"Old rockers never die; we just start to smell that way...or is it the amp?"

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PostPosted: Thu Dec 28, 2017 5:56 am 
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Bottle Rocket

Joined: Fri Sep 16, 2016 8:13 am
Posts: 17
Old BF Shred wrote:
You could try a 270 pf cap across the 100k resistor after V3a (between the .1u cap and ry4b on schematic). Did this with a friend's Nomad 55 and he loves the result. Of course it affects ch2 as well, but really helped ch3, giving it more 'bite' as well as volume.


Thanks! So the gain will be similar to a drive channel pushed with an overdrive?

I have to put the 270pf cap here, just on legs of 100k resistor, like in picture?
Thanks!

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PostPosted: Thu Dec 28, 2017 12:58 pm 
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Mark IV
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Joined: Tue Oct 07, 2008 11:26 am
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Location: So Cal
That is the correct place. I'm not saying it will sound like you've engaged an overdrive...that is subjective, for sure. It does not really increase gain, except in the sense that it provides a bit more output to subsequent stages. I feel the Nomad has enough gain on tap, just lacking in ability to cut through a loud band mix, IMHO.

You may end up wanting to use an OD pedal anyway.
But if you want more 'cut' to help stand out in the mix, as well as some increase in volume, this worked out well on my friend's amp. I also did the reverb and loop capacitor mods which were a big help. He was looking to replace the amp...now he's keeping it. Of course, YMMV.

Plus this is simple to try (just carefully tack it to the legs of the 100k resistor) and to reverse later, if you wish.
I used a substitution box to find the value (270) that sounded best to us, but you could try a range from 150pf to even 470pf to see what you like. 270 seemed just about right, at least to start.
Again, this will affect ch 2 as well, but you can always adjust it down with its own tone and volume controls. The real benefit is it makes ch 3 more usable.

There are other ways to increase gain on ch3 alone (which I don’t intend to get into here) but, they could change the basic tone of ch3 too much...my friend likes the basic Nomad tone, just wanted help in a live band situation.

Good luck! :)

_________________
Stiletto Ace head
Triaxis/50-50
4x12 and 1x12 cabs
Studio Cal 22+
Various Hamer, G&L, Jackson

"Old rockers never die; we just start to smell that way...or is it the amp?"

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PostPosted: Thu Dec 28, 2017 7:08 pm 
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Bottle Rocket

Joined: Fri Sep 16, 2016 8:13 am
Posts: 17
Old BF Shred wrote:
That is the correct place. I'm not saying it will sound like you've engaged an overdrive...that is subjective, for sure. It does not really increase gain, except in the sense that it provides a bit more output to subsequent stages. I feel the Nomad has enough gain on tap, just lacking in ability to cut through a loud band mix, IMHO.

You may end up wanting to use an OD pedal anyway.
But if you want more 'cut' to help stand out in the mix, as well as some increase in volume, this worked out well on my friend's amp. I also did the reverb and loop capacitor mods which were a big help. He was looking to replace the amp...now he's keeping it. Of course, YMMV.

Plus this is simple to try (just carefully tack it to the legs of the 100k resistor) and to reverse later, if you wish.
I used a substitution box to find the value (270) that sounded best to us, but you could try a range from 150pf to even 470pf to see what you like. 270 seemed just about right, at least to start.
Again, this will affect ch 2 as well, but you can always adjust it down with its own tone and volume controls. The real benefit is it makes ch 3 more usable.

There are other ways to increase gain on ch3 alone (which I don’t intend to get into here) but, they could change the basic tone of ch3 too much...my friend likes the basic Nomad tone, just wanted help in a live band situation.

Good luck! :)


Thanks a lot! I will try.. hope the volume will not be too much for my ears!
And, if you can, I'd like to know how to increase gain on ch3 even if it change sound of ch3.. if You can I will be very happy and maybe I will not need use od to boost and not to change the amp with another with more heavy sound for my leads.
Thanks :D


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PostPosted: Tue Jan 02, 2018 6:00 pm 
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Mark IV
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Joined: Tue Oct 07, 2008 11:26 am
Posts: 870
Location: So Cal
I can’t really recommend any of those methods specifically for the Nomad, as I have not tried them. As you’ve done some mods yourself, I tend to assume you have, at least, a basic understanding of working on amps, including, of course, the dangers of working around high voltages.

But understanding what components to change to achieve your sonic goals is something you want to know well before diving in.

I can only say that there are some very good books available on this topic. A search on the web and, in particular, guitarist’s forums (like this one) should turn up suggestions.
A fairly recent one I like is Merlin Blencowe’s book, “Designing Tube Preamps for Guitar and Bass, 2nd Edition“ but it’s not really an entry level book. But I can’t personally recommend an entry level book, assuming you’re just getting started, as I have not bought one in over 40 years (lol).

Also, as you may already be aware, the Mesa circuit boards can be easily damaged if you are not really careful. There are some very fine traces on those boards that can be a nightmare to repair if damaged.

Good luck! :)

_________________
Stiletto Ace head
Triaxis/50-50
4x12 and 1x12 cabs
Studio Cal 22+
Various Hamer, G&L, Jackson

"Old rockers never die; we just start to smell that way...or is it the amp?"

Image


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PostPosted: Sun Jan 07, 2018 5:09 pm 
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Bottle Rocket

Joined: Fri Mar 22, 2013 9:42 am
Posts: 16
Jerry at FJA Mods is the guy I would talk to if i was you

http://www.fjamods.com


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