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Question Regarding USA Lead amps

soheil

Power User
I have a Mesa/Boogie Mark IV and I use axe FX II everyday. The thing is, the real amp has lots of controls and settings, I've checked the Wiki, searched the forum, and I couldn't find a direct answer to the question that I have. The wiki says:

Based on: Mesa Boogie Mark IV. Tight, focused, hi-gain sound, great for fusion and rock leads. 6L6. LEAD+: Mid Gain switched on. LEAD BRT: pull Bright. LEAD BRT +: Mid Gain and pull Bright.

Since on the real Mesa Mark IV amp, we have a pull FAT knob on Gain, and we also have a switch that selects between HARMONICS voicing and MID GAIN voicing, this is the part that it becomes weird and wiki does not help. what does "+" mean on real amp? pulling the gain knob? or turning the switch on the amp from Harmonics to Mid gain? I would be very thankful if someone answer this without referring me to the wiki, since wiki is not clear on that.
 

AdmiralB

Experienced
I can't answer the "what does + do" question, but the "harmonics/midgain" is simply switching in a larger cathode bypass cap on one of the overdrive gain stages, which increases the gain slightly and also allows a little more low-end through.
 

soheil

Power User
I can't answer the "what does + do" question, but the "harmonics/midgain" is simply switching in a larger cathode bypass cap on one of the overdrive gain stages, which increases the gain slightly and also allows a little more low-end through.
Thank you for your answer. your answer will raise yet another question for me, How can we emulate these 2 modes in our axe fx IIs? (If possible) do you know the answer?
 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
The Fat switch works the same as Pull Fat.

USA Lead: Mid Gain off, Pull Bright off.
USA Lead +: Mid Gain on, Pull Bright off.
USA Lead Brt: Mid Gain off, Pull Bright on.
USA Lead Brt+: Mid Gain on, Pull Bright on.

So all of the lead modes of the MKIV are represented using the four models above in conjunction with the Fat switch and Presence Shift switch.
 

soheil

Power User
Thank you for your prompt answer Cliff. Correct me if I am wrong, If I want to model Mark IV on Harmonics Mode with Pull FAT On from Gain knob, and Lead Drive pushed in, I should use USA Lead, with FAT switch on PRE page of Axe FX II turned on. right?
 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
Thank you for your prompt answer Cliff. Correct me if I am wrong, If I want to model Mark IV on Harmonics Mode with Pull FAT On from Gain knob, and Lead Drive pushed in, I should use USA Lead, with FAT switch on PRE page of Axe FX II turned on. right?
Correct.
 

guitardoc

Experienced
The Fat switch works the same as Pull Fat. USA Lead: Mid Gain off, Pull Bright off. USA Lead +: Mid Gain on, Pull Bright off. USA Lead Brt: Mid Gain off, Pull Bright on. USA Lead Brt+: Mid Gain on, Pull Bright on. So all of the lead modes of the MKIV are represented using the four models above in conjunction with the Fat switch and Presence Shift switch.
This should be Wiki'd.
 

Dimebucker

Experienced
Cliff do those Usa Lead and Usa Lead Brt have Harmonics switch then engage ,if there were no Mid Gain switch engage for those two?


The Fat switch works the same as Pull Fat.

USA Lead: Mid Gain off, Pull Bright off.
USA Lead +: Mid Gain on, Pull Bright off.
USA Lead Brt: Mid Gain off, Pull Bright on.
USA Lead Brt+: Mid Gain on, Pull Bright on.

So all of the lead modes of the MKIV are represented using the four models above in conjunction with the Fat switch and Presence Shift switch.
 

Zmonk

Inspired
PRESENCE SHIFT can be found on the Power tab of Axe-Edit.

Ah, thanks. It turns out using the USA LD 2 YLW (or any of the TriAxis models) it appears in the front panel only, but for the MKIV based USA Lead models it does appear in Axe-Edit as well as you stated.
 
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