# Technical question about master volume placement



## Budda (May 29, 2007)

One of the cool things about the axe fx is that it allows you to experiment with parameters and values that may take a lot of time and effort to tweak in real life. Not being a guy who's into fixing or modding his amps, this makes for some fun findings in the virtual realm.

My question for the mod/repair guys is this:

Why does moving a master volume from pre phase inverter to pre triode seem to have less compression ("more open sound")?

For reference, I was playing around with my Orange Rockerverb 50 model and decided to try the 3 MV locations (pre-PI, post-PI, pre-triode) and found that the pre-triode had the most "open" tonality (without changing other settings).

Here's hoping I understand the answer.

Here's a very quick clip to showcase the difference -

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https://soundcloud.com/sears-was-here%2Fpi-vs-triode-mv


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## jb welder (Sep 14, 2010)

'pre-triode' is a little vague.  Each preamp tube contains 2 triodes, so there are a lot of spots that could mean.
However, digging through the 'blocks guide', they say that the 'pre-triode master' is the default for the HiWatt models. So Hiwatt's generally have another triode stage between the tone stack and the PI, as opposed to something like a JCM800 master type, where the PI is right after the tone stack.

If the Orange model doesn't have the extra triode, it might be pushing the master further forward, ahead of an earlier triode. However it is being done, it's probably moving the master ahead of a stage that would otherwise be getting over-driven. Therefore, cleaner, more open outcome.


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## Paul Running (Apr 12, 2020)

From the owner's manual:

*Master Volume* – The Master Volume is a very important control. It determines the distortion and dynamics characteristics of the power amp simulator and its setting can dramatically change the amp’s sound. When it is turned up, the tone controls will have less influence and the sound will have more touch sensitivity (bloom). Settings for Master generally correspond to knob positions on the amp that is being modeled. With a little experimentation, you’ll learn to dial in a selection for Input Drive and Master combinations. When you select an amp type, the Master will automatically alter the setting s, to be in sync with that amp. If an amp doesn’t have a Master, the “correct” setting will be applied—i.e. “10” or maximum. At high settings, less Input Drive is usually required, especially for high-gain types. Amps designed for preamp distortion will typically sound better with the Master set low to prevent the tone becoming muddy or noisy. This includes the “USA Lead” types. Amps with negative feedback tend to have “crunchier” power amp distortion which may become “raspy” when driven too hard. Experiment with the interactivity of Negative Feedback and Master on distortion tone. When Power Amp Modeling is disabled, either globally or in a specific block, Master Volume becomes a level control with 40dB range. For more on disabling Power Amp Modeling, see Power Amp Modelling On/Off (p. 12) and your Owner’s Manual. If more power amp gain is desired, Master Volume Trim in the Advanced menu can be used. The most common reason for “muddy” tones with high-gain amps is setting the Master Volume control too high*. The Tone page includes a horizontal meter called “Headroom” which indicates the voltage at the virtual power tubes in dB. If the Master Volume is too high the meter will be predominantly near 0dB.
* This applies to amps where the power amp is intended to run “clean” like a 6160, Recto. Non-Master Volume amps produce distortion from the power amp and this will not apply.


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