post gain

A forum for discussing the Vypyr series amplifiers, Sanpera footswitches and share settings
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mav
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post gain

Post by mav » Sun Jan 02, 2011 4:37 pm

hi there

is the post gain knob supposed to actually change the gain you are playing with or is it 'just' a volume knob?
i was playing with the knob on my new vypyr75 but i couldn't hear a change in the tone besides of the volume.

i was looking for a decent 70's ac/dc tone but didn't found one :(

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Re: post gain

Post by Classic30inCincy » Sun Jan 02, 2011 4:46 pm

Correct....

Pre-Gain provides "bite"

Post gain provides volume.

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Stryker57
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Re: post gain

Post by Stryker57 » Sun Jan 02, 2011 6:36 pm

post gain allows you to do 2 things
1 adjust the volume on a given preset
2 adjust the headroom on a clear channel.

in short a high pregain and a low post gain gives a more distorted sound
a low pregain and a high post gain gives you a clearer sound.

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WashburnTabu
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Re: post gain

Post by WashburnTabu » Sun Jan 02, 2011 11:41 pm

mav wrote:hi there

is the post gain knob supposed to actually change the gain you are playing with or is it 'just' a volume knob?
i was playing with the knob on my new vypyr75 but i couldn't hear a change in the tone besides of the volume.

i was looking for a decent 70's ac/dc tone but didn't found one :(
As I understand it:
Tubes and TT power circuits are fixed gain. Depending on the input level, the tube/TT can be pushed into distortion. Distortion happens when the input signal goes over the amplifiers voltage supply in that tube section, or over top of the TT clipping cicuit. The pre-gain controls the pre-gain tubes/TT"s distortion (overdrive). Since it is high gain (like 100 to 1), and the tubes have a small plate, and the TT clipping circuit, it can be easily overdriven.
The post gain controls the signal level into the power tube's/TT's power section, essentially the volume. The power tube's/power TT also add's distortion when pushed to the near/over the limit by a large signal (volume). Since power tubes have lower gain ratios as compared to pre-amp tubes/TT sections and larger plates and higher current and voltage capabilities, the "head room" is much higher, needing a much larger input signal to drive them into distortion. Hence the "cranked" tube amp motto for achieving the tube amp tone.
The master volume allows you to get that cranked tone, without actually dime'n the dial (max volume).
You won't hear much of a difference until the post is set really high, and there are other factors as well. All of the controls work together (guitar included) to get the sound/tone out of the amp. Some amp models have more gain and clean head room than others.
Also the vypyr's work similar to other Peavey SS amps with the exception of the DSP (digital signal processor) which is the modeler.
ex;
input->Transtube analog pre-amp circuit->DSP digital->Transtube analog power section->speaker.

Summary:
High pre-gain setting= more pre-gain tube/TT distortion.
High post gain setting= more power tube/TT distortion, but only when pushed near or over the head room limit.


I use the plexi red;
stomp= bypass
pre-gain=6.25
low= 3
mid= 9
high= 9
post= 6
guitar volume= max
guitar tone at 40-50%
bridge humbucker.
Matthias Arp's settings sound really good in his youtube video,but not for me.
Last edited by WashburnTabu on Thu Jan 06, 2011 8:21 pm, edited 1 time in total.
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mav
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Re: post gain

Post by mav » Thu Jan 06, 2011 3:41 pm

many thanks for the detail explanation.

i experimented a bit but i have to say that i can heardly make out any difference between low and high post-gain.
maybe i just expected to much change.

the pedal on the sanpera I: does it set the post-gain or the master volume ?

Maiden82
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Re: post gain

Post by Maiden82 » Thu Jan 06, 2011 5:16 pm

Its a volume control for the guitar signal so to speak. Its also a wha when activated and pitch shifting when that is selected.
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WashburnTabu
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Re: post gain

Post by WashburnTabu » Thu Jan 06, 2011 8:13 pm

mav wrote:many thanks for the detail explanation.

i experimented a bit but i have to say that i can heardly make out any difference between low and high post-gain.
maybe i just expected to much change.

the pedal on the sanpera I: does it set the post-gain or the master volume ?
Volume pedal on the sanpera is the master on the vypyr.
Note: I edited my above post, but left in the wrong stuff.
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mav
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Re: post gain

Post by mav » Fri Jan 07, 2011 5:02 am

WashburnTabu wrote: I use the plexi red;
stomp= bypass
pre-gain=6.25
low= 3
mid= 9
high= 9
post= 6
guitar volume= max
guitar tone at 40-50%
bridge humbucker.
Matthias Arp's settings sound really good in his youtube video,but not for me.

how exactly do i have to read your settings?
the vypyr has 7 glowing LEDs on the controlls, so i can' set mid and high to 9 ;)
but it ain't the usual o-clock-setting either, cause pre-gain 6.25 is the lowest setting possible and would be dead silent.

perhaps you meant 62.5% and 90% of the maximal value ?

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WashburnTabu
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Re: post gain

Post by WashburnTabu » Sat Jan 08, 2011 7:35 am

mav wrote:
WashburnTabu wrote: I use the plexi red;
stomp= bypass
pre-gain=6.25
low= 3
mid= 9
high= 9
post= 6
guitar volume= max
guitar tone at 40-50%
bridge humbucker.
Matthias Arp's settings sound really good in his youtube video,but not for me.

how exactly do i have to read your settings?
the vypyr has 7 glowing LEDs on the controlls, so i can' set mid and high to 9 ;)
but it ain't the usual o-clock-setting either, cause pre-gain 6.25 is the lowest setting possible and would be dead silent.

perhaps you meant 62.5% and 90% of the maximal value ?
Sorry, Those 9's should be 7's.
Vypyr counts like this. 1st led is 1. Each led above the first is ".25" in value. So it would count like this; Value=1, first led bright. Value= 1.25, 1st led bright with second led dim. Value= 1.5, 1st led bright with second led bright. Value=1.75, 1st led dim with second led bright. Value= 2, second led bright with all others dark. So an led by itself is a whole number value. This repeats for the rest with "high noon" or straight up being the 4th led by itself.
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Re: post gain

Post by markcm » Mon Jan 10, 2011 10:55 am

good thread! thanks

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Re: post gain

Post by JedTaylor777 » Wed Sep 02, 2015 8:04 pm

on line you can get the views of the owners manual for most of Peaveys amps past and present. These manuals to the unknowing public have little worthwhile information to consider before the use of an amp. But, for the sake of the gain stages and the how to set up the initial tones for a varying degree of over drive, most of the manuals do give you a starting point on how to best drivve the gain stages...in preference to pre amp or power amp drive and the settings for the different eqs and other component knobs. There are a few of these manuals that are not specific to each type or model of am through the full range of different amp builds, in general it will give you the guidelines as to why and how setting a circuit in such a manner benefits the actual achieveable tones for rock, country, blues and thrash metal so on..... Now the older the amp origin the less likely it will be stating current terminology. How ever it will give generalized settings for a starting point. I found this extremely usefull for the ultra amps and for the revolver and the transformer amps. for the bandit and the studio pro, the chorus and the 212 chorus or special models. My point is that there are many ways to get the original settings but, on some models it is set to a specific year of the model and may not have the
different year models of a series of amps with structural changes through a 10 or 15 year model period. This I m told is a matter of taking it up with Peavey parent company and the additional year models can be had

The soul purpose of this information...to give individuals the opportunity to know that resources are availible for the amp user both online and at Peavey INC

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