#1
In a non-master amp like the Marshall 1959, when the volume is cranked, does the distortion come from the preamp tubes, power amp tubes, or a combination of both?
#4
Quote by blue_strat
Both, though power amp OD takes more volume to achieve than pre.


Does this mean a higher wattage plexi has more power amp distortion?
#6
If I recall, the 1959 is mostly poweramp gain, there isn't much preamp gain is the circuit.
Gear:
Modded Steinberger Spirit (white) (SD-AH/EMG Select)
Modded Steinberger GP-2R (white) (EMG81/60)
Peavey XXL head
Hughes and Kettner Cream Machine
Hughes and Kettner Blues Master
#7
The original Plexis were almost pure power tube saturation at high volumes, hence the reason the tone is typically thought to sound good. Once they added the MV series in the 70s, the circuit changed so that even with the master all the way up and with the pre gain down, you still get a substantial amount of pre amp tube saturation as well. I believe amptone.com has an article on this.
E-peen:
Rhodes Gemini
Fryette Ultra Lead
Peavey 6505
THD Flexi 50

Gibson R0 Prototype
EBMM JP13 Rosewood
Fender CS Mary Kaye

WTLT

(512) Audio Engineering - Custom Pedal Builds, Mods and Repairs
#8
Quote by blue_strat
Both, though power amp OD takes more volume to achieve than pre.


This is from Mojave Amp's web site.

"A non-master volume amp does not have preamp distortion and normally needs to be run at high power levels to achieve an overdrive sound. Higher power levels result in higher volume. "

Anyone want to weigh in if this is true or not?

If it is, then the preamp tubes in non-master amps are only used for boosting the signal from the guitar to the power tubes.
Last edited by mountain2012 at Jul 15, 2009,
#9
Quote by mountain2012
Does this mean a higher wattage plexi has more power amp distortion?

No, actually quite the reverse. Higher wattage=more clean headroom.
Current Gear:
LTD MH-400 with Gotoh GE1996T (EMG 85/60)
PRS SE Custom 24 (Suhr SSH+/SSV)
Ibanez RG3120 Prestige (Dimarzio Titans)
Squier Vintage Modified 70s Jazz V
Audient iD22 interface
Peavey Revalver 4, UAD Friedman BE100/DS40
Adam S3A monitors
Quote by Anonden
You CAN play anything with anything....but some guitars sound right for some things, and not for others. Single coils sound retarded for metal, though those who are apeshit about harpsichord probably beg to differ.
#10
Another fun fact is that you can jump the channels in a Plexi-style amp and get even more gain.

╠═══════╬═══════╣

THE SINE WAVE SURFER σƒ τλε τρπ βπστλεπλσσδ

╠═══════╬═══════╣


[quote="'[BurnTheDusk"]']Boss pedals may be built like tanks but I would rather buy a cardboard box that is on my side than pay for a tank that is working against me.
#11
Quote by mmolteratx
The original Plexis were almost pure power tube saturation at high volumes, hence the reason the tone is typically thought to sound good. Once they added the MV series in the 70s, the circuit changed so that even with the master all the way up and with the pre gain down, you still get a substantial amount of pre amp tube saturation as well. I believe amptone.com has an article on this.


this ^

to break it down for TS...

higher wattage = headroom, which is how much you can push it before it starts to clip (or distort/break up/overdrive, whatever you want to call it).

so, naturally, by the time you reached that point with a non-master amp, it would be louder than (but not NECCESSARILY better sounding than) a lower wattage non-master that has also been "pushed." yes, more gain would be present in the higher wattage amp, but not in the way you're thinking of it (that is to say, not as more/heavier distortion). gain is simply signal strength, not a synonym for overdrive, although a stronger signal will push your tubes to (and beyond) the point of clipping. when valve amps clip, rather than reject the clipped frequencies (as in most ss amps), they "pull" them back in, resulting in a soft, natural compression.

kinda' getting off topic, what i'm getting at is that you can reach the point of clipping easier on a low-watt amp, in a nut shell.
#12
I guess the question I meant to ask from the beginning: Is there any clipping in the preamp stage of a non master volume amp when it is cranked to 10?

I know there is no preamp distortion KNOB, but are the preamp tubes being pushed to the point of clipping?
#14
Okay the question is answered. On most non-master volume amps there IS clipping in the preamp.

This amp specifically has no preamp distortion whatsoever and the article says:

"The Rocker 30's Natural channel is controlled by just one volume pot and features a single-stage preamp incapable of preamp distortion, so any break up on this channel is pure power amp drive."

That's a pretty cool feature since a distortion pedal as opposed to an overdrive pedal will sound good on the natural channel of the Orange when it is cranked to 10.
#15
^ doesn't the Orange Rocker 30 have a built in attenuator? or am I thinking of another model... maybe the rockverb???
Last edited by GrisKy at Jul 16, 2009,
#17
s***! i remember seeing one that did... idk, maybe it was modded, i'll see if i can't find out. i remember where i saw it, but it's been a day.
#19
The old OR series have that feature too.

╠═══════╬═══════╣

THE SINE WAVE SURFER σƒ τλε τρπ βπστλεπλσσδ

╠═══════╬═══════╣


[quote="'[BurnTheDusk"]']Boss pedals may be built like tanks but I would rather buy a cardboard box that is on my side than pay for a tank that is working against me.
#21
Quote by mountain2012
Is it just me or does this dimed plexi have more gain than the dimed orange?

Orange (at 1:00)

Plexi

Marshall has the Bray mod.

And at 1:00 into the Orange demo, all you are hearing is power amp gain, all he did was crank the master volume, not the gain.

This is what a stock Marshall non-MV sounds like cranked to 10
http://www.youtube.com/watch?v=9_ae1P9w4Hw
Last edited by al112987 at Jul 17, 2009,