Any tweaking tips for valve power amp/guitar cab setup?

X

xpenno

Power User
Hi guys,

was offered an Engl 840/50 power amp at a price that I couldn't turn down so I decided to have a play with the AxeFX 2 into the power amp and then into a Marshall 2x12 guitar cab.

I just wondered if many others are running a tube poweramp/guitar cab setup and if you have any setup/tweaking advice for dialling it in?

I started off by turning off power amp sims which works well for high gain amps but when using any of the non-master volume amps they all sound like crap (flat, no distortion etc.). To try and rectify this I switched the poweramp sims back on and knocked down the speaker resonance settings to zero which seemed to keep the breakup that is obviously part of the power amp model whilst at the same time not being overbearing in the highs and lows. I guess this a workaround but I wonder if there is there an ideal method for keeping power amp sims on whilst using a tube power amp?

Any help/tweaks/advice will be greatly received, so thanks in advance.

Cheers

Spence
 
Superb Topic! was struggling to figure this out . like you said high gain amps sound awesome , but the non MV amps sound with no distortion ..
 
xpenno said:
I wonder if there is there an ideal method for keeping power amp sims on whilst using a tube power amp?
Click to expand...

I guess Mr. Miyagi has the solution: "Sag on - Sag off"

In other words - do it per amp block and keep the global power amp modeling option on.
For the vintagey amps that generate most of their distortion in the power amp you want sag on to keep the power amp modeling. For modern stuff turn sag = 0 to disable the modeling because the Engl does the job already.

What you did with the speaker resonance parameters makes perfect sense. The Engl is interacting with the speaker so the Axe does not have to model that. Of course you could still use resonance for creative tweaking.
 
xpenno said:
Hi guys,

was offered an Engl 840/50 power amp at a price that I couldn't turn down so I decided to have a play with the AxeFX 2 into the power amp and then into a Marshall 2x12 guitar cab.

I just wondered if many others are running a tube poweramp/guitar cab setup and if you have any setup/tweaking advice for dialling it in?

I started off by turning off power amp sims which works well for high gain amps but when using any of the non-master volume amps they all sound like crap (flat, no distortion etc.). To try and rectify this I switched the poweramp sims back on and knocked down the speaker resonance settings to zero which seemed to keep the breakup that is obviously part of the power amp model whilst at the same time not being overbearing in the highs and lows. I guess this a workaround but I wonder if there is there an ideal method for keeping power amp sims on whilst using a tube power amp?

Any help/tweaks/advice will be greatly received, so thanks in advance.

Cheers

Spence
Click to expand...



I never leave power amp sims on, you may be happy with the sounds you get that way but with a tube amp the double filterig sounds nothing like what a real traditinal rig sound like, for this reason i wont use it that way, too overhyped sounding.


Power amp off in the global menu, leave the sag parameter set to whatever default so the preamp sags as a combination pre/poweramp would.

Speaker and transformer distortion set to minimum.


I agree that the modern tones sound fine as is but i dont use the the onboard poweramp sims this will also turn on the resonance parameters.

Instead I set the axe for full output and drive my tube poweramp into real distortion that way. Hit the poweramp hard until it distorts.


Also if you know the frequency centers of your prescence and depth knobs i like to match them up as well, though i leave the digital prescence at its neutral setting and use the poweramps prescence knob.

I also set the digital depth control to zero and use the real depth on the amp for real negative feedback.


I also enjoy the typical "fx loop " placement this allows, my fx are between my axe preamp and my tube poweramp.
 
I'm using a Mesa 2 90 and I keep the power amp section on, to my ears it sounds better. You have to be careful how you set the presence on the power amp. I set it between halfway to around 1 o'clock.
 
IMHO: Given that you are rocking 50 Tube Watts per side (like two 50W heads!), my guess is that you are operating your power amp in the linear region most of the time (i.e. you have a sh*tload of clean headroom) therefore, your high gainers sound good with power amp off because modern high gainers are getting the majority of their disto from the preamp (and a little frequency spectrum coloration from your power amp). The crunchy and clean amps do not sound "right" with power amp emulations off because they are not getting the power amp break up and response those kinds of amps/tones call for since your amp is probably not being pushed hard. So, if you want to stick with your tube power amp and cab setup. I would follow rdnzl's basic advice above.

Dial in at volume. Use sag/poweramp to taste on cleans and crunches. Leave off or minimal for high gainers. Use tonestack and/or inline EQ block to adjust for your amp and cabs coloration as needed/desired.

Easy.
 
Last edited:
Thanks for all of the suggestions guys. I've had a play with some of the ideas above and am getting on nicely now. Using the SAG parameter to turn off power amp sims on a per amp basis works really well. An the master volume amps work well if you keep on the PA sim and lower the high/low resonance values to 0. I still can't get on with the plexi 100w as to me it's sounded a bit strange for a while now so it could just be that.

Cheers for the help, I'm certianly getting there now!

Spence
 
Ok so just in the way of a record and to potentially help others here is a list of changes that I'm making to run into my Engl Poweramp.

Global
-Power Amp Sims On
-Cab Sims Off

Amp Block
Basic Page
-Presence 0
-Depth 0
-Master Vol 3-5 for non-master amps, 10 for master
-Use Input drive to help round off the top end if required and roll back gain with Input Trim

Speaker Page
-Low/Hi Resonance 0

Dynamics
-Thunk 5 (Only if amp feels a little lacking, usually stuff that used to have high depth values)

Tone
-Brightness Adjust to taste but usually between 0 and -2dB just to take the edge off
-Adjust Bright Cap if required (I use this on amps like the JCM800, when set around 100pF the top end is much more usable)

That's about it! Thanks for all of the suggestions.

Cheers

Spence
 
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