Level Management and IR Clipping (Ext Amplifier and GPDI/IR)

Stage & Studio Valvulator GPDI/IR
1

Hello all

I am using the following combination of gear:

  • Ampeg V-2 Tube head and Ampeg 2x12 Cab (non master volume amp)
  • Fryette Power Station PS100
  • Fryette GPDI/IR

The Ampeg V-2 is set to Edge of Breakup, and plugged into the Power Station AMP IN
The GPDI/IR is is the Effect Loop of the Power Station, using the FROM AMP FX SEND and TO AMP FX RETURN connectors on the GPDI/IR.

The idea is to use the GPDI/IR as a second channel to the Ampeg, and to level match them so switching is possible without huge unintended volume jumps.

My “problem” starts when I switch from NORMAL to EXT AMP on the GPDI/IR.

Using the NORMAL setting I adjusted the gain/volume knobs on GPDI/IR so that the IR CLIP led did no trigger for most of my playing. So far so good …

When I switched to EXT AMP setting the volume through the GPDI/IR increased by a lot .. , making switching pretty unusable in a live context. The IR CLIP led was now permanently on.

To level out the two amps I have to increase the Master Volume on the GPDI/IR, bit now the IR Clip led is also Permently on for the GPDI/IR …

So … no way to level out the two amps without driving the IR loader into clipping ..

So ---- my questions ..

  • How far away are we from actual clipping when the IR CLIP led lights up ? (how much headroom)
  • Is there a way (without introducing more equipment) to keep the Edge of Breakup sound of the Ampeg, and still lower the signal strength that comes into the GPDI/IR.

I can imagine that inserting a passive instrument level attenuator between the Power Station FX SEND and GPDI/IR FROM AMP FX SENX could fix the level jump, so that I actually could control the level that goes into the IR loader.

I know that both the Power Station and GPDI/IR have level switches for the loops. What is the best level settings for connection the Power Station and the GPDI/IR:

So .. lots of questions, and possibilities here .. But it basically boils down to level matching between a non master volume amp, and the GPDI/IR .. without clipping the IRs.

Kind regards Nils.

2

Does your Ampeg have a effects loop ?

3

No sadly not. That’s why I use the fx loop on the power station

4

I see you considered the External Amp Loop level switch, and the answer to that question is pretty much whatever works.

That switch on the GPDI changes from a low level send and hi level return (LO Mode) or vice versa. Same goes with the loop level switch on the PS-100.

Which combination is optimal is going to depend on the amp. In this case, the external amp is effectively the PS-100. So if both switches are set to LO, the GPDI is going to see a low level from the PS-100. Whatever the PS-100 gets back from the GPDI is going to depend on the GPDI loop level setting.

There is no hard rule here because every amp combination is different.

I generally recommend getting the Amp/Power station level setup optimized first, and then adjusting the GPDI to that, working mainly with the level switches of the two units.

The IR loader is driven by the 1W power amp in the GPDI, and that power amp is controlled by the Master Volume on the GPDI. Whatever external return signal comes into the GPDI return is the signal that gets sent to the IR loader via the 1W power amp stage. However, only the preamp out of the GPDI goes to the PS-100 return.

The IR Level is its output level, so it’s not going to affect how much drive signal gets to the IR loader. You’re depending on the MV for that, and of course, the MV setting is going to be set much differently for clean sounds.

No lie, it’s a balancing act, and I can sympathize. Every time I do this, I have to go back and turn the MV on the GPDI to remind myself which mode I’m in.

You could introduce the Cyclops into the equation and that will help manage the level issue. But the tradeoff, besides adding another level of complication is that you lose the ability to process the V-2 through the IR loader.

I hope helping you understand the signal flow makes this process a little easier. My hunch is that your eyes are crossing right about now…

Dave

5

Thanks a lot David for your reply.

I think my solution to this will be an passive attenuator between the power station FX SEND and GPDI/IR FROM AMP FX SEND … That way I can balance out the initial level difference between the amps.

Is there any way to verify the headroom left when the IR CLIP led starts to wake up ? :slight_smile:

Kind regards Nils.

6

Please see additional edits above. I’m still working this out as I type :slight_smile:

Basically you can hit the IR loarder hard enough to activate the Clip LED to the point where it’s always blinking on and off about equally. As soon as it is more on than off, you will start to hear some compression and distortion.

Dave

7

Hello again

I have now tried a passive FX Loop attenuator between the Power Station Send and the GPDI/IR From Amp FX Send jacks, and it works really well. These units go for around 70-80 dollars, and makes it possible to balance out your external amp and the GPDI/IR without any tonal penalties.
The unit I used was this: https://www.thomannmusic.no/jhs_pedals_little_black_amp.htm

Kind regards Nils