Poweramp attenuator settings

which amp? Solid state?
Basically, you want to gain stage your rig...

The attenuators (they are NOT volume controls) are to allow control of when an amp reaches full power, relative to the speakers being driven.
Yes, when at minimum, an amp can reach full output if driven hard enough (high input level). When wide open, they will reach full output with a LOWER input level. finding the balance is the challenge.
In other words, you need to gain stage (google it) your system.
For a SOLID-STATE amp...
1. power off, then disconnect the speakers.
2. power on and turn attenuators wide open.
3. turn up your input level until the amp clips.
4. back off attenuator controls a bit.
Your amp should now not clip at that input level... it will still be able to reach full power, but that's why you match impedance and wattage of the speaker.

 

Because different signal sources have different output signal levels. For instance, the output levels of a mixing console will probably be a lot different than what your bass pre amp has.

As an example, if your pre amp – or the aforementioned mixer – has a really hot output and you have the amps gains set for max, you’d have the problem of your system level going from nothing to ear-splitting with say, only 1/4 of the pre amp’s volume control’s travel. Ratcheting down the amp’s gains would allow you a wider sweep of the volume control. Make sense?

Regards,
Wayne A. Pflughaupt


Administrator, Pedulla Club #45
Administrator, Tobias Club #133
Fretless Club #943
Big Cabs Club #23
My Rig: Stage and FOH Friendly
My Basses

 

It's actually easier to set attenuator levels when dealing with a known line-level device like a mixer. The procedure listed above is pretty dang close and about the best you can do with regards to gain structure. Bottom line: when you crank up the preamp volume, you want a quasi-linear response from the power amp with no clipping and an optimal signal / noise ratio. No two power amps are alike: my DriveCores require little if any attenuation, my old QSC RMX units had to be cranked down to 37% (...that's a real value as defined by dbx!).

Riis

 

Keep in mind that the pre amp may not – actually, probably doesn’t – deliver a clean signal at its maximum setting. It can start clipping as much as 30% below max.

That said, to answering your question: If the amp never clips even with the pre amp at max, it means the pre amp doesn’t deliver a strong enough signal to drive the amp to its maximum output.

Regards,
Wayne A. Pflughaupt


Administrator, Pedulla Club #45
Administrator, Tobias Club #133
Fretless Club #943
Big Cabs Club #23
My Rig: Stage and FOH Friendly
My Basses

 

If the amp never clips during gain staging then you can run it "wide open" using that input signal source level.
I have QSC, Crown and Yammy amps, and they all "clip" at some level when driven by my A&H consoles.
But remember, it can be a trade-off between output levels and induced noise.
Meaning that just because you can run them wide open doesn't mean you should.. if it's all whisper quiet, then fine.
Me.. in that scenario... I'd back off both the attenuator and the input levels just a bit. You lower the potential noise floor and optimize your ouptut levels.. If it's too loud, turn down the input level , NOT the amp attenuator.

 

When setting your input level on your poweramp you were playing right?
Your preamp needs an input to preamplify right?
Just turning up the preamp won't send the poweramp anything if you aren't plugged in and providing the preamp signal.

 

for soc9...that's for class D too?

 

As far as I know....ALL SS (solid state, meaning it's not a "TUBE" amp).
If you crank up a tube amp with no load/impedance (speakers) attached, be prepared to "let the smoke out" and prep for a LARGE repair bill.

Meaning DO NOT use my directions above on a TUBE amp!!

 

Given the preamps, I would be inclined to find the maximal operating band for them and then establish the power amp input attenuation level.

I had a Vha-1 ...or was it a vht-1. Years ago and I forget. Loved it tonally but the noise floor made it unsuitable for me. If I had really needed it, I might have invested some time in figuring that aspect out. It was so close to cool...

How are you sending your signal to the FOH? Seems like you'll need 2 lines or mics. If I understand what you're doing which is not a given...

So what cab's are you driving with this beast ? Is there a crossover ? Depending on the cab's I wonder if something like the SfX microMix would be an addition. Let you funk with the preamps and combine before the power amp to drive a backline cab sort of thing...

I did something like that using an Alembic F2-B years ago. At the time it ws the best way I could find to gain balance my effect chain and dry signal before the amp. The f2b has a mono summed output as well as the A& B outputs....

 

Oh cool, you're in Oregon. Where about ?

 

Ah. I've ridden my bike through there. Eola Hills bike tour. Nice country down there. I'm across from Hood River on the WA side. Funny on the GB thing. I run an f12.6 and if I need more, add an f12.sub. I just don't need more than the single 6 for my ear.

I have an extra 12.sub cab of you want to try that out some time. When I got the GB bug, I did 2 subs and 2 12.6's I ran that setup exactly once ... Wt 800 slaved with a plx 2402... I could barely crack the volume ;-) looked nifty though...

 

Subs are about FOH control, not volume (tho' they can add that).
They are about giving the sound guy control over the house mix.. so YOU don't need to blast everyone out of the room to be heard from the stage!
Needing them depends on music style and room size. Probably not really necessary for a folk group in a wine bar tho'!
I used to run a couple of Yorkville LS100P's (1500w ea) for subs, but cut back to one since TWO was overkill for most clubs/bars/venues my old rock band used to play.
Current band runs a 15" sub each side now.. and one venue we play (house PA) has SIX dual-18" subs UNDER the stage.. lotsa bass!!

 

I believe he is referring to a fEARful 12/sub. Which can be used as a FOH sub but in his case is used to reinforce backline bass amps.