how to set gain structure for pedal pre>>>power rig??

lomo · #1 10-20-2011, 04:32 PM

I'm messing around with a Crown XLS 1500 and an Eden WTDI pedal pre. I set the pedal gain knob where I like the tone. When setting the master on the power amp and pedal should I leave the master on the Crown dimed and adjust volume with the pre (as I assume occurs in an integrated head), vice-versa, or does it really matter at all?

jnewmark · #2 10-20-2011, 04:37 PM

Quote:

Originally Posted by lomo

I'm messing around with a Crown XLS 1500 and an Eden WTDI pedal pre. I set the pedal gain knob where I like the tone. When setting the master on the power amp and pedal should I leave the master on the Crown dimed and adjust volume with the pre (as I assume occurs in an integrated head), vice-versa, or does it really matter at all?

I have nothing to add, but I am curious about this pedal pre.

How do you like it ?

rpsands · #3 10-20-2011, 05:10 PM

I get the volume coming out of the pedal as hot as I can without breaking up and then adjust volume on the power amp.

bongomania · #4 10-20-2011, 05:16 PM

As long as the input stage of the power amp is not clipping, it truly does not matter whether you use the output level of the pedal, or the volume/gain knob on the power amp, to set your final volume. If the input stage of the power amp clips, then turn down the volume on the pedal.

lomo · #5 10-20-2011, 05:20 PM

Quote:

Originally Posted by bongomania

As long as the input stage of the power amp is not clipping, it truly does not matter whether you use the output level of the pedal, or the volume/gain knob on the power amp, to set your final volume. If the input stage of the power amp clips, then turn down the volume on the pedal.

Is there no issue with overheating or overworking the power amp if I leave it dimed?

BTW, jnew, the pedal reproduces the tone of a WT405 nicely and I dig it.

lomo · #6 10-20-2011, 05:34 PM

Quote:

Originally Posted by rpsands

I get the volume coming out of the pedal as hot as I can without breaking up and then adjust volume on the power amp.

This makes sense to me.

BurningSkies · #7 10-20-2011, 05:38 PM

Quote:

Originally Posted by lomo

Is there no issue with overheating or overworking the power amp if I leave it dimed?

BTW, jnew, the pedal reproduces the tone of a WT405 nicely and I dig it.

No, you won't 'overwork' the power amp. The amp inside is always outputting fully. If you look at the schematics, you'll find that the attenuators are before the power stage.

Your real concern is probably the S/N between the preamp and the power amp. Running the pre as hot as you can before the input stage of the power amp allows you to be louder and cleaner rather than running without attenuation and having very low preamp level.

lomo · #8 10-20-2011, 05:40 PM

Quote:

Originally Posted by BurningSkies

No, you won't 'overwork' the power amp. The amp inside is always outputting fully. If you look at the schematics, you'll find that the attenuators are before the power stage.

Your real concern is probably the S/N between the preamp and the power amp. Running the pre as hot as you can before the input stage of the power amp allows you to be louder and cleaner rather than running without attenuation and having very low preamp level.

Perfect. Thanks!

BurningSkies · #9 10-20-2011, 05:43 PM

* I should qualify that 'hot as you can' means as much signal without the input stage of the power amp clipping. I believe the Drivecore's input sensitivity is fairly low, so you can probably push pretty hard.

lomo · #10 10-20-2011, 05:56 PM

Quote:

Originally Posted by BurningSkies

* I should qualify that 'hot as you can' means as much signal without the input stage of the power amp clipping. I believe the Drivecore's input sensitivity is fairly low, so you can probably push pretty hard.

Yeah-I find getting a clean signal with the VT Dlxe is very good but the LDS 15/6 can chew even more volume and I like to feed it. With the WTDI I can push harder into the Crown and remain clean, and the WTDI has rudimentary/ single knob compression in it as well which also helps milk it to the max .

rpsands · #11 10-20-2011, 07:30 PM

I think you might be off a little BS, on the power amp thing. I don't think it is always outputting fully--I think it's always trying to put out as many volts as is required by the input voltage * the voltage gain the amp is trying to do. So how hard it's working at the output section is going to depend on a combination of the voltage gain you're asking for and the input signal.

Doubt that makes any sense but it sounds right in my head. :P

BurningSkies · #12 10-20-2011, 07:35 PM

Quote:

Originally Posted by rpsands

I think you might be off a little BS, on the power amp thing. I don't think it is always outputting fully--I think it's always trying to put out as many volts as is required by the input voltage * the voltage gain the amp is trying to do. So how hard it's working at the output section is going to depend on a combination of the voltage gain you're asking for and the input signal.

Doubt that makes any sense but it sounds right in my head. :P

True. The output voltage swing is dependent upon the input voltage, but at any given time, the amp is ready and unthrottled at the output stage, its attenuated at the place the input voltage is hitting the power amplifier.

bongomania · #13 10-20-2011, 07:37 PM

It's all in how you use the words--the gain stage of the power amp is always at 100% gain potential. The amount of actual power output is dependent on the input voltage from the preamp and the "volume" attenuators on the power amp.

BurningSkies · #14 10-20-2011, 07:47 PM

Quote:

Originally Posted by bongomania

It's all in how you use the words--the gain stage of the power amp is always at 100% gain potential. The amount of actual power output is dependent on the input voltage from the preamp and the "volume" attenuators on the power amp.

+1

This. That's what I'm trying to say in a much clumsier way.

walterw · #15 10-20-2011, 10:16 PM

i vote to run the preamp pedal in the middle of its master volume range, so as to give a reasonable signal to the PA out of its XLR jack;

use the knob on the power amp to dial in your stage volume, confident that you can change it without messing up the mix out front.

Oobly · #16 10-21-2011, 02:23 AM

I reckon adjust the preamp output while watching the pretty lights on the Crown.

Play like you mean it, in other words, get the signal as loud as it will get when you play normally and then adjust the preamp output so the -10 light goes on, but not the clip light. Then adjust the power amp dial to get the volume you want.

Actually, this is how you should set all the levels when trying to get the best signal to noise ratio. It's called gain staging.

lomo · #17 10-21-2011, 06:53 AM

So far the best tone and volume come from running bass--VT Dlxe--WDTI--Crown because I can keep the drive and master on the VT low enough to stay quite clean, and then boost and compress the clean signal into the Crown for max output. I would have preferred a simpler, single pedal chain, but this is far superior to either pedal alone IMO.

rpsands · #18 10-21-2011, 09:45 AM

The VT is not hot enough to run the Drivecore (at least it wasn't for me) without quite a bit of dirt.

That was my experience too. I had to run it into the Tonehammer, so I just replaced the VT with something I liked better for tubetone/dirt.

* Putnam could probably mod the VT for more clean output.

lomo · #19 10-21-2011, 09:52 AM

Quote:

Originally Posted by rpsands

The VT is not hot enough to run the Drivecore (at least it wasn't for me) without quite a bit of dirt.

That was my experience too. I had to run it into the Tonehammer, so I just replaced the VT with something I liked better for tubetone/dirt.

* Putnam could probably mod the VT for more clean output.

Works perfectly with the WTDI used as boost, compression and added eq. A few more patch cables than I like but the result is excellent. I really love the VT's clean tone.

rpsands · #20 10-21-2011, 10:38 AM

Yeah, I liked it too, but now I've got room for a fuzz wah