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Crown XLS Drivecore Amps Input Sensitivity

S

sleepytime

Nov 10, 2007
911
19
Chicago, IL
#1
I picked up an XLS1000 yesterday and was disappointed with the output in several applications. I am guessing that, due to the Drivecore Series 1.4Vrms input sensitivity, most users of these amps are not seeing anywhere near full output power. I would appreciate if some electronics gurus would weigh in. If you are using a standard 1.0Vrms preamp, how substantial is the penalty in output? Could it be approaching 50% or more?

Some of my observations, using a single 8 ohm 2x10...

1. I was hoping to use my SansAmp BDDI as an input. That ain't gonna happen. It doesn't even get loud enough to annoy the neighbors, even bridged at 8 ohms. (Edit: This is a V1 unit with no line level switch.)

2. Using the Line Out/Preamp Out on a couple of combos, the volume picks up quite a bit, but using 1 channel, supposedly at 210W, I'm guessing a 60W combo amp would about match it, and the output LEDs aren't doing much with the output level dimed.

3. Using a modeling pedal, which has an output level pot and apparently approaches 10Vrms, the amp absolutely roars without even bridging the output. I think a pair of 4x10s in bridge mode would have a 100% kill radius of at least 25 feet.

So, experts? Opinions? Sadly, I think a 1.0V input in stereo mode with 2 8-ohm cabs may be inadequate, though full rated output should be over 400W. Running bridged at 4 ohms would certainly do the job, but I am not seeing the flexibility I was hoping for with this amp. I know this is kind of long, I hope it makes sense.
 
#6
One thing I have noticed with mine is that it likes certain preamps more than others. The effects send out of my MB F1 sounds great, nice and loud, but my old BBE 383 bass pre is noisy and lackluster. :hmm:
 
#7
CharlieC said:
No such issues whatsoever with my XLS 1000...

The Crown XLS DriveCore series are the best power amps I've ever used, hands down!

I am driving my XLS 1000 with:

1. Tech 21 VT Bass pedal
2. Line 6 Pod X3 Bean
3. and my absolute favorite --> http://www.talkbass.com/forum/showthread.php?t=687422

... and I am pushing 2 Ampeg 4x10's, bridged-mono, on a 4-ohm load for 1000+ watts

Cheers!
Click to expand...

The point I was trying to make was that, while I'm sure your rig sounds awesome at the XLS1000's max output, I don't think the VT's 1.0V output is giving you 1100 watts. While 500 watts is probably overkill with those cabs, running 8 ohms Stereo mode and getting 80 watts/channel instead of 210 becomes an issue.
 
#8
sleepytime said:
The point I was trying to make was that, while I'm sure your rig sounds awesome at the XLS1000's max output, I don't think the VT's 1.0V output is giving you 1100 watts. While 500 watts is probably overkill with those cabs, running 8 ohms Stereo mode and getting 80 watts/channel instead of 210 becomes an issue.
Click to expand...

Yes, the output from my XLS 1000 is more than enough to push my drivers to excursion without even tripping the clip LEDs, and for that I am a happy man.

At 8-pounds, and runs cool all night long, it can do no wrong in my book -- especially for the ridiculous price I paid for it + the 3-year no-fault guarantee. Ignorance is bliss! It's more than I hoped for and then some :-)
 
#9
CharlieC said:
Yes, the output from my XLS 1000 is more than enough to push my drivers to excursion without even tripping the clip LEDs, and for that I am a happy man.

At 8-pounds, and runs cool all night long, it can do no wrong in my book -- especially for the ridiculous price I paid for it + the 3-year no-fault guarantee. Ignorance is bliss! It's more than I hoped for and then some :-)
Click to expand...

Yeah, I guess I can't complain about bang for the buck. I'm more curious about the extent to which input level can affect output level. It seems like that little 1.0V - 1.4V difference is pretty substantial.

I'll bet your rig sounds great. I'm looking at the VT pedals. Haven't decided on the little one or the Deluxe.
 
#11
sleepytime said:
Yeah, I guess I can't complain about bang for the buck. I'm more curious about the extent to which input level can affect output level. It seems like that little 1.0V - 1.4V difference is pretty substantial.

I'll bet your rig sounds great. I'm looking at the VT pedals. Haven't decided on the little one or the Deluxe.
Click to expand...

Thanks! and you could not go wrong with either VT Bass, as both are great!

Since you are in the market for one, you might enjoy this SVT Shoot-Out that I staged on my personal web space

http://www.zinfanus.com/svt

Cheers!
 
#12
rpsands said:
I am pretty sure the VT can exceed 1v.
Click to expand...

I hope it can, but the manual for the Deluxe says...

XLR Out Pad Switch: -20dB pad to match the output to equipment
with different input level requirements. In the line level (up) position, the
output is 0dB. In the instrument level (down) position, the output is -20dB.
​

I believe 0dB is 1.0Vrms, but I'm not an engineer. That's why I am seeking an all-knowing guru.
 
#13
BDDI output varies all over the place depending on how you've set the controls. Sometimes to get full output you have to settle for a tone you don't like, i.e. lots of stuff boosted. But BDDIs have always liked amps with high-ish sensitivities, even the V2s with the inst/line slide switch.

Many ways around the problem. Simple J-FET preamp in bass. Simple J-FET or transistor outboard preamp after the BDDI. Maybe an ART Tube MP preamp? Seems to have a pretty decent output level, and around 50dB of gain. I've never used one (second opinions encouraged) but it looks like it might do the trick.
 
#14
craig.p said:
BDDI output varies all over the place depending on how you've set the controls. Sometimes to get full output you have to settle for a tone you don't like, i.e. lots of stuff boosted. But BDDIs have always liked amps with high-ish sensitivities, even the V2s with the inst/line slide switch.

Many ways around the problem. Simple J-FET preamp in bass. Simple J-FET or transistor outboard preamp after the BDDI. Maybe an ART Tube MP preamp? Seems to have a pretty decent output level, and around 50dB of gain. I've never used one (second opinions encouraged) but it looks like it might do the trick.
Click to expand...

Hmmm...fitty nine bucks...
 
#15
Yep. You could try it before the BDDI, or after it, and pick which way you liked better.

If I were to try it, I'd put it after the BDDI and have the BDDI's output switch set to instrument (not line) so as not to overload the ART's input stage.
 
#17
I don't know what the output is on my Yamaha PB-1 preamp. I do know that without even pushing the XLS1000 hard I can easily blow ___ up. Big ___ too.
:D

Sounds like your SansAmp BDDI simply isn't enough to drive it alone. A friend of mine tried his with an inexpensive Presonus TubePre and according to him it drives it well.
 
#18
The VT Bass gets very loud if you start pushing up both the volume and gain, I seriously doubt you will not get enough input with it. If thats not enough, then you need more speakers, not more input gain...

I actually have the opposite prob with the VT... trying to use it as an overdrive pedal you have to pump the gain for nice crunch but that makes it too loud when you switch it on compared to the clean signal
 
#20
Also, with most power amps, the "volume" knob actually adjusts the input sensitivity. If your input is weak, turn up the input attenuator on the power amp. Theoretically, a power amp can be driven to full output at any level setting. The further you turn up the power amp, the less input voltage it takes to send it to full output.
 

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