# amps help!!

Posts: 9
edited October 2008
hi all, i'm a newbie and i'm from italy
i need help to set my new driverack 260 with my little p.a.

i use a labgruppen 2000c for the 2 top in stereo ( q10 with 2x15\" and a 2\" horn)

and 2 crest audio cc1800 for the sub ( 4 q10 sb with a 15\" each , every amps drive2 sub at 4 ohm in bridge )

now the first question:

here are the specs of my amps...

labgruppen 2000c:

INPUTS
Sensitivity, switchable for full output into 4 ohms = 0.775 or 2,2 Vrms
Gain, switchable = 38dB(0.775mV) or 29dB
Impedance = 20 kohms, balanced
Common mode rejection at 1 kHz = 50 dB

REAR PANEL
Switches:
Gain =38 dB or 29 dB
Link = Tandem mono, channel A and B
Polarity B = Polarity reverse of channel B
Clip limiter A and B= On - Off
MLS= 0, -2, -4, -5 dB
Allows amplifier gain to be switched between 29dB and its normal gain at 0.775mV input sensitivity

OUTPUT IMPEDANCE = 1 kHz 0.06 ohm

MAX OUTPUT POWER
4ohm stereo -5dB=570W -4dB=680W -2dB=1100W 0dB Full=1400W, Peakpower=1900W

CREST AUDIO CC1800 POWER SPECS:

4 Ohm Bridged = 1850 W
Max RMS Output Voltage: ....... 73 V / Channel
Frequency Response: ....... 10 Hz - 100 kHz (+ 0 dB / - 2dB @ 1 Watt)
Power Bandwidth : ....... 10 Hz â€“ 35 kHz; +0, -3 dB at rated 4 Ohm power
Damping Factor: ....... >150:1 @ 8 ohms (20 Hz to 1000 Hz)
Gain: ....... selectable between x40 (32 dB) and x20 (26 dB)
Input Sensitivity (x40): ....... 1.32 V +/- 3% for 1kHz, 2 Ohm Rated Power
Input Impedance: ....... 15k Ohm Balanced
Class: ....... modulated rail, H
Power Supply: ....... Linear Torroidal Transfomer
1/8 Power Draw: ....... 400 Watts / 3.4A @ 8 Ohms
685 Watts / 5.71A @ 4 Ohms
1000 Watts / 8.34A @ 2 Ohms
1/3 Power Draw: ....... 1000 Watts / 8.34A @ 8 Ohms
1650 Watts / 13.75A @ 4 Ohms
2340 Watts / 19.5A @ 2 Ohms

as you can see the labgruppen report:
Gain, switchable = 38dB(0.775mV) or 29dB

the crest report:
Gain: selectable between x40 (32 dB) and x20 (26 dB)

and now????
what i need to do??

please..teach me to set my new jewel!!!

i

• Posts: 3,777

Gadget, explain the science here. Are the input switches merely for quieting the system, or for some other thing?

DRA
• Posts: 9
I don't understand what you want to say...the switches serve only to change the input sensibility.
these data have been taken by the original documents of the amplifiers.
thanks still for everything of your help.
• Posts: 4,915
The differebt input sensitivities simply make the amp usable in a broad range of applications...Most modern analog consoles run +20 to +28 db (+20 to +28 dbv where 0dbv = 1 volt...)

The digital consoles +20 TO +28 DBU...

Consumer gear, -10 db...

So amps with a wide range of input sensitivity make it ideal fo almost every situation...simply match the gain of the console with that of the amp.
• Posts: 9
I wanted to know if in my driverack 260, I have the possibility' to put the 3 amplifiers to the same input level. if this and' possible, as must I do??

these are the values of the 2 types of amplifiers:
labgruppen: Gain, switchable = 38dB (0.775mV) or 29dB
crests: Gain: selectable between x40 (32 dBs) and x20 (26 dBs)

the levels of the 2 types of amplifiers are all different ones as you can see up.
to different values there will surely be different (apart the power) levels of exit.

the mixer that I use and' an allen&heath wizard 20s
how do I owe set to the best?
driverack you can help me in this?

still thanks !!
• Posts: 3,777
labgruppen: Gain, switchable = 38dB (0.775mV) or 29dB
crests: Gain: selectable between x40 (32 dBs) and x20 (26 dBs)

Use these. Although it really shouldn't matter.

DRA
• Posts: 4,915
I concur...
Ive added a FAQ for this here:
http://www.dbxpro.com/forum/viewtopic.php?p=7043#7043
g
Nice use of color Dra...
• Posts: 9
thanks for this precious help!!!