Will this work?

[tabdog]

Hi Folks,

My 21 year old son had his Rack and it's contents stolen. It had
his amp, rack tuner, power conditioner and preamp inside, along
with cords and stuff. He still has several bass guitars and a Genz
Benz 410T XB2 speaker cabinet. It is rated at 700 watts RMS @
8 oms.

He is in a band.

He is broke and I am disabled and on a fixed income. There for,
I am trying to get him back in the game in a hurry, and on a
budget.

I bought a Crown XLS 202 two channel power amplifier for $100
plus $30 shipping. It is on it's way now. Then, I got a used Hartke
VXL Bass Attack Preamp/Pedal for $50 at a pawn shop. I made a
speaker cable with stuff around the house.

The Crown amp is rated at a guaranteed 600 watts RMS @
8 oms, bridged at the Crown web site. The users manual
states that it has 400 watts @ 8 oms bridged.

Which is right???

The Crown amp does not have a switch to put it in the bridged
mode. You have to have an input on both channels with a
"custom "Y" cable",





Here is "Y" cable I adapted from two XLR/Line cords and a Radio
Shack "Y" connector,



That is what I got together. That's everything but the bass and
speaker for under $200.

Is it gonna work when the amp gets here?

Is that gonna move enough air and sound decent???

Thanks for any help,

David

[waleross]

It looks like it will work. I recently had a Crest Power Amp that I plugged my pre( a Big Muff) into the input and then ran a speakon into my cab from the back of the power amp.
I would make sure that your speaker is connected correctly, etc. I'm sure others will give you their input as well.
Best of luck and take care.

[agedhorse]

Hold on a minute...

The bridging method on this Crown amp has some specific requirements that MUST be followed or it will not work properly.

The bridging adapter method requires the one channel's balanced input be driven with an inverted polarity signal. This means that straight through cables and adapters will not work.

1. The output 1/4" splitter is not very robust but should work ok for testing purposes. Just beware that if it gets pulled out partially during this bridge mode "test", there is a distinct possibility that the amp may oscillate and get damaged. Intermittent cables and connections are a bad deal under these specific condituions.

2. One XLR male connector must be wired with tip to pin 2, sleeve to pin 1 and pin 3. This should go into channel 1 on the amp.

3. The other XLR male connector must be wired with tip to pin 3, sleeve to pin 1 and 2. This should go into channel 2 on the amp.

4. The output terminals will be the red binding post on channel 1 going to the + speaker output (either tip if using 1/4" or 1+ if using SpeakOn) and the red binding post on channel 2 going to the - speaker output (either sleeve if using 1/4" or 1- if using SpeakOn). Both chan 1 and 2 level controls need top be set identiaclly and in your case, all the way up is probably best.

5. IF you are using the SpeakOn output of the amp, use the Speak-On of channel 1 and the + output is 1+, the - output is 1-.

6. If using 1/4" output connectors in bridge mode, be absolutely sure any bare metal on the shell (sleeve terminal) doesn't touch anything since it is not at ground. This is the reason why 1/4" connections should not be used with any bridged amp. While the output voltage on this amp isn't likely to kill or hurt you (some amps this is definately not the case) it still deserves adequate caution and shorting to ground under these conditions can destroy your amp regardless of how good the protection circuitry may appear to be. It's not a specific fault that's well protected against.

If it's not making sound at low volumes, you may have other flaws in the logic. Also, I do not know if there's adequate drive signal available to achieve full output from the amp,

[tabdog]

Thanks Waleross,

I thought that you could not use the speakon connection for the
bridged operation. But I looked in the instructions and found a
diagram for wiring the speakon connection when bridged,



How would the other end of the cable be wired???

I gonna keep reading.

I hope I am ready when the Crown amp gets here.

Thanks again,

David

[tabdog]

Originally Posted by agedhorse

Hold on a minute...

The bridging method on this Crown amp has some specific requirements that MUST be followed or it will not work properly.

The bridging adapter method requires the one channel's balanced input be driven with an inverted polarity signal. This means that straight through cables and adapters will not work.

1. The output 1/4" splitter is not very robust but should work ok for testing purposes. Just beware that if it gets pulled out partially during this bridge mode "test", there is a distinct possibility that the amp may oscillate and get damaged. Intermittent cables and connections are a bad deal under these specific condituions.

2. One XLR male connector must be wired with tip to pin 2, sleeve to pin 1 and pin 3. This should go into channel 1 on the amp.

3. The other XLR male connector must be wired with tip to pin 3, sleeve to pin 1 and 2. This should go into channel 2 on the amp.

4. The output terminals will be the red binding post on channel 1 going to the + speaker output (either tip if using 1/4" or 1+ if using SpeakOn) and the red binding post on channel 2 going to the - speaker output (either sleeve if using 1/4" or 1- if using SpeakOn). Both chan 1 and 2 level controls need top be set identiaclly and in your case, all the way up is probably best.

5. IF you are using the SpeakOn output of the amp, use the Speak-On of channel 1 and the + output is 1+, the - output is 1-.

6. If using 1/4" output connectors in bridge mode, be absolutely sure any bare metal on the shell (sleeve terminal) doesn't touch anything since it is not at ground. This is the reason why 1/4" connections should not be used with any bridged amp. While the output voltage on this amp isn't likely to kill or hurt you (some amps this is definately not the case) it still deserves adequate caution and shorting to ground under these conditions can destroy your amp regardless of how good the protection circuitry may appear to be. It's not a specific fault that's well protected against.

If it's not making sound at low volumes, you may have other flaws in the logic. Also, I do not know if there's adequate drive signal available to achieve full output from the amp,

Oh,

your a life saver Aged Horse!!!

Thank you so much...

I am going to read that over and over until I have it down.

That is just what I needed.

Those guys at GC (God bless um) just didn't know how to
help me.

I feel less like I'm winging it now.

Thank you TB. This place rocks,

David

[Rick Auricchio]

Since you're on a shoestring budget, you have to be extra careful to avoid damaging anything.

I would go with just one channel of the amp, avoiding bridge-mode altogether. This simplifies your input and output connections. You will get 200w using one channel, and that should drive the speaker cabinet quite well. Forget the cabinet's 700w rating; it will probably not take anywhere near that power level before the speakers encounter mechanical distress.

Only use bridge mode if a single channel is inadequate. But get something working first without worrying about the tricks needed to run bridge mode.

[agedhorse]

If 200 watts is adequate for the necessary volume, that's a fine way to go, using one channel of the power amp in stereo mode.

If you need more volume than you can get with 200 watts, there's nothing wrong with powering that cabinet at around 600 watts which is about (+/-) what a GBE-1200 you will get with a GBE-1200 at 8 ohms. Of course a little common sense should be used and the GBE-1200 has an appropriate HPF to protect the drivers when driven really hard, but 600 watts is only 150 watts per driver and well within their ratings.

[JimmyM]

i can't help, but i did just get a bass attack and that's a pretty wise choice for bassists on a budget.

[Calaverasgrande]

thanks aged horse, I was about to jump in and offer the low down on hooking up an amp in bridged mode. Then I realized I have been writing user documentation all day and emailing a ton of people about this software rollout at my job. I don need to be doing another itemized list of instructions, but robo-me took over...
Also, it is likely both 400 watts at 8 AND 600 watts at 4 ohms. Also, like others have said, keep the bridge mode thing in reserve. Only pull that trick out if he absolutely cant get loud enough. My worry is that he could end up blowing his speaker cab and the amp if the bridge mode isnt done right. I mean, imagine 600 watts of positive polarity only. It will probably blow the VC's right?
Is that an older amp? I havent had to do bridge mode like that in decades.