help-wiring a cable for bridged mono?

[UncleScabby]

Can anyone give me some insight on wiring a speaker cable for bridged mono? It would be dual banana plug at the amp end, and speakon twist/lock on the cabinet end? I'm assuming its the Speakon end that needs the attention. I actually have the cable, I think it just needs to be changed inside the plug?

[Ron]

What amp and speaker combination are you using?

[UncleScabby]

I'm using the Ampeg svt 610

http://ampeg.com/pdf/SVT-610HLF.PDF

& the Ampeg B-4r--the Ampeg site doesn't have the pdf for some reason, but you can view it here under Docs. FYI the B series heads did not come with the Speakon outputs like it says in the manual, hence the banana plug.

http://www.zzounds.com/item--AMPB4R

[Ron]

You don't have to do anything special with the speaker cable. The speakon connector will only have two terminals, one positive and one negative. Just connect those to the respective bridged mono output banana plugs at the amp.

As a side note, with the amp bridged, don't ever connect another cabinet to the second speakon connector. That would be too much of a load and turn the amp into something crispy.

[UncleScabby]

thanks Ron!

[Killjingle]

Ron,

Im curious as to how well that head matches up power wise with that cab. Looks like the head peaks out at 1350W and the cab is at 1200W. He was underpowering the cab b4 and having all kinds of clipping probs from running his head too hot.

[Killjingle]

BUMP

[lonewolf]

That head is a few hundred watts overpowered as far as musical instruments (especially bass) is concerned. This is not a big deal, but he should be very careful not to drive it too hard or the speakers can go beyond their excursion and POP.

Unlike with PA, you want to match up the RMS values between amp and cabinet on instrument rigs. Its OK to get around 20% higher on the amp for more headroom. Peak values don't apply much here because instruments such as bass don't generally have instantaneous peaks like you have with a mixed sound source.

In this case, you have a 1000W rms amp driving a 600W rms cab. Ideally, you would want a 600w-750w rms amp driving this cab.

[Ron]

Was it the same amp/cab combination (running one channel) that was clipping before, or a different amp?

If it was the same amp and cab running one channel then it was only 420W "continuous" before, which would definitely be under-powering the 610 cab.

IMO it's a lot harder on the speakers running under-powered and clipping than to have some headroom with an amp rated higher than the cab rating. But... if the volume is pushed to the point of clipping for extended periods with the amp rated higher than the cab, bad things could happen.

It is odd to me that Ampeg rates their amps in "continuous" power and their speaker cabs as RMS. Most definitions equate the two ratings, but I wouldn't be so sure. Your best bet would be to contact Ampeg and find out if they recommend pairing the 610 and B4R.

[Killjingle]

That head is a few hundred watts overpowered as far as musical instruments (especially bass) is concerned. This is not a big deal, but he should be very careful not to drive it too hard or the speakers can go beyond their excursion and POP.

I thought this too.

Was it the same amp/cab combination (running one channel) that was clipping before, or a different amp?

yes

It is odd to me that Ampeg rates their amps in "continuous" power and their speaker cabs as RMS. Most definitions equate the two ratings, but I wouldn't be so sure. Your best bet would be to contact Ampeg and find out if they recommend pairing the 610 and B4R.

Ampeg says "I guess". WTF? Thats why I figured I would seek other advice.

Its OK to get around 20% higher on the amp for more headroom

makes sense to me

IMO it's a lot harder on the speakers running under-powered and clipping than to have some headroom with an amp rated higher than the cab rating. But... if the volume is pushed to the point of clipping for extended periods with the amp rated higher than the cab, bad things could happen.

thats actually what I told Greg; that he will have to be very mindful!

thanks to the both of you;

heres my concern on top of all this; he has a sonic maximizer in his loop and is pushing his 33 K 3+ over flat on his EQ; so hes pushing the speakers a little harder anyway. we also thought about taking the maximizer out (which I generally hate; but he has great tone) and putting a compressor in instead. But that still equates to having a constant compressed signal driving hard depending how loud he is.

[Ron]

heres my concern on top of all this; he has a sonic maximizer in his loop and is pushing his 33 K 3+ over flat on his EQ; so hes pushing the speakers a little harder anyway. we also thought about taking the maximizer out (which I generally hate; but he has great tone) and putting a compressor in instead. But that still equates to having a constant compressed signal driving hard depending how loud he is.

Greg could put a compressor in line after the sonic maximizer and then set up the compressor as a limiter only (ratio above 10:1, ideally infinity:1). That way he wouldn't be sacrificing any tone but still have a hard limit on the output level that the amp could reach.

To find the limit point would be fairly easy, although it does require some adjustments at high volume levels.

Set up the compressor with the ratio maxed and the threshold set at the highest point (so that it isn't compressing anything). At that point set the amp/maximizer up to where you feel it is at its maximum useful, unclipped level. Then set the input and output gains of the comp so that it is transparent (switching it in and out doesn't change the volume or color the tone). Then bring down the threshold to the point where it just starts to kick in and limit the volume.

At that point the only control that would allow the amp to clip would be the output level control of the comp. The attack and decay times on the comp wouldn't really be important, I'd set them for quickest attack and least amount of decay.

I think I have that all correct.

[Killjingle]

we are gonnna attempt that.

thanks again Ron.