700B and speaker out DC protection?

[BMWR75]

Hey Guys,

I've installed the White Oak PCB and LED light board in my 700B. Am now starting to think about installing Watts Abundant's DC protect relay board.

See the picture below. Are the brown caps and two parallel resistors hanging off the positive speaker outputs typical.

Please share your experiences with installing this DC protect board. Is it an easy or challenging project?

 

[Zach C.]

I think you'd be crazy not to.

100VDC will smoke a speaker VC quick.

The owner's manual recommends fusing, but I think pretty much everyone agrees that this is inadequate.

 

[BMWR75]

I emailed Watts Abundant about buying the assembled board.

 

[jbeckva]

Hey Guys,

I've installed the White Oak PCB and LED light board in my 700B. Am now starting to think about installing Watts Abundant's DC protect relay board.

See the picture below. Are the brown caps and two parallel resistors hanging off the positive speaker outputs typical.

Please share your experiences with installing this DC protect board. Is it an easy or challenging project?

View attachment 11799

Those are the "stock" Zobels. When you get the DCP, all of that comes off... Then with hex standoffs that screw onto the top of the speaker posts (make sure you suck all that solder off of them), the DCP mounts on top of the standoffs and has it's own Zobel built in.

 

[jbeckva]

ps.. yeah pretty easy... You'll need to run a few wires from the diode bridge on over for power, but aside from that those connectors and a small screwdriver finish it off. Definitely a "must have" - Lee I think actually had one fired off, and he said it pretty much worked as advertised. I have a feeling too that the 400 version saved my butt just last night, messing around with preamps... Would have probably had a couple of D9's with burnt out drivers for sale on CL, cheeep!!

 

[Northwinds]

ps.. yeah pretty easy... You'll need to run a few wires from the diode bridge on over for power, but aside from that those connectors and a small screwdriver finish it off. Definitely a "must have" - Lee I think actually had one fired off, and he said it pretty much worked as advertised. I have a feeling too that the 400 version saved my butt just last night, messing around with preamps... Would have probably had a couple of D9's with burnt out drivers for sale on CL, cheeep!!

 

[laatsch55]

I was going full tilt boogie with a 700 on my horns when an output gave up, and I mean FULL TILT. Contacts in the relay fried. Cheap, 11.00 relay.

 

[BMWR75]

board is on order from Watts Abundant

 

[laatsch55]

You were a hard sell.

 

[premiumplus]

All of my Phase Linears have the DCP boards. Very cheap insurance, and it also eliminates the turn on/turn off thumps. Easy to install too.

 

[laatsch55]

If they're White Oaked there are no turn on/off thumps.

 

[Gepetto]

If they're White Oaked there are no turn on/off thumps.

We fixed that

 

[Rat44]

I use a set of AR-9's as my main speakers and a set of ADS-810's also.
No replacements available so I get concerned about damaging the drivers.
The AR-9's dip very low in the impedance and are very hard to find good amps that can drive them 'properly'.
I have owned PL-400's and like them but never ran them with speakers that could dip to 2 ohms.
Toying with the idea of building a pair of wopl 400's to use with the 9's.
Would that be wise or should I look to the Crown 300 series ?
Ran 400's bridged back in the 70's but that didn't turn out very well.
Thinking about bi amping my 9's to get the most out of them .
Or am I going down the wrong road and need to step up to a 700 ?
Wish they had that board available when my AR 10 IIs took a direct hit from a PL 400.
Thanks for any ideas .

Dennis

 

[laatsch55]

A 2 ohm load requires lots of current. The 700 would be a better choice if you're kicking some SPL's. The Pig pushed some 2 ohm subs for Steve for a couple weeks in Phoenix and didn't seem to mind, but that was at 28hz and down...

 

[laatsch55]

At what frequencies do the 2 ohm dips appear?

 

[Rat44]

At what frequencies do the 2 ohm dips appear?

My bad.
They dip to 3.2 ohms.

 

[Gepetto]

My bad.
They dip to 3.2 ohms.

That is pretty typical of most woofers at their mechanical resonant point.

 

[laatsch55]

Mechanical resonant point would be.........where they have a self sustaing output regardless of input>?? I'm Pretty dumb on speaker stuff here Joe......

 

[Gepetto]

Mechanical resonant point would be.........where they have a self sustaing output regardless of input>?? I'm Pretty dumb on speaker stuff here Joe......

It is where the mass of the cone combined with the spring stiffness of the surround peaks. If you drove the speaker with a constant 1V p-p input signal over a frequency sweep range of 5 to 200 Hz, you would notice a peaking at a frequency somewhere around 30-40Hz which is where most 12" woofer free air resonances lie. This peaking would be measurable in the sound pressure level put out by the woofer. The woofer electrical impedance gets squirrely at this same frequency, peaking from 6-8 ohms often up to 30-40 ohms. It is in this area that the load gets hard to drive/control. You have heard that term before, these speakers are hard to drive...

Right around resonance is where you tend to get these dips

 

[laatsch55]

But with the dips you get the peaks?? 30-40 ohms, right alongside 3-2 ohms would drive electronics nuts I suppose. Does the topology of an amp have everything top do with how an amb handles this or are there certain accross the board things that are hard to control period?