40 VDC sub output -- injured RSS265HO?

[50 watt head]

I've known that my Dayton SA-240 plate amp has had issues for awhile now -- it developed a hum/noise problem last spring, I returned it for repair over the summer, got it back but it still has the same issue.

Well, I finally got around to checking it out myself, and no wonder it was humming -- there's steady 40VDC on the output when the mains is switched off.

I'm giving up on the amp, it's haunted -- but my concern now is my RSS265HO-4. You guys think it's alright? It's been exposed to that DC on various occasions over the last 6 months. I hope it's not been harmed :(

[envisionelec]

Re: 40 VDC sub output -- injured RSS265HO?

I've known that my Dayton SA-240 plate amp has had issues for awhile now -- it developed a hum/noise problem last spring, I returned it for repair over the summer, got it back but it still has the same issue.

Well, I finally got around to checking it out myself, and no wonder it was humming -- there's steady 40VDC on the output when the mains is switched off.

I'm giving up on the amp, it's haunted -- but my concern now is my RSS265HO-4. You guys think it's alright? It's been exposed to that DC on various occasions over the last 6 months. I hope it's not been harmed :(

Please explain how you can unplug the amp and get 40V off the speaker outputs? Are you saying that the Auto-On is turned off and then you measure 40V?

40V DC will push the cone out a couple inches and destroy the voice coil in several seconds. I don't think you're reading the meter correctly. Maybe 40mV?

Does it still hum if you unplug all input cabling leaving only the woofer connected to the amp?

[50 watt head]

Re: 40 VDC sub output -- injured RSS265HO?

Clarification: when I measured 40VDC on the output, the amp was plugged into the wall but switched to OFF. I measured the 40VDC with both DVM and scope with no load. Told you it was haunted

It did quite a number :D on a smaller 8" woofer I had on my bench, that was my clue that it was passing DC.

Please explain how you can unplug the amp and get 40V off the speaker outputs? Are you saying that the Auto-On is turned off and then you measure 40V?

40V DC will push the cone out a couple inches and destroy the voice coil in several seconds. I don't think you're reading the meter correctly. Maybe 40mV?

Does it still hum if you unplug all input cabling leaving only the woofer connected to the amp?

[envisionelec]

Re: 40 VDC sub output -- injured RSS265HO?

Clarification: when I measured 40VDC on the output, the amp was plugged into the wall but switched to OFF. I measured the 40VDC with both DVM and scope with no load. Told you it was haunted

It did quite a number :D on a smaller 8" woofer I had on my bench, that was my clue that it was passing DC.

Not haunted - just f***ed.

Was it "fixed" by Parts Express? They're not so great at repairs, to be honest. They really should make it right for you, IMO.

[50 watt head]

Re: 40 VDC sub output -- injured RSS265HO?

Not haunted - just f***ed.

Was it "fixed" by Parts Express? They're not so great at repairs, to be honest. They really should make it right for you, IMO.

Yes, it was a PE repair. I don't want the hassle and expense of shipping it for repair again. As long as my RSS265 is healthy and unharmed, I'll be OK. Probably will take my chances with the newer SA-250 amp.

[Whitneyville1]

Re: 40 VDC sub output -- injured RSS265HO?

How many mA of current is the output? That will also make a difference in how much it takes to "cook" the RSS. I'd contact P-E customer service again, post haste, if there is damage to your sub. I doubt that they'd replace it, but they might be able to repair it or make an adjustment to the price of a replacement if it isn't still under warranty.

[envisionelec]

Re: 40 VDC sub output -- injured RSS265HO?

How many mA of current is the output? That will also make a difference in how much it takes to "cook" the RSS. I'd contact P-E customer service again, post haste, if there is damage to your sub. I doubt that they'd replace it, but they might be able to repair it or make an adjustment to the price of a replacement if it isn't still under warranty.

40V is half the rail voltage. So...likely a couple Amperes. There's nothing in them to protect against a shorted output device.

[50 watt head]

Re: 40 VDC sub output -- injured RSS265HO?

Yeah, good question, I'll have to look into that.

How many mA of current is the output? That will also make a difference in how much it takes to "cook" the RSS. I'd contact P-E customer service again, post haste, if there is damage to your sub. I doubt that they'd replace it, but they might be able to repair it or make an adjustment to the price of a replacement if it isn't still under warranty.

[50 watt head]

Re: 40 VDC sub output -- injured RSS265HO?

There's nothing in them to protect against a shorted output device.

Yikes. Well... perhaps I ought to rethink ordering the SA-250. Anyone think I ought to go with the Bash 300 instead?

[Whitneyville1]

Re: 40 VDC sub output -- injured RSS265HO?

40V x 2A= 80Watts maybe mostly DC= not good at all. That's when you hope there's lots of AC leaking thru, but 80 watts of 60 or 120 Hz would be LOUD. I don't think this has a happy ending.

[AJ]

Re: 40 VDC sub output -- injured RSS265HO?

40V x 2A= 80Watts maybe mostly DC= not good at all. That's when you hope there's lots of AC leaking thru, but 80 watts of 60 or 120 Hz would be LOUD. I don't think this has a happy ending.

Huh?

P=E^2/R=40^2/4= 400W. 200W for an 8R driver. Either way, the AC line fuse should have blown; if it didn't, that amp is poorly designed.

[50 watt head]

Re: 40 VDC sub output -- injured RSS265HO?

OK, just measured with an 8-ohm dummy load, 10VDC, so around 12 watts DC. So, worst case, 25 watts DC might have been running into my sub here and there.

Just removed my RSS265HO-4 driver and it appears to be fine, no cooked or burnt odor, DCR measures OK.

[envisionelec]

Re: 40 VDC sub output -- injured RSS265HO?

OK, just measured with an 8-ohm dummy load, 10VDC, so around 12 watts DC. So, worst case, 25 watts DC might have been running into my sub here and there.

Just removed my RSS265HO-4 driver and it appears to be fine, no cooked or burnt odor, DCR measures OK.

Ok, so it is current limited. Good. These plate amps are all pretty much the same - but the reason there is 10 volts at the output can stem from a number of causes. And frankly, I can't remember any of them at this hour. But they are plentiful.

The BASH is completely different and has a nifty switching power supply design which makes it lightweight.

I have a barely used BASH 300 if you're interested for a great price. PM if interested.

[50 watt head]

Re: 40 VDC sub output -- injured RSS265HO?

I have a barely used BASH 300 if you're interested for a great price. PM if interested.

Hey, your inbox seems to be full.

[envisionelec]

Re: 40 VDC sub output -- injured RSS265HO?

Whoops.

Fixed.