[BGA]

I have checked for clipping at woofer terminals and can't get 40hz sine wave to clip on scope, but at 40hz at 18volts, red LEDs are lit solid. I of course turned things down immediately. Perhaps it's the servo system going into overload?? Still had nice smooth crest's?? I am now trying speaker level connection's but can't get signal to pass through to mains at all ?? Wondering if this could be a Class D integrated issue?? I'm going to have to get with NAD on this I'm afraid. Kind of at a loss right now? Have any of you had issues with speaker level inputs not passing to mains ?

Are you quoting the 18v correct? That seems way too high for output voltage over RCA, that would cause most inputs to clip go into some form of protections mode.

[dallaire1]

Exactly at 18 volts at 40hz anyway. I listen probably louder than most. Im connected to pre outs now, at 3.9volts instead of the sub outputs at 1volt.

[Danny Richie]

The amount of power that you are sending these things should be giving you a ton of output.

I know you keep saying that you have them wired correctly, but everything still points to not having them wired correctly.

This also makes me cringe a little.

I listen probably louder than most.

Your picture is of a pair of spatial speakers in a completely untreated room, or at least nothing on the front walls, corners, or immediate sides.

Open baffle speakers really need to have a front wall that is almost covered in something that will break up and/or absorb the back waves. Those corners really need some traps too.

I recently heard some Spatial X4's in a treated room, and then in the same room with all of the treatment removed, and with all of the treatment removed it was completely un-listenable. They were unbearable at any level over a normal speaking voice level.

So I can't help but think your room is as large or even a larger problem than your issue with not having bass output from the servo subs. 

I would highly recommend corner traps, wall panels (absorbers), and diffusers to cover most of the up front area.

[dallaire1]

It's funny you say that Danny. I moved everything into my fireplace room, long rectangular room. Just threw up a few panels to kill the zingers ! Sounds much smoother after analyzing and correcting with REW. Kicked Dirac to the curb for now as it is pretty darn smooth now without Dirac. However the amps perform the same. Room treatment can't reduce circuit overloads in electronics.


 

[Danny Richie]

Nice! Now keep going with that. Some diffusion between your corner traps and the fireplace would be good.

Keep going down the side walls too.

Also, the space behind your corner traps will work even better with a bunch of loose insulation behind it. The thicker the better for corners and low bass.

You have something going on with the amps, wiring, or with what is driving them. We'll solve it.

Send the amps to me and I'll try them in my system right away and let you know what happens.

[77SunsetStrip]

Are you quoting the 18v correct? That seems way too high for output voltage over RCA, that would cause most inputs to clip go into some form of protections mode.

He said measured at the woofer terminals so that is the output of the amp.  18V on the input to the sub amp would be a BIG problem.

Unanswered question remains.  What do the LEDs he observes flashing actually indicate?  Still cannot fathom the NAD amp volume at 80% to achieve an acceptable listening SPL. 

Am I misunderstanding?  It takes 80% of the NAD output capability to drive the Spatial speakers to a satisfactory listening volume.

Take Danny's offer and send him the Sub amps pronto. 

[EdwardT]

This still does not satisfy my curiosity. Line level ought to be 1.4 volts at +4dBu and an amp output of 18v into 4 ohms is only 81 watts, that just can’t be enough to clip any robust sub speaker. Something is definitely sideways here.

[77SunsetStrip]

This still does not satisfy my curiosity. Line level ought to be 1.4 volts at +4dBu and an amp output of 18v into 4 ohms is only 81 watts, that just can’t be enough to clip any robust sub speaker. Something is definitely sideways here.

Agree.  Wish there was somebody nearby dallaire that could help out.

[dallaire1]

I will get them out this week to you Danny. I know Ron B. had possession of am M33 for review some time ago, if he still has it that would be great for testing. Just don't know if it was a loaner or not ?

[dallaire1]

This morning I have shipped 1 of the amps back, the one that has intermittent "buzzing" every minute or so, yet still plays fine. I have read on Claytons forum that one of his members had to send back one of his as well with the same issue. I am doing this so Danny can send me back an amp that he deems "fine". I will then reinstall it into the system and see if it lights up the overload indicators at the same volume level as before. Both amp simultaneously would overload at exactly the same volume, so I find it incredibly hard to assume they are both bad. I don't want to incur the cost of shipping for 2 amps if the one I get back doesn't behave any differently. When I get the amp back that is deemed "perfectly fine" and does happen to not go into overload at the same level, THEN I will know to send the other amp back as well. I am not too hopeful the amp, once returned with "no buzzing" will overload any different than the one I'm holding on to for now. It would be great to see it NOT light up. Guess time will tell.

You should have the amp on the 23rd Danny via UPS

[Danny Richie]

This morning I have shipped 1 of the amps back, the one that has intermittent "buzzing" every minute or so, yet still plays fine. I have read on Claytons forum that one of his members had to send back one of his as well with the same issue. I am doing this so Danny can send me back an amp that he deems "fine". I will then reinstall it into the system and see if it lights up the overload indicators at the same volume level as before. Both amp simultaneously would overload at exactly the same volume, so I find it incredibly hard to assume they are both bad. I don't want to incur the cost of shipping for 2 amps if the one I get back doesn't behave any differently. When I get the amp back that is deemed "perfectly fine" and does happen to not go into overload at the same level, THEN I will know to send the other amp back as well. I am not too hopeful the amp, once returned with "no buzzing" will overload any different than the one I'm holding on to for now. It would be great to see it NOT light up. Guess time will tell.

You should have the amp on the 23rd Danny via UPS

I'll check it out when it gets here.

[77SunsetStrip]

Both amp simultaneously would overload at exactly the same volume, so I find it incredibly hard to assume they are both bad.  . . . . . .   I am not too hopeful the amp, once returned with "no buzzing" will overload any different than the one I'm holding on to for now. It would be great to see it NOT light up. Guess time will tell.

Sorry if I missed confirmation of precisely what the LEDs blinking/on mean to eliminate assumptions?  Thought you said earlier Brian at Rythmik never replied.  Did you find the function of the LEDs defined somewhere in Rythmik documentation?  It does not make much sense for Rythmik to put overload indicator LEDs in a location that would in 99% of installations not be visible.

While waiting on Danny's diagnosis, suggest it would be good use of the time to discuss the issue with NAD.

[dallaire1]

I woke this morning at the usual 3:30 having coffee in my listening room just to hear now the other amp  intermittently "buzzing" !!! Will be shipping this one back as well. The other was louder than this one so I never really noticed it. This is with nothing but a power cord plugged in! I have never had buyers remorse so bad in my life. And I have to pay for shipping under warranty ! Really ??? Buyer beware! I would ask Brian but he seems unreachable huh? Don't even trust these amps anymore.

[dallaire1]

I will be contacting NAD for sure. If that is the issue I would be VERY surprised! But if it is, then I will stand corrected as a man and extended my deepest apologies to GR Research!

[dallaire1]

I just wrote Brian at Rythmik, quote


"Hello Brian, can you please tell me what the RED LEDs indicate when flashing on the circuit side of the A370PEQ. I am assuming clipping indicators ? I have been having problems with the lights flashing at moderate to high volume levels. I am hooked up to an NAD M33 class D integrated amp using the "preamp outputs at 3.9volts" I have sent back to Danny one amp because of buzzing loudly while idle with nothing but a power cord hooked up. Now this morning I have discovered the other amp starting to "buzz" quite loudly in a dead quiet room. I am very frustrated. I don't know how else to hook them up ? I tried the speaker level connections to no avail, wouldn't pass signal on to the mains ?

Also I have noticed on your site, in the "amplifier spec section" it clearly calls out power output for all amps into "4 ohm loads" but on the A370PEQ it just says "370 watts" ? into what load?

Thanks Brian"

[dallaire1]

I have done all the research I can on the NAD to no avail regarding subwoofer issues. I did however stumble upon a recall on Rythmik amps on AVS forum dated back to January 2021. I do not know what amps where recalled but mine were purchased on May 29th 2021.

[77SunsetStrip]

Have you checked to see if a firmware update is available for the M33?

[BGA]

I woke this morning at the usual 3:30 having coffee in my listening room just to hear now the other amp  intermittently "buzzing" !!! Will be shipping this one back as well. The other was louder than this one so I never really noticed it. This is with nothing but a power cord plugged in! I have never had buyers remorse so bad in my life. And I have to pay for shipping under warranty ! Really ??? Buyer beware! I would ask Brian but he seems unreachable huh? Don't even trust these amps anymore.

The buzzing you hear may be DC on your lines. One of mine did the same randomly but hasn’t buzzed once since I put them on my Puritan line conditioner. It’s just coming from the amp itself and not through the speakers, correct?

[dallaire1]

Yes, coming from the amp only. This just tells me the mains input filtering on these amps is WAY less than desirable. I have to sit in a quite room with company and have someone say "what's that buzzing noise" ? to which I reply "that's just my amplifiers buzzing". wow. I Guess if you have them in a sealed, sound damped enclosure it may be fine and inaudible ? but for an OB situation, no way...they should come with a sheet of NO REZ.

[Early B.]

Yes, coming from the amp only. This just tells me the mains input filtering on these amps is WAY less than desirable. I have to sit in a quite room with company and have someone say "what's that buzzing noise" ? to which I reply "that's just my amplifiers buzzing". wow. I Guess if you have them in a sealed, sound damped enclosure it may be fine and inaudible ? but for an OB situation, no way...they should come with a sheet of NO REZ.

You're blaming the gear again. If it's a DC problem, you have dirty power. That's an easy fix. However, it sounds like you have multiple issues.