NAD M33 Streaming Amplifier Review

[pogo]

I'm more curious if the built-in M33 phono stage + ADC is better than an outboard Puffin using digital out to connect to the M33.

I have now connected the Waxwing wirelessly to my M33 via a Bluesound HUB. The sound advantages are clearly audible, especially with quiet pickup systems. The range of functions is already great. An MDC module with these options would be desirable.

 

[pogo]

Here are measurements of the self-noise of the Waxwing in phono mode with input gain = 0dB and 72dB:

Input gain = 0dB

Input gain = 72dB

 

[Armchair Audiophile]

I wanted to bring attention to an issue I’ve encountered with my NAD M33, particularly around the subwoofer output level. While I love the M33’s design and sound quality, the ultra-low output from the sub out line has made it challenging to get the performance I’d expect, especially at low listening levels. Here are the specific issues:

1. Low-Level Listening Problems: The subwoofer doesn’t consistently receive a strong enough signal to activate at lower volumes, impacting the full audio experience.
2. Dirac Calibration Issues: This low output has caused real complications with Dirac measurements, one of the key features that drew me to the M33. Proper calibration is practically impossible when the sub signal isn’t accurate.

After reaching out to NAD support, they acknowledged this as a known issue. However, there’s currently no fix planned, nor a timeline for addressing it in a firmware update. Unfortunately, any posts about this on the forum are quickly removed, with instructions to contact support directly, which has left me and others in the community without a forum to openly discuss this problem.

If you’re an M33 owner or considering buying one, I encourage you to be aware of this limitation. It’s a fantastic unit otherwise, but this issue can be a dealbreaker for those relying on full-spectrum sound or Dirac calibration.

If anyone has found a solution, I’d love to hear about it. NAD suggested turning the gain on my sub all the way up as a fix. This gets the sub close to proper levels. It still does not address the problem that the signal is so low, that unless you are listening at high volumes, the sub does not exit standby.

 

[fcracer]

If anyone has found a solution, I’d love to hear about it. NAD suggested turning the gain on my sub all the way up as a fix. This gets the sub close to proper levels. It still does not address the problem that the signal is so low, that unless you are listening at high volumes, the sub does not exit standby.

SVS subwoofers are the solution. I use the SVS3000 Micro and I can keep the SW volume at -10 which provides sufficient output to match my 90db floor standers during the Dirac calibration. To ensure the subwoofer wakes from sleep, I use a 12V trigger which works superb.

The M33 puts out 1.1V maximum from the sub-out. SVS customer service is exceptional btw. Here’s the info on sensitivity from SVS:

Thank you for your email and interest in SVS.

The wakeup voltage from standby is 5mv and the amp can be driven to full power at 350mv (gain sensitivity) if the gain is set to full, this is for all of our subwoofers.

No more than 4v on the input otherwise it will clip and oversaturate the input stage.

If you’re committed to your current subwoofer, I can share some other tactics to help the subwoofer wake up but it will require using REW and some trial and error. The goal is to get Dirac to increase the subwoofer gain so that the M33 outputs as much voltage as possible so that the sub wakes up. Let me know and I can PM you.

 

[AlfaHolic]

I wanted to bring attention to an issue I’ve encountered with my NAD M33, particularly around the subwoofer output level. While I love the M33’s design and sound quality, the ultra-low output from the sub out line has made it challenging to get the performance I’d expect, especially at low listening levels. Here are the specific issues:

1. Low-Level Listening Problems: The subwoofer doesn’t consistently receive a strong enough signal to activate at lower volumes, impacting the full audio experience.
2. Dirac Calibration Issues: This low output has caused real complications with Dirac measurements, one of the key features that drew me to the M33. Proper calibration is practically impossible when the sub signal isn’t accurate.

After reaching out to NAD support, they acknowledged this as a known issue. However, there’s currently no fix planned, nor a timeline for addressing it in a firmware update. Unfortunately, any posts about this on the forum are quickly removed, with instructions to contact support directly, which has left me and others in the community without a forum to openly discuss this problem.

If you’re an M33 owner or considering buying one, I encourage you to be aware of this limitation. It’s a fantastic unit otherwise, but this issue can be a dealbreaker for those relying on full-spectrum sound or Dirac calibration.

If anyone has found a solution, I’d love to hear about it. NAD suggested turning the gain on my sub all the way up as a fix. This gets the sub close to proper levels. It still does not address the problem that the signal is so low, that unless you are listening at high volumes, the sub does not exit standby.

I had the same problem. I now use the 12 volt trigger out from the M33 to turn on my subs.

 

[pogo]

A sub connected without a trigger cable would be a nogo for me. You save yourself a lot of trouble, especially when calibrating.

 

[Armchair Audiophile]

The 12v trigger makes a lot of sense. Unfortunately, my Rel S3 SHO does not have one. I could leave the sub in the "always on" setting, but that seems like wasting a lot of juice for my limited listening sessions. In previous rigs, I used the high level connection to my Rel from my monos. The standard high-level setup does not really work with Dirac though. Thanks for the input guys. The 12v trigger is some of the best advice I have received yet.

 

[Chagall]

The 12v trigger makes a lot of sense. Unfortunately, my Rel S3 SHO does not have one. I could leave the sub in the "always on" setting, but that seems like wasting a lot of juice for my limited listening sessions. In previous rigs, I used the high level connection to my Rel from my monos. The standard high-level setup does not really work with Dirac though. Thanks for the input guys. The 12v trigger is some of the best advice I have received yet.

Maybe look at something like minidsp 2x4 that outputs 2V and can be used as "brains" for all your subs.

 

[doorofnight]

I am using a 31Hz sinewave test tone to wake up the subs, if needed.

The volumeknob on my subs is set at 45%, so they wake up at low volumes. They usually wake up at normal volume with normal music without any problems.

 

[fcracer]

The 12v trigger makes a lot of sense. Unfortunately, my Rel S3 SHO does not have one. I could leave the sub in the "always on" setting, but that seems like wasting a lot of juice for my limited listening sessions. In previous rigs, I used the high level connection to my Rel from my monos. The standard high-level setup does not really work with Dirac though. Thanks for the input guys. The 12v trigger is some of the best advice I have received yet.

Another "surprise" you should be aware of is that when you activate the subwoofer, something in the gain stage takes away headroom such that any hot recordings that go beyond 0db full scale and/or where inter-samples go above 0db, there will be audible distortion. This only occurs in VERY rare circumstances with poorly recorded sources. If you're interested in hearing the distortion for yourself, I can dig up a particular song that I use for testing inter-sample over issues.

 

[Esuarp77]

The 12v trigger makes a lot of sense. Unfortunately, my Rel S3 SHO does not have one. I could leave the sub in the "always on" setting, but that seems like wasting a lot of juice for my limited listening sessions. In previous rigs, I used the high level connection to my Rel from my monos. The standard high-level setup does not really work with Dirac though. Thanks for the input guys. The 12v trigger is some of the best advice I have received yet.

Hi “AA”,
your mentioning of REL using their high level cable in connection with Dirac RC caught my eye.. I have their t9x Sub in a 2.1 system and would like to try out Dirac for some room issues I am experiencing (mainly reverb and some boominess). I still could not figure out from reading various forums etc whether there actually is a possibility to include the sub in the calibration process?? Only if connected via LFE maybe? Is that worth it or have you found some other strategy?

Thanks in advance for sharing any advice you might have!
P

 

[pogo]

BluOS 4.8.7. Released November 19, 2024
• Initial support for the Bluesound NODE ICON, CYRUS 40 ST and Monitor Caspian.
• Gain control on M66 analog inputs.
• DSD support for the Bluesound NODE ICON, NODE (Gen 5) and NODE NANO.

 

[pogo]

Small setback on the M33 after the new BluOS update.
I can no longer equalize my headphones
Switching off the DL filters when plugging in headphones is actually correct, but now makes equalization impossible.

 

[Hear Here]

The 12v trigger makes a lot of sense. Unfortunately, my Rel S3 SHO does not have one. I could leave the sub in the "always on" setting, but that seems like wasting a lot of juice for my limited listening sessions. In previous rigs, I used the high level connection to my Rel from my monos. The standard high-level setup does not really work with Dirac though. Thanks for the input guys. The 12v trigger is some of the best advice I have received yet.

My REL S812 subs have a switch marked Always On and Standby. In the latter position, they sense an incoming signal and turn themselves on - virtually instantly. After your listening session has ended, the subs will turn themselves off after no signal for 10 minutes or so. No need for triggers!

I've found another way around the "no trigger" problem for anyone who needs them. An extension lead with a Master socket into which you plug your preamp (or whichever item you turn off by remote), then there are 4 Slave sockets into which you plug the devices without a trigger than you want turned off when the preamp is switched to Standby. The Main senses the demand from your preamp. If it falls below 1 watt (Standby is typically 0.5 watt), it turns off the slaves. When the preamp is turned on and draws more than 2.5 watts, it turns on the slaves. No need for triggers - clever stuff, eh?

https://www.amazon.co.uk/dp/B00GNXY51I?ref=ppx_yo2ov_dt_b_fed_asin_title

PS - It has a 6th socket that is always on - for your router for example.

PPS - This device has poor Amazon reviews, so I'll hold fire on a recommendation or otherwise, until it arrives in the next day or so.