Comments on Naim preamp & amp Components with Wilson Duetts

Background: replaced my Levinson 326 PreAmp with a Naim NAC 272; added Uniti Core; upgraded all cables with transparent; kept Levinson 432 amp.

Problem: When powering up or off the ML amp; horrid loud pop and crackle thru Wilson Duettes; did not exist before when controlled by my ML 326 preamp. Does not matter if NAC 272 PreAmp is off first or not; once preamp is powered up; loud pop and crackle.  This is worrisome!

Hope to test out Naim 250DR or 300DR amp to see if there is a difference and to assess how they will power and sound with my Wilson Duettes.  N/A distributor has been fairly unresponsive and my local Naim dealer has been working at this for 2 months......a bit frustrating.

Looking for feedback and comments on experiences with Naim amps with Wilson duettes or issues with other manufacturers amps with the NAC 272 preamp. Thanks in advance

Original Post
jGolf53 posted:

Background: replaced my Levinson 326 PreAmp with a Naim NAC 272; added Uniti Core; upgraded all cables with transparent; kept Levinson 432 amp.

Problem: When powering up or off the ML amp; horrid loud pop and crackle thru Wilson Duettes; did not exist before when controlled by my ML 326 preamp. Does not matter if NAC 272 PreAmp is off first or not; once preamp is powered up; loud pop and crackle.  This is worrisome!

Hope to test out Naim 250DR or 300DR amp to see if there is a difference and to assess how they will power and sound with my Wilson Duettes.  N/A distributor has been fairly unresponsive and my local Naim dealer has been working at this for 2 months......a bit frustrating.

Looking for feedback and comments on experiences with Naim amps with Wilson duettes or issues with other manufacturers amps with the NAC 272 preamp. Thanks in advance

using naim amp or preamp with other brands is not always a good thing.  For electrical reasons, it is not always a good match.  

I am using myself an all tubes preamp with naim nap 300, and it works very well.  Before i tested a conrad johnson with nap 250 and it was not good match: a lot of nasty noise, hiss and hum.

I know that naim and wilson have synergy.   But perhaps you don’t use the appropriate cable too?   good luck 

 

The Wilson's have nothing to do with your pop and crackle....

The Levinson amp is not playing well with the Naim - try a Naim amp with stock Naim cables as a baseline.  A 250DR should drive the Duett's fine, a 300DR will be icing on the cake. Good luck

ATB,

Mark

Thank-you...this was exactly my reaction to my dealer and they argued to no end that my problem was with my Levinson amp...which is nonsense since it ran perfectly with the ML Preamp and the Wilson Duettes.  Which I hope to prove out by testing the 250 DR.  We did replace the speaker cables with high-end Transparents.....I hope I don't have to turnaround and purcahse Naim cables.

French Rooster posted:

maybe i am wrong, but even if the 272 is not powered, it is connected to the ml amp. It may also give some electrical consequences?

The speakers cables can also have problems.... or, as you said, the ml amp have a problem....

The only consequence of an unpowered pre-amp is to provide a low impedance path from signal to return at the input of the power-amp.
This should reduce the tendency to a power-on surge from the power-amp.

Speaker cables shouldn't cause a power-on surge from a correctly operating power-amp, but an unsuitable load (including unsuitable cables) can make a power-amp unstable (or even start to oscillate) during operation.

Golf, as Huge asked earlier in the thread, if the amp is the only thing connected to the speakers, do you still get the pop and crackle?  

I don't know the ML amp very well, but note that there is a power save circuit that can be switched on and off - does this have any effect?  

Yes mismatch in electronics is never fun.

home demoed a Chord QBD76HDSD, and was about to drop my money down. Turned some light switches on and off and the Chord would loose lock on the signal. Very disappointing as I loved the sound of it over over my nDAC/555ps.

crackie posted:

Yes mismatch in electronics is never fun.

home demoed a Chord QBD76HDSD, and was about to drop my money down. Turned some light switches on and off and the Chord would loose lock on the signal. Very disappointing as I loved the sound of it over over my nDAC/555ps.

If it was that good, couldn’t you have changrd the light?!

Huge posted:

If the 272 is left unpowered and you still get a loud noise when powering up the power-amp, then there is a problem with the power-amp.

I have tried every sequence of turning on the components:  Pop is the loudest when 272 is either on first or turned off last. I believe the problem is related to the interconnect between the 272 preamp and the ML amp.....this was not a problem when I used the ML 326 preamp.

Richard Dane posted:

Golf, as Huge asked earlier in the thread, if the amp is the only thing connected to the speakers, do you still get the pop and crackle?  

I don't know the ML amp very well, but note that there is a power save circuit that can be switched on and off - does this have any effect?  

Yes on the ML amp there is the'standby' mode...which is what i power on first.  So here is the sequence: 1) ML on to standby; 2) ML to on; 3) N272 on; 4) Loud pop then crackle.

Huge posted:

Have you tried changing the grounding switch in the 272?

By default it's set to 'Chassis', so try setting it to 'Floating' (or vice versa).

that is an interesting observation and will check it out.  We have decided to replace the 272 with a new unit as the first new 272 unit had a constant hum in the chassis.....dealer had to be convinced that perhaps the 272 was faulty...let's see what happens with the pop then..

jGolf53 posted:
Huge posted:

Have you tried changing the grounding switch in the 272?

By default it's set to 'Chassis', so try setting it to 'Floating' (or vice versa).

that is an interesting observation and will check it out.  We have decided to replace the 272 with a new unit as the first new 272 unit had a constant hum in the chassis.....dealer had to be convinced that perhaps the 272 was faulty...let's see what happens with the pop then..

Some toroidal transformers do have a mechanical hum (my 300PS can be heard about 2m away).  Provided this is from the physical component itself and not the speakers, it's usually nothing to worry about.

jGolf53 posted:
Richard Dane posted:

Golf, as Huge asked earlier in the thread, if the amp is the only thing connected to the speakers, do you still get the pop and crackle?  

I don't know the ML amp very well, but note that there is a power save circuit that can be switched on and off - does this have any effect?  

Yes on the ML amp there is the'standby' mode...which is what i power on first.  So here is the sequence: 1) ML on to standby; 2) ML to on; 3) N272 on; 4) Loud pop then crackle.

If the pop occurs when the power-amp is already on and then you power-on the pre-amp then that's because, as Richard points out that's the wrong order!

You need to power-on from source components first to power-amp last.  All components produce some degree of switch on surge (even if it's extremely minor), so if the later amplifiers are already turned on they will amplify these (perfectly normal) switch-on surges - hence the pops, bangs and crackles!

jGolf53 posted:
Richard Dane posted:

What about if you power on the power amp last. This is best practice anyway.

that is when the pop and I mean POP is the loudest

This suggests one of the following...

1  the 272's grounding switch is in the wrong place for the ML amp

2  The ML is actually expecting a balanced input and can't cope with the -ve input being grounded (in this case the instructions for the ML power-amp will tell you that the power-amp must only ever be used with a matching ML pre-amp, and you're not operating it appropriately).

3  there's a fault with the 272

4  there's a fault with the input circuit of the ML (e.g. it has a bias current or voltage present at it's input or it's 0V is improperly grounded).

5  the power-on mute circuit in the ML may have failed.

Huge posted:
jGolf53 posted:
Richard Dane posted:

Golf, as Huge asked earlier in the thread, if the amp is the only thing connected to the speakers, do you still get the pop and crackle?  

I don't know the ML amp very well, but note that there is a power save circuit that can be switched on and off - does this have any effect?  

Yes on the ML amp there is the'standby' mode...which is what i power on first.  So here is the sequence: 1) ML on to standby; 2) ML to on; 3) N272 on; 4) Loud pop then crackle.

If the pop occurs when the power-amp is already on and then you power-on the pre-amp then that's because, as Richard points out that's the wrong order!

You need to power-on from source components first to power-amp last.  All components produce some degree of switch on surge (even if it's extremely minor), so if the later amplifiers are already turned on they will amplify these (perfectly normal) switch-on surges - hence the pops, bangs and crackles!

good point...perhaps I wasn't clear.....when i power the N 272 first then I power the ML amp on there is an extremely loud pop then crackle.  If I reverse the order of powering on (Amp first then source) the pop is still there but not as loud.

Huge posted:
jGolf53 posted:
Richard Dane posted:

What about if you power on the power amp last. This is best practice anyway.

that is when the pop and I mean POP is the loudest

This suggests one of the following...

1  the 272's grounding switch is in the wrong place for the ML amp

2  The ML is actually expecting a balanced input and can't cope with the -ve input being grounded (in this case the instructions for the ML power-amp will tell you that the power-amp must only ever be used with a matching ML pre-amp, and you're not operating it appropriately).

3  there's a fault with the 272

4  there's a fault with the input circuit of the ML (e.g. it has a bias current or voltage present at it's input or it's 0V is improperly grounded).

5  the power-on mute circuit in the ML may have failed.

Huge ---- I think you have nailed it with #2 point.  This has been my contention since day one...but the dealer just doesn't agree.  Prior to the switchover to the NAC272 -- my ML 326 preamp had a balanced connection to the ML amp.  Which is why when we switched to Naim components whe went RCA at all connections.  I think the ML amp is simply not compatible with the NAC 272...which is why i soon hope to test out a Naim 250 DR amp.  Unfortunatley, the NA distributor has not been very helpful with my dealer.

Hi jGolf53,

Yes, running equipment with balanced inputs from unbalanced outputs is unpredictable; usually it works fine, but sometimes it just doesn't (it depends on the design of the balanced input).

Trying the 272 with the grounding switch set to 'floating' may sort the problem, but there's no guarantees, and it may cause other problems instead.

In any case the 250DR is a cracking power-amp (if you'll excuse the expression - this side of the pond cracking is slang for 'excellent' - not producing cracking noises!  ).

Thank-you...We watch enough BBC mysteries and I have been forced to watch Dowton Abbey without subtitles .....I have heard that term..."cracking"...but heard pronounced slightly different....thanks so much for helpful advice and comments....will keep forum posted on progress.

Update for all those tips and suggestions:  I am now testing out a replacement Amp....the Naim 250DR.  My dealer worked hard to get the Naim NA distributor to ship a test unit for me.  We changed the interconnects to banana plugs.  So now my Naim 272 preamp is connected to 250DR...driving my Wilson Duettes.  Only a few hours of testing but a few major differences:  minimal pop on startup, crackle gone and the sound is just fantastic.  Great depth and separation, very fast....a very pleasant surprise.  hard to believe that this little 80 watt 250DR can produce sooooo much better sound than my Levinson 432 with 450 watts per channel.  The Uniti CORE is a amazing source; excellent sound and interface.  Tidal HiFi sounds terrifc.  My Classe SACD player...is quickly losing it's luster in comparison.

thanks to all for the feedback....now I'm dreaming about the 300DR.....

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