This... Is a very interesting part. To see what the crossovers and whatever do to the AC mains frequency.Your local mains frequency is 50 Hz? Would be interesting to see any difference based on the fact that ClassG33’s is 60 Hz, I believe.
This... Is a very interesting part. To see what the crossovers and whatever do to the AC mains frequency.Your local mains frequency is 50 Hz? Would be interesting to see any difference based on the fact that ClassG33’s is 60 Hz, I believe.
This... Is a very interesting part. To see what the crossovers and whatever do to the AC mains frequency.
Sorry to get all internet-y... but this, times 10^6.The other interesting thing to consider is the induced signal in the speaker from the Mac's transformer could be very partially fed back to the input via the NFB loop and it could be modulated somewhat, depending on the fluctuations in the field due to currents flowing in all the channels whilst playing robust content.
I don't blame the McIntosh at all and it's not faulty IMO. Plenty of amplifiers have stray radiated fields from large transformers. Back in the vinyl and tape deck days, much time and effort was spent by me and millions of other audiophiles, carefully arranging HiFi components to ensure their transformers didn't induce noises in EQs, cassette decks and turntables. Knowing where the transformers were and moving things from right to left in cabinets, spacing and order of stacking was extremely important. But to get it in a unconnected loudspeaker is pretty awesome in my book.
You should simply move the amplifier to the other side of the cabinet, that will cut down the noise significantly I would expect, as the TXF is further away from the speaker and its internals (depending on where the inductors are inside), or preferably into its own cabinet or stand. You bought a beast of an amp and its letting you know that. I think you should also reach out to McIntosh service department and relate your experience- see what they have to say.
I remember once, years ago putting a loudspeaker on top of an amplifier I was testing and heard what I thought was a buzz in the unconnected speaker. I blamed the magnet assembly and the top panel of the amp and promptly forgot about it. I'll bet it was the same thing, but I dismissed it at the time as "impossible".
I've definitely had sensitive headphones that have picked up radiated mains and the concept is the same- but they were terminated.
Your experience, @ClassG33, encouraged me to investigate and work out just WTF was happening in your case.
If anyone wants some analyzer FFTs of the induced mains in the centre speaker drivers, from the toroidal in my pics I can do that in the morning? It is just a proof of concept that it could happen and be audible, not indicative of the OP's actual severity.
What is the input impedance of your spectrum analyzer? Just curious.
This is the answer, just send it in. Mcintosh amps do not do this normally and I've seen and owned a lot bigger amps from MacI'm pretty sure McIntosh wouldn't release such a design unless there is some issue with your particular amp.
Thannk you @restorer-john.The QA-403 I'm using now for audio spectrum analysis, is 100kOhm- single ended, 200kOhm differential. It can do up to 384k FS for the A/D (~180kHz BW).
View attachment 358418
Did you ever call McIntosh support to see what they say?Guess I don't know haha!
I guess my goal here is to determine if this is indeed a problem - I am gathering that it's 95% sure to be a problem, based on experience from other people much more intelligent then me, plus the fact that I have listened to, setup and worked on many systems with McIntosh amps of even higher toroidal power (MC611, MC462), tube amps like the 275, ma352/252, etc.that have easily been within a foot of other B&W speakers, and do not have this issue. Also other brands with powerful toroidal amps, and never had the issue.
I consider the possibility of "maybe I just didn't notice at the time?" However this is too loud not to notice.
I have had this setup with an Arcam AVR20 which is toroidal, albeit lower power...
That's not relevant, it can have toroidal transformers for power supplies and can still have autoformers for output impedance matching, though in this case the OP said there were no autoformers used in this amp.Sorry you're correct this uses toroidal transformers
It is normal, for a short duration only, could be as long as 100 ms, though normally shorter. This amp has inrush current limiter anyway so it really wouldn't make much of a noise even for that short duration.So it is normal for the amp to create a brief noise within itself?
The brief surge is coming straight from the amp itself, not the nearby speakers. It is less then 1 second, then is silent. The tone SPL from the speaker is constant from the moment it picks it up.
Hi @peng. How do you know it has a inrush current limiter. What is used to make a inrush current limiter?It is normal, for a short duration only, could be as long as 100 ms, though normally shorter. This amp has inrush current limiter anyway so it really wouldn't make much of a noise even for that short duration.
No risk at all, as the speakers are not powered, and are no connected to the amp so no risk to the amp either. If the terminals are shorted, the noise should be reduced, it won't solve anything, just confirming something we already know.@DavidShe . How would I go about that? Sounds risky lol
OK. Thank you very much. Is a inrush current limiter a single component or a assembly of components making a circuit. I'm very curious because this device has such a high capability for inrush.It's in the 255 manual. Someone posted that earllier, but here's the figure again.
View attachment 358470
There's the manual
No idea how it's done, can't tell by just the block diagram. As always, there are different ways.OK. Thank you very much. Is a inrush current limiter a single component or a assembly of components making a circuit. I'm very curious because this device has such a high capability for inrush.
Not really that high, the amp is rated 200 WX5 and the power requirement is only 120 V at 10 A.I'm very curious because this device has such a high capability for inrush.
If you have the same thing, and do not have this issue, that is telling.This is the answer, just send it in. Mcintosh amps do not do this normally and I've seen and owned a lot bigger amps from Mac
than this one. 4 MC1.2 and 2 MC611 all sided by side. Quiet as a mouse, running 3 bi-amped speaker and a TT as a primary.
Streaming was an afterthought.
Macs don't make noise, cabling and broken equipment does.
BTW I have a MC225 that has all but one original 12AX7 tellie and NOTHING has been touched combined
and with a rebuilt Samra C20. It is as quiet as my Nords idling with the same speakers. They are not a noisy
amp at all.
MX110z, Mc225, Mc240, Mc275; One of two sets. I sold one set in 2022. They don't make noise, but they
sure sound good. Infinity RS4b, wonderful combo with any of those amps.
May your Amp be healed by the Amp Gods. McPassZilla (Like Zeus)
Regards