I agree it sounds like you may have a slightly noisy transformer in your MF A5.
I'd consider trying a DC blocker. The Audiolab DC Block is pretty good, and I currently use one to cure a buzzing toroidal transformer in my set-up.
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I agree it sounds like you may have a slightly noisy transformer in your MF A5.
I'd consider trying a DC blocker. The Audiolab DC Block is pretty good, and I currently use one to cure a buzzing toroidal transformer in my set-up.
'Buzzing' might not be the best description for the sound, but it is not like the kind of hum you might hear associated with earthing problems. In a phone conversation with John Sampson of JS Audio last year I mentioned it as an afterthought (it really doesn't bother me much) he just said something along the lines of 'very common, just one of those things'.
Still might be worth me trying this Silent Coat though.
Sorry about the thread hijack Kev. :)
I have 3 very buzzy toroids in my Croft amps which I can hear very clearly when up close. When I used Silent Coat on the cases there was a noticeable reduction in noise but also less vibration getting through to my valves. I should have had them ripped out and put in a separate box but alas Glenn is no longer with us sadly.
It is no coincidence that Glenn top of the range preamps were indeed two separate boxes with the rattly toroids separate from the rest of the delicate tubes.
Worth checking the central bolt in your toroid for tightness.
Sometimes just giving it a nip with a pair of pliers can solve buzz.
I've used silentcoat directly on transformers, didn't make it sound worse.
Avoid RF treatment around transformers though, found it kills the top end.
Built a DC blocker and fitted it to my balanced mains a while back?
Quickly removed it, as dynamics and air took a hit.
System dependant as usual of course, YMMV
No worries.
I built one of these https://sjostromaudio.com/pages/inde...yle-heavy-duty into my Mod 686.
Does what it says on the tin.
I did try an external DC blocker first to see if it was DC related or pure mechanical hum.
Fortunately for me, it was DC related. My amp is now silent.
The Audiolab DC Block did not knacker the sound in my setup but of course YMMV. There are quite a lot of +ve reviews of the Audiolab on the Richer Sounds site: https://www.richersounds.com/audiola...RoC0CUQAvD_BwE
But peakload is only 600 VA. With 800VA in my amp, it is simply not big enough.