James Evans
Bedroom Bodger
Quick lunchtime test, disconnected tx from load, still same level of mechanical noise from tx. Will see if I can try tap washers/addis/whatever as isolation later, although I get the feeling it just needs looking at.
I'm really hoping not to plug that toroid in tbh Might come to it yet though. Qudos back in system for now.James I'd be really interested to hear in your thoughts between the Qudos and the SE200's (after you sort your hum problem out) and particularly how the ETI transformer sounds compared with the RS Components toroidal?
Shame, but at least you know it's not some strange interaction with the amp boards.Quick lunchtime test, disconnected tx from load, still same level of mechanical noise from tx. Will see if I can try tap washers/addis/whatever as isolation later, although I get the feeling it just needs looking at.
Les's ETC Tx's (as seen on the Avondale FB pages) is a work in progress for a amp I believe but cant confirm this and as yet not confirmed if they will be used !!I guess if Les is using them then they must pass his tolerance tests. Going to drop mine back in to ETC tomorrow hopefully and see what they can do with it. My qudos amp with Canterbury Toroid and smaller EI TX is completely mechanically silent. I do have a monoblock with a particularly hummy toroid, mostly quietened by being put on the end of a dc blocker. The matching mono is pretty much silent. Same manufacturer/toroid in each amp (old Onix monos)
Mike,Those numbers seem exceedingly low.
Understood. However, those numbers are typical of a very quiet CPU fan, which is almost inaudible. If that's all the noise that they make, then yours must be very good indeed.The Hi-Fi room is quiet. 30” granite external walls and triple glazing and living in the middle of nowhere.
Even if not correct levels on an absolute basis the two readings still give a viable comparison.
Thanks, that's what I was wondering re the pi. I had some 15Rs to hand, no change unfortunately.James
I noticed a similar problem with my SE200s when no input was connected. One channel had a hum the other was silent (Dual mono) . When connected to my source though the hum disappeared (Naim Atom HE) so I didn’t bother pursuing. Interestingly I didn’t notice the hum when I was running the NCC220’s although it’s possible it was there and I didn’t notice
If your source is a pi driven by an iFi power then your source won’t be earthed at any point. Try 20R resistor to earth from the signal screen.
JamesBeen chasing my tail with this trying to figure out where the noise is coming from, cleaned up the wiring, re-seated the toroid, still there, taken vellemans out of circuit, still there, re-routed power wires to amp boards, still there. Turns out the noise is coming from the sole source, rasp pi, but not with the Qudos amp, totally silent with that, psu noise on both channels with this SE200, and only when both channels of the source are connected to the pre (passive). With only one channel connected no noise (so maybe an earthing issue?). Pi stack is powered by an ifi ipower on a separate dc blocker/filter to the power amp one.