Avondale SE200 Announcement on FB

[James Evans]

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.

 

[James Evans]

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?

I'm really hoping not to plug that toroid in tbh Might come to it yet though. Qudos back in system for now.

 

[S-Man]

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.

Shame, but at least you know it's not some strange interaction with the amp boards.

 

[James Evans]

Tried some isolation under it, no dice. This is it removed and sat on the table (turn vol up):

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in the amp:

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Double click thumbnails to play. Putting the lid on the amp turns it into an echo chamber.

 

[Mike Hanson]

That's a noisy bugger!

 

[Richard Lines]

Good morning all,

I was aware from Graeme's experience that his transformers were 'noisy' so I was a bit concerned that I would experience the same problem. I've dug out the two pictures I sent to Graeme.

These were obtained using the NIOSH SLM app on my iPhone - granted this isn't a precision dB meter. The first taken at the listening position:-

and the second with the phone right up close to the amplifier:-

Not a lot of noise really........

James - don't know if you want to download the app and compare??

Regards

Richard

 

[Mike Hanson]

Those numbers seem exceedingly low.

 

[laverda]

Measured mine: at the listening position and I can still hear a very faint hum.

and next to the amp, at 6" really annoying, this reading is two Tx's side by side in a duel mono config.

 

[laverda]

I did say some some time ago I could live with the hum but upon reflection why should I have too!!. (their not cheap) I haven't been able to do any listening lately (many weeks) and the issue forgotten about but this morning I fired the kit up and strait away all I can hear is a faint hummmmmm. I can only conclude they're not really fit for my/our purpose. If you can live with the hum/buzz (I did for years with some Naim NAP250s) you'll be fine, the fact I have other large EI's that are totally silent in operation can only suggest ETC EI's ar'nt up to the job maybe??.

 

[James Evans]

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)

 

[laverda]

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)

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 !!

 

[Richard Lines]

Those numbers seem exceedingly low.

Mike,

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.

Regards

Richard

 

[Mike Hanson]

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.

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.

 

[James Evans]

Well, couldn't resist dropping the RS toroid in to get the amp up and running again. Speaker 0V rewired to clean end of cap board, velleman 0v slotted in to the middle of the cap board. I now have a very quiet toroid, but I appear to have acquired quite invasive psu noise on both channels. Arse. Photo whist being checked over, wiring clipped back together again after this, although psu wiring still same as below, so maybe I need to dress that a bit?

 

[James Evans]

Been 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.

 

[OzBrit Audio]

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.

 

[James Evans]

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.

Thanks, that's what I was wondering re the pi. I had some 15Rs to hand, no change unfortunately.

 

[laverda]

Been 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.

James

Ive built quite a few of these SE200's along with the pre production boards and never had any issues as your having.

OK with only one channel powered, (using only one PSU?) it may/might be that your running two PSU's off one secondary the PSU's don't like that. Try running both modules off one PSU, I know its a faf but may answer the question. Ive never wired up an amp as you have here but don't see why it wouldn't work.

 

[James Evans]

Hi Graham, I don't think it's the amp at all, with the pi disconnected and using an old cdp as source it's completely silent. Sadly I don't listen to cds I could maybe try my active pre (Exposure 7) in place of the passive but that adds its own flavour over the passive. With the Qudos I was running the pi directly into it, no pre at all.

 

[James Evans]

This is how things stand currently:

You can see the passive to the left of the amp. If I disconnect one channel from the pi the noise vanishes, total silence on both channels, as soon as I connect the 2nd pi channel back the hum comes back on both channels.

I'm assuming there's a loop forming, and am wondering if lifting the screen on one channel's interconnect would potentially help?

It's potentially of interest that when I had the ETC transformer in there, with dual centre tapped secondaries I only had noise on one channel.

And, hum aside, I'm liking how it sounds!