[Likui]

thanks

 

[Amictus]

Aaargh! My Lyr, having been impeccably silent, has suddenly developed a hum this evening... I have contacted Tech at Schiit...
 
Sad face.

 

[clowkoy]

  Aaargh! My Lyr, having been impeccably silent, has suddenly developed a hum this evening... I have contacted Tech at Schiit...
 
Sad face.

Have you tried changing the tubes?

 

[Amictus]

 
Have you tried changing the tubes?

Yes. This is the story as I have related it to Schiit...
 
My Lyr is suddenly emitting a hum. LOUD with low impedance cans, less so with the HD650. I have tried changing the power cable and plugging it into a different socket/extension cable to the amp. No improvement. The Lyr transmitted noise when I tapped the case and the tubes, as though it were suddenly 'live' somehow. One of the tubes sounded louder than the other, so I put in another pair, which were a little quieter when tapped, but the result was pretty much the same. The case didn't transmit noise when tapped this time, however. The hum is still there whether the DAC (Audiolab M-DAC) is on or off.
 
This is a new thing. What's happened? The Lyr had not been touched, moved or tube-rolled between the last normal listening session and the advent of the hum...
 
And then...
 
OK. I tried changing the tubes to some Siemens E88CC, and the left channel disappeared. The bottom of the tube had lit up, but not the top. I swapped those out for some Orange Globes - everything was fine, apart from the hum - and then returned to the Siemens, and both tubes and channels functioned correctly this time. The hum is still there but not too noisy with the HD650s. I have socket savers installed. Should I try removing those?   
Any advice?
 
Anyway, the guys from Schiit suggest trying the Lyr without the socket savers. I'll get to it in the morning. It's 11.30 p.m. here in London.

 

[vkalia]

I developed some hum yesterday - turned out the tubes were not sitting properly.  Re-seating them firmly solved it.

 

[clowkoy]

I'd remove the socket saver and clean the tube pins with Deoxit.

 

[Amictus]

  I developed some hum yesterday - turned out the tubes were not sitting properly.  Re-seating them firmly solved it.

 
 

  I'd remove the socket saver and clean the tube pins with Deoxit.

Thanks, folks. So far I have separated the mains cabling from the coax to the DAC and the interconnect as far as possible; I removed the tubes which are current and have removed the socket savers, and then tried the tubes again. Same result. I then replaced the socket savers. The hum is there but no worse. In fact, it is a lot better than when it first hit. I can use the Lyr with pleasure with the HD650s, but not with the low impedance SR1i. I read somewhere that a) the Lyr is not supposed to be silent and b) it is not supposed to work with low impedance cans. Be that as it may, I'm on the case now and my dander is up. Thanks, clowkoy, I'll order some Deoxit. I'm also going to try one of these - http://www.jkaudio.com/pureformer.htm - if I can find one in the UK.

 

[Amictus]

Well, I have finally got round to shipping the Lyr back to Schiit. It cost over £76! Still, they received it in 24 hours, which is amazing. I'll report on the result. I mainly use the Lyr for my HD650s with which they have very good synergy, so I am curious about the Valhalla 2.

Oh dear. Schiidiction.

 

[Amictus]

My Lyr has been repaired by Schiit (no details about that yet), and is now enjoying a second American tour thanks to Fedex. It is currently in Memphis. My Deoxit has arrived and I am preparing to welcome the beast home. The last few weeks have been very solid state. 

 

[Amictus]

My Lyr has returned from Schiit. They found no fault. A hum is a still there - bearable with the HD650, but a bit excessive with the Grados. The enormous hum that it developed one day is not present. Oh well, it is a comfort that Schiit found nothing wrong with it. Whatever happens now, I'm not sending it back again - £76+ is quite enough investment for no result.
 
I am trying to be philosophical about it. My Lyr is cranky, petulant and has occasional breakdowns. At least I haven't married it. Alcohol will help, maybe. Help me, that is.

 

[fabio-fi]

If Schiit didn't find anything wrong with your unit, it could be some kind of mains issue.