2. amps-preamps
  3. 191540-10159

Pass Labs XA30.5 Fuse Issue/Question

Hi all!

I recently acquired a Pass Labs XA30.5 from our friends at The Music Room and paired it with my Harbeth P3ESR speakers. It worked perfectly for about a week, delivering great sound with the needle hovering around 12 noon, even at high (to me) SPL. However, after a week, the fuse blew.

To get back to listening, I checked the back panel, purchased a set of 4A slow blow fuses (as labeled), and installed a fresh one. That’s when things started getting strange.

The unit powered on as usual, but as soon as I increased the volume to a moderate level, the needle swung wildly and pinned itself to the far right before the fuse blew again. I assumed it was just a bad fuse, so I replaced it with another. Same result. I tested the amp with a different set of speakers and a different source/preamp, but the same issue occurred every time.

I’m completely puzzled. It seems unlikely that all the replacement fuses are bad—could they be mislabeled? Does this pattern suggest any other potential issues?

I’ll reach out to Pass Labs if I can’t figure this out, but I wanted to check if anyone here has experienced something similar with their Pass equipment.

Thanks!

 

zm
audphile1's avatar
audphile1
4,793 posts
 

+1 on calling pass labs and the music room. I would start with pass labs to gather some data points for the conversation with TMR.

Question - do you have the amp connected to the wall or to some sort of power conditioner/strip?

gs5556
1,232 posts
 

You should play the amplifier through another set of speakers before calling the seller or Pass. Tripping a mains fuse at higher playing volumes makes the Harbeths the prime suspect.

yogiboy's avatar
yogiboy
5,638 posts
 

" I tested the amp with a different set of speakers and a different source/preamp, but the same issue occurred every time."

You should return the amp and get a refund from TMR. It sounds like that Pass is a lemon!

yoyoyaya's avatar
yoyoyaya
711 posts
 

The meter on the Pass XA amplifiers measures bias current. Under normal circumstances it should barely move at all, and then only when playing very dynamic music at high levels. If the amp was shorted it may have incurred permanent damage and so exhibit the same behaviour with different speakers. Pass gear is extremely reliable but no product is infallible so it may also be a component failure within the amp. In any event, it should be taken back to the supplying dealer for investigation.

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