ARC LS25 mkII noise level

The only way to know is to use your own ears. To my ears, it is not even close. In your case, maybe there is something going on inside of the pre that is not right. I love the sound of tubes but I have been turned of by the noise, especially from the preamp. There are some good tube preamps. I have never heard the LS25 but Atmasphere, Lamm and First Sound make some great pre's. The Atmasphere uses the 12au7 and unfortunately, it is getting very hard to find quality 12ua7's out there NOS. Both are pretty much handmade and cost well over $5,000.00. Maybe someday I wlll try one of these pres.

Jazzgene, I'm pairing my LS-25mkII with a ARC SD-135 solid state amp. Speakers are Triangle naia's 93db sensitivity.

Thanks all for your response.

I will call ARC tomorrow. I did a voltage check and everything is good. Although I can read schematics and have some tech skills, I can't figure out where in the circuit this noise might be coming from. If the power filter caps were no good, I would think the noise would be louder and the voltages would be off.

I noticed some strange looking powdery dust covering the main board. I wiped away what I could. No change in noise.

Powdery dust? Did you check the RCA's for green leafy substance? Sounds like a smugglers preamp.

Please post what ARC recommends.

Resolution:

After doing a through noise measurement and consulting with a very qualified tech here in NYC and the head tech at ARC, my LS25 II is indeed within spec. It comes down to my expectation and the fact that the Focal 1027 be's are very sensitive. Although Focal publishes them to be at 91db, it is very conservative. It is more close to 95db or so.

ARC uses as a reference, a pair of 87db speakers. It is quite interesting to me that a low cost Arcam solid state preamp is dead silent. The sound quality is much inferior, however. So like life, compromise is a part of audio as well.

The good news is that there is a simple mod to reduce the gain on the LS25mkii by 6db. My tech is quite sure this will do the trick. So all is well!