Pass Labs Class A Amp Warmup Question
 

Hey gang,
I know many folks here love and enjoy Pass Lab amps.

Some of you may remember I built up two Nelson Pass-designed Amp Camp amps last summer.

I've set these up again over the long Memorial Day holiday weekend to get some real hours on them and on my (also DIY) GR-Research X-LS Encore speakers (which I recently found out need 400 hours of running in), and have an anecdotal observation that they seem to require about an hour of warm-up time to fully come "on song". When I listen to them as soon as I switch them on, they seem to be a bit thin and 2-dimensional sounding. Once they've been on for an hour so, though, they really do sound very good, especially when run as a pair of bridged monos.

Here they are set up on the floor in a quickie set-up configuration (sorry for the quality of the quickie iPhone 12 "snapshot")

https://photos.imageevent.com/puma_c...DIY-Stereo.jpg

Is this observation consistent with your experiences? What do you guys that have a Pass Class A amp typically do? Do you leave the amp on all the time, or fire it up for listening sessions?

Lastly, I'm not telling you guys anything you don't know, but Nelson Pass is a genius.

I would look to Kent English at Pass Customer Service for his experience and opinion.

Thanks, I know Kent. Cheers.

Stephen, I've owned and loved the Pass Labs 100.5s for quite a few years now.I leave the back switch on, but power up with the front switch to listen. They sound fine right off the bat, but sound better by the end of the first record and then, prior to the end of the second record, they sound more relaxed and simply disappear and all that is left is the music. The soundstage is open and wide on the first record, but becomes deeper by the second record. Most importanty, an ease to the sound is fully there by the second record. Hope this helps.

Many thanks. Yes, I've found that about 45 minutes of warmup is about where they get "on the cam", as we say in motor racing.

I've been listening to my little Amp Camp amps as bridged mono blocks since the beginning of the long holiday weekend, and I have to say that now that they are getting more hours on them, they are starting to sound very good indeed. Nelson Pass, I tell ya what...

And...for 654 bucks, they're rather amazing.

https://photos.imageevent.com/puma_c...large/ACAs.jpg

😻

I leave my Pass preamp and phono on all the time. The amps are in stand by and I turn them on about an hour before I sit down to listen. I don't notice much change after they have been warming up for an hour. This is the first solid state gear I've owned that doesn't make me want any tubes in the system.

Tnanks, Dave. :thumbsup:

I'm finding the same thing; the little ACAs seem to come on-song after about 45-60 minutes.

Thanks, Dave, I'm finding pretty much the same thing; the ACAs need about 45-60 minutes of warm-up.