I have an XA30.5 and the meter has gone from normal very low deflection (no signal present) to almost full meter deflection (no signal present). Any user friendly fixes or ideas as to what causes this?
The only thing I've measured is DC offset, about 22mv left, 10mv right.
The only thing I've measured is DC offset, about 22mv left, 10mv right.
That's not it, it rests at far left side of the meter in standby, but swings over almost all the way right when powered up. Spiders would be flying.
But hey, you had the best guess so far!
But hey, you had the best guess so far!
Yeah, it's just packing it up and tossing it into the void that's the bummer.
ZM, I haven't left it running long enough to get to temp. Kinda leary at this point.
I'll boot it up and report back.
ZM, I haven't left it running long enough to get to temp. Kinda leary at this point.
I'll boot it up and report back.
Does it function as a normal amplifier? The offset looks okay and if the temp is good it could be the meter drive circuit.
Could be. I have it running now and it sounds fine.
When I first bring it out of standby, the needle goes full deflection to the right then recoils to ~3/4 deflection. I tried cranking it up and never got any movement at music peaks. These speakers are not particularly sensitive, driving them that loud should have produced a little movement.
I'll keep an eye on it - it's eventually just going to be driving some 107dB/W sensitivity tweeters so it doesn't need to do a lot.
When the pandemic madness is behind us I might send it to you guys to check out.
When I first bring it out of standby, the needle goes full deflection to the right then recoils to ~3/4 deflection. I tried cranking it up and never got any movement at music peaks. These speakers are not particularly sensitive, driving them that loud should have produced a little movement.
I'll keep an eye on it - it's eventually just going to be driving some 107dB/W sensitivity tweeters so it doesn't need to do a lot.
When the pandemic madness is behind us I might send it to you guys to check out.
That's 2 posts for spiders, I guess I can crack it open and take a peek. The amp has sat unused for a bit, I guess something could have built a nest in there and is causing some strangeness.
I noticed that the meter creeped a little higher as the temps came up and I was then able to induce a little wiggle to the needle with high volume - I just don't want to drive the needle into the stop. I also want to re-check DC offset with the amp up to temp, but other than the needle it seems to be playing fine.
I noticed that the meter creeped a little higher as the temps came up and I was then able to induce a little wiggle to the needle with high volume - I just don't want to drive the needle into the stop. I also want to re-check DC offset with the amp up to temp, but other than the needle it seems to be playing fine.
I ran it a while last night, after a few hours the meter is almost full deflection. Since the deflection is increasing with temp, it concerns me that it might be something more bias related. still sounds and runs fine, but I don't want to fry something hoping it's just a faulty meter circuit. I guess I'll pull it back out of service and go to plan B.
DC offset decreased on the one channel I spot checked, down to 4mv or so.
DC offset decreased on the one channel I spot checked, down to 4mv or so.
time to open it and check Iq of channels properly
read this: Pass Labs X150.5 , checking/adjusting offsets ,Iq and gain – Zen Mod Blog
not same amp, but checking approach pretty much the same, and you are expecting to read around 200mV at bias 2pin headers, in your amp, too
P100 on MoBo is meter trimpot, see what some wigglejiggle will do
read this: Pass Labs X150.5 , checking/adjusting offsets ,Iq and gain – Zen Mod Blog
not same amp, but checking approach pretty much the same, and you are expecting to read around 200mV at bias 2pin headers, in your amp, too
P100 on MoBo is meter trimpot, see what some wigglejiggle will do
I talked to Pass Labs, he mentioned the meter trimpot but wanted to verify current draw from the wall first. We decided tossing it into the void and sending it home to Pa's elves would be the course to take.
If they find a spider has turned the meter trimpot, I'm buying a big can of bug spray.
If they find a spider has turned the meter trimpot, I'm buying a big can of bug spray.
