WOPL 400 4-Fin Blew the -15v Pico Fuse

Gibsonian said:
Never noticed that but I will look for it next time it occurs.


I don't think so because it always stops the intermittent output when I turn it down, immediately. If thermo I'd think there would be a time delay until cooler.



But this is not a relay board tripping as it is not output off until I cycle it. It is intermittent output, like digital skipping, but goes away once I turn it down (volume on preamp)
Click to expand...
Just a WAG here but have you ruled out that the preamp could be the problem?
 
This prolly worthless data as speakers connected but got 1 milliamp dc offset both channels. Been hard to disconnect and tear apart when sounding this good!
 
I haven’t determined the arm resonance on the BL-91 because I’d rather play music too…

Maybe tonight. Probably not.

I do want to find it out so I can then fill the trough and see if the resonance changes with the damper active…
 
Ok. Back to my problems. It appears that via phono input, amp doesn't cut out at elevated spls. I have my theory, but why would digital (in from dac) do this and phono not?
 
If you have a scope, put the output of the DAC on the scope and you will see signals in the region that you cannot hear. That may be the cause, because the amp is trying to amplify that bandwidth too, assuming there is no DC coming from the digital source. Easy to check that with a digital meter.
 
Resolved the issue and yes in roundabout way was preamp. Found the TT, the tuner, the CD player all worked fine, only the streaming audio was the problem. CD and streamer go thru same DAC. So anyhow, there is setting on output voltage in the streaming software, changed it from what I would consider standard 2.0V to 1.0V and wala, issue is gone. Guessing 2.0V setting is actually more than that in reality and tube preamp was getting overloaded. Thanks for all the input. The WOPL is seemingly bulletproof as well as sounding superb. I can remember back in the days before full monty WOPL and cranking loudly was always clouded with worry about failure (had lots of empirical evidence) No more worries, just trouble free operation. Thank you Joe!
 
Gibsonian said:
Resolved the issue and yes in roundabout way was preamp. Found the TT, the tuner, the CD player all worked fine, only the streaming audio was the problem. CD and streamer go thru same DAC. So anyhow, there is setting on output voltage in the streaming software, changed it from what I would consider standard 2.0V to 1.0V and wala, issue is gone. Guessing 2.0V setting is actually more than that in reality and tube preamp was getting overloaded. Thanks for all the input. The WOPL is seemingly bulletproof as well as sounding superb. I can remember back in the days before full monty WOPL and cranking loudly was always clouded with worry about failure (had lots of empirical evidence) No more worries, just trouble free operation. Thank you Joe!
Click to expand...
Overdriving the system. I have to watch that on my internal and external soundcards. I've found I need very little output on that Windows volume slider for proper sound.
 
George S. said:
Overdriving the system. I have to watch that on my internal and external soundcards. I've found I need very little output on that Windows volume slider for proper sound.
Click to expand...
Interesting because an audio forum I used to frequent would say to turn up the preamp to max and limit the input (presumably with a volume or sensitivity control) on the amplifier for the desired sound pressure level.
I tried this and what I found was that the distortion was lower with the preamp at max and the power amp set lower. I assumed the opposite, but there it was.
Also, guitar players know, to get the "dirty" sound you have to crank up the amp and keep the volume control on the guitar at a level that will not melt your eardrums; not the other way around.
Of course, none of this means anything to a PL400 because there is no limiting potentiometer on the input.
 
I was overdriving my preamp, not the amp. This caused the sound to cut out. Before reducing my source voltage I couldn't listen too loud, nor ever clip the amp. Now I can listen as loud as my drivers and ears can stand it.
 
You must log in or register to reply here.
Back
Top