Brown Note D'lite making really loud hum and whoosing sounds

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docmh
Posts: 25
Joined: Thu Nov 20, 2008 8:38 am

Brown Note D'lite making really loud hum and whoosing sounds

Post by docmh »

I was changing preamp tubes in my Brown Note 22/33. I'm running 6L6 tubes, impedance selector on 16 ohms to run an 8ohm speaker cab at at 33 watts like I was told to do on this forum in an earlier post. Tubes biased to 32ma. I was playing the amp today and it was fine. I swapped a few different power tubes in to hear the differences and rebiased them each time with no problems. I decided to try different preamp tubes to see what they sounded like. After turning the amp on I had no output signal to the guitar. I checked the tubes and they were all lit. I thought I blew one of them so I replaced them all with new tubes. The amp signal was back but with a very loud whooshing sound for lack of a better description and a seriously loud hum. I think I blew a resistor or something but don't see anything obvious. No smoke, no burning smell no obvious burned resistors.
I checked the Power Tube bias and they still read 32ma. I swapped power tubes again with no change and new preamp tubes. Any ideas of what could have happened?
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67plexi
Posts: 788
Joined: Sun Apr 09, 2006 8:34 pm
Location: Juneau Alaska

Re: Brown Note D'lite making really loud hum and whoosing sounds

Post by 67plexi »

Voltage chart

You may have blown your output transformer

Do you have a tube tester you may have installed a shorted or bad tube

Check your speaker with a other amp make sure the voice coil is still good

Post your voltage readings
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Bob-I
Posts: 3791
Joined: Thu Feb 02, 2006 10:06 pm
Location: Hillsborough NJ

Re: Brown Note D'lite making really loud hum and whoosing sounds

Post by Bob-I »

90% of tube amp problems are tube, and visible light has no bearing on tubes good or bad. Did you go back to tubes you know were good?

It's really difficult to troubleshoot these on the internet. Post where you live and maybe a forumite will offer to help. If you're anywhere near central NJ I'd be happy to help.
docmh
Posts: 25
Joined: Thu Nov 20, 2008 8:38 am

Re: Brown Note D'lite making really loud hum and whoosing sounds

Post by docmh »

I am sooooo embarassed. I had a pedal with a really low battery hooked up to the amp. I should have just checked the obvious first and removed the pedal.
Just prior to that, I had another amp that blew a preamp tube while I was playing it. With that amp, the volume went real low. I changed the preamp tube and it was all right ever since. I just assumed I had another tube problem.
I'm not a tech but I've been playing a long time and I can't believe how sometimes I overthink a simple problem.
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stelligan
Posts: 1465
Joined: Sat Sep 30, 2006 3:58 pm
Location: Nashvull

Re: Brown Note D'lite making really loud hum and whoosing sounds

Post by stelligan »

The nose knows.
From my extremely limited experience, if there is no smoke or electrical smell to be whiffed it's usually something minor. It passed the "smell test". :wink: Glad it was an easy fix!
wjdunham
Posts: 343
Joined: Thu Jan 22, 2009 6:57 pm

Re: Brown Note D'lite making really loud hum and whoosing sounds

Post by wjdunham »

It is indeed some times the simplest things... I just spent HOURS debugging a hum problem with my stand alone reverb/Dumblator unit. I had the unit sitting on top of an amp, and it wasn't until I picked up the unit to move a cord that was routed underneath and it went dead quiet that I realized the hum was being induced by the amps power supply section, coupling in to the high gain reverb recovery which was directly over the power supply. DOH! I normally have it mounted in a rack unit and keep it far enough away from the amp that it's not a problem. I open it up and put it on top of the amp to try a couple of different tanks and it starts humming like crazy, chased my tail for a while on that one...

Glad your's turned out to be not so serious either.
Bill
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