Skip to content
Vox AD30vt amp prob...
 
Notifications
Clear all

Vox AD30vt amp problems...

8 Posts
6 Users
0 Likes
11.3 K Views
(@dwebb3)
New Member
Joined: 15 years ago
Posts: 2
Topic starter  

soooo last night i was at band practice and i had to use my little 30 watt vox amp.My bandmate was using a half stack for the second guitar so i had to turn the vox all the way up(and it was the first time i've ever done that...).So we start practicing and the little amp measures up with the half. Were about an hour in and right in the middle of the song the sound just cuts of....We tried everything, seeing if it wasnt plugged in, changing the guitar, changing the cable, checking if we changed a setting on accident but to no avail...When i got home i tried again because we thought it was over heated and it still didnt work. But....when i plug headphones into the amp it works fine...so can anyone give me a diagnosis?


   
Quote
(@gabba-gabba-hey)
Reputable Member
Joined: 15 years ago
Posts: 355
 

Maybe a speaker wire came loose? You'll probably have to open it up to check ... hopefully it's something simple like that.


   
ReplyQuote
(@dwebb3)
New Member
Joined: 15 years ago
Posts: 2
Topic starter  

Maybe a speaker wire came loose? You'll probably have to open it up to check ... hopefully it's something simple like that.

Thank you...i've been waiting for someone to reply...lol


   
ReplyQuote
(@kent_eh)
Noble Member
Joined: 18 years ago
Posts: 1882
 

It's possible that one of the wires in the speaker that goes from the terminal strip to the voice coil broke, or possibly the coil failed.
Do you have a multimeter and a soldering iron?
And do you know how to use them?

You said this amp has never been pushed to those levels before, right?

BTW, how new is this amp? does it have any warranty left?
Thank you...i've been waiting for someone to reply...lol
Waiting an hour... Around here that's nothing.
Most people only log in once a day, or less. Patience will be rewarded.

I wrapped a newspaper ’round my head
So I looked like I was deep


   
ReplyQuote
(@bluezoldy)
Reputable Member
Joined: 20 years ago
Posts: 329
 

It might be worth checking out the Valvetronix forum:

http://www.valvetronix.net/forums/

Mine's gone wonky a couple of times and I've had to follow the reset procedure in the manual.

Also a common complaint is that they have very cheap input jacks in them which dry out and corrode. This can be fixed with proper electrical contact cleaner (not WD40 type products).

♪♫ Ron ♪♫

http://www.myspace.com/bluemountainsblues


   
ReplyQuote
(@ibanezjunkie)
Eminent Member
Joined: 15 years ago
Posts: 21
 

tubes blown?

Fortune, Fame, Mirror, Vain, Gone Insane But The Memory Remains


   
ReplyQuote
(@kent_eh)
Noble Member
Joined: 18 years ago
Posts: 1882
 

I just took a look at the schematic and it could easily be something in the power amp section. The headphone output comes off before the power amp section.

But, if it isn't something simple like a speaker wire come loose, you might want to check your warranty status.
Unless, of course you like to fiddle with electronics at the circuit level (like some of us do).

I wrapped a newspaper ’round my head
So I looked like I was deep


   
ReplyQuote
(@trippingcobras)
New Member
Joined: 14 years ago
Posts: 1
 

I have one of these as well, they are prone to having issues with the amplifier portion of the amp. Your headphones work because you are using the preamp section of the amplifier. More than likely the problem lies with the LM3886 audio power amplifier; don't worry, it is a single chip.
If you are capable of soldering, you have to remove the old chip which is 11 pins. This can be a real pain to desolder. I use braided copper to remove the old solder. I haven't had to repair mine yet, but I believe you can get these chips for about $6 + shipping and handling. Just do an internet search, these are fairly common. http://www.national.com/ds/LM/LM3886.pdf

Obviously I can't completely troubleshoot your amp without first taking a look, but this should point you in the right direction.

Best regards


   
ReplyQuote