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Author Topic: VOX Mini 3.. No speaker output  (Read 8968 times)

camperman

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VOX Mini 3.. No speaker output
« on: July 17, 2013, 01:16:57 PM »
I have a VOX Mini 3 which appears to be working perfectly through the headphones but is producing no output at the speaker.
The speaker is working fine and I've tried the obvious faulty contact in the headphones socket and but that's not the problem.

Does anyone have any suggestions of where to head next to find this fault please?

Thanks
Ed

Roly

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Re: VOX Mini 3.. No speaker output
« Reply #1 on: July 18, 2013, 12:29:30 AM »
Well if it's driving headphones okay, and the speaker tests okay, and the contacts aren't dirty, that just about leaves only one thing (since that socket is the only thing between the amp output and the speaker), a dry solder joint or crack on the printed circuit due to being wrenched at some stage (the headphone socket does mount directly on to the PCB, and there is no front panel retaining nut - right?  (how did I guess?)).

Wiggle the socket while looking at the solder side of the PCB, and it's Sydney to a brick you will see some movement in, or by, the solder joints and they need to be made good.

HTH
If you say theory and practice don't agree you haven't applied enough theory.

midibob

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Re: VOX Mini 3.. No speaker output
« Reply #2 on: August 22, 2013, 03:26:55 AM »
Hi Ed,

You will more than likely find the output chip has blown.
I've spent a lot of time on these amps and if you are interested follow this link :-

http://www.badcaps.net/forum/showthread.php?t=20949

I have also developed a daughter board to enable a fairly easy repair.

Midibob

g1

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Re: VOX Mini 3.. No speaker output
« Reply #3 on: August 22, 2013, 08:15:52 PM »
  That's quite something midibob, thanks for sharing!
How much do the daughterboards go for?

midibob

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Re: VOX Mini 3.. No speaker output
« Reply #4 on: August 23, 2013, 09:09:25 AM »
I'll PM you.

Midibob

g1

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Re: VOX Mini 3.. No speaker output
« Reply #5 on: August 23, 2013, 11:53:07 AM »
  Thanks midibob!
For anyone needing to repair one of these, midibob's daughterboard is priced very reasonably.
  He doesn't want to list the price here in case it goes against forum advertising policy, but send him a PM if you need one.

joecool85

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Re: VOX Mini 3.. No speaker output
« Reply #6 on: August 27, 2013, 06:08:37 AM »
  Thanks midibob!
For anyone needing to repair one of these, midibob's daughterboard is priced very reasonably.
  He doesn't want to list the price here in case it goes against forum advertising policy, but send him a PM if you need one.

It does not go against forum policy so long as they aren't spamming the forum with ads etc, a simple mention of price is fine.
Life is what you make it.
Still rockin' the Dean Markley K-20X
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midibob

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Re: VOX Mini 3.. No speaker output
« Reply #7 on: August 27, 2013, 03:19:26 PM »
That's good to know.

If anyone is interested they are £10 each.
PM me if you want one.

Midibob

phaess

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Re: VOX Mini 3.. No speaker output
« Reply #8 on: April 23, 2014, 09:55:42 AM »
I received the daughter board from Midibob, installed it, and now the amp is good as new!

mattc_uk

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Re: VOX Mini 3.. No speaker output
« Reply #9 on: June 13, 2021, 04:16:59 AM »
We've got a VOX Mini 3 Gen 2, and it just gave up on any guitar output last night, just as my son was using it. Mic input works fine, but guitar input has failed completely.. no output in the headphone jack either. @midibob would your daughter board be able to fix this issue on the Gen 2, or am I looking at a new amp?  :-\

Jazz P Bass

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Re: VOX Mini 3.. No speaker output
« Reply #10 on: June 13, 2021, 11:47:52 AM »
It appears that you may have an Input Jack issue.
If the Mic Input works then the output stage is fine.
The 'daughter board' is meant to resolve an overall 'no output' issue. (blown output ic)
« Last Edit: June 13, 2021, 07:28:01 PM by Jazz P Bass »

midibob

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Re: VOX Mini 3.. No speaker output
« Reply #11 on: June 13, 2021, 03:32:26 PM »
As Jazz P Bass says the output must be OK if the Mic is working.

For info I don't make these boards anymore but all the details are on Badcaps.net in the Forum for anyone wanting to make their own.

joecool85

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Re: VOX Mini 3.. No speaker output
« Reply #12 on: June 14, 2021, 04:21:48 PM »
I had forgotten all about these.  Midibob, if you don't mind sharing a picture of the board and maybe some info, I'd love to have it here on this forum!
Life is what you make it.
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Jazz P Bass

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Re: VOX Mini 3.. No speaker output
« Reply #13 on: June 14, 2021, 06:52:03 PM »
The Vox amp uses the TPA3091 D1 ball grid array ic (cute!).
Midibob chose to use the SSM2305.
The layout that he chose is directly off of the datasheet.
https://www.badcaps.net/forum/showpost.php?p=350727&postcount=33

midibob

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Re: VOX Mini 3.. No speaker output
« Reply #14 on: June 15, 2021, 08:59:18 AM »
Here's a copy of the installation instructions but I must stress I don't make them anymore and don't have any!