Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => The Newcomer's Forum => Topic started by: JoeHolic on February 22, 2021, 06:22:54 PM

Title: 1970s Vox Escort BM1 - Can I bypass internal speaker mute when using line out?
Post by: JoeHolic on February 22, 2021, 06:22:54 PM
Hi,
I’ve just bought a nice little Vox Escort BM1 ‘Busker’s Amp’; it sounds great with guitar and harmonica. I’d like to be able to send a signal to my PA, via the line out, while continuing to monitor my sound via the internal speaker; at the moment, the speaker is muted when the line out is in use.
I’ve asked around and it seems that, due to the resistors on the line out circuit, this would be fine on this amp; apparently, all I need to do is make the contact, that disengages when a jack is inserted into the line out socket, permanent.
How would I make the contact permanent? Could I just bend/push the copper pins, so that they remain under the inserted jack plug, or should I try soldering the connections with some wire? Any help would be much appreciated.
Title: Re: 1970s Vox Escort BM1 - Can I bypass internal speaker mute when using line out?
Post by: g1 on February 23, 2021, 02:12:41 PM
Don't bend the pins.
There are 2 ways it could be done.  One of the speaker terminals gets grounded through that jack.  So you could just run that speaker wire directly to ground, but you must be sure it is the correct one or you could damage the amp.
Otherwise, you can solder a wire across the appropriate terminals of the jack.
It's very difficult to tell you which terminals without pictures of the jack & wiring.
Title: Re: 1970s Vox Escort BM1 - Can I bypass internal speaker mute when using line out?
Post by: solderer25 on February 23, 2021, 05:34:53 PM
I have the schematic for this amp if that will help you. The slave output jack which you are looking to modify does indeed connect one of the speaker terminals to ground. The connection between these terminals breaks when a jack plug is inserted hence silencing the speaker. As g1 has pointed out, just short out the relevant terminals with a length of wire.
Title: Re: 1970s Vox Escort BM1 - Can I bypass internal speaker mute when using line out?
Post by: JoeHolic on February 24, 2021, 04:10:57 AM
Hi,
Thank you both for taking the time to help; it's really appreciated.
I've attached a few photos; the final one shows the tabs lifted by the inserted jack, thus muting the internal speaker.
Am I right in thinking that, in order to bypass this mute, I need to solder two wires that bridge the pins: using the second photo, one wire bridging the tabs with the green and yellow wires, and one bridging the tab with the blue wires to the tab without a wire?
If you need more or better photos, please let me know.
Thanks again for your wise words; you're amazing.   
Title: Re: 1970s Vox Escort BM1 - Can I bypass internal speaker mute when using line out?
Post by: g1 on February 24, 2021, 04:02:55 PM
Just one wire bridging tabs that connect to yellow and green is all you need.
The other tabs you can ignore.
Title: Re: 1970s Vox Escort BM1 - Can I bypass internal speaker mute when using line out?
Post by: JoeHolic on February 25, 2021, 02:42:28 PM
That’s great.
Thank you so much.