I have run through at least 8 videos detailing the same mod and NO ONE ELSE had given the part number for the jack. Thank you sir - you have earned your upvote. The clear diagram was an excellent bonus as well.
I've been trying to find an explanation like this for speaker jacks for a few days off and on now. Finally! Your video is my solution! THANK YOU for the video and the clear explanation!!! Subscribed and liked!!
That's really good to hear. I always make these vids hoping they're helpful to someone so I really appreciate that feedback. Make sure you also check out this video: ua-cam.com/video/9IQlyGviLJY/v-deo.html and this video: ua-cam.com/video/l6txwhjeC8Q/v-deo.html They're both similar.
Holy Cow! I'm in the middle of building a carrying case with a built in amp and you just gave me a tremendous idea! I have three mini amps that I built over the last three years, one of which has a not so good speaker.
This was very informative. It wasn't really a "how to" though... it just focused on the wiring. It would be nice to see the whole process start to finish.
I buy most of my electronic components from Mouser but any electronics store should have them. I'm sure you can get them from eBay and Amazon too. Just search for "switchcraft 12a jack". Thanks for watching... hopefully this helped.
Steve, for my first cigar box amp I cheated and bought a 5W mini amp on Ebay for $15. I gutted the plastic case and used the parts, including the knobs, and put them into an Acid cigar box. Very little soldering and very easy to build. It's got just as much volume as the one I built from a kit and the one I built using individual parts with an amp chip. I also built a practice amp, slash pedal board, from a Footnote amplifier I bought on Parts Express for $9. No soldering involved!
Can I do this to a fender champ 100? It sounds great on its own but I really like the option of being able to connect external speaker cabs so I can stack it up
I'm not familiar with that particular amp but this mod works on the vast majority of combo amps. Check out these 2 videos as well because I go into a lot more detail. ua-cam.com/video/9IQlyGviLJY/v-deo.html ua-cam.com/video/l6txwhjeC8Q/v-deo.html
Cool video man..quick question. If you wanted to keep the internal speaker of the combo amp working when connecting to an ext cab, would it be as simple as using a stereo jack socket rather than a shunt jack? Basically turning a 2x12 combo into a 4x12? I would have thought there would be volume drop that would need to be fixed as well?
First off, thanks for watching and commenting. What you're asking sounds like an simple question, but it poses a more complicated one. If you followed this tutorial but used a standard mono jack, you'd get the result you're suggesting. The internal speaker would remain powered when the external cab is plugged in. However, you first need to know more about the stability of the amplifier. For example, let's say your amp shipped with an 8-ohm speaker in the cabinet and it's 8-ohm stable. In that case, you'd want to change out the internal speaker for a 16-ohm speaker and also use a 16-ohm cabinet to achieve the 8-ohm load. If you left the 8-ohm speaker and added an 8-ohm external cab, the amp would be running at a 4-ohm load which would probably burn out your output transformer. So you'd need to know the specs on the amp before doing the mod to ensure you aren't overloading the transformer. Also, there's a good chance you'll need to buy new speakers to match the load. I hope that made sense.
I suppose everything wears out eventually but it's a Switchcraft (which are known to be quite reliable). I know I have guitars with Switchcraft jacks that are 20+ years old and that jacks still work perfectly. Honestly... I'm pretty sure the circuit will give out long before the jack.
Sorry but I'm looking at the diagram paused at 3:34. Surely that's inverted? I'd expect the tip to go to the speaker and the shunt to the internal circuit board Therefore when no jack socket in, it shorts, = normal operation. When inserted the live external tip goes to the speaker, and the shunt is disconnected? EDIT NO it's correct. I'm trying to do the exact opposite, which is also useful. I'm wanting to allow my combo (switched off!!) that I keep in my living room to be driven by an external head, these tricks can work both ways :)
Thanks for checking out the video and paying such close attention. You made me rewatch it to make sure I stated everything correctly. You might actually want to check out this video I made. ua-cam.com/video/l6txwhjeC8Q/v-deo.html It sounds like you're trying to do something like this.
@@musicalmiscellany Yes sorry if you read my first comment before I edited (in your email) you might've thought you'd done something wrong but I was approaching from the other direction and focused on that, you were of course totally correct. Actually if you wired two in series .. you could I'm sure set it up so that a combo could either be set up to drive another cabinet OR be driven by another head :)
@@spaceavenger54 Tip + (Sleeve -) is the standard for speaker cabs. There are some rare systems that use Tip - but the vast majority of cabs on the market are Tip +.
Usually the amps and pedals all run off a Center Negative or in other words a Positive Ground System completely opposite of any Normal Operating System. Which means the power and speaker connections are reversed.
That is a good point. Thanks for adding that. However, if the speaker output is coded red/black (or whatever +/- color/stripe combo), you'll still want to follow the way it's hooked to the internal speaker.
I would not try that. First of all the headphone jack is stereo and the cabinet is mono but also, a headphone output delivers a fraction of a watt. Having such low signal could damage the speakers in the 412.
Hi, Thanks for the tutorial. I actually want it the other way where the speakers stay on as I have a couple of VU meters I want to plug in. How do you do this?
Are the VU meters expecting a speaker level (powered) signal? Typically they're expecting a line level (passive) signal so if you plugged in a speaker jack... that would blow the meter. But if that's what you wanted to do, you'd simply change out the shunted jack for a standard mono jack. If you're wanting to get a copy of the input signal (probably more likely for VU)... you could just add a second input jack and wire it to the same +/- of the input. It would effectively be a copy of whatever you plug into the amp's input.
Hi! How about if I want to connect headphones instead of a single speaker? Also shutting off the amp speaker when plugged in. Can that be done with that same type of jack? Thanks.
That's a very different ballgame because you don't want to plug a speaker level voltage into a set of headphones. It would likely damage the amp (and possibly the headphones). You'd need to create a small headphone amp to do what you're asking, and you'd probably want a separate volume control for the phones. It's a lot more work than just adding a jack but it is doable.
Have you ever had an experience after doing this where your amp makes a thumping/clicking noise?? I did this modification on a Peavey bass combo amp and it worked perfect before, now after installing the shunt jack, its making the clicking/thumping sound
I can't think of a reason you'd be getting a thumping sound. Sometimes there's a grounding issue when you add a jack but that usually results in hum. Does the thumping go away if you touch the jack or the cable ends? If so, that's typically a grounding issue but again... it's usually hum you'll hear.
No sir I’m aware of what a ground hum sounds like but I’ve never heard this before. I’m not sure if it’s a short somewhere or what. It’s like a consistent clicking noise
Would mounting the 1/4 shunt jack directly onto the amps metal frame cause this problem maybe?? Any videos I’ve seen of you installing a jack, it’s mounted to wood or is a plastic mono jack.
@@cbazz333 Good thinking. It's possible there's some interference with the grounding due to the metal. That should be an easy thing to test. Just unmount the jack from the metal panel, wrap the jack in electrical tape (or some other insulator), test it again, and see if the clicking/thumping goes away. If it does, you've found the source of the noise.
That would definitely not work in this arrangement. If you plugged power into this jack it would send power into the power amp and probably fry the circuit board. However, it you wanted to use it as a cab, it would be pretty easy. You could simply use 2 mono jacks (one going to the speaker and another going to the circuit board) and mount them on the back of the amp (make sure to label them somehow). Then create a small 1/4" cable to connect the two jacks. Keep the cable short and use right-angle connector and it would sit flush against the back of the amp so you wouldn't even notice it. If you did that, you could use it as a combo, a head, or a speaker cab based on which jacks you used. It would be a very flexible setup. You could even use the internal amp to power an external speaker cab while simultaneously using an external amp to power the internal speaker.
@@musicalmiscellany THANK YOU for saving my circuit board, so that shank output jack would not work? Could i just add one jack to the back and maybe a switch? one way is internal speaker and one way i have to plug an amp to the speaker? (in this way, if the internal amp dies at a gig, i can use a lunchbox amp to power the same speaker). for a working guitarist, a combo and lunchbox amp is all i have to carry..
@@CalitranoN You could do that but the problem is the switch would have the full power of the amp so you'd want to make sure your switch is rated for active signals and properly grounded. That always makes me a little nervous. I think the 2 jack method would be the safest.
@@musicalmiscellany ok,,, a guy did my transistor combo, with a toggle and a jack... the toggle disconnects the internal and makes the amp a cabinet... i can then use a lunchbox amp to power the speaker... it works great. I would like to do that on another amp. Do you have a video with two jacks? I am not sure how to do that?
@@CalitranoN With a low power amp, it might not be so bad, but with a high powered amp/head, the switch method makes me a little bit nervous. I could just be overly conservative when it comes to electrical shock though. I don't currently have a video about the 2 jack method but based on your comment and a few others that have come up here, I think I need to make one. I'll probably get it posted in the next couple weeks.
How would you do this on a 2x10 combo? I'm looking to add an external speaker jack to an old Peavey Studio Chorus 2x10 and use a cab because of the incurable amp rattle. Any advice would greatly be appreciated...thanks in advance!
I haven't seen the inside of the amp but it would be essentially the same process. The 2 speakers are either wired in series or parallel but chances are there's only 1 output (+/-) on the circuit board. If that's the case, it's exactly like this video. Run the output to the jack, then the speakers. If it has two outputs on the board, then you probably have to get the schematic for the amp to tap in at the output transformer before it's been split to two signals. Does that make sense? Also, check out this video... I made it later after I got some feedback on this video... ua-cam.com/video/9IQlyGviLJY/v-deo.html
If you wanted to do that, you could simply use a standard mono jack in place of the shunted jack. However, be careful to match impedance if you going to add another speaker to the active circuit. In other words, if the amp is 8-ohm stable and the internal speaker is 8-ohm, you'd need to swap the internal speaker to a 16-ohm speaker and then use a 16-ohm external cab to still run at an 8-ohm load in parallel.
@@smiddlyrabone8900 quick clarifier... 2 8-ohm speakers in series results in a 16-ohm load. 2 8-ohm speakers in parallel results in a 4-ohm load. The wiring I described earlier would give you a parallel circuit. You could wire an extension jack in series but it's a bit more tricky because of how the circuit works. You could probably do it with a shunted jack. I'd have to think about that a little bit.
@@musicalmiscellanyThats weard because the guy at Sweetwater music said i could do it if i did it in series , and that it would be bad for my amp to run them in parallel. now im confused, i have a fender champ X2 10 inch speaker 8 ohm and i just built a speaker cabnet and bought a ledgend 12 in 8 ohm speaker for it and i wanted to run both speakers at the same time, maby ill just run the 12 inch by it self its 75 watts im a beginner at this ohm-watt stuff. i just wanted more volume with 2 speakers
I have run through at least 8 videos detailing the same mod and NO ONE ELSE had given the part number for the jack. Thank you sir - you have earned your upvote. The clear diagram was an excellent bonus as well.
That's so good to hear. I make these videos hoping they'll help someone else so I really appreciate this kind of feedback. Thanks for watching.
Perfect mate - shunted mono jack. Got it. Ain't no amp safe around me no more.
Ha ha. Sounds like I started something. Thanks for watching.
The cabinet has more bass for sure. Nice playing!
Thanks for checking out the video. It really is a simple mod that makes any combo more flexible.
I've been trying to find an explanation like this for speaker jacks for a few days off and on now. Finally! Your video is my solution! THANK YOU for the video and the clear explanation!!! Subscribed and liked!!
That's really good to hear. I always make these vids hoping they're helpful to someone so I really appreciate that feedback. Make sure you also check out this video: ua-cam.com/video/9IQlyGviLJY/v-deo.html and this video: ua-cam.com/video/l6txwhjeC8Q/v-deo.html They're both similar.
Okay, I've seen a many of these videos on this mod but this is hands down the best (and subbed)
That's great to hear. I always make these videos hoping they're helpful to someone so thanks for that feedback. I appreciate it.
Holy Cow! I'm in the middle of building a carrying case with a built in amp and you just gave me a tremendous idea! I have three mini amps that I built over the last three years, one of which has a not so good speaker.
Awesome. I always hope my ideas inspire others.
I just ordered the jack from Amazon. I'm on my way baby!
@@bobjohnston4325 Awesome. I can't wait to see what you're building.
Thanks for the great video.
Thanks for checking it out. Hopefully it was helpful.
Thanks for this video. Right down to the part number. It doesn't get any easier than that folks
Thanks for watching and I’m glad it was helpful.
Great video!
Thanks for checking it out. I hope it was helpful.
Great explanation
Glad it was helpful! Thanks for checking out the vid.
This was very informative. It wasn't really a "how to" though... it just focused on the wiring. It would be nice to see the whole process start to finish.
Thanks for that feedback Marty. I've got a little combo amp here that I could modify and make a video of the process. That's a great idea.
Good afternoon Kale,where did you get that jack i missed it,i got a project going on where i could use one.Thanks for sharing that
I buy most of my electronic components from Mouser but any electronics store should have them. I'm sure you can get them from eBay and Amazon too. Just search for "switchcraft 12a jack". Thanks for watching... hopefully this helped.
@@musicalmiscellany thanks Kale,just ordered one on Amazon,i appreciate it 👍
Very cool! I'm more into wood than wiring so pickups and amps are still black magic to me. I'll have to try to make an amp some day.
They're definitely different skill sets. Soldering gives me inner peace. LOL. That said it stresses some folks out.
Steve, for my first cigar box amp I cheated and bought a 5W mini amp on Ebay for $15. I gutted the plastic case and used the parts, including the knobs, and put them into an Acid cigar box. Very little soldering and very easy to build. It's got just as much volume as the one I built from a kit and the one I built using individual parts with an amp chip. I also built a practice amp, slash pedal board, from a Footnote amplifier I bought on Parts Express for $9. No soldering involved!
Can I do this to a fender champ 100?
It sounds great on its own but I really like the option of being able to connect external speaker cabs so I can stack it up
I'm not familiar with that particular amp but this mod works on the vast majority of combo amps. Check out these 2 videos as well because I go into a lot more detail.
ua-cam.com/video/9IQlyGviLJY/v-deo.html
ua-cam.com/video/l6txwhjeC8Q/v-deo.html
Cool video man..quick question. If you wanted to keep the internal speaker of the combo amp working when connecting to an ext cab, would it be as simple as using a stereo jack socket rather than a shunt jack? Basically turning a 2x12 combo into a 4x12? I would have thought there would be volume drop that would need to be fixed as well?
First off, thanks for watching and commenting. What you're asking sounds like an simple question, but it poses a more complicated one. If you followed this tutorial but used a standard mono jack, you'd get the result you're suggesting. The internal speaker would remain powered when the external cab is plugged in.
However, you first need to know more about the stability of the amplifier. For example, let's say your amp shipped with an 8-ohm speaker in the cabinet and it's 8-ohm stable. In that case, you'd want to change out the internal speaker for a 16-ohm speaker and also use a 16-ohm cabinet to achieve the 8-ohm load. If you left the 8-ohm speaker and added an 8-ohm external cab, the amp would be running at a 4-ohm load which would probably burn out your output transformer.
So you'd need to know the specs on the amp before doing the mod to ensure you aren't overloading the transformer. Also, there's a good chance you'll need to buy new speakers to match the load. I hope that made sense.
@@musicalmiscellany You sir are a gentleman, thanks so much for getting back to me, makes all the sense.
I wonder if that shunt could wear out? Is it a very dependable jack so far?
I suppose everything wears out eventually but it's a Switchcraft (which are known to be quite reliable). I know I have guitars with Switchcraft jacks that are 20+ years old and that jacks still work perfectly. Honestly... I'm pretty sure the circuit will give out long before the jack.
Sorry but I'm looking at the diagram paused at 3:34. Surely that's inverted? I'd expect the tip to go to the speaker and the shunt to the internal circuit board
Therefore when no jack socket in, it shorts, = normal operation. When inserted the live external tip goes to the speaker, and the shunt is disconnected?
EDIT NO it's correct. I'm trying to do the exact opposite, which is also useful. I'm wanting to allow my combo (switched off!!) that I keep in my living room to be driven by an external head, these tricks can work both ways :)
Thanks for checking out the video and paying such close attention. You made me rewatch it to make sure I stated everything correctly. You might actually want to check out this video I made. ua-cam.com/video/l6txwhjeC8Q/v-deo.html It sounds like you're trying to do something like this.
@@musicalmiscellany
Yes sorry if you read my first comment before I edited (in your email) you might've thought you'd done something wrong but I was approaching from the other direction and focused on that, you were of course totally correct. Actually if you wired two in series .. you could I'm sure set it up so that a combo could either be set up to drive another cabinet OR be driven by another head :)
If you have no intention of ever using the internal speaker, can you just bypass it?
Yes. If you wanted to use the circuit as a head you could simply wire the speaker leads to a 1/4" mono jack. That would work.
@@musicalmiscellany thanks for the quick reply. Does the positive speaker wire go to the tip or sleeve part of the mono female jack?
@@spaceavenger54 Tip + (Sleeve -) is the standard for speaker cabs. There are some rare systems that use Tip - but the vast majority of cabs on the market are Tip +.
Usually the amps and pedals all run off a Center Negative or in other words a Positive Ground System completely opposite of any Normal Operating System. Which means the power and speaker connections are reversed.
That is a good point. Thanks for adding that. However, if the speaker output is coded red/black (or whatever +/- color/stripe combo), you'll still want to follow the way it's hooked to the internal speaker.
Can you plug a 4x12 into a headphone Jack in an amp to play through? Will it work?
I would not try that. First of all the headphone jack is stereo and the cabinet is mono but also, a headphone output delivers a fraction of a watt. Having such low signal could damage the speakers in the 412.
Hi, Thanks for the tutorial. I actually want it the other way where the speakers stay on as I have a couple of VU meters I want to plug in. How do you do this?
Are the VU meters expecting a speaker level (powered) signal? Typically they're expecting a line level (passive) signal so if you plugged in a speaker jack... that would blow the meter. But if that's what you wanted to do, you'd simply change out the shunted jack for a standard mono jack. If you're wanting to get a copy of the input signal (probably more likely for VU)... you could just add a second input jack and wire it to the same +/- of the input. It would effectively be a copy of whatever you plug into the amp's input.
Hi! How about if I want to connect headphones instead of a single speaker? Also shutting off the amp speaker when plugged in. Can that be done with that same type of jack? Thanks.
That's a very different ballgame because you don't want to plug a speaker level voltage into a set of headphones. It would likely damage the amp (and possibly the headphones). You'd need to create a small headphone amp to do what you're asking, and you'd probably want a separate volume control for the phones. It's a lot more work than just adding a jack but it is doable.
Have you ever had an experience after doing this where your amp makes a thumping/clicking noise?? I did this modification on a Peavey bass combo amp and it worked perfect before, now after installing the shunt jack, its making the clicking/thumping sound
It is a 200 watt combo amp, I don’t know if wattage makes a difference
I can't think of a reason you'd be getting a thumping sound. Sometimes there's a grounding issue when you add a jack but that usually results in hum. Does the thumping go away if you touch the jack or the cable ends? If so, that's typically a grounding issue but again... it's usually hum you'll hear.
No sir I’m aware of what a ground hum sounds like but I’ve never heard this before. I’m not sure if it’s a short somewhere or what. It’s like a consistent clicking noise
Would mounting the 1/4 shunt jack directly onto the amps metal frame cause this problem maybe?? Any videos I’ve seen of you installing a jack, it’s mounted to wood or is a plastic mono jack.
@@cbazz333 Good thinking. It's possible there's some interference with the grounding due to the metal. That should be an easy thing to test. Just unmount the jack from the metal panel, wrap the jack in electrical tape (or some other insulator), test it again, and see if the clicking/thumping goes away. If it does, you've found the source of the noise.
Can I do the opposite attach an external amp to internal speaker with the same jack?
That would definitely not work in this arrangement. If you plugged power into this jack it would send power into the power amp and probably fry the circuit board. However, it you wanted to use it as a cab, it would be pretty easy. You could simply use 2 mono jacks (one going to the speaker and another going to the circuit board) and mount them on the back of the amp (make sure to label them somehow). Then create a small 1/4" cable to connect the two jacks. Keep the cable short and use right-angle connector and it would sit flush against the back of the amp so you wouldn't even notice it. If you did that, you could use it as a combo, a head, or a speaker cab based on which jacks you used. It would be a very flexible setup. You could even use the internal amp to power an external speaker cab while simultaneously using an external amp to power the internal speaker.
@@musicalmiscellany THANK YOU for saving my circuit board, so that shank output jack would not work? Could i just add one jack to the back and maybe a switch? one way is internal speaker and one way i have to plug an amp to the speaker? (in this way, if the internal amp dies at a gig, i can use a lunchbox amp to power the same speaker). for a working guitarist, a combo and lunchbox amp is all i have to carry..
@@CalitranoN You could do that but the problem is the switch would have the full power of the amp so you'd want to make sure your switch is rated for active signals and properly grounded. That always makes me a little nervous. I think the 2 jack method would be the safest.
@@musicalmiscellany ok,,, a guy did my transistor combo, with a toggle and a jack... the toggle disconnects the internal and makes the amp a cabinet... i can then use a lunchbox amp to power the speaker... it works great. I would like to do that on another amp. Do you have a video with two jacks? I am not sure how to do that?
@@CalitranoN With a low power amp, it might not be so bad, but with a high powered amp/head, the switch method makes me a little bit nervous. I could just be overly conservative when it comes to electrical shock though. I don't currently have a video about the 2 jack method but based on your comment and a few others that have come up here, I think I need to make one. I'll probably get it posted in the next couple weeks.
How would you do this on a 2x10 combo? I'm looking to add an external speaker jack to an old Peavey Studio Chorus 2x10 and use a cab because of the incurable amp rattle. Any advice would greatly be appreciated...thanks in advance!
I haven't seen the inside of the amp but it would be essentially the same process. The 2 speakers are either wired in series or parallel but chances are there's only 1 output (+/-) on the circuit board. If that's the case, it's exactly like this video. Run the output to the jack, then the speakers. If it has two outputs on the board, then you probably have to get the schematic for the amp to tap in at the output transformer before it's been split to two signals. Does that make sense?
Also, check out this video... I made it later after I got some feedback on this video... ua-cam.com/video/9IQlyGviLJY/v-deo.html
I'm the alligator's brother. I'm coming for you.
Huh?
what if you want to run both speakers?
If you wanted to do that, you could simply use a standard mono jack in place of the shunted jack. However, be careful to match impedance if you going to add another speaker to the active circuit. In other words, if the amp is 8-ohm stable and the internal speaker is 8-ohm, you'd need to swap the internal speaker to a 16-ohm speaker and then use a 16-ohm external cab to still run at an 8-ohm load in parallel.
@@musicalmiscellany so i cant run a 10 inch 8ohm in amp and a 12 inch in cabnet 8ohm in series
@@smiddlyrabone8900 quick clarifier... 2 8-ohm speakers in series results in a 16-ohm load. 2 8-ohm speakers in parallel results in a 4-ohm load.
The wiring I described earlier would give you a parallel circuit. You could wire an extension jack in series but it's a bit more tricky because of how the circuit works. You could probably do it with a shunted jack. I'd have to think about that a little bit.
@@musicalmiscellanyThats weard because the guy at Sweetwater music said i could do it if i did it in series , and that it would be bad for my amp to run them in parallel. now im confused, i have a fender champ X2 10 inch speaker 8 ohm and i just built a speaker cabnet and bought a ledgend 12 in 8 ohm speaker for it and i wanted to run both speakers at the same time, maby ill just run the 12 inch by it self its 75 watts im a beginner at this ohm-watt stuff. i just wanted more volume with 2 speakers
P.S. the Champ is 15 watts