Instructables

I want to add an external speaker jack to a Dorchester Music Maker (record player)

I bought this sweet looking record player which also has a cassette player at Value World, Indy's largest thrift store. both tape and record player work just fine. It has a small speaker in the front which doesn't sound very loud. I'd like to add a jack where I can plug an external speaker to it. Is this possible to do? I opened the player and it has about a 4 inch speaker with only a red and black wire going to the pc board. I don't know how to solder and was hoping this is something I can do easily. I don't mind learning how to solder or if there are alternatives that's even better! I've been searching all over the world for someone who has done this before but nobody.. I've seen other similar things being done and I'm concerned if I should somehow wire a preamp or some precautions I should take when adding an external speaker. By the way, the speaker I'm using is a Bose Sound Link speaker. I would appreciate some help here. I'm such a nub.

Picture of I want to add an external speaker jack to a Dorchester Music Maker (record player)
niftynev2 years ago
Danyforreal, hi, we'll get this working for you somehow!  You can be the first in the world to do this!  I'll show how to do it without soldering too if I can.

We'll try the direct connection between your 2 units first.  method first. I'm thinking the worst that can happen is the bose may get too high a signal at even the lowest volume of your dmm & distort the sound, but I very strongly doubt anything will be damaged (especially the bose!) if we get this part wrong.  With a small speaker your dmm has it would be lucky to be a watt going into it at max volume.  You may have to quickly dive for the volume control of the bose that's all!

Trouble is, a bit of wiring up of a little 'interface' circuit would then be needed to get the signal level right.   I've already found a suitable interface circuit if you need it.  I'll post that here for you as well.  Many thanks to Tomi Engdahl <then@delta.hut.fi> for that info!  Nevertheless, we could come up with a 'no solder' way of wiring that up for ya!  I found you a suitable 'no solder' jack to mount in your 'dmm' as well, so no soldering here either!

I've made up a 6 step method for you that I use myself to 'tap into wiring' without damaging the existing wiring, & it's a reliable, flexible, & long term connection!

You could use this method to modify your dmm without soldering. Calrad electronics in California make a nifty phone jack, for example, that you don't have to solder to! - it's got screw connections! Item number 30-491T  Looks like if you buy it through krp electronics you can get it for half the price!   You'll find it here =>

http://www.krp.com/PANEL-MOUNT-35mm-STEREO-JACK-W-TERMINAL-SCREWS_p_3078.html

Check the length of it's thread to see how thin a panel it needs to fit. Find a spot on the back or front of your music maker, & drill a suitable sized hole for the jack to pass through snugly. Then you just need to connect the black wire that goes to your internal speaker ALSO to the earth connection of your phone jack.

A very similar situation with the red wire to your internal speaker, except we need to join the other 2 terminals (L & R) of the jack together first, or you'll hear the sound in only one side of your nice soundlink speaker!. You mentioned only one speaker in the music maker, so I'm assuming that it's mono. I've made a pic for you of how it goes together.

Hopefully this setup won't be too touchy on the volume so you won't require any other mods, but we can do it if it's required.



___________________________________________________________________________________________
NO SOLDER WIRE JOINING METHOD - IN 6 STEPS  (follow pics called step 1 to step 6)

Step 1 => Carefully remove about 5mm of insulation from the wire you
                  are tapping into without damaging the strands of wire.  I first
                  carefully nip a mark all around the wire at each end where I'm
                  going to remove the insulation without cutting into the  wire
                  strands. The whole  idea is to NOT damage the existing
                  wiring.  A stanley knife or a  sharp pair of small wire cutters
                  should do the job if you're careful.  Take your time.

Step 2 =>Strip about 15mm of insulation from the end of the new wire
                 you are going to run to the new jack.  Line up the end of the
                 insulation of the 2 wires next to each other.

Step 3 =>Twist the strands of the new wire around & around the existing
                 bare wires' strands you exposed & along them, in a tight sort
                 of spiral using the 5mm to 'use up' all  15mm of loose
                 strands.  You can 'form' the wires so their wire ends are lying
                 all nice & flat & parallel with a little work.

Step 4 =>Stick about 20 mm of electrical tape centrally across the join,
                 so it evenly covers up the bare wires.

Step 5 => Tightly & neatly wrap the tape around the wire bundle, trying to
                  keep it from spiraling too much, but still tight.  Try not to spin
                  the wires themselves around while you do this - you are
                  wrapping the tape around the wire not the wire around the
                  tape!  Plus you risk fatiguing the connections between the
                  speaker & the pc board.

Step 6 => Wrap a small cable tie around the centre of the join & tighten
                  it up good & firm.  Cut off the excess cable tie end close to the
                  lock part & I can pretty much guarantee that connection for a
                  lifetime - unless it goes underwater!  It won't fatigue like a
                  soldered joint can when the connection is moved around.
_________________________________________________________



You can use an off-the-shelf stereo 3.5mm male to 3.5mm male audio cable to connect the 2 units together. No mods to your bose, & no mods to the cable. You just have to decide how long a cable you need between them. So yeah, electrically, it looks like a perfectly feasable idea. Be good to hear how you progress.  Good luck! 
step 1.jpgstep 2.jpgstep 3.jpgstep 4.jpgstep 5.jpgstep 6.jpgspeaker_to_line_circuit.gif
danyforreal (author)  niftynev2 years ago
Holy guacamole!! Your reply reminds me of why I love Instructables so much!! Now shortly after I posted this I found an ible where the person did this by adding a switched phone jack. This allowed the internal speaker to be usable when not connected to an external speaker. That is exactly what I want to do. You were right about your guess that the internal speaker is Mono. I went ahead and ordered this part from mouser electronics:

http://www.mouser.com/ProductDetail/Switchcraft/35PM1/?qs=zRnNmUVysJfv5rljj6r4T2bc3SwQlWOIcGNxAuqrWm8%3d

I really appreciate you taking the time to find a solder less jack. I have no problem learning how to do it, and I actually want to learn. I have a small solder gun that I bought a year ago that I plan to use. I have some wire lying around in my studio that I will use as well. I'm going to take a picture of the switch when it gets here. And I plan on making this into an ible and credit you for your awesome help!!
Cheers for that mate! I'm pleased to be able to share what I know with you, & I'm especially glad that you seem to be cottoning on to what I rave on about!


Anyway, apologies dany but you're gonna really need a Stereo version of the socket that you've got, unfortunately! The reason is that you need to be able to send the same mono signal down the left & right wires of your interconnecting cable, through to your stereo amp. I'm guessing you'd want to hear the sound through both speakers of your amp, even though it will be mono.

This one is available & should do the job -

http://au.mouser.com/ProductDetail/Switchcraft/35RAPC4BH3/?qs=%2fha2pyFadui5Yb7gGU5G92QirQ4SwutsMTP6wpOB3A8%3d

It's gonna need to be soldered to though sorry! But that's ok I'll try to show you how.

Could you please send a pic of your soldering iron/gun? We need to make sure it's suitable for your job. You're gonna need some 'multicore' 0.56 to 1mm solder though, to give yourself a good chance of nice connections. It's the best & well worth the extra cost. A whole roll of it might be a bit dear but you can get a little bit in a bag from an electronics hobbyist retailer.
danyforreal (author)  niftynev2 years ago
Oh pooey, I thought that the bose speaker would take the mono signal and play it out both speakers. But phew thanks for that. I will go to Radio Shack and get it. They had the stereo version of this same jack, I saw it when I was there to buy the Mono jack. As far as the soldering gun, it's actually a torch from Bernzomatic that has a soldering tip on it. They call it a micro torch. It came as a kit with a plumbing torch. It can be used as a torch and as a soldering gun when you add the appropriate tip. It runs on butane gas, I don't know if that is relevant but I thought I'd mention it. Here is the link to it:

http://www.bernzomatic.com/PRODUCTS/TORCHES/MICROMINITORCHES/tabid/251/ctl/Detail/mid/1260/xmid/6950/xmfid/3/Default.aspx

You can google it and find loads of info on it. Now can you fill me in on the details of the solder wire? Do you think Radio Shack will sell it? and I don't mind buying a whole roll of it. I have a studio full of stuff that I buy and keep handy for when who knows I will use it. Now as I look this stuff up. "Multicore" is the brand? I will go shopping for all the stuff as soon as I hear back from you. Thanks for being patient with me =) I was not kidding when I said I was a nub!


Your iron should be ok, as long as you don't spend more than just a couple of seconds on each solder connection.  I hope you have a small soldering tip for it!

The solder I use is like this -

http://australia.rs-online.com/web/p/solders/4364847/

The important part is the 'crystal 511'  part.  That's the flux, that cleans the metals as you solder & allows the solder to flow nicely.

Mouser has a switched stereo 3.5mm panel socket -

http://au.mouser.com/ProductDetail/Switchcraft/35RAPC4BH3/?qs=%2fha2pyFaduhEWyjopjDcYUtvksdUuJMJ9%252b40m%252bEVf24%3d


The data sheet for the socket is at -

http://www.switchcraft.com/Drawings/35rapc__h3_cd.pdf

This socket is usually for pc boards, but you may find one with solder tags, which would be easier for you.
niftynev2 years ago
I forgot to include the diagram for you!  Sorry bout that.  I've included it this time.  Also there's a pic of the type of cable you will need to connect the 2 units together.  Hope it helps.
rewire a dorchester.jpg3.5mm phone cable.jpg
danyforreal (author)  niftynev2 years ago
niftynev, I got the phone jack in the mail today. Unfortunately it was the wrong one. I went to Radio Shack and to my surprise they had the right one there. Here is a picture of what it looks like. Sorry it's dark but I had to shoot it with my macro lens on my iphone and I can't use the flash to light it up without blowing it out. It has three prongs to connect to. If you notice the thing that captures the cable input has a little prong that touches it. When you insert the male end of the cable into the jack the metal bar is pushed off the intruding prong to remove the signal from it. This allows it to switch from the internal speaker to the exterior speaker. I will make an illustration that better shows this piece phone jack. It is 1/8 inch, and it's made for use with a Mono set up.
photo.JPG
danyforreal (author)  danyforreal2 years ago
I drew up this quick illustration showing in more detail the way this jack is built. I have no clue how this needs to be wired in order for it to work :/

In figure 1, I show you the basic layout of the way this phone jack is built. the ports are numbered in order from bottom to top. it shows that in the second port that makes up the small bar that intrudes on the big bar and touch each other.

In figure 2, I show how inserting the cable into the jack makes the big bar separate from the small bar. this sends the signal to the external speaker and silences the internal speaker. I hope this helps. =)
illustration.jpg
danyforreal (author)  niftynev2 years ago
This is wonderful!! It totally makes sense and seems very simple to do! I have that cable you posted, It's the 1/8 inch or Mini cable. Just waiting on my phone jack to arrive in the mail. It will be the kind that has a switch that passes the signal to the external speaker when it's plugged in and when it's not plugged in, passes the signal to the internal speaker. Maybe you can redo one of your awesome diagrams for me with the new jack? please =) You've been a great help!