How to build an audio signal tracer for less than $3

[@GeorgeChristofi]

I notice I have a creaky chair!

[@Quark.Lepton]

Umm….we thought it was something else…🤣

[@tutorsurrey]

Great video! I have read several webpages, threads and viewed several videos and this is the best.

[@sadunnakipoglu9471]

Thank you and appreciate your effort. Greetings to you from Turkey .

[@douglasbollinger3626]

I ordered some parts to build this for cb/ham radio repairs. I hope I can get it working. Thank you for sharing the video!

[@GeorgeChristofi]

It's a useful tool for repairs. I couldn't get by without a tracer of some description.

[@douglasbollinger3626]

@@GeorgeChristofi I got the amplifier in the mail the other day, still waiting on the little speakers. I'm trying to find a tube of some sort like you used, but not sure what to use. I don't know really how to use a tracer yet, but hoping to learn. Thank you again!

[@GeorgeChristofi]

@@douglasbollinger3626 I used a tube that some medication came in. My latest probe kit build has used a a tube that vitamins came in.

[@douglasbollinger3626]

@@GeorgeChristofi Ok, thank you, gives me some ideas!

[@douglasbollinger3626]

@@GeorgeChristofi I got it put together today, except for mounting it in a tube or something, but it works! Thank you for sharing!

[@robtitheridge9708]

very neat george. One inprovement you could make for RF work is to add a small 1 or 2 trasistor pre amp so you can check signals coming off the tuneing cap and coils and before the 1st if stage.

[@GeorgeChristofi]

It would be something I would do in a bigger unit for sure. This was more an example that the build is not complex or beyond anyone who has just got into the hobby. It certainly is a valid point to make the unit more flexible.

[@robtitheridge9708]

@@GeorgeChristofi Agreed and for traceing audio it's perfect

[@Codeeze]

Thanks for the inspiration George - I have some of these boards arriving today, so will have a play later and see what I can rustle up. I already have a few Sig tracers, but you can never have enough... :D

[@GeorgeChristofi]

Nope, never have enough!

[@oldgold4u3971]

Hi George. A very well-presented video, and thanks for sharing your ideas and knowledge. Please tell me how the geranium diode is placed in the circuit for RF tracing, and do the two input capacitors remain there? Cheers, Richard

[@GeorgeChristofi]

The geranium diode really can be placed in any orientation as it is just rectifying AC so whether you take the positive side of the waveform or the negative it doesnt matter too much. The capacitors do stay in line.

[@oldgold4u3971]

@@GeorgeChristofi thank you

[@jimmiemack1947]

From the probe to the input are there diodes, caps or resistors? Thanks.

[@thehappylittlefoxakabenji8154]

neat little unit cant say I am impressed with the excruciating little squeaker !

[@GeorgeChristofi]

It isn't bad considering it was all chinese stuff from Aliexpress. sure, it isn't the most sensitive, the nicest to listen to or even the best way to do things but it was a simple throw together with parts I had lying around!

[@thehappylittlefoxakabenji8154]

@@GeorgeChristofi yes I do that sometimes use what ever is to hand it does get the job done I used to use a crystal earpiece and jack socket in a ball point pen case to trace signals worked well if you could find a crystal earpiece that worked ! thanks for the Sub !

[@tonybegood111]

Excellent George. ...by the way great Audio and video. ...

[@GeorgeChristofi]

Many Thanks. I am trying to get it better all the time... Now I have to work on getting my hair tidy and getting a personality!

[@blugoose86]

Interesting choice of test music. LOL Reminds me of my childhood. Too bad you don't have the "45". You could have played the "B" side and we can hear it backwards.

[@old64goat]

Nice little probe.

[@GeorgeChristofi]

Thanks Bill. I'm happy with the way it's working. Given that it fits in the small tube it turned out nice.

[@Valerifon1]

Hello George, I just found this video and have subscribed to your channel. I just have 1 question for the moment. I've looked through the comments (and found the link to the schematic on the UK site - thanks!) and I don't see it mentioned so I'll ask: where did you get the clear probe tube shell please? This is just the project I've been looking for and am looking forward to assembling it. Cheers - Luther

[@elsaarmstrong-zp6ng]

Where in the UK can you buy the little pcb for this probe?

[@GeorgeChristofi]

I don't know as mine all came from China direct.

[@tutorsurrey]

George, my crocodile clips don't seem to fit as well as yours. What single, or four pin connectors could I use, possibly JST type?

[@GeorgeChristofi]

pretty much anything will do.

[@TheOpenAirGarage]

Nice signal tracer. Will come in super handy.

[@GeorgeChristofi]

I was happy it turned out so well and with not a great deal of real effort.

[@keithbrandaw7229]

hello George , Very compact probe sensitive, great video George!

[@GeorgeChristofi]

It is a great little tracer. Not the most sensitive but not totally deaf either Keith.

[@conundrum112]

Hi George, very well done.

[@GeorgeChristofi]

Many thanks Harvey, thanks for stopping by.

[@conundrum112]

No worries George.

[@comment8767]

I love these Canadian videos. 0:58 Check out the dual earrings!

[@GeorgeChristofi]

Canadian? I'm from London! Triple earrings too!

[@Rebel9668]

LMAO...They're coming to take me away Ha-Haaaaaaaaa...I love old novelty songs like that. I have that one here along with a ton of others. Had to introduce Charlie Drake's "My boomerang won't come back" to a young guy the other day who didn't get it as the reference I used about it when he said he'd gotten a boomerang. Love the signal tracer build.

[@GeorgeChristofi]

I used to collect records that were either novelty or banned from radio play.

[@GeorgeChristofi]

If you want something different, have a search for Judge Dread. He was a very large English guy who sang rude reggae songs.

[@Rebel9668]

David Allen Coe had a few of those banned ones as I recall, lol. Finger F******* Sally comes to mind off the top of my head. I'll check out that Dread. :)

[@GeorgeChristofi]

Got some of his too. As well as Andrew Dice Clay. Judge Dread was doing the nursery rhymes in the 70's. I think every single one of his records was banned the minute they were released. There are so many over here because the BBC was run by prudes. I think my favourite is still Father Abraphart and the Smurps, 'Lick a Smurp for Xmas (all fall down)'. That was a response to the fact that the Smurfs originally given out by petrol stations were painted with lead based paint.

[@ajw6715]

The little speakers can be found in old laptops.

[@harveysvintageaudio]

Nice device, I need one.

[@ferfromla]

Quick question. Would it be possible for the 386 board to be put into a box and have a lead come off the box with a probe? In other words could it be built so that the 386 doesn't have to be part of the probe apparatus? Keep it in a separate box and just branch a lead off with a probe put into an old pen so as to make it less cumbersome? From the probe to the input are there diodes, caps or resistors? Thanks.

[@GeorgeChristofi]

That would be a perfectly feasible approach to tale. The only thing to do is to make sure you use shielded cable for the link to prevent the pickup of spurious signals.

[@gilbus4989]

Song brings back memories-lol

[@boyetmb4389]

Your genus , i like that

[@spankysmp]

George - is this easy to build for a novice? I watched todays RC Live and it finally clicked as to why they are so useful with the help of a circuit diagram when tracing faults. I know Graham uses his a lot. Which board should I look for? Thanks. Has someone got 'plans'?

[@GeorgeChristofi]

It really is novice level because the audio board is already configured. all you do is add the input section. if all you are doing is looking for audio then the only thing you need to add is a capacitor to protect the input. I used a 2Kv rated one simply because I pole about in valve sets and can come across voltages up to 700v in places. Another version of this type of generator is www.pasttimesradio.co.uk/build/diyradio.html and this can be built very easily. if you take the schematic from that website, the probe is actually everything in front of c2 and can be used with any audio amplifier module. Mosslack and robert gibbons on youtube are working on a good kit which is close to completion and you can either wait for the full kit or work from the schematic. Mosslack (Doug) has been working on a lot of generators and the final one seems to be the best of the lot.

[@Pyridox]

Thanks for the idea. That little amplifier module is nice & compact. Where did you get those small micro speakers, on ebay? LOL Napoleon XIV''s classic song. I remember when that first came out on the radio here in the US in the late 60's it quickly got banned.

[@GeorgeChristofi]

They came from AliExpress. About 2 pounds a pair I think.

George, here's a question , and the answer might help a lot of us out. Is there a place where you can just email your bill of materials and pay for the components and it's a done deal? Today I exhausted myself trying to find old radio capacitors that could handle 650 Volts. Where can we buy stuff without getting robbed or sent counterfeit garbage?

[@GeorgeChristofi]

The problem is that the modules are chinese and can be had from a variety of places. Mine came via AliExpress but the seller has either stopped selling or has changed name. The other problem is where people are located in the world. I could link to ebay uk but the seller might not ship abroad, I could link straight to china but the price varies by country and from different sellers. and I don't have favourite sellers, I just shop by ratings and price. here is a search link for the module from Ali, you can choose any one that fits your needs and you will have Ali protection against fraud. If it doesn't arrive, you do get refunded but the shipping times are quoted in months, not days. www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20200927035331&SearchText=lm386+module

[@GeorgeChristofi]

@ I find it better to bulk buy parts. Valve radios can be particularly expensive but if you shop around spares can be had quite cheaply. I tend to buy high voltage caps in bulk direct from china and that is a big saving over the one off prices. Resistors again, larger quantities can save a lot but you only save if you are actually going to use the components otherwise its dead money. Modules and kits really are best from china direct...

[@GeorgeChristofi]

@ the poly caps are usually the 630v ones for 240v sets, the electrolytics are 450 or 500v ones. US sets have lower voltages but it doesn't hurt if you use higher voltage caps.

[@tutorsurrey]

Omg I finally got to my work station and misremembering this video, removed the green connector by force. Now I will have to drill holes in the board to connect the speaker, which probably won't work anyhow! Doh!

[@GeorgeChristofi]

We all have those moments!

[@babygaum9992]

Can I know the price

[@andrewfish1117]

good video I enjoy spoken commenty rather than crud music

[@GeorgeChristofi]

I use music sometimes for effect or to fill in obvious procedures but like you, not a fan of music in the background distracting me from the video.

[@Luke-12V]

Hello, buy ?

[@dekil19]

cool to share schematic? thanks

[@GeorgeChristofi]

I haven't got the one for the module but I am guessing the default LM386 amplifier circuit is identical to it.

[@pedrojuan5550]

Do you still sale this product?

[@GeorgeChristofi]

I never sold this, it was a board purchased from AliExpress.

[@williamrollinger3637]

Greetings, George....Great video. I just had one question, Where did you get the tube? I think it is the perfect size...Compared to others I've seen.

[@GeorgeChristofi]

The tube actually came with my post surgery medication! It originally held a syringe with a dose of blood thinners. Instead of just throwing them away, I did notice that they were 'pen size' and wondered what I could put in them. I hate wasting things that could be useful, much to the annoyance of my wife!

[@williamrollinger3637]

I know what you mean about the wife...same here. I know I won't be able to find the tube like that around here, so I guess I will keep looking. Thanks for the quick reply, keep up the good work!@@GeorgeChristofi

[@overload3996]

@@GeorgeChristofi meet the wife half way, make her a vibrator .

[@GeorgeChristofi]

@@overload3996 I did... I converted a cheap poundland one into a USB powered pulse width modulation controlled monster... the video is on this channel!

[@JerryEricsson]

@@williamrollinger3637 I used to comment about the wife myself. Then, last month, after a 3 month battle with cancer, she passed away. Broke my heart, even now three weeks since her passing, I find myself turning to talk to her only to realize she isn't there, then the thought hits me that she can't come back and the tears once more flow. God how I miss her, we had our 51st anniversary 4 days before she passed away, she was still able to talk, and we reminisced for hours.

[@johnnytacokleinschmidt515]

4:20 internal battery powered and it stays isolated.

[@kennynvake4hve584]

You would make a very good radio voice...announcer

[@GeorgeChristofi]

I actually used to be a radio presenter!

[@VintageElectronicsGeek]

What, no hi-fi!?! I don't want it then! JK :) Works really good...now, its real world test time! ~Jack, VEG

[@GeorgeChristofi]

It is good enough for signal tracing! The speakers look like they are laptop type parts.

[@loverofthelostnarc]

There's no circuit diagram anywhere.

[@GeorgeChristofi]

it is a ready built module from AliExpress

[@johntaylor3940]

MAKE ME ONE PLEASE

[@seeithappen1]

They are coming to take me away .... ha ha hi hi hoo hoo ... the men in the white coats ...

[@BovyPatrik]

Ge moet die zijn tang is bekijken (vanaf 7'00") ;-) Afgezabberd tot en met.

[@pam8352]

can you produce a schematics because i am not native english speaking and it is difficult for me to understand the video?

[@vishva8kumara]

A pre-amp..