MP3 / iPod Headphone Amplifier TDA2822M Stripboard Veroboard Layout

The TDA2822M IC is a stereo power amplifier that I often come across in old walkmans/radios so I thought I would make a stripboard project for you people. Because I'm sure if you're an avid junk collector like me you will probably have one of these however if you don't; no worries you can buy them really cheaply from the grey market (or probably on digikey or something) below is a link to a grey market china shop I use often and so have had no trouble with. you could buy 50 of them for £3.56 ! so if you have 50 friends who have iPods that can't power headphones properly because they have piss weak amplifiers in them - since that idiot sued them - you can make 50 headphone amplifiers and sell them to your mates or whatever. Grey Market ICS

Anyway using this kind of IC is much better than using that well known CMOY amp design that is essentially more of a line buffer (which is useful in itself) but doesn't give you any extra power - where as this does!

The other cool thing about this IC is that you can run it from as low as 1.8 volts.

I know I will get questions asking me about its performance using different headphones so I am going to preemptively post the typical output power from the datasheet.

if you're new to reading datasheets this may look abit like gibberish but I'll give you a quick description of what you're looking at.
this is the part of the datasheet that deals with "Po" or power output and this is measured in watts (or in this case miliwatts
and they get these results from using a 1 KHz sinewave which is a typical test condition for testing a lot of electronic components (as listed under the Parameter section)
They then list the "Test Conditions" which in this case uses Rᴸ (Resistive Load - which in this case is a pair of headphones)
the other number "Vs" - is "Voltage Supply" (which I'm sure you know is whatever voltage you're powering it with)

Then we get to the Min./Max section - this is basically the Power Output of the IC (in miliwatts) using some basic test conditions.

So.. using this table I can get an idea of the Power Output with the headphones I own.
for example I have a pair of headphones on the desk here (for abuse)
using my meter on the resistance range I know that their impedance is about 4Ω and I am powering the stripboard (below) using 2 AA batteries which should be 3 volts.
using the table above I know that the Power Output will be about 110mW - which is very dam loud when we're talking headphones. (there will obviously be some discrepancy because music isn't just a 1KHz sinewave but it's good enough to gauge how much Power we're going to get out of this thing.

Hopefully that is clear enough to understand (I know I'm not the best at grammar etc. - my brain is often all over the place)
but I urge you to take a look through the whole datasheet because it's very interesting (most datasheets are) HERE

Anyway - when you turn this on don't have your headphones on/in your ears in case you've made a mistake or your MP3 player is playing too loud. Use this amplifier at your own risk

Adjustable Load Stripboard Veroboard Layout

I've done a similar adjustable load before but I've tweaked this one a little so it performs better and so on.
PSU UT = power supply under test
the one I made can sink over 2 Amps. you just need to make sure you have a big heatsink.!

it's also a good idea to mount the big resistors offboard cause they get hot.

Dark Activated LED Flasher Striboard Veroboard Layout

Around here we get the odd brown out because the local transformer station is inadequate and hasn't been updated since the 50's so obviously it can't handle the fact that houses have more than one electrical appliance. anyway I made this low power device to be put with my torch so I can find it when all the lights go off.

after you build it - you adjust VR1 so that the LED blinks when it's dark and it should last quite a while with 2 1.5v batteries powering it.
try and get the lowest power LED you can find - remember, it will also blink all night.

Rez Overdrive Stripboard Veroboard Layout

I've been working on a lot of projects recently which I couldn't really post on here due to complexity etc.
but today I thought I would try and design something for my blog using one of the cool parts I got from Linear Technology
and thus born was the Rez Overdrive which you can use on guitar (demo at bottom) or synths etc.
the Whole circuit only draws 2.45543mA (yes, I got a 6.5 digit meter recently - it's a Keithley 2015 THD - check it out if you like multimeter porn)) so in theory it will last a hell of a long time if you use batteries.

Also I added D1 as an afterthought to protect the circuit from reverse polarity accidents - so it isn't on the schematic.

Logic Pulse Generator - Logic Pulser Stripboard Veroboard Layout

Often with projects that uses Logic devices such as previous projects like the devils drone sequencer or the Sound Activated Dancing LEDs you need to create a clock signal to make the logic transition from one state to the other. you don't want to have to deal with the clock (or oscillator) part of the circuit in the experimentation stage so you need something that is capable of creating a clock signal. This is just that piece of test gear.

it also uses the same power supply you're using to power the Logic ICs in question.

here is an example of a commercial version http://uk.rs-online.com/web/p/needle-point-probes/5375163/?origin=PSF_437277|alt

aswell as the layout and schematic - I have included some oscilloscope pictures of what it actually does.

Sorry if my explanation is a little off today in the making sense department - I am suffering from cluster migraines and one of the symptoms is Aphasia. the important thing is that the actual layout and circuit are correct - which as you can see - is the case!

As you can see I have soldered a nail to the pulse output - I've found this is the ideal probe

Adjustable Pocket Power Supply Stripboard Veroboard Layout

This is something I've been meaning to make for quite a while.

Basically the idea was that should you go around charity shops, car boot sales, yard sales, thrift stores and other such places it would be nice to have a power supply capable of giving you various voltages to check if things you are potentially going to buy actually work. the resistors are selected for 3 volts, 5 volts, 9 volts and 12 volts and you may notice that the resistor values (R2, R3, R4 and R5) are very specific and in some cases not available - these values are due to not being able to alter R1 when you switch the voltage.  

there are 2 ways to get around this

1.add resistors in series or parallel eg. for R5 I put 2K and a 68r resistor in series and that was near enough to get me my 12 volt output

OR..

2. use 5K/4.7K trimpots and calibrate with your DMM - using that method you can of course easily set it for voltages you think you will need the most.

Sound Activated Dancing LEDs Stripboard Veroboard Layout ( for the holiday seasons )

With all the various holidays coming up I thought I would do a nice decorative project. This makes LEDs light up with any kind of sound - it might make a cool halloween effect that makes LEDs flicker as people walk past your house or you could have it on your TV or something at christmas or of course anything else you could think of (if you have any ideas let me know)

as usual it is built and tested - it works beautifully and is quite sensitve however if you want to control the sensitivity change R4 to something like a 2K potentiometer or trim pot and adjust to suit.

for the microphone I used one I salvaged from and old phone similar to ( Mouser number 665-POM5238PR ) but I'm sure any kind of microphone will work.

S.A.L.O. (Smooth And Light Overdrive) Stripboard Veroboard Layout

This is just a little overdrive circuit I threw together the other day - I had an MXR octave fuzz that refused to work so I gutted it and made this thing to fill the box.

I didn't use a schematic or any pre-planning I just threw it together and hoped it did something and it did and it was quite a pleasing something. I will trace it so I've got a schematic to post at some point but until then here is the layout

The first 10 seconds is the guitar with no overdrive on

Devils Drone Sequencer Veroboard Stripboard Layout

This has taken some time to design and it's not perfect but it sounds pretty cool (As you can hear from the sample) it follows on from the devils triangle I did earlier this year ( Found HERE and no you don't have to build that to make this work!)
This is quite a big project and as you can hear I have built it using the stripboard layout provided (as I do with all my layouts) so take your time because I really can't spend lots of time answering why things don't work. The truth is that unless you have the board in front of you there is no possible way to troubleshoot things. But if you take it slowly it should be good.
also don't forget to check out the "tips and troubleshooting" page above

I would also recommend not to do this if you're in-experienced

Marshall Bluesbreaker Stripboard Veroboard Layout

There is no schematic for this because I did this one years and years ago and I can't find the schematic that had the right component numbers to it and usually it causes confusion when components don't match their numbers on the schematics.
This particular layout was made from tracing an original unit and some of the component values differ from schematics that are on the net and I assume that they either cloned theirs without removing the components and measuring them and just went by what the component was marked as - this is where people go wrong because some manufacturers mark their components wrong to hinder cloners.

anyway here is the layout

Mini Push Pull Amplifier Stripboard Veroboard Layout

This is a bit of an experimentalist amplifier - the transistors on the BoM won't give you that much amplification however if you put some power transistors in there like BDT63/BDT62 you will get a lot more amplification.

I made this for my iPods headphones and essentially what I did is make one board for each channel so I can stack them on top of each other and it is quite a compact nice little amp.

Peizo Pickup Transducer Preamp Stripboard Veroboard Layout

this is actually from a request from a guy called Jim (sorry don't know your last name) who wanted a peizo preamp because they are so expensive. they are essentially just a high impedance preamp
and you could probably use this for other things like hiZ microphones and whatever.

there is a gain control on this and it uses an op-amp that is able to function as a single rail op-amp which cuts down the component count which is always useful when you need to hide this inside a guitar cavity or something.

Poor Mans Audio Signal Generator Stripboard Veroboard Layout

this is something I made in school 15 odd years ago. you had to take a square wave, use a passive filter network to convert the signal to triangle and sine - this also has square and integrator waveforms. it's quite good up to 1 KHz but after that it starts to clip and go funny but it's more than adequate as an extremely cheap audio signal generator using 2 transistors and 1 LM555 timer IC - if you've gone through alot of my projects you'll notice how useful this IC is by now.

I have done another signal generator project that uses a proprietary ICL8038 IC Project can be found HERE which is more fully featured as far as project function generators go but the IC can be costly in certain places where as you can go on the grey market (IE eBay china sellers) and pick up hundreds of them for next to nothing.

Adjustable Mains Hum Notch Filter Stripboard Veroboard Layout

I built this for those of you who have guitars with single coil pickups or indeed anything that picks up mains interference up (that annoying set of speakers in my bed room for example) anyway this little device reduces the mains hum by several orders of magnitude

it is adjustable between 45Hz and 90Hz so just put it before your amp or whatever and adjust the trim pot till the hum goes away.

it uses the same Texas Instruments TLC071 OP-AMP as I used in the last project for pretty much the same reason

Temperature Controlled Fan Controller Stripboard Veroboard Layout

I built this for 2 things - 1. my computer is getting a little hot and I like quiet for as much as is possible so having a little automatic controller turning on a few fans when it gets too hot is ideal for me. and 2. my homemade power supplies could do with fans and again I don't want them running all the time but with this particular temperature sensor LM35DT as it is a TO-220 package you can screw it to the heatsink you have your regulators on (with the usual isolation of course) so the fan only runs when the regulator gets abit hot.

(v)R3 controls at which heat the fan will turn on at however it is a little tricky to calibrate so it will be a case of trial and error unless you have known heat sources.

I also used a TLC071 OP-AMP for a couple of reasons 1st. it is a single supply op-amp so I didn't have to piss about with dual supplies etc. and 2nd I got it free from Texas Instruments excellent sample service

I used a TIP41A because that's what was nearest to my hand. I know the schematic says TIP41C but it doesn't really matter - the letter designations just refer to the voltage the transistor can handle and none of them go below 40 volts so use whichever you can get or even any similar NPN power transistor will be fine.

Simple LED Flasher Stripboard Veroboard Layout

I've done LED flasher type circuits before on here but usually they were for something someone wanted so they did specific things like fade in and out and so on.

So I thought for a little 10 minute project I would do one of the very first projects I ever made as a little boy. I was very proud when I made my first LED flash. it's not like now where people just load up the "blink" sketch in Arduino. this is a proper old school relaxation oscillator.
my original one had a few more components but I've managed to whittle this down to 3 resistors, 2 transistors and a capacitor + an LED obviously.

this particular circuit is known as a relaxation oscillator and there's lots of theory and stuff behind that but in extremely simple terms: it charges a capacitor until something "disturbs" it. in this case the "disturbance" is the threshold voltage of Q2 (the voltage at which the Base conducts) this quickly discharges the capacitor which results in a short blink.
which looks nicer than the conventional square wave oscillator which the LED stays on the same length of time as it is off

everyone loves a flashing LED

if you get this reference then you're ace.

Adjustable Lab Power Supply With Current Limiting ( L200C ) Stripboard Veroboard Layout

it's been a while since I've done a new layout - I've been and continue to be ill but I thought I would try and do something so people don't give up coming here. so with a body full of painkillers etc. I designed this little power supply.
it differs to my previous power supplies in that it is an extended range one. IE it goes from 0 volts upwards rather than 1.2volts upwards.
the way this is done if by creating a negative reference voltage and feeding it into the L200C regulator.

this also has current limiting so you can set it to drop out if a circuit tries to draw more current than it should (due to short circuits etc.) which can avoid circuit catastrophes.

anyway here you go.

Soft Latch True Bypass (Relay) Switch For Guitar Effects Stripboard veroboard Layout

People often like to retrofit their guitar effects with "true bypass" switches but this usually means wrecking the pedal case by drilling holes in it and stripping out the buffered section etc.

Personally I don't like doing this modification, I like there to be a buffer because there is always a degree of signal loss in pedal chains but this is here for those who do like to do it.

as it uses a mechanical relay (which can be found at Rapid Electronics or wherever - the one I used is the 12v version of this one ) it is exactly the same as a true bypass switch and adds nothing to the signal.
it is quite small so it can fit in some pedals (like a tubescreamer) or you could use it externally to maybe bypass a whole group of pedals (or just one of course)

it's worth mentioning that this has many other uses such as controlling high power relays with a little tact/push switch and so on

NB: if you find you're getting misfire clicks you can make the capacitor a higher value - that part acts as a crude debounce - the higher it is the more stable it becomes but the slower you can turn it on and off but I found 220n was fine for guitar bypassing

hope you like.

for the purpose of perspective

Nintendetar Guitar Fuzz Stripboard Veroboard Layout

This is something I made a long long time ago and subsequently made actual PCBs for which I still have but due to the fact my agoraphobia has reached such levels I can't post them anymore so I don't bother selling them. however it's a cool effect so I made a stripboard for it. I also Made an Add-on board a while back located HERE

or with the Oscillator Add On..

Greg Fryer Brian May Treble Booster Deluxe Schematic Stripboard Veroboard Layout

this is one of the best treble boosters I've built and I've built alot of them being a Brian May fan.
this was traced from the circuit board and I have made 2 changes (that don't affect the sound)

1. in the original there are 2 power supply capacitors (47uf and 33uf) in parallel which was obviously used to keep production costs down - Greg will have initially put in the standard 100 uf capacitor but if his other pedals/products used 33uf and 47uf caps - it would have been cheaper to just parallel a couple of those up to get near enough.

2. the other change is that there are 2 10pf capacitors in series again this will be a production cost thing - it would be cheaper to use 2 10pf capacitors in series than adding 1 4.7pf cap to the build (if he used a lot of 10pf capacitors in other builds which he most probably will do.)

so with those changes noted: it sounds no different to the original unit but you can always swap them if you don't believe me.

Sparky 5 Watt Amplifier Stripboard Veroboard Layout

I thought it was about time to tackle something that's been on my todo list for a while and that is to make a follow up to the infamous Ruby amp (made by Runoffgroove.com) which is a popular circuit among the DIY community.

So I thought the best idea was to use an amplifier IC in the same family as the Ruby's amp IC which after an extensive 5 minute search on Texas Instruments website lead me to the LM384 (DATASHEET) which is a 5 watt mono audio amplifier.
it needs a minimum of 12 volts to run though I would run it at 15 volts

All the way up it goes into crazy distortion but before that it is a really nice sounding amp, you get a nice clean and then the louder it goes the more it clips - but nicely - I must do some sound clips!

it powers a 1 x 12" cab very nicely - I've not tried it with a 2 x 12" cab yet but I think it will be fine.

so I introduce to you the SPARKY Amplifier - why did I call it the "SPARKY"? fuck knows, I think it was cause I was watching that cartoon where the piano comes to life.