A quick intro to those who are still working (like me) with tangent or CMoy amps and have SMD or Pins on small parts to solder... I have Young-Onset Parkinsons Disease (Michael J. Fox, Muhammad Ali etc. etc.) so my hands are not as steady as they used to be...do not BUILD...when you can Mooch...

These EVM (evaluation modules) are built and designed for testing by huge IC firms... just look around and...'um... sign up...hehe..if you can't get Eval boards get sample parts! OP AMPS and many other components are FREE from the original manufacturer. Some are "alternative" parts and the DIP are usually the cheapest. SMD and SOIC devices tend to NOT come in single qty unless you pay a few dollars.

Easy search tools are online for various OP AMP power requirements, form factor and output ratings. Low voltage power requirements are best for portable iPod versions, however 12v+ power with amps over 10W per channel are available for speaker applications. Build your own iPod boombox or dock with amp & speakers!


Most IC firms have free SAMPLES and/or discounts for quantities of ONE. They usually deal with THOUSANDS of parts on tape reels. It's expensive for them to send you ONE part.,so they built these "testbed" or sandbox modules for customer testing...all pre made and with easy pins for attachment to power and audio inputs/outputs! Search IC makers websites and get free samples! These are NOT for resale and are for testing only...;)

You usually get ONE only...but of each type! Order seperate parts or all together!

Also see tangents excellent DIY amps & improved designs from Chu Moy's/Sijoase. Buy his low cost pre-fab IC boards!

http://tangentsoft.net/audio/cmoy-tutorial/ he has some parts and parts #'s for most distributors

and see the headwize DIY forums for the bleeding edge stuff...! ya way cool.


Links to pictures of Sijoase's amps...was some talkway back of IC board production runs from Sijoase schematics...? hum?

erckgillis (author) 4 years ago
I need to update this soon!
tigerdog3306 years ago
wait so i just ordered the eval board here: http://focus.ti.com/docs/toolsw/folders/print/opampevm-sot23.html
for free then i was reading the pdf (http://focus.ti.com/lit/ug/slou060b/slou060b.pdf ) and it was a little confusing but from what i can understand, it says you need to get the sample amps separate and put them together yourself? please correct me if im wrong because if i understand correctly then i just ordered another thing i cant use.
erckgillis (author)  tigerdog3304 years ago
erckgillis (author)  tigerdog3305 years ago
yes, you have to assemble many of them yourself...that is why they are cheap or free....try soldering...
nvm it came in the mail today.. so it turns out its just the board with the circuits printed and you need to add all the parts on your own.
fothic156 years ago
I got a bunch of stuff in the mail today but its all teeny, tiny chips. How do I get a board for it???
erckgillis (author)  fothic155 years ago
lol...you have to MAKE them...
warri0r135 years ago
Hi, i know it's an old instructible, but i have a question. When i'm registering my TI account, then what to put as my company?
erckgillis (author)  warri0r135 years ago
How to get the EVM PA2000D4 as a free sample?
Or do you have any links for free EVM as for http://redirectingat.com/?id=487X782&url=http%3A//focus.ti.com/docs/toolsw/folders/print/opampevm-sot23.html?
planes8919 years ago
in that first picture, i cant find that part on ti's website can you post a link? thanks
erckgillis (author)  planes8919 years ago
Both the Op Amp SLOP 329 and the EVM (Evaluation Module) PA2000D4 have links to http://focus.ti.com/lit/ug/slou091a/slou091a.pdf
wait is this the $49 board here in the picture?
cupnoodles26 years ago
Hey do u have schematics for that cmoy u have there? thanks my mail is positiveguy11@yahoo.com
cdubnbird7 years ago
ok so I'm not nearly as tech-savvy as everyone else. i just want a decent audio amplifier that can fit in an altoids tin and preferably have two headphone ports. i looked at the sites and was thoroughly confused (and half of them didn't even come up). If someone could refer me to a site where i could get an amp for free that'd be super cool?
cdman00258 years ago
Where do you reccomend to use or get free eval kits from? Please putllinks
erckgillis (author)  cdman00258 years ago
Must use "social engineering". Sorry for a quick link spend the $49. Cheaper than ANY kit you can buy or build for that quality (see photo).
Beg borrow conjole you CAN get free via email, use their cloest competition as reference , cc emails from one to another. Get a price or discount then negotiate....you can do it.... I'm working on a whole EVM SYSTEM...for free!


Lazy try $5 boards - http://focus.ti.com/docs/toolsw/folders/print/opampevm-sot23.html
I clicked buy with TI E store and I got them for free for some reason.... ?????
pmac937 years ago
where else can i sign up for free samples besides ti?
theres a ist of places here.....
Derin7 years ago
w00t high tech japanese caps
LinuxH4x0r7 years ago
Are there any fm transmitters? If so, could you please post a link? Thanks
erckgillis (author)  LinuxH4x0r7 years ago
Any specific link to free samples? (ti, national, etc)
erckgillis (author)  LinuxH4x0r7 years ago
You have to sign up and ask!

like at TI! http://www.ti.com/home_b_samples

right on their Homepage...did ya look at all?


No, I got that, I meant do you know of any specific ones? I signed up for ti, but I'm not sure what to get
erckgillis (author) 7 years ago
Of course you can BUY a FM Transmitter (using your MP3 player as a pre-amp) for a few dollars...

Heh that is so cool im gonna go do that thank you very good instructable +1
admanrocks8 years ago
OK, so im not that electronic savy, i have the schematic for my amp, so i was wondeing if anyone can tell me whats going on. thanks, adam
erckgillis (author)  admanrocks8 years ago
OK, I see several issues...
1-This is a inverting or power supply/filter opamp, we'd prefer a audio amp like a quality Burr Brown
2-this requires a power bypass, virtual ground or a voltage reference circuit. You realize this is 1/2 a amp rignt?
3-also a poor circuit for a gain adjustable amp...
4-read the Tagent tutorial & start with a cheaper CMoy with fewer parts and lower cost for better quality
5- don't start off with a SOIC opamp try a DIP which is easier for DIY

good luck

tagent tutorial
admanrocks8 years ago
Are there any free amps that are put together?
erckgillis (author)  admanrocks8 years ago
You can get FREE parts, then build. Assembeled amps are not free. The EVM modules are still missing connectors (audio input/outputs and Power) and are usaully $45-99 each. However some can be had cheap or free (see below). Fully assembeled amps are avail on ebay and some CMoy / Tangent amps are avail fully built but never for free...geez how much do you want... lol Not much money in giving away assembeled amps! Get your free parts, and build one...it's more fun...
planes8919 years ago
hm says they cost 49 dollars each, guess those arent free
erckgillis (author)  planes8918 years ago
beg...it works...ask for overstocks/out dated or opsoltet versions. Or perhas YOU can you build one of their quality & size for $49? Add $4 for jacks, battery and a case and you are DONE! No CMOY parts, no PCB or Fab work, no Wires Gain or or mess...way cool... Just pick your TI OpAmp and Power needs.
Arrgh4069 years ago
the best way to find free parts is to go to digi-key, find the part you want,click on the manufacturer's link and write an email to them.
erckgillis (author)  Arrgh4069 years ago
Yes, if you get a "reject" send them the email from a 'positive' competitor and that you'll buy from them... I love America!
Arrgh4069 years ago
a while back i got over $100 of free stuff from ti
erckgillis (author) 9 years ago
Found many Eval Boards at National Semiconductors site, many completed PCb were only $10 for purchase...I ordered some free samples of Op Amps and DC/DC convertors...limit was 5 orders of upto 5 items each....wow...no shipping on in stock items...consider it free packaging materials as they come in small hobby sized boxes with mylar wrap, reusable packaging...all for free...!
admanrocks9 years ago
what IC firms?
erckgillis (author)  admanrocks9 years ago
I used TI...but most all original manufactures have some samples... Check out National Semi www.national.com I use TI 'cause I'm in Dallas and usually get samples in a day or so...