Power regulators

Deperduci

Active member
My apologies if the wrong sub section but what equivalent chips exist to https://www.mouser.com/ProductDetail/Texas-Instruments/LM2940CT-15-NOPB?qs=X1J7HmVL2ZG1l9S5UEMUVA== ? Mouser says a year out, Tayda peed it's pants laughing when I tried searching..
it's for a solid state power board/quasi headphone amp. 12 v supply the BOM says can chintz using a 7818 but says the lm2940 for 9v supply to stabilize it's output doubler.

Or does anybody even have 1 of those laying in a box? or should I just saccrifice an after market 12v pdeal/pc supply 😉
 

Deperduci

Active member
This board here. and it's pdf BOM here if I can get away with the LM78xx series I will. It blows nonkey duts that was the last the shop had for a bit, I like finding these min amp projects.

see if the formatting stays with a Bill of materials Device# Qty Value Comment
Resistors
R1 1 2M2
R2 1 330k
R3 1 6k8 Test with LED first for brightness
R4 1 220R
R5 1 2R2
R6 1 47R
R7 1 1R- 1W Capacitors
C1 1 10n box film
C2 C6,C11 3 100n box film
C4,C5,C8 3 2200u/40V polarized electro (max. 12mm Ø)
C7,C3 1 100u/25V polarized electro (max. 5mm Ø)
C9 1 470u/25V polarized electro (max. 8mm Ø)
C10 1 47n box film C12 1 10u polarized electro
Diodes
D1,D2 2 1N5817
D3 1 LED
ICs
IC1,IC2 2 TDA 2003
IC3* 1 LM2940CT-15 (9V supply) uA 7818 (12V supply) The 15V LDO version is available from mouser P# LM2940-15/NOPB
Other Heatsink** 1 anything that fits the three TO220 ICs on one piece. Running without heatsink will destroy one or more ICs!
*If you run this with a 12V wall mart you can use a 7818 voltage regulator. If running from a 9V supply you need the LM2940-15/NOPB regulator which successfully can stabilizee the approx. 16V coming from the voltage doubler in front. A normal 7815 will not be sufficient!
 

Deperduci

Active member
Now you see why I was digging as I make out the mail order for the parts I don't have by the box, like the voltage regulator and the 2200uf caps I want to feed this thing wired direct~ish from Black_eye or Space heater from Sushi Box to make a poor and old fart's JTM 45. As I said I might just locate a 12 volter to dedicated(hardwire through a fuse) and us the lm78xx since most places have those in stock.
 
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Deperduci

Active member
I hope it's the regulator which you didn't have to do, because I don't think I've ever seen a 12 volt Walmart or is that part of the company attempting to go green using a solar charged battery array for the stores...:unsure:
 

fig

Village Idiot
I hope it's the regulator which you didn't have to do, because I don't think I've ever seen a 12 volt Walmart or is that part of the company attempting to go green using a solar charged battery array for the stores...:unsure:
It’s an LM2940-15 . If it checks out, I’ll mail it to you. Then you can use a normal 9v according to the doc.
 

Deperduci

Active member
That would mean it's more a donut than cookie duster. (if my threads get derailed, I make sure it's out by a field and not downtown :p )
Why I thought it was from the box of breadboard, something he cooked up and then decided that expense or specifics weren't as needed. TheLM2940 is about 6x the price of using something from the LM78XX group.
 

Deperduci

Active member
@fig I might have the solution because I do have enough cranial flatulance to live down to my screen name
It’s should be here tomorrow, maybe next day. ;)
The PSU I have on the 5 watt headphone I got from the man downunda is already a 12v 1.5amp with 3.5 mm jack , I just have to watch the power jack, being center post positive as opposed to center ground like most of us build for. 🤦‍♂️ 🤬🤦‍♂️

Benny, Betty, those might work but I'll get the 18v version, I need to put together a tayda order for my 2 sushi box boards anyways and just say fudge it with a linear pot for this other project I got from Israel..
 

fig

Village Idiot
@fig I might have the solution because I do have enough cranial flatulance to live down to my screen name

The PSU I have on the 5 watt headphone I got from the man downunda is already a 12v 1.5amp with 3.5 mm jack , I just have to watch the power jack, being center post positive as opposed to center ground like most of us build for. 🤦‍♂️ 🤬🤦‍♂️

Benny, Betty, those might work but I'll get the 18v version, I need to put together a tayda order for my 2 sushi box boards anyways and just say fudge it with a linear pot for this other project I got from Israel..
Well, if you decide you want it, I’ll send it to you...it was well-packaged and shipped quickly…

hwHVEvu.jpg


I tested it and it functioned as expected per the datasheet example.

6TTvkU4.jpg
 

Deperduci

Active member
I might take it anyways and send you some excess 4049/4069 chips I acquired when I misordered for a flanger board. I have to check the sheets while i have the 12v PSU, not sure if the sushi box board is also 12v compliant or safe to just add a couple resistors to the 12v patch to make it 9. Where did you even find it?
 

fig

Village Idiot
ebay.

I’ve a feeling that the L78 would work, but I wouldn’t suggest using it without trying it myself first. If you’ll DM your address, I’ll get this in the mail. ;)

Edit: Just ask Nathan about his board. It may have some special current requirements. 🤷‍♂️
 

Deperduci

Active member
DM sent. I'll let Nate get a nap before I ask...I still have to juggle using a larger box like a 1590c/j or making something from both angle and sheet aluminum to hold it all.
 
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