Cheap Component Search

I havent had the trouble others have had soldering either of these. Which ones are people having issues with?

It must be a combination of jacks, solder (probably the flux inside), and temperature that causes trouble…

Long ago the few jacks I soldered (that was before I got into modular synth…) I had no problems. I changed everything since then: jacks, solder, soldering iron…
Now from time to time I get a “dry joint” on the jacks if I get lazy and don’t give them a light scratch with the file. Heating them much more (I go +50ºC…oops) solves the bad joint, but that’s not a good thing to do for everyday soldering, just to “repair” my lazyness…

1 Like

I sometimes shop unobtainable components from Unicorn-Electronics in USA.
Prices are pretty good and they have a lot in stock. And I have bought from them several times. They ship oversea.

3 Likes

https://unicornelectronics.com/webspecials/WS1004.html
I love grab bags.
I just noticed that the page title is “Antistatic Wipes”

3 Likes

I got a follow up on counterfeit TL074s (but only the ones that are rebranded LM324s, so still work as op amps)
you CAN, in fact, counteract the slew rate and current source capacity issues, without having to buy a whole new op amp!


the slew rate is not really a frequency dependent distortion (not within audible range, at least) therefore this can be done:
you want to make sure the MAXIMUM slope of your signal is less than, or equal to the slew rate of your op amp. Higher frequency components have higher slopes, so 20kHz would be the limit for audible sounds. As the slope is determined by the derivative of the signal and in the frequency domain everything is composed of many different sinusoidal components, the maximum slope is given by: Vpeak2PI*MaxFreq
If you equal that to your slew rate, you can find the maximum output voltage swing for your counterfeit opamp as Vpeaktopeak = (slew rate)/(2 * PI * MaxFreq)
in the case of the LM324, the slew rate is 600.000V/s (0,6V/us) and the max frequency I chose for the signal, to guarantee distortion free audio is 40kHz, so the maximum output would be just shy of 2V.

Now, you might ask “but I want a higher voltage to drive my gate/line!” but that can be fixed with a simple single stage transitor amplifier! The design of which I’m still testing to find the most stable for the least effort, so I will follow up again soon!

at least now, we dont need to throw away all those op amps we got scammed with lol

3 Likes

Just noticed this article from NCS that discusses fake TL074s (from a supposedly serious supplier, in his case) and also discusses why fakers might be faking these usually why-would-anyone-even-bother-faking-these chips:

EDIT: Which I now see links to @ChristianBloch’s post over here:

which starts by mentioning that I’ve mentioned fake chips before, so full circle I guess :slight_smile:

3 Likes

I hadn’t heard anything about a TL074 shortage. Not that I’ve bought any in a couple months. Tayda (who Skala I’m sure would say not to buy from, but I’ve never noticed a problem with chips from them) has about 2800 at the moment, which does seem low.

A little late but I have already bought the PT2399 from Alieexpress, they arrived very well packed in a plastic tube. I was positively surprised.

hey awesome! sorry everyone for the delay on that module it got a little held up due to a pitch shifter experiment, which might not make much sense, in the next week ill have an ETA. :slight_smile:

4 Likes

I ordered XR2206 from all over the world, some from Europe (eBay) and some from China (AliX) and had a few from Unicorn-electronics (US).
The PT2399 I have for my projects are all bought locally.
A number of K140UD12 to the Polivoks VCF has also found its way to me from Germany, Russia and Ukraine (eBay).

When buying from China I am aware of the risk of fake stuff and only buy pretty cheap stuff.

I must have bought my 74’s 8+ months ago, they look a lot like the fake ones.

I also have a bunch of 72’s they have the logo like the fake one but the rest of the package looks more like the genuine 74. I guess I should make a test board and see what they are doing.

Rob

1 Like

Doepfer uses nice 3.5 mm chassis jacks. They are particularly nice because their center hole is lined with some isolating plastic (the picture shows an example of those.) where other manufactures are metal. This prevents one when inserting a jack from shorting that to GND, which usually can’t be prevented from happening with the all metal jacks. Especially if you are using a cable splitter and want to plug a jack into some module this short might mute the signal going to the other end of the split, leaving you in silence (which although brief in time may give you some time to contemplate life, the universe and everything, but after having done that a few times, becomes a boring). The Doepfer modules do not know such problems. But I’ve not found any jacks like these so far. Does anyone know a source of this type of jack ( other than Doepfer modules )?

doepfer_A_136

1 Like

In my first 3 cases all my modules are with this jack socket, and i had a lot of problem, the plastic thread is easily damaged, so sometimes super glue, and other trash, now I use the Tayda all in metal more strong.

2 Likes

I have a bunch of these. Not quite the same as the ones Doepfer uses, but same result:

This is not necessarily the same seller I got them from, so you may want to search a bit to get the cheapest price.

No bad experience like Dud with the sockets damaging easily?

i just think that mine are 6.35 Kosmo one, Doepfer it’s Eurorack so 3.5 :upside_down_face: sorry.
and i used some 3.5 plastic one for other project with no problem.

1 Like

No, they’re pretty solid.

2 Likes

Has anyone tried the tayda nano clone? I normally buy elegoo but they are out of stock on elegoo’s website and on amazon.

1 Like

I use them all the time (there’s one running a foot to my left as I write), they’ve been fine.

2 Likes

thank you :slight_smile: