** WARNING - Fake 2SC1583 Transistors 'C1583' batch '52G' **

[aminoacid]

whoopps..!

recently ordered 100 pc 2sa733 from ebay member "maryma6688" in china for 6$ ink shipping. one of 6 in stock i think...

hehe...

interesting to see what/if ill recieve...

[Gaetano]

You may get 2SA733's, they are not that hard to get yet, it's just that you need to select some high gain ones for Q8, 9, and 10 (I found ~ 1/20 high enough from one batch, => 5/100pcs.). Low gain ones won't do any harm though, just make sure that you test them to ensure that they are 2SA733's, as they may damage something if they are KSA733 (different pinout). It's much better to test them first, than to try to find out why you x0xb0x doesn't work after they are soldered in.

[aminoacid]

just got the package to day! they dont look used. do look authentic.

the 733´s are for q1 and q2. in the boom the right modell is 2sa733"P".

the ones i just recieved says on the text:
A733
G 528


i was told by a friend that what hfe class the transistor was didnt matter! so i guess its not a problem for them being non "P" class. right?

i also guess G528 dosent tell me much right?

[Gaetano]

Sorry,

but a 'G' is a KSA733(G) with Hfe = 200-400

Flat Face up: (...) EBC<- need to cross over the legs to ECB

a 'P' is a 2SA733(P) with Hfe = 200-400

Flat Face up: (...) ECB

if you cross the legs they should work, the Gain = Hfe (class) actually does matter though (but both of these are in the same class, so it doesn't matter here). Although I got some 2SA733G's which were ~Hfe = 150, (out of range). Also they may sound different as they are different transistors. But if your mate knows about transistors get him/her to check that the legs are the correct way around using a $10 tester, to be sure.

[aminoacid]

okey!

thanks a lot!

learning some everyday!

[entrypoint]

I have just bought some 2SC1583s from an online supplier. They are marked up

C1583
52G

as described here. The picture on the website showed batch 42Q. Are all these definitely fake/counterfeit/wrong? How can I test if they will work in my x0xb0x easily (without building the box!). I want to be sure before I try to send them back for a replacement...

[Gaetano]

To test them without a dedicated transistor tester, just measure the Hfe (gain), with a multimeter with a Hfe tester built in. Just make sure the legs are long enough to go in the holes of the tester, otherwise you will need to push a resistor (wire end) or something down the hole to make contact and touch the pins to these.
NOTE that a 2SC1583 is an a dual NPN type.

IF THEY ARE NOT NOT FAKE:
------------
C1583
52G
------------
| | | | |
| | | | |
| | | | |
| | | | |

B C E C B

From the left with the writing facing you the legs are B C E C B, just test the left two and the middle 'B C E' then the right two and the middle 'E C B'.
Plug them into the 'NPN' side of the tester.
The Hfe should be about 400-800 (for each side). If you get nothing then try plugging them into the 'PNP' side below.




IF THEY ARE FAKE:
------------
C1583
52G
------------
| | | | |
| | | | |
| | | | |
| | | | |

B C E C B


If these are the fake ones that I found then they will be dual PNP type, the legs will be BCECB (the same). The meter will tell tell you that they are FAKE as you will get a similar 400-800 Hfe reading: when you plug them in the 'PNP' side of the tester.

I hope this helps, also you may want to mention who the online trader is, to help others not get stung if they are fakes. How many did you end up getting?

[entrypoint]

Thanks very much for the help. My attempt to post a reply a few days ago seems to have been eaten. Anyway, they turned out to be the fake PNP type. If anyone is interested they came from Dalbani but I must say they were excellent about the situation and replaced the three chips I had free of charge and immediately with no fuss. So I now have three chips from batch 69G which check out as dual NPN types on my meter. Actually they look like they are possibly pulls (leads are short and looked clipped, evidence of heat marks on the ends) but that is fine by me. So thanks again for the help and now I am looking forward to building my next x0x!

[Gaetano]

I hope you got refunded the difference if they 'are' used, as the 'new' ones are $11+ each their site

[bothersaidpooh]

Hmm. There are a lot of these about it seems.

FWIW the best way to get genuine parts is (crazy as it sounds) "recycle" them from dead VCRs etc.
usually if its a few years old the parts will be ok even if the appliance doesen't work.

plus the chances of failure are lower as they have been time tested (contrary to popular belief transistors in low current applications don't degrade)

best bet is to test the pinout, gain and leakage with a Component analyser or dmm, if ok then use as normal.

i have a few C945's here somewhere...

[Gaetano]

Be careful people, I noticed a lot of fakes floating around lately, you can usually recognise them by the bad uneven stamping on them, be careful in particular of the 2SA733AP's and 2SK30A-O's and other of the rarer parts floating about at the moment.

[Brassteacher]

When I saw the title of this post, I was interested, and then went to check my small stash of 2SC1583's. Sure enough, two of them had the 52G date code, but in this case they are actually dual NPN, common emitter. Are they real? I don't think so, the vintage 2SC1583's I have lying about measure around 620 on Hfe, but the ones with the 52G date code only measure around 350 or so.

They came from a x0x kit that was being sold on eBay over the summer. One of my former students had bought it, and sought my help in building the kit. It's a good thing he's intelligent, and a fast learner, as it only took me 10 minutes to teach him how to solder correctly! So, he wound up doing most of the grunt work. He was a bit annoyed at first that I insisted on putting every chip, and all the C1583's and the C2291 in sockets. Turned out later he was very glad I did. When we first started testing his x0x after assembly, with all the parts that originally came in the kit installed (except the tantalum caps, I substituted from my stash of electrolytics) it played just fine. However, with my background (besides teaching music) being in high-end audio repair and mods, and more recently vintage analog synth repair, I was no stranger to the counterfeit part issue (You want spectacular? Watch a $2,000 power amp go up in smoke because the new output transistors were fake). After playing with it awhile, I plugged some of my vintage C1583's and a vintage C2291 in, and the difference in the sound was amazing, as in MUCH better. It seems that the C2291 in the kit was real at least, as swapping just that transistor out with the vintage one seemed to make no difference at all. Yes, we swapped it back and forth a couple times.

I guess I have too much of a soft spot, because his x0x has two of my C1583's in, both in the filter, as it seemed to make no real difference in the VCO, and I have two of his C1583's in my parts bag. I knew they sounded different, but I didn't think of measuring Hfe until I saw this post. I guess I can use the two 'fakes' as expo converters, or the bottom of a Moog filter, since the lower Hfe will actually not be too far off the Hfe of a 2N3904.

As an aside, the most commonly faked transistors are Motorola/On semiconductor power transistors in the TO-3 package, MJ15003 and MJ15004, and MJ15024 and MJ15025. Odd thing is, they are not rare, and still in production, but they are not cheap. If I remember correctly, even Mouser had a batch (BIG batch) of fakes shipped to them, and did not discover the problem until a few complaints came rolling in.

[decoder23]

i tested some 2sc1583 transistors today that i recieved last week, and they are fake, batch 52G... i ordered them form dalbani... sigh

[bcbox]

Dalbani is a decent source but they are definitely not inspecting incoming parts.
They are the ones selling the 2SK30AO's with Idss value that doesn't measure correctly to be 'O' parts.
When I buy parts from them now I inquire for a pic of the actual part first; and four of five times they will not reply. Of course when I request a quote for large qty of parts they reply immediately.

[Brassteacher]

Small update on the "real" C1583 transistors with the code 52G. The ones I have, as I posted before, are in fact real, but are apparently factory seconds or re-marked NTE42 transistors (NTE42 is the listed NTE sub for C1583). The "G" on the end of the code is the Hfe rating, and G-rated C1583s should have a minimum Hfe of 400. The ones I had measured in the mid 300's, so they appear to be rejects. However, the original TB-303 used F-rated C1583s, and those have Hfe ratings between 250-500. Long story short, if you get a C1583 52G and it tests as a dual NPN with the correct pinout, and the Hfe measurement is between 250-500, go ahead and use it! Just put the highest-measuring one in the Q21 slot.

As always, if in doubt, throw it out (or go shove it in the ear of the person who sold it to you, legs first ).