Genuine 2SC5200 ???

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#61
jpnascim said:
Well,

The subject appears much more delicate and confusing than I thought ! 🙂

I've e-mailed Toshiba yesterday and asked them for tips reagarding identification of an original Toshiba transistor, explained my case and offered to send my pictures to them. Let's see if I can get a response. If I don't, I will try the "suicide approach" and use my transistors in a simple amplifier circuit. Of course I will have to turn it on from a safe distance and maybe look for a shelter ! 😀
Since I am still learning some basic principles of audio amplifiers through a lot of reading it will take some time until I build my first amp (maybe months) but I promise to report the results regarding the doubtful pair of transistors.

Recently, I got to know that OnSemi produces equivalent transistors named: MJL3281 and MJL1302. Does anyone know if they are good substitutes for the Toshibas ?

Thank you
Click to expand...


The MLJ's are more robust than TOS, but IMHO, not as good sounding. 😉 The TOS are more detailed and delicate. (Better micro dynamics). One thing to note is that the MJL1302 from ON is made with the same old technology tht the MJ15022/23/24/25 were made, i.e. Powerbase. However the 21193/94/95 (both MJ and MJL) are made with the newer perforated emitter technology and therefore to me sound closer to TOS as TOS used that in the 1302 productions.

I did correspond with TOS, got nothing valuable out of it. They sent me one laminated page with the different package types, the pictures for the TO-3PL was not large enough to be of any real value. I hope you get a good answer that will benefit the forum.
 
#62
Hi K-amps,

The 2SC5200 has a slightly lesser SOA than the 2SC3281, which has a slightly lesser SOA than the MJL3281A, but the 2SC5200 can still dissipate the heat.

I choose the 2SC5200 because of its lower internal capacitance, which leads to high speed operation and thus better sound definition.

Cheers ........... Graham.
 
#63
The Toshiba parts are also about 1/3 the price of the Onsemi's. At least from my usual sources. That's enough to parrallel a couple more to stay farther inside the SOA, have more surface area in contact with the heatsinks, reduce beta droop . . .. "etc, etc, etc" as the King of Siam once said. And still cost a little less.
 
#65
Arrow and Digikey. Both are big enough to buy direct from Toshiba and they also have some very big customers they cannot afford to **** off.

Of course, the price advantage last time I looked was due to high prices on the Onsemi stuff. They tend to be back order items. These may well come down after a while. If things change, I'll take another look.
 
#68
I have been working on a Power amp module from a Hartke Bass amp. it uses 3x pairs of 2SC5200/2SA1943's per module. I have one module that works, and one that had 2 bad transistors on it. one of each had shorted.

So, after going through the whole board and checking everything i found that the emitter resistors had failed on the A1943 side. so i replaced them and powered up the amp with just 2 pairs of transistors installed.

I only brought the amp up to +/-50Vdc and everything looked good, no dc offset, clean, flat scope trace (Input shorted to gnd).

So i powered down, connected my signal generator and powered up again. everything fine. bring up the signal level a bit, trace looks good but this time i noticed my scope trace was very dim. before i could blink the lights dimmed and the breaker popped on my Variac????

Hmm thats strange, and yup, more blown 1943's the amp must be oscillating is all i can figure.

Now WHY is it oscillating??? everything appears to be just fine. and everything appears to be exactly the same at the other module i have that works good so.....

Do you think it is possible that the A1943 transistors were all bad even though they tested fine? and that they were justed stressed but hadnt failed. or do you think there is another problem i just havent found yet???

Also, how hard would it be to swap in some IRP9240/240 mosfets instead?? seeing as now i have no more 5200/1943 but i will soon have access to several thousand 9240/240 mosfets ???


ZC
 
#69
Also,


I purchased 4 pairs of 5200/1943's on ebay. i have no idea of there real or fakes. what do you think of the test circuit shown earlier in the post???

or, can anyone reccomend a test circuit that will allow me to test my new devices BEFORE i put them in the amp and potentially damage other parts...


Thanks


Zc
 
#73
Graham Maynard said:
It is so sad to see that suppliers think they can get away with selling non-original devices.

I've pulled one hard working ( 60W continuous dissipation) 2SC5200 from a heatsink to show a genuine component.
Unfortunately the part number writing has fared less well than the device itself.

Below the first '2' there is an 'R' for the gain range.
Below the '00' there are batch letters 'O B'
Then beneath - the country of origin.


Cheers ......... Graham.

PS. I have several 'R' spec Toshiba 2SC3281 with higher gain than 'O' ones.
Click to expand...

That one looks very much like the ones I got from Digi-key...
 
#74
found a source of genuine TOS and SAN devices, but they are constantly backordered. actually been buying from the company for years, but wanted to make sure the devices i was getting were genuine. i work at a pro-audio shop, and see lots of amps using c2500/a1943 devices. i ordered a few pair, but the 5200's were backordered, so they sent me some Sanken replacements (which according to the data sheet, actually have a larger SOA). i tested and compared the capacitances and forward voltages, and found them all almost identical to the originals. i'm not going to post the name of the company unless the moderator approves (hello, mr. moderator? is it ok, or not?).... original TOS devices seem to have their numbers laser etched into the epoxy package, not printed with ink. i had to rub heatsink grease into the lettering to read it.
 
#79
ok, company is centerpointe..... i did however get one counterfeit from them today, not 2sc5200 or 2sa1943, but a 2sa11xx (don't have the device here at the moment, but it's one of the large sanken transistors with the two mounting holes)... the 2sc device was genuine, but the 2sa had a 2 digit date code, where the original was 2 digits and a letter. sanken has 4 "dimples" in the plastic, two of which have digits in them, the fake had no digits in them. the original had capacitances consistent with other devices with 5mm die sizes, the capacitances on the fake was about 1/3 those of the original. c/p says that this device was old stock, and would replace it. i am going to take pictures of this one, along with a genuine one, and post it here, as well as send a copy to c/p so they can identify any fakes they have in stock. i'll supply capacitance readings as well, since they seem to be able to identify (most of the time) the die size.
 
#80
It is unfortunate that we have to resort to these posts to verify the authenticity of these parts. I myself have been burned so many times on parts that are not quite original that to the sometimes dismay of small parts shop owners have to scrutinize and bring datasheets along for every semiconductor i have to buy, you may be surprised at how little these parts vendors know about what they carry or what they dont want to know about what they carry for fear of losing a chunk of their bottom line. I cant buy any 2c2240 locally because they are all fake , same with 2sc1845. Go figure the only "Genuine" 2sc5200/a1943 locally are available from a chinese owned electronics shop 3 doors down from the fake carrying shop. I have cracked one open and verified authenticity and devoidness of white goo along with proper 4mmx4mm wafer size.. I spoke off the record to a shop owner and he is well aware of the rampant counterfeiting and works overtime to order genuine parts, even if that means not being able to stock some popular items in which i feel there needs to be more owners with this mindset rather than referring to their "no returns on parts" policy to save their butts along with the "Generic" title given to semis not even licenced abroad..ust my rant for the day 😱)..


Colin
 
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