Before the knee jerk reaction of “only buy brand new from Mouser”, hear me out. What is your collective experience with getting real vs fake, on old obsolete chip amps that show up on the surplus market from time to time? I’m not talking about the stuff everybody uses, but specifically the 5 to 8 watt 14.4 volt single supply amps designed for old school 1980’s car stereos? I have a buddy just starting out in electronics again after 20+ years, and he just can resist playing with these things - because that’s where he left off. Stuff like the TDA2002, TA7205, BA5406. I fool around with these old parts too, but if I get a bad one it’s a don’t care. So far the only “bad” one I ever got was a BA5406 that I couldn’t get to stop oscillating. Different part numbers show up all the time, including types I’m not familiar with. The available quantities are often so low that you can’t put together a “test” order and expect to get a half dozen next week like I do when I find old TO -3 power transistors to stock up on. I’m not talking about a lot of money to be out of, or anything that would start a fire if it was no good. 12 to 18 volt power supplies. I’m perfectly willing to throw 20 bucks at an experiment and so is my buddy. So far almost all of these parts have been trouble free. I was just wondering about the collective experience with the lower tier stuff that might not have as much “incentive” to fake as say the TDA2050 or 3886.
Just thinking aloud:
* all those are Asian sources.
* I would not be surprised to find tons of REAL "car radio class" chipamps,which were also used in TVs, boomboxes, the ubiquitous 10W + 6.5" speaker practice amps, karaoke machines, etc. , because these were made there for decades and by the zillions, so overstock is predictable.
Why fake them when there are so many real leftovers nobody wants?
* by the same token, how/why would there be an inexhaustibe supply of made/used in tiny numbers EXPENSIVE hard to find components? Such as Toshiba/Hitachi/Sanken Lateral Mosfets , high spec Bipolars, ultra low noise ICs and transistors, etc. , which were never much used there in the first place?
Up to the 80´s Chinese Electronic Industry was not a factor, and they started slowly rising from the very bottom, after 90´s Japan decline slowly put these out of the World Market and Taiwan>Korea>China started replacing them.
Also Malaysia and Singapore in the latter years.
So in my point of view, *some* cheap massive components are very likely "good" ; Hi Tech High Spec ones, not that much.
Just a recent thread about AD797 proves this.
REALLY trust a supplier selling over 5000 AD797 for 95 cents each when Mouser sells them for almost 14 bucks and stock is about 250 units?
I guess your friend will do fine, specially if he sticks to car radio type stuff.
TBA810 and similar European, Hi Fi types would be harder to believe.
FWIW I once bought a lot of Hitachi or Toshiba TDA2002 , not a typo, from a "close up factory and sweep the floor" auction, here in Argentina, from a guy who had made car radio boosters in the 80´s and was destroyed by cheap dollar and no tariff Customs.
The real thing, worked flawlessly (although their specs are slightly lower than more modern TDA2003), bridged in 12V lead battery fed Guitar amplifiers.
I had been using TDA2005, a bridged TDA2003 very popular chipamp for that job, and when supply dried up I modified PCB for 2 of these.
Almost forgot: your friend will probably find the Korean version,with slightly changed name, such as "KA****" or something.
I would trust those even more.
* all those are Asian sources.
* I would not be surprised to find tons of REAL "car radio class" chipamps,which were also used in TVs, boomboxes, the ubiquitous 10W + 6.5" speaker practice amps, karaoke machines, etc. , because these were made there for decades and by the zillions, so overstock is predictable.
Why fake them when there are so many real leftovers nobody wants?
* by the same token, how/why would there be an inexhaustibe supply of made/used in tiny numbers EXPENSIVE hard to find components? Such as Toshiba/Hitachi/Sanken Lateral Mosfets , high spec Bipolars, ultra low noise ICs and transistors, etc. , which were never much used there in the first place?
Up to the 80´s Chinese Electronic Industry was not a factor, and they started slowly rising from the very bottom, after 90´s Japan decline slowly put these out of the World Market and Taiwan>Korea>China started replacing them.
Also Malaysia and Singapore in the latter years.
So in my point of view, *some* cheap massive components are very likely "good" ; Hi Tech High Spec ones, not that much.
Just a recent thread about AD797 proves this.
REALLY trust a supplier selling over 5000 AD797 for 95 cents each when Mouser sells them for almost 14 bucks and stock is about 250 units?
I guess your friend will do fine, specially if he sticks to car radio type stuff.
TBA810 and similar European, Hi Fi types would be harder to believe.
FWIW I once bought a lot of Hitachi or Toshiba TDA2002 , not a typo, from a "close up factory and sweep the floor" auction, here in Argentina, from a guy who had made car radio boosters in the 80´s and was destroyed by cheap dollar and no tariff Customs.
The real thing, worked flawlessly (although their specs are slightly lower than more modern TDA2003), bridged in 12V lead battery fed Guitar amplifiers.
I had been using TDA2005, a bridged TDA2003 very popular chipamp for that job, and when supply dried up I modified PCB for 2 of these.
Almost forgot: your friend will probably find the Korean version,with slightly changed name, such as "KA****" or something.
I would trust those even more.
Oh, there´s a lot of closeout auction buyers,they buy *everything* for a fixed price, no matter what, and then sell small lots or even by unit.
Fake AD797 seller mentioned a few days ago sold >>5000!!!<< of them in a short time (less than 3 Months?) by the unit or in packs of 10.
hes old them betwee 95 Cents and 2.65 Dollars.
Just do the Math.
They actually seem to be remarked 741 or worse, which he could have bought for 10-15 cents each, by the thousands.
I can get them for 25C in Argentina, what CAN the Chinese price be?
Fake AD797 seller mentioned a few days ago sold >>5000!!!<< of them in a short time (less than 3 Months?) by the unit or in packs of 10.
hes old them betwee 95 Cents and 2.65 Dollars.
Just do the Math.
They actually seem to be remarked 741 or worse, which he could have bought for 10-15 cents each, by the thousands.
I can get them for 25C in Argentina, what CAN the Chinese price be?
741CN in ST markings less than 15 cents US here in India in retail quantities....TI too.
The other thing you must note is that there are a lot of chip factories who have to deal with newer chip designs.
For example, the CPUs in computer have gone from 65nm to 7 nm or so today.
The 65 nm production lines then become obsolete, whether or not the machines are in good condition.
These then end up making the auxiliary chips like USB, sound, IDE controllers and so on. Also LCD TV parts, and there is a huge new market for LED lighting related products, Bluetooth chips and so on.
And even older equipment is used for chip amps.
Basically you get the machinery at a cost that has no relation to reality, as in take it away, pay whatever you feel like, like a close out sale.
ST is an example of a company which took over a lot of products after they were phased out by the original innovators, so how is it surprising if a Chinese factory does the same thing?
And yes, the prefix actually means that the factory stands by its products, the prefix changes but the numbers don't.
JRC genuine 5532 was 30. fake was 20 (Indian Rupees), I settled on TL072 for phono pre amp, it was TI marked, cost 15 Rupees, or about 20 cents US.
By the way, the 810 chip amp is not available here, the FM radios here use one channel of the 6283 stereo amp, one channel is not used (no BTL).
The other thing you must note is that there are a lot of chip factories who have to deal with newer chip designs.
For example, the CPUs in computer have gone from 65nm to 7 nm or so today.
The 65 nm production lines then become obsolete, whether or not the machines are in good condition.
These then end up making the auxiliary chips like USB, sound, IDE controllers and so on. Also LCD TV parts, and there is a huge new market for LED lighting related products, Bluetooth chips and so on.
And even older equipment is used for chip amps.
Basically you get the machinery at a cost that has no relation to reality, as in take it away, pay whatever you feel like, like a close out sale.
ST is an example of a company which took over a lot of products after they were phased out by the original innovators, so how is it surprising if a Chinese factory does the same thing?
And yes, the prefix actually means that the factory stands by its products, the prefix changes but the numbers don't.
JRC genuine 5532 was 30. fake was 20 (Indian Rupees), I settled on TL072 for phono pre amp, it was TI marked, cost 15 Rupees, or about 20 cents US.
By the way, the 810 chip amp is not available here, the FM radios here use one channel of the 6283 stereo amp, one channel is not used (no BTL).
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No experiene with these particular chips, but I have had some bargains when buying stuff where the market has simply disappeared. Things like ADSL line-drivers (AD815 etc.), some older high-power CFB opamps (like the LT1210) etc. can be found cheaply. Just because a lot of the fakes come from chinese sellers doesn't mean that everything is fake or that all chinese sellers sell fakes.
I wrote up my approach to this a while ago - might be helpful for someone else? Buying “suspicious” parts… | theslowdiyer
Hasn't saved me completely. but it's at least kept my losses to the actual parts and not to any burned equipment etc. and I've walked away a couple of times and probably been saved there as well.
I wrote up my approach to this a while ago - might be helpful for someone else? Buying “suspicious” parts… | theslowdiyer
Hasn't saved me completely. but it's at least kept my losses to the actual parts and not to any burned equipment etc. and I've walked away a couple of times and probably been saved there as well.
TDA7297, 4440, 1185, 6283...(stereo)
TDA7388 (quad) ...these are used here in car audio, new production.
TDA are from ST, the others are "Good Copies", meaning marked as theirs by the factory which makes them, which I prefer to re marked fakes.
The numbers are original, the prefixes by the maker.
Sometimes the logo of the factory is there too, and these are trustworthy compared to amateur fakes, where they take a cheap chip and mark it as a rare chip, to get a higher price.
You can try those if you feel the new old stock may be fake.
Have fun...
TDA7388 (quad) ...these are used here in car audio, new production.
TDA are from ST, the others are "Good Copies", meaning marked as theirs by the factory which makes them, which I prefer to re marked fakes.
The numbers are original, the prefixes by the maker.
Sometimes the logo of the factory is there too, and these are trustworthy compared to amateur fakes, where they take a cheap chip and mark it as a rare chip, to get a higher price.
You can try those if you feel the new old stock may be fake.
Have fun...
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I’ve used plenty of those old AD815’s. As well as the L165’s.
I’ve also gotten my share of “seconds”. Bought a big batch of 2N5879/5881 pairs after I cracked a few open to confirm that aluminum TO-3 from 1980 was real (it was). However, about one in eight was so low in hFE as to be useless. The batch ran the gamut of three to about 300 so most of them were good. They were giving them away at 50 cents each eventually till they were gone. Perfect source for fixing old low power receivers and power supplies. Any place you’d use 3055’s and 2955’s and you’re too cheap to “waste” an MJ15024 running it at half capacity or less.
I’ve also gotten my share of “seconds”. Bought a big batch of 2N5879/5881 pairs after I cracked a few open to confirm that aluminum TO-3 from 1980 was real (it was). However, about one in eight was so low in hFE as to be useless. The batch ran the gamut of three to about 300 so most of them were good. They were giving them away at 50 cents each eventually till they were gone. Perfect source for fixing old low power receivers and power supplies. Any place you’d use 3055’s and 2955’s and you’re too cheap to “waste” an MJ15024 running it at half capacity or less.
Bose is no longer as reputed as it was?
It did strike me as odd that nobody copied the 901 series speakers after the patents expired...too complicated maybe.
And over hyped perhaps, as is usual with small makers....as it seems to have been with Carver for example?
Now it seems Bose is out sourcing production from the lowest bidder, a lesson in how to shoot yourself in the foot.
Do it yourself, or stick to big brands...
It did strike me as odd that nobody copied the 901 series speakers after the patents expired...too complicated maybe.
And over hyped perhaps, as is usual with small makers....as it seems to have been with Carver for example?
Now it seems Bose is out sourcing production from the lowest bidder, a lesson in how to shoot yourself in the foot.
Do it yourself, or stick to big brands...
Nobody wants to lost money or time with desoldering !!!
- I use only national ads websites for old products, only from privates
- I use well known sources for NOS
- when I can't find what I want, I try to win at bay/alex lotery !
Last bad experience was with TDA1562. Three orders before getting a working chip
- I use only national ads websites for old products, only from privates
- I use well known sources for NOS
- when I can't find what I want, I try to win at bay/alex lotery !
Last bad experience was with TDA1562. Three orders before getting a working chip
TDA200x are 10% distortion at “rated power”, which is actually driven WAY into clipping. Non clipping power is some 30% less. Simply supply voltage limited, you just have to understand how many real watts you can get off 12 volts. Backed off like it should be it’s about 0.2 %. Not wonderful, but useful for what it is.
My favorite of this class of amplifier was the Toshiba TA7205. Same kind of distortion at 5.8 watts “rated power”, but more like .01% at half a watt or so. Noticeably cleaner. Been years (or is it decades now) since I’ve even seen some for sale. I did pick up some TA7240’s that I haven’t even had a chance to “evaluate” yet. It’s stereo with an internal preamp section, so enough gain to feed directly off a mic. Feedback arrangement is different, so it may not even be the same class of part. Not sure if I’ll fire them up first or if Mark will. I’ve got 4 and 5 kw PA amps and lots of tubes to keep me busy - I just use little projects like that as a distraction so I can come back to the big ones with fresh eyes and perspective. You won’t believe how many errors you find and problems you solve (before something fatal has a chance to happen) that way.
My favorite of this class of amplifier was the Toshiba TA7205. Same kind of distortion at 5.8 watts “rated power”, but more like .01% at half a watt or so. Noticeably cleaner. Been years (or is it decades now) since I’ve even seen some for sale. I did pick up some TA7240’s that I haven’t even had a chance to “evaluate” yet. It’s stereo with an internal preamp section, so enough gain to feed directly off a mic. Feedback arrangement is different, so it may not even be the same class of part. Not sure if I’ll fire them up first or if Mark will. I’ve got 4 and 5 kw PA amps and lots of tubes to keep me busy - I just use little projects like that as a distraction so I can come back to the big ones with fresh eyes and perspective. You won’t believe how many errors you find and problems you solve (before something fatal has a chance to happen) that way.
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