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2SB649A real and equivalents?
2SB649A real and equivalents?
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Old 23rd August 2019, 04:16 PM   #1
merly is offline merly  United Kingdom
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Default 2SB649A real and equivalents?

Why do transistors seem to come and go so quickly? Is there really a need for manufacturers to change them and retire them so quickly?

I need a 2SB649A. I understand that virtually all of these on ebay etc are fake and I can't find one at RS or Farnell or Mouser etc (I live in the UK). I have seen people glow all warm and bubbly about Cricklewood Electronics. First they told me they had real ones from Hitachi. Then when I questioned them on how they could be new when they hadn't been made for a decade they told me they cannot guarantee their 2SB649A's are real. All they could say is they had not recieved any complaints. Say no more. No sale. Now the NTE374 looks like an exact copy, but again problems.. Farnell and RS make this a special item whereby you have to pay an extra 10-16 even if you only want 1.You can get the odd NTE374 on ebay but are NTE's faked?

This is for my NAD C370 that has bit the dust. And I am a newbie to diy and repair, though I have an engineering degree so I should pick up things quickly. Though I expect what will actually happen is no-one will respond to this post. Cos I aint cool and flashy and making my own amps.. yet

Last edited by merly; 23rd August 2019 at 06:20 PM.
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Old 23rd August 2019, 05:14 PM   #2
Enzo is offline Enzo  United States
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Quote:
Though I expect what will actually happen is no-one will respond to this post. Cos I aint cool and flashy and making my own amps.. yet
Just a tip: saying that sort of thing won't increase responses.

I don't know how quickly that particular part came and went, but transistors are amazingly flexible, you should be able to find a good sub for it by meeting its basic specs.
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Old 23rd August 2019, 05:42 PM   #3
merly is offline merly  United Kingdom
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Originally Posted by Enzo View Post
Just a tip: saying that sort of thing won't increase responses.

I don't know how quickly that particular part came and went, but transistors are amazingly flexible, you should be able to find a good sub for it by meeting its basic specs.

Am I right in thinking that on the power channel output side all trannies should be matched? But elsewhere say in the pre-power circuit equivalents will do and matching not quite so important....?
Are the NTE on ebay likely to be faked? Are fakers faking NTE?
Why is it so hard to get real parts? It's madness.

Last edited by merly; 23rd August 2019 at 06:02 PM.
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Old 23rd August 2019, 06:10 PM   #4
mlloyd1 is offline mlloyd1  United States
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2SB649A real and equivalents?
Another reason you know they were lying is those parts were made by Hitachi, not Toshiba.

mlloyd1
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Old 23rd August 2019, 06:13 PM   #5
Vovk Z is offline Vovk Z  Ukraine
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2SB649A real and equivalents?
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Originally Posted by merly View Post
Am I right in thinking that on the power channel output side all trannies should be matched?
Usually not. Matching transistors show bad design (or High-End, that is the same ) (except for some special exceptions). You just have to check that they mutch some of their characteristics.
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Old 23rd August 2019, 06:20 PM   #6
merly is offline merly  United Kingdom
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Originally Posted by mlloyd1 View Post
Another reason you know they were lying is those parts were made by Hitachi, not Toshiba.

mlloyd1

Oops my bad, I meant Hitachi. Either way, they couldn't guarantee they were real. So they must be fake.

I wouldn't mind fake if it meant they had faked the characteristics and spec. I'm amazed at the shear scale of fakes out there. Virtually every semiconductor on ebay etc and from small shops is fake. Also upsetting is a lot of service technicians use these fake parts in repairs.

Last edited by merly; 23rd August 2019 at 06:27 PM.
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Old 23rd August 2019, 07:23 PM   #7
jackinnj is offline jackinnj  United States
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2SB649A real and equivalents?
How many do you need and where are you located -- just pm me.
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Old 23rd August 2019, 10:43 PM   #8
Enzo is offline Enzo  United States
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MAtching not usually needed, the circuit tends to balance them out, but they do all need to be the same type. In other words don't mix Motorola, Toshiba, and NTE all on one side of an output stage. As to drivers and other smaller ones, they work singly, so there is nothing to match them to.
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Old 29th August 2019, 09:23 PM   #9
Mark Tillotson is offline Mark Tillotson
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Originally Posted by merly View Post
Why do transistors seem to come and go so quickly? Is there really a need for manufacturers to change them and retire them so quickly?
Cost - noone buys them in quantity, then you are losing money hand over fist keeping the production schedule active. These days the volume is in class-D amps, so linear stuff sells in way way less volume, the market consolidates to fewer popular transistors, plus some specialist semiconductor firms doing small runs.
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Farnell and RS make this a special item whereby you have to pay an extra 10-16 even if you only want 1
That's usually because its in the US, not the UK, so you pay for the airmail/customs handling - the charge is per order not per part.
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Old 30th August 2019, 03:01 AM   #10
wg_ski is offline wg_ski  United States
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What you will probably end up doing is using a KSA1220. (And C2690 for the NPN). At least Mouser has them back in stock now.
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