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Old 24th August 2007, 11:57 AM   #21
AndrewT is offline AndrewT  Scotland
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Hi,
I listen to 2sb649/d669 drivers regularly.
They produce a nice sound.
I think they make great drivers.
They have a continuous 25degC 1.5A current rating but are rarely if ever asked to deliver that level of (peak) current when assembled into a power amplifier that is connected to a speaker within it's specified load range.
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Old 24th August 2007, 12:56 PM   #22
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here's an image of the '649a cracked open -- this is the PMC Singapore version, not Hitachi (Renesas)

Click the image to open in full size.
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Old 24th August 2007, 01:52 PM   #23
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jackinnj,
Itīs amazing isn`t it? What can we expect all over? It has probably nothing to do with the original.
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Old 24th August 2007, 02:24 PM   #24
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Quote:
Originally posted by Lumba Ogir
jackinnj,
Itīs amazing isn`t it? What can we expect all over? It has probably nothing to do with the original.
I wouldn't necessarily say that -- my balance is only acurate to about 1 mG and the two devices weight are (out of their plastic shell) are identical even though the PMC unit is shaped a bit differently. (Will have to get my wife to take it to her lab where it can be weighed with much more precision.) The Hitachi case was tougher to crack.

After I do the gardening chores I will do some tests on the devices.
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Old 24th August 2007, 03:21 PM   #25
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Zeljko,
Quote:
And how it look inside, look at that size of silicon chip! (Post #17)
It has to be done that way. There is a large plate allowing proper attachment to heat sink.
It is not case with the other packages and again, Hitachi`s specifications imply only TO-126.

Andrew,
I actually meant those others. You can not have missed my opinion on Hitachi.
I am sorry for the misunderstanding.
Kindly regards
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Old 24th August 2007, 11:59 PM   #26
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When in doubt why not use MJE340 and MJE350?
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Old 25th August 2007, 12:26 AM   #27
bawang is offline bawang  Malaysia
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Burnedfingers, I asked this to myself a while back the MJE340/350 is only rated for 500mA output vs 1.5A for the Hitachi devices. Greater drive to the final output devices.......
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Old 25th August 2007, 07:37 AM   #28
AndrewT is offline AndrewT  Scotland
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Quote:
Originally posted by bawang
Burnedfingers, I asked this to myself a while back the MJE340/350 is only rated for 500mA output vs 1.5A for the Hitachi devices. Greater drive to the final output devices.......
the maximum current rating is irrelevant to the ability to drive the output stage.
The driver SOA sets the limit for ability to drive the outputs when the outputs are driving a reactive load.
The MJE is surprisingly good at this due to the knee in the SOA ocurring at a very high voltage. This comes from the high Vce0 and it's intended use at high Vce.

From memory the MJE matches the 649/669 at about 70Vce and outperforms it above that.
The 649/669 is better than most other similar drivers between 50Vce and 70Vce.
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Old 26th August 2007, 12:28 PM   #29
Zeljko is offline Zeljko  Croatia
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I still don't know do I need send back those transistors to seller or not??
Did you anyone see that type 2SB649/2SD669 before, or do you know someone who knows make the judgment do they fake or not? Please help me what I need to do!

Thanks!

Regards!
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Old 26th August 2007, 12:55 PM   #30
AndrewT is offline AndrewT  Scotland
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Hi,
mine are PMC and look similar to post22.
the backplate is a 6mm square centred around the mounting hole and then a smaller 3mm square extended down to hold the chip.

The only failures I have had were my fault, swapped NPN & PNP in one assembly, slipped test probes in another couple.

If you want a refund, you may have to prove they are fake.
Being unsure is probably not enough, unless your retailer really wants your future custom.
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