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.
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.
here's an image of the '649a cracked open -- this is the PMC Singapore version, not Hitachi (Renesas)
An externally hosted image should be here but it was not working when we last tested it.
Lumba Ogir said:
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.
Zeljko,
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
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
the maximum current rating is irrelevant to the ability to drive the output stage.bawang said:
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.
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.
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.
There are copies, and there are counterfeits. The copies may well be reasonable substitutes for the originals; the counterfeits may be entirely unusable.
I've examined and noted the differences between an original Hitachi B649 and a few possibly copied D669As - the most obvious is the shape of the metal heatsink tab at the back. The front of the copied 669As look similar to the pictures at the beginning of this thread. The original Hitachi always has 3 'rays' around the mounting hole and a very clean-cut outline of the metal tab at the back, the copies occasionally have no rays and the metal tab outline is rough. Incidentally, some of the possible copies came from a sealed pack with the Hitachi logo and the text Taiwan at the bottom - these have 3 rays like the original Hitachi.
The DC beta on most of the probable 669A copies measures around 140-170, which is a tad higher than the tight cluster around 140 or so for the real Hitachi B649. This is probably not conclusive, because of normal NPN/PNP variations, process variations, binning, batches, etc.
However, if the beta is clustered higher than 200, it warrants careful examination. I have one very different-looking D669A outlier with a beta of 360 or so - this has a mounting hole with no 'ray' at all, and a very rough finish on the leads. This is most probably a counterfeit - a small-signal transistor masquerading as a D669A.
I've examined and noted the differences between an original Hitachi B649 and a few possibly copied D669As - the most obvious is the shape of the metal heatsink tab at the back. The front of the copied 669As look similar to the pictures at the beginning of this thread. The original Hitachi always has 3 'rays' around the mounting hole and a very clean-cut outline of the metal tab at the back, the copies occasionally have no rays and the metal tab outline is rough. Incidentally, some of the possible copies came from a sealed pack with the Hitachi logo and the text Taiwan at the bottom - these have 3 rays like the original Hitachi.
The DC beta on most of the probable 669A copies measures around 140-170, which is a tad higher than the tight cluster around 140 or so for the real Hitachi B649. This is probably not conclusive, because of normal NPN/PNP variations, process variations, binning, batches, etc.
However, if the beta is clustered higher than 200, it warrants careful examination. I have one very different-looking D669A outlier with a beta of 360 or so - this has a mounting hole with no 'ray' at all, and a very rough finish on the leads. This is most probably a counterfeit - a small-signal transistor masquerading as a D669A.
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