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Old 26th April 2004, 06:49 PM   #21
HtP is offline HtP  Netherlands
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Quote:
Originally posted by jean-paul
A development sample from 1997 !? SAA7321 and/or SAA7350 ( or others, forgot the count with 1 bit chips really ) were in development then, isn't it ?

If I look at the pictures in post #1 and post #2 I see they are marked exactly the same except for the datecode which is 10 years later and the A, hence my suspicion about the datecode and genuinity. Also font and ink seems different. The same chip in post #2 in the lower right corner, what about that one ? Is that a development sample from 1987 then ? ( I suppose the 4182 code says it all ).
As far as I know, the last developement of the TDA1541A was the TDA1541A version N3X which was never released. A pitty because it was the best one I have seen. Batch number was 7784 with week number 8714. Therefore I agree with Jean-Paul about the error in the weeknumber. The Philips logo was added about that time and the print style changed. I have TDA1541 with weeknumber 8631 without logo which is without any doubt a Philips part. The logo was added because of copyright issues. Also on the ic masks, a logo was added.

Question to Bernhard: why are you so sure that is must be fake?

regards,
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Old 26th April 2004, 08:09 PM   #22
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Quote:
Originally posted by HtP
Question to Bernhard: why are you so sure that is must be fake?
Henk,

I was just kidding, note the in my post, because Jean-Paul likes to suspect fakes

But now as you ask...

I have 1541 with 3944 batch and 8718 date code.
Also I have 1541A with 10795 batch and 8801 date code.
This chip is 4184 batch and 9727 date code, so could be 8727 date code and printing error.

But all my 1541 including S1 have 5Y beside date code while my 1541 A has 2Y and my 1541A S1 without silvercrown from CD880 and S1 silvercrown bought in shop have 2 without Y.

But this chip got 5Y and pretends to be an A.

Also all my 1541A have Philips logo.

Is it a new perception that 1541A S1 have no Y ?

So if there is the Y, it is a fake ???



Question to you as you seem to be an expert:

What you think about using passive I/V conversion with floating ground for the TDA, driven by the TDA's output voltage, buffered with opamp ???
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Old 26th April 2004, 09:08 PM   #23
HtP is offline HtP  Netherlands
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Quote:
Originally posted by Bernhard


Henk,

I was just kidding, note the in my post, because Jean-Paul likes to suspect fakes

But now as you ask...

I have 1541 with 3944 batch and 8718 date code.
Also I have 1541A with 10795 batch and 8801 date code.
This chip is 4184 batch and 9727 date code, so could be 8727 date code and printing error.

But all my 1541 including S1 have 5Y beside date code while my 1541 A has 2Y and my 1541A S1 without silvercrown from CD880 and S1 silvercrown bought in shop have 2 without Y.

But this chip got 5Y and pretends to be an A.

Also all my 1541A have Philips logo.

Is it a new perception that 1541A S1 have no Y ?

So if there is the Y, it is a fake ???



Question to you as you seem to be an expert:

What you think about using passive I/V conversion with floating ground for the TDA, driven by the TDA's output voltage, buffered with opamp ???
Data sheets for released parts were printed on white paper. Data sheets for development parts were initially printed on yellow paper, later on white also. The Y indicates that it was a development part. I do not know if it is still used that way but certainly the Y does not indicate that it is fake.

Aswer to your question:

1. It is active I/V conversion, not passive conversion.

2. At the analog output very difficult, at least more difficult than normal active I/V conversion.

3. It will introduce signal dependent delay for the digital data, including the BCK. This will give frequency modulation to the spectrum. How much depends on the rise time of the digital signal, and the amplitude of the analog signal.

4. It will sound very interesting but I do not think that you will like it.

regards,
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Old 26th April 2004, 10:15 PM   #24
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Quote:
Originally posted by Bernhard


I was just kidding, note the in my post, because Jean-Paul likes to suspect fakes

Ahum, I said remarked with which Henk seems to agree. Just as suspicious as the markings on the S1's you showed ( especially after the explanation of HtP ).

Bernhard, it is economically not interesting to produce fakes so you won't likely find such chips. Remarking gives profit without much costs. They are around these days driven by the hype/facts about TDA1541A.
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Old 26th April 2004, 11:11 PM   #25
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Quote:
Originally posted by jean-paul
Just as suspicious as the markings on the S1's you showed ( especially after the explanation of HtP ).
My S1 ???

What you think is suspicious ?
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Old 27th April 2004, 12:56 AM   #26
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Perhaps someone could shed some light on the background to this fake/not fake saga and where this thread in general is heading.
Are you i.e. the accusers suggesting there is some kind of backdoor operation going at TSMC after hours or perhaps some questionable east European types are breaking into the Infineon or Atmel fabs at the weekend and knocking off a few TDA1541AS1's? Afterall, semiconductor fabrication plants are not the sort of thing to be found in a hobbyist's garage.

ray.
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Old 27th April 2004, 07:07 AM   #27
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Some people remark old but NOS TDA1541 chips with the marking TDA1541A-S1 to gain higher profits ( TDA1541 = 3 to 6 euro, TDA1541A-S1 = 40 to 50 euro ). Not such a strange phenomenon when you think of rebranded 2SA1302, rebranded Intel & AMD CPU's and others.

A bit like the chip in post #1.
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Old 27th April 2004, 07:32 AM   #28
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Quote:
Originally posted by jean-paul
Some people remark old but NOS TDA1541 chips with the marking TDA1541A-S1 to gain higher profits
My chips come from Philips Eindhoven, I don't know where your chips come from
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Old 27th April 2004, 07:35 AM   #29
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You can have whatever branding you want on chips you buy from me

Y marking costs 50 cents extra.
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Old 27th April 2004, 09:57 AM   #30
gio_b is offline gio_b  Italy
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Unhappy tda1541 to 1541a

i have a cd 960 philips with a tda1541 non philps.can i replace it with a good philips tda1541A?does it plays better???
and more....
in 960 there are 4 op 5534d jrc 6216 for analog signal,can i replace with other equivalent...opa627 ad860 ad826 are good??
ciao ciao
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