TDA1541A; Tales from the world of make believe…

The TDA1541A in a Marantz CD-94

Could B.J.M. Kup1 ever have suspected that his initial work on the TDA1541 would spark a movement of scammers? Or is it just simple greed of us, that we want to have the “best” TDA1541 that’s available to us? In this article, I am trying to find out more about second-hand items you can buy on the internet, and their backgrounds.

So off we go in our browsers to find this one, magic TDA1541A! It doesn’t matter if we have to buy it on FleaBay, AliExpress, Yoycart, Amazon, or Alibaba. Should we go for that “Taiwan” stamped one, or is an S1/S2 within our reach, and how much are we willing to spend on this ‘exotic’ IC? Today you could spend $600 on a TDA1541A but it doesn’t come with a warranty or certificate. And sometimes even the original box and tubes that were used to ship the TDA1541A are shown in the advertisement so the TDA1541A must be genuine. What strikes me the most is that the companies (read eBay/Amazon) that allow these people to sell these remarked ICs, do not check if the ICs are tampered with or if that their sellers deliver what they advertise. eBay even states: Counterfeit products are illegal and not allowed on eBay -> yeah right!

This item was bought by someone who later added in the comments: the crowns have different paint tone than other markings. Obviously not a real thing. Arrived quickly.

A lot of ICs on sale are ‘refurbished’ or salvaged from old equipment. The original ink is sanded off them, then the IC gets painted and after that remarked. This remarking is done with stamps, but also with laser. Be aware that this so-called ‘laser marking’ can damage the IC. So the only thing that you can do is to buy the IC and check it with acetone if the stamp comes off? The best thing IMHO you can do is to do some research first. The first thing to do when checking an IC is to look at the font style. The font style is very specific to a batch and because it is factory stamped, the font style is always identical. The second thing is to look at is the batch number and date code. The batch number and date code can only be produced within a certain timeframe. So as an example we take an IC with batch number 11113_HSH8910_S1; this IC was produced around the Year 1989 in week 10. We know for a fact that the S1s were shipped to Arcam and Marantz, and that Philips used them in the Q-selection. So now you know what to ask the seller about the origin of the IC he or she is selling. The third thing to look at is the Philips stamp. The lines in the Philips logo have to be separated by some black. If these three lines overlap each other then you are probably looking at a remarked IC. This is the reason why some sellers blur their photographs, or more specific: blur the Philips logo. Last indicator is the price of the IC; On several sites, you can buy a 11264_HBH9718_S2 for $68, and considering the real value of an S2 this IC is ‘probably’ remarked. And always remember: if it sounds to be too good to be true, it probably ain’t.

Clearly visible: Added S2 and Crowns; Color of the ink used is not the same. Photo Credit:

The forgers are also known for following trends. Carlos Candeias supposedly modified some Marantz CDA-94s with a TDA1541A S22. Recently one came up for sale with this IC: 11335_HSH9628_S2. And guess what? Several ICs with the same batch number came on the market as if a mysterious box with Philips ICs just surfaced in the middle of China. If you are interested in buying one, you can buy one in China for $169.34! The ‘mythical S2s’ from TSMC Taiwan never stopped being produced as well. The 11264_RSH9713_S2 was only used by Marantz in the Project D1 DAC and the CD-7. Rumor has it that Marantz only got 2500 S2’s off this batch from TSMC3, which they mainly used in the previously mentioned Project D1 DAC and the CD-7 (production 750 units). It was such a special selected IC, used by Ken Ishiwata that the remainder was sold to Chinese resellers (pun intended).

Two TDA1541A S2s in a Marantz Project D1 Dac. Photo Credit:

But what are you buying? Most of the ICs sold on the WWW by these ‘scammers’ are in some way upgraded to more exotic types by just changing the print on the IC. Or the ‘scammers’ might just add something like an S1/S2 stamp with some crowns: mission accomplished! Regardless of the quality selection that was already done by Philips when they left the plant. So you could end up with a TDA1541 non-A from an old CD-Player, a selected TDA1541A/R1 that was sold to Sony, a genuine ‘printed’ salvaged one? So basically buying a TDA1541a on the aforementioned websites seems like a lottery. I read a story recently about a guy comparing an S1 selection with an S2 selection, and he stated that the old S1 from 1988 sounded better. The only thing he forgot to add to his disappointment was that the S2 could have been remarked. If the S1 was the better ‘chip’, Ken would have used those for his Marantz CD-7!

Signetics NE5534; top fake, bottom real one. Photo by courtesy of:

What is more worrisome is that some people take S1 or S2 selections out of CD players, and put fakes in place to make a double profit. The first example of these practices I saw was in China where S1s were taken out of a Marantz CD-99SE. How do I know? I check every CD-99SE that comes for sale in Japan. Another story that I read recently was about somebody who wanted to buy a Marantz CD-7. The buyer wanted to check the authenticity of the S2s, but every request to check the S2s was denied by the seller. Smells fishy or not? But how can you check if somebody is being dishonest (be careful, sometimes they just don’t know themselves) or is trying to sell you a CD player with a fake IC? Check if the TDA1541a is socketed; this could hint at a fake IC. You can also check the soldering of the IC by removing the bottom plate. Sounds weird? No, the last time I traded a CD player, my CD player was checked thoroughly by the other party!

This seller offers date 9743 or 9744, take your pick!

So it is a pity that Philips never opened up their archives, so we could learn about all the different versions and selections from one of the most famous ICs that was ever made. A lot of what is known about the TDA1541A is parroted by everyone on the internet. This leads to countless assumptions in dozens of fora around the world. All that we are left with are some spec sheets, some scarce stories from Nat. Lab. and some lines of text from Elcoma. It encouraged me to make my database of every TDA1541A that I encounter so that I could see the broader picture of what Philips has produced in all these years. So what selections did I encounter in the last 1,5 years?

Different versions of the TDA1541

[1] After 1984 and under the pressure of the Audio PD B.J.M. Kup in Nijmegen (Elcoma) was allowed to work on the production of the 16-bit converter that the Nat. Lab. had been working on. He was able to integrate both stereo channels into one IC, which reduced the price of the converter part of the CD player. In the same year (1984) the 16-bit converter was completed and given code number N2990.

[2] Input needed.

[3] Input needed.

This page remains under construction. New insights or information can cause adjustments to this page. Do you have interesting information? Let me know!

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