TDA1541A for ReVox B226

[David@NY]

Hi,

I have a ReVox B226 and recently acquired some TDA1541A/S2. I noticed TDA1541 and TDA1541A differ slightly in that TDA1541A uses external ocillator. I'd like to replace the TDA1541 on board with the TDA1541A. However being a novice diyer I have no idea if that would bring any negative electrical consequences.

I've searched the board but couldn't find any concrete answer. Can anyone shed some light on this?

Thanks a bunch,
David

 

[TDA1540]

the capacitor between pins 16 and 17 is there IIRC

haven't you got the manual yet?

http://www.schori.info/

 

[David@NY]

Hi TDA1540,
I have to check the board to see if there is anything connecting pin 16 and 17. If not, does that mean I need to put a IIRC capacitor (correct term?) between pin 16 and 17? If so what kind?

I just downloaded the manual from the site you posted. What am I suppose to do with it?

Thanks,
David

 

[Fin]

For further details please mail a TDA1541A/S2 to:..............


Obtain the datasheets for TDA1541 and TDA1541A:-

TDA1541 Datasheet

TDA1541A Datasheet

Then compare what should be connected to each pin - you will notice that TDA1541 has "n.c." (not connected) beside pins 16 and 17. TDA1541A requires a 470pF capacitor connected between pins 16 and 17.

Then you need to look in the manual for your player - as suggested above - and see if the capacitor is there. Also check inside the player to make sure it is there. If the capacitor is there (which it should be - as suggested above), you can just remove the TDA1541 and replace it with the TDA1541A/S2.

 

[Fin]

BTW - if you plan to do other mods to this CDP, maybe you should leave the TDA1541 in place for now - then replace it with the TDA1541AS2 when you are finished. Also remember to work ESD safe.

 

[David@NY]

Hi fin,
I'll check my player tonight and make sure there's a 470pF capacitor installed.

I did noticed that pin 16 and 17 on TDA1541A requires oscillator connected to them. But where/how do you know the oscillator required is a 470pF capacitor?

Thanks,
David

 

[Fin]

Hi Dave

If you look at the block diagram for TDA1541 on page 3 of the datasheet - you will see that the oscillator is internal and that the capacitor is also shown to be internal.

The block diagram for TDA1541A on page 3 of its datasheet shows the internal oscillator, but the capacitor is external.

This means that some older 1541 machines might be expected to have no external capacitor. However, most of them seem to have the external capacitor and there is some debate about the actual existace of the internal capacitor in the 1541. OTOH, it could mean that Philips knew of the pending arrival of the A version of the chip and specified the inclusion of the external capacitor to facilitate future upgrades.

The 470pF capacitor is specified in the datasheet.

 

[David@NY]

Hi Fin,
Ah I see the 470 pF. I was doing a search in the PDF and didn't find anything. It's actually in the diagram that can't be searched. Doh!

 

[David@NY]

Just to let you guys know that I've replaced the stock TDA1541 with TDA1541A/S2. The difference in the sound is night and day. The sound is very solid from top to bottom with added thickness. The only gripe I have right now is that it's a bit "stiff". Maybe it'll smooth itself out after some run-in. I'd recommend whoever's running TDA1541/A try the S2. IMO the change is worth the price.

Now I'm thinking changing the hook up wire from AC socket to the PCB. Any recommendations?

 

[Fin]

Is the sound still "stiff"? Has it changed at all in the last few days?

 

[David@NY]

The sound is still "stiff" (tight if you will) but I think it has loosen up a tiny bit. It maybe just my hallucination.

The details of the sound has been improving -- I'm hearing more details every hour.

 

[David@NY]

After a couple of days listening (~20 - 30 hours) the sound has refined a bit. The sound changed from stiff to tight to firm. Now it seems to have stablized some what. The amount of details and macro-dynamics still amazes me. Now I feel like I'm listening more to the music than sound than before.