TDA1541 DEM reclocking

I use two 74/163 dividers to derive dem from clock signal. Connected dem in CD304 (1 plain 1541) without transformer on pin 16 with coupling cap of 470pF (the "old" PS dem cap) Pin 17 unused. Works fine, nice mod this dem reclock. Little like EC did.
11.2896 Mhz (Kwak 7) is first divided by 4, and then by 16, then you get 176,4 kHz, so within the range the 1541 needs for dem osc. frequency.
 
Andypairo said:
Hi,
in my first post I mentioned that honinbou's schematic was identical to HtP's except for a inverted signal, and I wanted to know which of these circuits does work...

It seems that whatever you put on pin 17 really doesn't matter that much...:xeye:

Opinions from those who built it?

Cheers

Andrea


did honinbou build it?
 
Hoping to hear from someone with direc experience....

As said before i did, the simple way, divider -> coupling cap -> pin 16
I have a project with 4 1541 dacs, on that one i had build ECdesigns dem circuit with the filters ans transformer, but i didn't get any sound out of it. I want to try his D-I dac in time.

But the dem reclock is a mod really worthwile to try, its about the same improvement as when a better clock added (Tent, Kwak 😉 )
It is logically to believe why it is improving sound: the demodulator circuit works with the dem reclock added in the same (divided) pace as the masterclock. When the cap is between pin 16-17 the dem circuit works too but on a more deviating frequency (temperature?) and never exact in line with master clock.
 
Hi,
I've just built a DEM reclock using a 74xx161 as a divider for BCLK, feeding pin 16 via a 470pF cap.
I totally agree with tubee. This is a very good mod to do, and it is like a further veil has been removed from the detail (akin to when you fit a sensible clock module).

Not sure what frequency I'm using for my DEM clock, but assuming Q4 is CLK/16 the frequency is 176.4kHz - which is supposedly in range.

This is such a simple mod to do, took me 30 minutes to knock up a simple little board with the divider on, you should try it if you get the chance.
😀

Cheers,
Phil
 
Hi,

I used 74HCT161, but didn't put much decision making into that choice (might have heard it quoted here and so decided to order the part - I ordered it a few months ago, intending to do this mod sooner).
Seems to work well, even if it was quickly lashed together.

Cheers,
Phil
 
Nice to read about the succeeding Phil of this DEM mod and i'm glad it enhances listening pleasure. The background, also with a proper opamp, is more black with this mod. Want to try an LM4562 bu have to wait until they're available. Have some Black Gate Nx caps to accompany them.
 
Hi Andrea,

Well, I can't say its as good as Henk's, because I haven't tried his, but it is definitely a great improvement.

I can't recommend it enough.

Hi Tubee,
I'm waiting for the 4562 as well. I have some sample orders in the post, but apparently, there on back order so there is a delay. They must be popular.

My IV stage is very basic. I have a LT1361 (50MHz) with some ridiculous 470uF Elna Silmics and some 0.1uF caps as power supply decoupling. I did have just a feedback resistor when using a slower opamp (omitting the 2.2nF capacitor as in the 1541 datasheet) but had to fit the feedback capacitors to stop this opamp oscillating.

Can't wait to swap in the 4562!

Cheers,
Phil
 
Hi, everybody, I have a big problem about DEM reclock, need your help. I had tried this reclock using 176.4MHz into Pin16 via 100p about 4 days ago, in the beginning, it sounds very well, but many hours later, the music gradually disappeared, and terrible noise began. I recheck every pad again and again, and rework again, but of no use. The next day, I turned it(1541A) on, the music had come back, no noise, but not long time , one hour later, music disappeared, terrible noise come back. would you tell me what's the problem?

I had used 74HC4040 and TCXO for BCK, LRCK reclock for many weeks with no problem, so I tried to use the same clock and connected pin5(4040, 4fs) to Pin16 via 100p. but problem happened.(please forgive my poor english)
 
yojiunn said:
Hi, everybody, I have a big problem about DEM reclock, need your help. I had tried this reclock using 176.4MHz into Pin16 via 100p about 4 days ago, in the beginning, it sounds very well, but many hours later, the music gradually disappeared, and terrible noise began. I recheck every pad again and again, and rework again, but of no use. The next day, I turned it(1541A) on, the music had come back, no noise, but not long time , one hour later, music disappeared, terrible noise come back. would you tell me what's the problem?

I had used 74HC4040 and TCXO for BCK, LRCK reclock for many weeks with no problem, so I tried to use the same clock and connected pin5(4040, 4fs) to Pin16 via 100p. but problem happened.(please forgive my poor english)

Probably solder spash btween pin 17 and MSB pin (#18). Been there, done that.