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"Reference" TDA1541A DAC with I2S-BUS architecture

Surface Finish for future PCB´s

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In my system i don´t use the bypass caps, because my Fairchild Stealth Diodes have a extreme soft recovery and don´t produce much HF noise.
Also we have the shunt reg´s. in the lines.

I think you should try it by yourself in your system with and without the 0,1µF caps.
Perhaps you could post your experiences.
 
In my system i don´t use the bypass caps, because my Fairchild Stealth Diodes have a extreme soft recovery and don´t produce much HF noise.
Also we have the shunt reg´s. in the lines.

I think you should try it by yourself in your system with and without the 0,1µF caps.
Perhaps you could post your experiences.

Yes I will. Since I'm using DSEP-12A I guess it can be omitted.
 
Oliver,

Could you explain the use of TL431ACLP for me please. I see that the Salas reg boards you sell, are described as "pre" shunt regulators, implying that the real regulation goes on at the TLA1541A board, and the TL431ACLP suggests this too, but I don't understand it.

Could you clarify for me please, especially as I am hoping to use Hypnotise Blue Edition boards for this build, and I want to get it right.

Many thanks
Lucas
 
OK, so for a single non-paralleled DAC, I should probably skip them and get lower jitter. Then if I decide to add another chip, I can introduce some TL431s.

I'm not entirely convinced of the idea of paralleling chips, even though some of the top CD players have done this, and Thorsten seems to be unconvinced too. Lukas of Lampizator is a fan though, so who knows? I'll try a single chip - it's certainly cheaper!
 
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Sorry, I was referring to what Salas said at the foot of the page about the comparison between the Salas and the TL431.

I erroneously used the word "jitter" in place of "noise" as I was distracted by the noise of my 4 year old hassling me at the time.

When it comes to shunt regs, I do trust Salas' advice as he has devoted such a considerable amount of effort on developing them, and they are highly celebrated, so I think I will skip the TL431, and any associated shunt-reg parts after the Salas. With a bank of smoothing caps the Salas alone should be superior to any supply in any commercial TDA1541A CD player, no?
 
Hi Oliver,

The boards arrived just now. Many thanks. They are b-e-a-utiful!

I think I have worked out where to connect the Salas shunt regs directly, omitting TL431As. Could you take a look at the attachment and see if I've made any boobs.

I am unsure how to connect TLA1541A pins 16, 17 (oscillator), as they were linked to the reference pin of the -15v TL431 shunt reg previously. Should they be left as open (unconnected) pins for my project, or what?

Also, what value resistors do you recommend for the Tube-I-zator if using with 6N2P tubes?
Many many thanks.

Lucas

tda1541_sans_TL431A.jpg
[/url][/IMG]
 
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Hi Lucas,

you made no boobs! :p

Go with the output of Salas shunts directly to the mid pin of the TL431A (anode) hole.

Please make no changes to the Pin 16 & 17 and let them connected to the 2K2 resistors.
These are connected to the anode of the 431A, not the ref.

For the Tube-I-zator with 6N2P please use 4x 200R´s for Rk and 56R for the I/V position with one TDA1541A.
Pay attention to the quality of the two R I/V´s! I would recommend the following resistors:

- PRP 9372
- Caddock MK132
- Texas Components TX2575 naked Z-Bulk foil (Vishay VAR)

If you use the optimum, it should look like here.

Best regards,
Oliver
 
Hi Lucas,

you made no boobs! :p

How did I manage that?

Go with the output of Salas shunts directly to the mid pin of the TL431A (anode) hole.

I will wire to the terminals of the TL431A, but surely not to the centre pin in every case. I observe that the negative voltages are, logically, powered from the anode (centre pin), but the positive voltages are powered from the cathode (left pin), with GND going to the remaining electrode, and refs (right pin) are all left open in this case as the Salas has it's own references.

Am I wrong?

Please make no changes to the Pin 16 & 17 and let them connected to the 2K2 resistors.
These are connected to the anode of the 431A, not the ref.

OK, so they are connected to the -15v through 2k2 resistors, and a complicated arrangement involving another ref resistor and two cap connections en-route. I will of course keep the 2x 2k2 resistors, and it will then connect to the -15v, but I was intending not to include any of the rest of that shunt reg circuitry, including the 4x Os-cons etc. Is that right?

For the Tube-I-zator with 6N2P please use 4x 200R´s for Rk and 56R for the I/V position with one TDA1541A.
Pay attention to the quality of the two R I/V´s! I would recommend the following resistors:

- PRP 9372
- Caddock MK132
- Texas Components TX2575 naked Z-Bulk foil (Vishay VAR)

Great! Thanks for that. Have you tried 6N2P? Lukas Fikus seems to be very keen on it.

I will be using PRP 1/4, 1/2 & 1 watt throughout, in every position, and Panasonic metal film 1% 5watt for all of the larger resistors, instead of Kiwame, as I know and trust them a lot.

I would buy the Texas Components resistors for critical positions if they were about 1/4 of the price. It will be PRP in critical positions in my DAC - I think they're really good, and also cheap! :)

If you use the optimum, it should look like here.

I am going to go with Auricap 2.2uF output caps as in the BOM, as Parts Express has them at half price at the moment. Did you try them already? Are they really awful, or are you just itchy to change caps a lot?

All the best
Lucas
 
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I will wire to the terminals of the TL431A, but surely not to the centre pin in every case. I observe that the negative voltages are, logically, powered from the anode (centre pin), but the positive voltages are powered from the cathode (left pin), with GND going to the remaining electrode, and refs (right pin) are all left open in this case as the Salas has it's own references.

Am I wrong?

Absolute correct!

OK, so they are connected to the -15v through 2k2 resistors, and a complicated arrangement involving another ref resistor and two cap connections en-route. I will of course keep the 2x 2k2 resistors, and it will then connect to the -15v, but I was intending not to include any of the rest of that shunt reg circuitry, including the 4x Os-cons etc. Is that right?

For that what you would like to do, cancel all parts in the orange field excluding the two 2K2 resistors.

An externally hosted image should be here but it was not working when we last tested it.

Great!

Thanks for that. Have you tried 6N2P? Lukas Fikus seems to be very keen on it.

I will be using PRP 1/4, 1/2 & 1 watt throughout, in every position, and Panasonic metal film 1% 5watt for all of the larger resistors, instead of Kiwame, as I know and trust them a lot.

I would buy the Texas Components resistors for critical positions if they were about 1/4 of the price. It will be PRP in critical positions in my DAC - I think they're really good, and also cheap!

The 6N2P are wonderful!! Please try to get the "-ER" version of them. That´s the hi-durable - long life version of it and sounds much better than the normal ones.

The PRP´s are absolute ok but for $4.50 each i would use the MK-132 in the I/V position.

I am going to go with Auricap 2.2uF output caps as in the BOM, as Parts Express has them at half price at the moment. Did you try them already? Are they really awful, or are you just itchy to change caps a lot?

The Auricap´s are neutral sounding caps and good for their price.
Surely there are better sounding caps on the planet, but how much would you like to spend for them?
It´s up to you. ;) At the moment i am using a pair of russian 1,5µF K75-10 hybrid bypassed by russian 0,047µF K-72P-6 teflon caps.
This combination is sounding so good, that i don´t think i change again.

:cheers:
 
All great answers. Many thanks. I already bought the EV version of the tubes. How did you discover the difference between them? Did Lukas Fikus state a preference, or is this from listening tests or what?

For resistors, I will start with PRPs throughout as I think they are much better than their price suggests. I'm not a big fan of the MK132, although I have some in my power amp. Anyway, PRPs are in the signal path of my whole pre-amp, so it makes sense.

I have always had the philosophy not to bother with really pricey boutique parts. If it's more than twice the price of a high quality standard part, it had better offer something pretty miraculous, but that is almost never possible - that last 1% of perfection is pretty hard to hear, and very subjective - I prefer to focus on the 99% of the sound that is made up of the design and component values, like trying different value decoupling caps for the 1541 or trying new tubes, like you said earlier. Lukas Fikus seems to have noticed the biggest differences from these kind of changes, in his extensive experience with this circuit.

That said, I'll go with the Auricap. ;)

Thanks for all the support Oliver. You are a scholar and a gentleman, as we say in England (or used to a long time ago.)

:)
 
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