Fetishizator for tda1543

[Gregje]

Hi,

I am (again) a newbe at this forum (used to be here some time ago, but then got 2 kids so my account has been kicked out).

Anyway, recently I wanted try to cook up some analog stage for a cd player.
First I played with an idea of building a tube stage (inspired by Lukasz Fikus Lampizator), but I have found at the same webpage a nice SS project which Lukasz calls Fetishizator. As I still shy from tubes (I´ve built myself a clone of triode ZEN, but thats it) I have decided to give this JFet project a go.

Not wanting to canibalize my Musical Fidelity CDP I got myself a cheapie Sony CDP190 which happens to have TDA1543 on board.
I soldered the circuit by Dietmar presented at Lampizator web page.

As I accomodated it to tda1543 I changed some of the resistors. The I/V resistor is 940 (470+470 and I feed the Gate of JFet frm the middle point, which gives 1.4V at the gate of bf254c (I use c!)). The source resistor is 3k9. The drain voltage is nicely half way between the supply voltages (which is 15V)
Finally, the Vref resitor for TDA1543 is 1k (the DAC chip in Sony is powered with 5V).

I can't really see what is wrong with this setup.
It does not clip. It is probably better than the original Sony (ok I did not bother to listen to it to start with). It is actually pretty good, but not really involving. The biggest problem is that the sound is a little bit thin (My Musical Fidelity (E60 I believe) is much better)
I would say it misses the body. Thought might be lack of bass, but if bass is there on a CD it is also on the output.
The only possibility I see now (which I haven´t tried yet) is to improve the power supply: bigger trafo and caps.

To be honest I am dissappointed as all my diy projects so far (Pass ZEN, Bride of ZEN, triode ZEN, JLH RIAA preamp, some TWQL single driver speakers) proved to be way better that anything I bought ready made from a HiFI store.

Do you think the lousy Sony is too lousy to squize anything decent from it?
Or have I messed up anything?

I will be happy for any suggestions.

Greg

[juma]

This Fet-ishizator circuit can not be taken seriously - the 92* resistor is actually doing the I/V conversion and BF245 is used as the (unskillfully designed) simple voltage amplifier.
Since you've yielded to exaggeratedly positive description of that poor circuit and built it, it's obvious that you need to invest some time in getting better acquainted with the concept in general - do it, it will pay of
There are many useful threads here (look in the "Digital Sources" section) and "search" button will be a great help

[Gregje]

Hi Juma,

Any particular thread you suggest?
Do you suggest I should not be doing passive IV conversion?

To be honest I like Lukasz philosophy so I trusted what he wrote about the Fetishizator.
Are you suggesting there is no way to save this project?

Anyway, if I were aware about the NP D1 when I started the other project I would have soldered the D1.

Greg

[juma]

It's easy enough to make a D1 and compare it to Fetishizator. You'll have far better I/V conv. and you'll learn something building it.
And there are circuits that perform better than D1 (D1 was made for specific DAC IC but can be used for many).
Spoon-feeding won't take you far, put some effort into learning process and you'll be able to build the circuit that suits your taste the best, and the more you learn, the more you'll be disenchanted by "Lukasz philosophy"

Tip: a few years ago a fellow member (rbroer) built a couple of really great I/V converters for TDA1543 and presented them here.

[Skorpio]

One thing puzzels me about this Lampizator thing. How does he get sound from a TDA 1543 dac without a I/V resistor?

AHDAC

[SY]

Skorpio, thanks for the link- the photos are priceless.

[Gregje]

Hi,

I did a few experiments recently.
I have transplanted the Fetishizator from the Sony CDP to a vintage Philips cd460 with TDA1541. I am pretty pleased with the result now. I do not think the difference I am hearing comes from a different dac chip. I guess it comes from a better power supply which I am applying now (and also a slightly higher voltage). I tried NE5532 and OPA2134 before going for the Fetishizator but the results were better with the the last one.