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-   -   tda1541a sound signature (http://www.diyaudio.com/forums/digital-line-level/190444-tda1541a-sound-signature.html)

Marcelinho 7th June 2011 11:20 PM

tda1541a sound signature
 
I have a Marantz cd-80 with the tda1541a-s1. I was always very impressed by the deep and good bass.
In comparison with newer players f.i. a multiplayer denon the upper midrange ( bells and cymbels are sounding rather dull;
If it were an instrument you would think it is tuned down a half note or more. It also seems like the upper frequencies are overpowered by the lower.
Maybe these are three ways to describe the same problem.
Inspired by the success stories of the tda1541 goeroes i decided to do some upgrades to this machine.
So far i did:
Replaced many but not all ps-elco's as they are 20 years old
New low jitter clock for 3 chip's
resistors in i2s lines
separate regulator and ground for 7220 dig. filter
replace i/v opamp for opa627
disable spdif
disable variable output
new mains connector
schottky diodes for the dac and analog output.
poor man's dem-reclocking by changing the capacitor to match a multiple of Fs-freq

The above mentioned mod's combined did improve the sound, but the problem described has not changed. It actualy starts to annoy me as i believe some instruments sound incorrect.

As i never see negative comments about this DAC...Can anybody confirm this to be a problem of the DAC or it's implementation?
What to do to improve on this specific issue.

new2hifi 8th June 2011 03:47 AM

I have a TDA1541 based Satch DAC (Diy HiFi Supply) with tube output. I liked it better than Mark Levinson 360S on the type of music I listen too, vocals.

However, Levinson 360S has extreme low noise floor and everything used to come from BLACK background. It is Levinson after all and 24bit DAC. There are many areas where it beats Satch but I wanted to experiment.

I started on this route when I heard TDA1541 based AMR CD-77. Wow! Wow again :D. This is the first time ever in my life the timber of acoustic guitar was true. It was as analog as vinyl record. In this regard AMR was better than super duper dCS gear that I also heard. dCS was less organic.

However, Satch DAC proved that just having the TDA1541 chip inside is not everything. There is much more to a DAC. Satch is not CD-77. Perhaps this is what you are also experiencing :rolleyes:.

Regards

jazz 8th June 2011 03:55 PM

Hi,

Have you tried going nos (I don't advocate either os or nos). Another big influence would be the iv stage as hinted by New2hifi. Maybe you could experiment with the recent I/V stage from mr Pass? It's very good...

regards,
Joris

Marcelinho 8th June 2011 05:06 PM

I didnt go nos as i want the changes to be reversable.
Any I/V stages without coupling cap's? or where i can re-use the already present dc-servo.

new2hifi 8th June 2011 06:55 PM

AMR CD-77 and Satch DAC, both are non-over sampling (NOS) and no digital filter. CD-77 actually gives many options but when I heard it was NOS with no filter. Not sure about CD-77 but I/V in Satch is passive via a resistor then the tube output.

I think CD-77 wins because of low jitter from CD drive to DAC, better digital design, better power supplies (tube rectification, cokes), better dual mono analog construction. Yes! I was impressed and sold but i am waiting for a DAC from AMR as CD player is out of my room for a long long time. It is not digital age of 80s but it is server age of 2011.

SoNic_real_one 9th June 2011 01:44 PM

I have a Philips Cd player with TDA1541, two universal players by Denon, one by Toshiba, one by Apex... Replaced all the opamps with better ones.

I like better the sound of the newer TI DAC's (PCM series) than the sound of old Philips TDA. The TDA in "NOS mode" sounded even worse to me.

Marcelinho 9th June 2011 02:04 PM

Hadn't much luck with changing the opamp's. The differences where to little for my shortterm soundmemory. Next time a do a swap, I try a left -right comparison.
Removing or changing the output-cap realy makes a difference (for the better)

As the sound differences are huge in all aspect's of the mentioned machines, The question is not what sounds good, but wat is a correct representation of the truth (disc-content).
Maybe a comparison with a good analog recording?

SoNic_real_one 9th June 2011 03:21 PM

I did a swap of just one channel OpAmp in one of my Denon that had dedicated dual OpAmps per channel. On Philips CD, there is just one dual opamp for both channels so yes, it is hard on short-term memory.

jazz 9th June 2011 05:57 PM

Hi,

I thought there was no dc servo and the cd80 uses a 220uF (c32) cap at the output anyway? Then again I don't care about caps in the signal path.

I do believe there are some circuits without a coupling cap around but you'd have to search yourself. Pedja Rogic also did some nice circuits around the 1541.

regards,
Joris

danico 9th June 2011 06:54 PM

1 Attachment(s)
Try to bias the opamp into "class A ".
I use the opa627 just like you do. Put a 2k resistor on pin1 and pin4 (output and -15v).

Its will clear up the highs and mids (vocals will be more smooth and airy) bass get tighter and instruments get more dynamic and focused.

You might not like the result fisrt,I didn't, but after a couple days
I got used to it.

Try to do a proper DEM clock circuit. I use it on only pin16 connected and works well.
In NOS BCK will be 2,8224Mhz 1N5711 in series with 12 to 15K resistor to pin16
then 2K2 resistor to -15V.
In NO-NOS you can use WS signal is 176Khz.

Check ecdesigns treat about DEM clock, or I send it to you if you interested.

Quote:

Originally Posted by Marcelinho (Post 2598164)
I have a Marantz cd-80 with the tda1541a-s1. I was always very impressed by the deep and good bass.
In comparison with newer players f.i. a multiplayer denon the upper midrange ( bells and cymbels are sounding rather dull;
If it were an instrument you would think it is tuned down a half note or more. It also seems like the upper frequencies are overpowered by the lower.
Maybe these are three ways to describe the same problem.
Inspired by the success stories of the tda1541 goeroes i decided to do some upgrades to this machine.
So far i did:
Replaced many but not all ps-elco\'s as they are 20 years old
New low jitter clock for 3 chip\'s
resistors in i2s lines
separate regulator and ground for 7220 dig. filter
replace i/v opamp for opa627
disable spdif
disable variable output
new mains connector
schottky diodes for the dac and analog output.
poor man\'s dem-reclocking by changing the capacitor to match a multiple of Fs-freq

The above mentioned mod\'s combined did improve the sound, but the problem described has not changed. It actualy starts to annoy me as i believe some instruments sound incorrect.

As i never see negative comments about this DAC...Can anybody confirm this to be a problem of the DAC or it\'s implementation?
What to do to improve on this specific issue.



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