Which DACs are interesting for modest DIYs running 16bit/48khz?

[Hayk]

I wonder if there are DIYs who would like the TDA1540 14 bit DAC. I can make the sign bit seperate and obtain 15 bit DAC. The signal to noise ratio is 85db, so the 16th bit is useless and the noise will self dither the truncating.
It is fast enough to be driven by the src at 96khz.
On Taobao it costs $10+$2 shipment.
Does it worth I trouble for a 6th plug-in?

 

[Hayk]

It looks, I already have on the mother board, all the necessary to drive in parallel 2 channel 1540. All I need to add is a,74hc74 to extract the sign bits. The connector will get extra 2x3 pins that will be only for this plug-in separated.
As the DACs are loaded the absolute value, it cannot be in differential but it needs a current steering to supply the positive or the negative input of the output differential.
Here I go for the 6th plug-in to carry only a pair of tda1540 running 15bit with current steering.

 

[Hayk]

I will use Grundig type tda1540 circuit as shown here

TDA1540 High Precision Synced TikTak - Bram Jacobse

I regularly get these questions , Can my CD player sound better, I read somewhere on the internet…… Can a Grundig Dynamic Element Matching (DEM) modification be done in my TDA1540 Player Can i...

www.bramjacobse.nl

My LRCK is 96khz, needs the double, I will use a devider by 32 the BCK, to get 192khz.

 

[Hayk]

Plug-in4 4xpcm1702 + 2X SAA7350, can still hold more. I read pejorative review about TDA1549 but looking more attentively, I see it has very low THD+N at -60db, about -50db with 18 bit data.
This is very small chip soic16 and costs a pair for differential $5 all Inc.

 

[Hayk]

I think I have enough DACs to implement. 21 DACs can be implemented in differential mono mode. I have 2 weeks to finish the 7 PCBs so I will stop here.
I resume when I start measuring.
Thank you for your attention.

 

[Hayk]

I nearly finished the motherboard, 4 layers, double side components, 60x53mm. The SRC board sits upon pinheaders covering the logic circuits.
Although it will cost me more than twice PCBs, I decided to make single DAC PCBs for expensive ones and 2 DACs for the cheap.
This gives 9 plug-ins.
TDA1540x2
CS4303x2
PCM1702x4
SAA7350 x2
AD1865 x2
PCM56 & compatibles(AD1856, PCM61,AD1861,AD1851,AD1860)x4
PCM67x2 & TDA1545A x2
PCM1794 x2 & CS4398 x2
Ad1853 x2 & WM8740 x2
I dropped out the AD1716E x2, negative reviews and the SM5865, x4 not affordable.
The TD6709, only one retailer in CA. RF parts, $4.5 but $15 for shipping.

 

[Hayk]

What I found about pcm1716, is that the filter is not good. It was replaced by a better one to be named pcm1728, which is still active.
If I am attached to this 24 bit DAC with mediocre 24 bit performance, THD+N -96db, it's 16 bit performance. 1.2% THD+N @-60db 16 bit, but with 102db S/N, the THD is 1.2-0.8=0.4%. This why I will give it a chance.The price from Ali is about $10 all Inc for a pair.

 

[Hayk]

SAA7350 problem and eventual solution.
This DAC has very low output current issue the switched capacitors, only 100ua p-p.
It uses low voltage opamp of 80's technology using 30k feedback resistor, resulting high noise and distortion. There enters the TDA1547 which has higher output current using 13k instead of 30k.
By using its 2 channels in differential, it allows to double the current, but how?
Bellow is the circuit of Pioneer laser disc player, it uses each channel differential as the DS application and sums the outputs. This decreases the noise by 3db.
My solution, not yet tried, is to amplify the current of the DACs using inverted transistors. When collector and emitter are swept, the transistor still functions but with low current gain and lower gain frequency product.
The solution is shown bellow which feeds the opa1632 differential inputs.

 

[Hayk]

I nearly finished the PCB job.It ended 12 plug-ins and a motherboard.
Bellow is the biggest, TDA1540x2 15bit, 70x50mm, the smallest AD1853, and the most difficult wiring the PCM57 DIP & SMD.

 

[Hayk]

I am ready to send the gerbers for manufacturing the PCBs. As 16 bit is priority, I will put aside the PCM1794 and CS4398 to reduce the cost.
I am interested in CS4191EQ. This is not a DAC, it is intended to function along CS4499eseq. It has adjustable Sigma delta, 5,6 and 7 bit as well 4 types of modulators. It costs $17, 2 channels, but the 4499 is $50. I will see if I can use an 8bit video DAC instead, as for 16 bit, I don't need ultra low noise.
I noticed that I was using for more than a decade CS4398 in my Ciirus based DAC without knowing as it needed special tools to open it. I can say, it doesn't sound bad, but nothing extra ordinary.

 

[Scytales]

The document bellow says the CS4397 was developed by the same team of Phillips TDA1541A.

Evolution of DAC & digital filter - DutchAudioClassics.nl

On March 8, 1979 Philips publicly demonstrated a prototype of an optical digital audio disc at a press conference called Philips Introduce Compact Disc in Eindhoven, Netherlands.

www.dutchaudioclassics.nl

Is it BS or real?

The document does not state what you have written in the above quoted message and that I have stressed in bold type.

The document states that "Apparently, the same skilled Philips engineers involved in the development of the TDA1541 also participated in the CS4397 DEM circuit." This cautious statement, made without any citation, would only means, if it is true, that the Dynamic Element Matching function block of the CS4397 got some insights from Philips engineers.

The CS4397 has been designed by Cirrus Logic engineers, among which is Dylan Hester, who never worked for Philips. Mr Hester wrote about this DAC (and the CS4392) on the AVS forum back in 2002 (example).

 

[Hayk]

I see many youtube comparative DAC videos demonstrating similar sounds from different DACs of different prices.
The SQ of a DAC has very little to do for its measurement, specially they are measured with 24 bit and tested with 16.
It has more significant difference due to the technology it is made of.
There are mainly 3 different ways of converting Digital to analog.
The mutibit, the single bit delta sigma and 2 types of mutibit delta sigma.
The mutibits, are 2 types, R-2R ladder , and switched currents of Philips.
The R-2R requires very high precision resistors, 0,05% is only good for 10 bit resolution. Laser trimmed resistors could increased it significantly which made PCM56 affordable and popular. Available as new and used.
Philips in 1980 came with a cheaper solution than laser trimmed with TDA1540. It has 4 lower bits in R-2R and a single resistor per bit along a capacitor to supply exactly half the current of the next bit.
The capacitors are charged periodically by an oscillator, called DEM.
A more economic of it is made of current sources continuously calibrated.
The TDA1541, is a cheaper version of 1540 which uses 10 bit R-2R and 6 bit DEM.
The single bit delta sigma or PDM, needs noise shaper to decrease the noise generated by the modulator in the audio range. This type of DACs has evolved into mutibit delta sigma of multilevel as shown bellow that of PCM1728. The best of this type to my opinion is the British WM8740, it can be used in mono and internal filter bypassed.
Another way is the hybrid R-2R of higher bits complimented by single bit delta sigma. Probably all today's DACs use this with 5-7 bit R-2R. The best for 16 bit is the PCM67 which has 10bit laser trimmed for 18 bit precision R-2R and complimented by a single bit delta sigma.
In short, to get different SQ from DACs is to compare, PCM56, TDA1540, WM8740 and pcm67. Any of the others is related (same same but different) to one of these 4 DACs.

 

[Hayk]

Sony has a DAC, CX20152. It is nearly the same as Toshiba TD6720, the 100khz version of TD6709. It is available at Ebay for less than $7 and $10 from UTsource.
This DAC is PDM to PWM converter, high up to 200 Mhz with sample and hold.
Lumpizator has tube output for this DAC used in Kenwood DP1000.
Source: Lampizator.eu https://share.google/wQ0iUbcA3DSByZJlr
This is single bit DAC but no any filter or noise shaper whatsoever.
I am simplifying back the mother board to make it 2 layers. I eliminated the TDA1540 as it overloaded and make an independent complete board for the TDA.
I will try to join a plug-in to the motherboard by cheating the manufacturer to be a single circuit to get for $4, 5 pieces of the motherboard and a plug-in. The maximum size 100x100mm will determine which plug in.

 

[Hayk]

According to AI, the top cd player in 1986, was the Sony pd502,552, equipped with cx20152. Philips was with TDA1540, 41.
Unlike the TD6720, the cx20152 needs external , integrator, S/H that allows the use of modern opamps.

 

[audio_tony]

According to AI, the top cd player in 1986, was the Sony pd502,552, equipped with cx20152. Philips was with TDA1540, 41.
Unlike the TD6720, the cx20152 needs external , integrator, S/H that allows the use of modern opamps.

There's a useful list of players and which DACs they used here: https://daclist.dnsbits.net/

 

[Hayk]

Thank you Tony, thank you very much. Very useful to find which cd players used that certain DAC.

 

[Hayk]

The Sony dp502 has triple gyro filter which looks very interesting. The simulation response shows 30khz BW. I am thinking to copy exactly the whole DAC as is.

 

[Hayk]

This is the TDA1540 with 15 bit resolution.
This DAC isn't 2's compliment, it is offset binary that is the MSB is similar to the other bits. Normally, I must invert the MSB of the 2's compliment to feed this DAC. instead, I sample it separately as sign bit and steer with it the output current -4ma to 0 to the either inputs of the differential amplifier.
The error I get is the gain difference because of the resistors of the differential amplifier. For that I added an adjust that fine adjusts +/-1% the two 1k 1% resistors for symmetrical output.
If I have added a 15th bit switched current of 4ma, it should have been to the precision of 14th bit, which is impossible to adjust.
To note that the DAC will run at 2fs.

 

[Hayk]

As I will be using at half speed, I may use a single DAC for both channels as it is expensive. It needs S&H and switches also eliminates the glitches that I introduce by the sign bit synchronization.

 

[Invisiblestorm]

I am designing a quasi universal board that can aquire many types of DACs.
It has 2 selectable inputs, a ASRC 4190 board, interface to drive right and left justified DACs in differential mode and OPA1632 as differential output.
The DACs are on seperate modules to be plugged in which requires dedicated PCB for each type. The DACs I chose are of low cost ones only but do I know all of them?
TDA 1545A $0.25 x2
PCM56j & compatibles $1 (used)-$3. x 4
AD1865 in smd. $6 (used) -$12. x 2
PCM1702U smd. $5 x 4
PCM1794. $2.5 x 2
WM8740. $2.5. x2
Any suggestions ?

You already have a very solid lineup covering most classic multibit and delta-sigma DACs. If you want to expand it, I’d add AD1862 as a higher-end step above AD1865, and PCM63 as a top-tier Burr-Brown ladder chip. You could also include a few cheap reference chips like AD1856 or PCM1716 for baseline testing. For a modern comparison, something like CS4398 would be useful. Overall, your list is already strong—these just fill the main gaps.