New DAC required?

[Jason Hubbard]

I have been using a TEAC VRDS 10 for many years and it has worked faultlessly.

One of the things I was always keen to try but didn't ever get around to was to add a DAC rather than use the onboard one.

There are quite a few ready assembled DAC boards on ebay at the moment (mostly from China/Hong Kong) - are any likely to give a signficant improvement over what I already have and and if so which would be the best choice?

[jean-paul]

Yes, the VRDS10 is good mechanically but those dreaded TDA1547 are "nothing to write home about" as we say in dutch. Almost any modern DAC chip is better technically and sonically.

If you want the best results replace the clock crystal for a low jitter clock and make a new internal DAC to avoid SPDIF with all its troubles. In fact you will only need a small PCB with a new DAC chip and some 3.3 V regs + caps on it. You can reuse the output stage but I recall some trick in the opamps (old inline types or something like that) in the VRDS10 but I can not remember what. Modded several of those years ago. The low jitter clock is a must in this one.

A WM8740 or WM8741, CS4397 or CS4398, ES9022 or 9023 will be better than what is used now. I can't say anything on the newer PCM types as i haven't used those a lot.

Make sure you build the DAC internally if you really want a big change. External is less good just because of SPDIF. If possible avoid SPDIF altogether. And buy a spare laser for your VRDS before they're gone if you like the machine.

[PJN]

If you are willing to do a little DIY, build a case, hook up transformer I just recently bought this DAC board Hifimediy “direct out” DAC: cs4398, w/upsampling 192/24 cs8421, TCX0 and TE7022 USB, MUNDORF MCAP |Hifimediy . It is a bargain for the money, sounds great and very versatile with USB, optical and coax inputs and includes a source selector switch.

PJN

[SoNic_real_one]

Like it was said, the SPDIF connection will only increase the jitter. If possible to tap into internal i2s lines, it would be better.

[Jason Hubbard]

Jean-Paul;
I looked around for a new laser mechanism (thankfully not needed right now but I see the point you were making - the lasers die quickly, the mechanisms are scarce and very expensive!!). Don't know if any will be remanufactured - looks like there are a lot of top end products out there that will go to landfill if they don't. I also saw that it was possible to replace just the laser diode - did not see very much follow up from DIY'ers taking that approach. I will get some belts and sled cogs as spares - they seem prone to failure as well and these are quite old players now.

Do you have any personal recommnedations on a good clock to use?

PJN;
The DAC you mention - it would seem a good idea given other comments in this thread to integrate the DAC into the housing of the player rather than having it off-board and connected with SPDIF. Does this DAC support I2S input (I didn't see mention of it in the link you posted). There are a few DAC's on ebay using PCM2706 as input with I2s capability and a CS4328 DAC - they are quite inexpensive.

SoNic_real_one;
Do you know the pickup points for the internal I2S connections? Or does anyone have a PDF of the circuit diagram?

Thanks again everyone - it is interesting to see what the possibilities are.

[SoNic_real_one]

You can look on the SAA 7350 (the OS for TDA1547) for the inputs.

[abraxalito]

Hi Jason - I'm not as down on SPDIF as some of the other guys are here. Certainly you wanna get shot of the 1547 in your Teac - which one you replace it with is a matter of personal taste. These days I'm rather partial to the multibit (as opposed to the noise-shaped) sound - hence I'd suggest looking into a TDA1541A or TDA1543 or PCM1702/4 based solution with SPDIF input. Those kinds of DACs when done right give (to my ears) an analog-type sound but if you start out with an eBay board it'll be bound to need fairly heavy modding (mainly of grounding and power supplies) for the chips to give of their best.

[jean-paul]

Jason, I use Tent XO modules on DIYflea PCBs from Ray's Audio Page for some time and they are a very good option.

Best is to use a low jitter clock, replace all electrolytic caps and replace the DAC for an internal new one. That is ,of course, if it is worth all the work for you.

[Carloshenri]

Jean-Paul,

I'm researching hopping up my CAL ALPHA DAC. 18 bit. CS4328-KP. The CS4398 pin lay out looks pretty similar. Looking at the two pdf's it's a little vague as to the similarities as some of the nomenclature is different. I'm having a little trouble getting a decent web search result of searches like: “CS4328-KP upgrades”, trying to learn what chips I can srop right in there.

I’ve already found some Bursa discreet component op-amps specifically designed FOR audio, very reasonable, too. Figured a more modern conversion chip would help in addition to the other ideas I’ve come up w/.

Research suggestions? Recommendations?

Thanks


Make it real

[SoNic_real_one]

There are lots of integrated OpAmps also specifically designed FOR audio.
Those discrete ones were tested and they didn't fare better than the newer integrated OpAmps. Just a waste of money IMO.