Non-Oversampling TDA's

[Guido Tent]

Originally posted by Bernhard
Little calculation:

TDA1541A nonos ( strong even order harmonics )
+ tube output stage ( strong even order harmonics )
+ tube preamp ( strong even order harmonics )
_________________________________________

very musical, transparent & holographic sound

Hi

Please carefully consider what may happen when cascading non linear stages creating even order harmonics............

(you may end up with odd harmonisc at the end)

cheers

[Fin]

Originally posted by jean-paul
It probably will surprise you but most of the time I listen to first generation Philips 1 bit systems now instead of multibit TDA machines.

I assume you are talking about SAA7321/3 equiped machines - like the CD624, CD634, CD850........

How do they compare to the multibit machines sound-wise?

What type of modifications or upgrades do you make?

I've had a CD624 since 1991. It sounded quite good compared to it's competition at the time but I haven't compared it to anything else recently. Currently in the process of trying to take it's performance to the max. by doing the following:

List of modifications
Tent XO2 Clock module and XO supply PSU
Separate transformer, power supply and regs for the output stage
Separate transformer winding, power supply and regs for the DAC
Separate transformer winding, power supply and regs for the decoder
Separate transformer, power supply and regs for the servos
Upgrade powersuplies to everything else.
Improve decoupling on most IC's
Improve grounding for most IC's
Change opamp to OPA2134 or OPA2064
Replace all existing electrolytics with Nichicon Muse and some Os-Cons and a few Black Gate PK.


A rare oportunity to purchase a TDA1541A machine (Marantz CD60) presented itself recently and it's on it's way to me as we speak. At last I will be able to compare these two dacs (in similar machines - CDM4/19, SAA7310......) for myself, and in my own system. The above mods will eventually be applied to the CD60 (and maybe non-oversampling).

Originally posted by jean-paul
PCM63 and CS4390 are a bit old cake as well like TDA15xx, PCM63 being still one of the best IMHO. BTW what do you think of PCM69 ? I have some K types but I can't recall I ever heard them in a cdplayer.

PCM63 is something else I would like to try at some stage in the future - have a SM5842 waiting for a home.

[carlosfm]

Originally posted by jean-paul
It probably will surprise you but most of the time I listen to first generation Philips 1 bit systems now instead of multibit TDA machines.

Do you like them?
I don't.

[Fin]

Originally posted by carlosfm



Do you like them?
I don't.

Have you tried the SAA7321 or just the SAA7350 in your CD52?

[kenev]

Dear all,

I read this thread and I would like to add a little of my experience with NonOS TDA 1541. I have built a double chip DAC, which is fed directly from the I2S bus of a CDPRO2. As an output stage I use Lesha's tubed buffer with a 6C45P.
Initially, the output stage was built using a resistor as an anole load. Later I replaced it with a CCS. I could never imagine the huge improvement this CCS broought to the DAC. A whole class up. There was a huge improvement in soundstage, which became extremely wide and deep. Also major improvement was noticed in seperation between instruments and resolution, minor details were more distinctive. In all, a very-very analog sound, now I have no hesitation listening to my CDs.
For the passive I/V I use a 22R resistor. I tried also 18R (to lower gain a little, since the 6C45P provides lots of gain), but the sound seemed kind of anaemic, lacking dynamics. The CCS is set at 18 mA, with Vg at -1.2 V.
I suggest anyone with a 6C45P output stage on his TDA1541 DAC should try a CCS.

Regards,
Evangelos

[carlosfm]

Originally posted by Fin
Have you tried the SAA7321 or just the SAA7350 in your CD52?

Yes, the SAA7350 is flat and undynamic.
But in my experience that's a characteristic of most bitstream (and delta-sigma) dacs.
Curiously, the YAC514 dac on my Yamaha cdp sounds good, better than those from Philips.
But nothing compares to a good multi-bit.

[tube-lover]

Dear all,

the first order of 12 pcs of TDA1541a S1 which I order from Holland is arrived. They all remove from old machine but unused.
The company told me was remove from Philips high grade parts wihch were repair stock.

I hadn't any instrument to test them but I made a simple hearing test compare with the standard TDA1541a. I only hear the background is more silience, little bit of punch dynamic was increase & little smooth sound stage. I can only hear will 6~8% inprovment.

But it actually quite good.

pls see the photos.


thanks

thomas

[cmt42001]

Thomas,

I recalled someone talking about using rechargable battery as cathode bias to improve the sound of the 6C45 tube stage. Can you please explain how this can be done?

Also can the 6c45 runs on AC filament and do you recommend this change?

[mevangel]

Hi Kenev,
can you post the schematic of the CCS you used?
Regards.

Marco

[kenev]

Hi Marco,

Initially, I built Gary Pimm's BBMCCCS:

Battery Biased CCS

The one I built was an older version with lithium button cells, it's now revised.

Later, I tried Bas Horneman's battery biased CCS:

http://home.zonnet.nl/horneman/mosfet.htm

This CCS uses the DN2540 depletion mode MOSFETs and could also be self biased, but with a battery bias it presents a higher impedance, which is better for a CCS.

Didn't notice any difference between these two, at least sounwise, but I would opt for the latter, as it uses less batteries.

Regards,
Evangelos