Philips CD880 mods

[jean-paul]

changed coupling caps, a Sanyo Oscon (scavenged from a computer) placed near 7220 with a bead-on-wire and thats all.

Send me a PM with your adress and I'll send you some new ones.

 

[tubee]

Send me a PM with your adress and I'll send you some new ones.

Done.

This oscon has been beside a warm Pentium processor for about 8 years, but i wanted to try an Oscon for the first time of my life.

 

[tubee]

Plain CD650

Good clock is very important, is you experimental clock still available?

The NE5534/LM833 doesn't like the HF from non-os dac, opamps tend to slew (clipping into supply voltage) when they get a lot of rubbisch extra. Thats why a transistor or tube I/V can sound so good imo

Bernard: what pre-amp poweramp do you use? Same story as above with amplifiers.

Warmup time of DAC chip is one minute.

Parts around it need more. Example: settling time of lytics is a lot longer. And there are 3 lytics in a plain 650 around the dac, many more in whole CDP.

 

[tmblack]

Tubee,

open the case and there are tons of RF interfering with my TV.
What op amp can survive in such a hostile environment?

What clock, IV converter do you use?

Tom

EE

 

[tubee]

Clock = Kwak 7 or Tent's XO
I/V from rbroertjes, url on post 31
Will use tubes also: still busy with project: 4 dacs parallel, passive I/V with E88CC/6922 amplification.

open the case and there are tons of RF interfering

Marantz cans their opamps and HDAM's with copper in CDP's for HF shielding, this could be self made also.

 

[tmblack]

Which tube I-V do you like Tubee?

Tom

EE

 

[tubee]

I don't want to build my CDP full of tubes, 1 doubletriode for R/L should do imo.

This is a nice one i think:

http://www.geocities.com/agalavotti/zerodac.htm

But will use Thorstens:

http://img185.exs.cx/img185/2008/dacout6im.gif

The L's and C's before grid are for extra linearisation of ONE 1541 dac without SAA7220.

Power supply (with some adaptations)
http://www.fortunecity.com//rivendell/xentar/1179/projects/toccata/Toccataps.gif

Search guys, its ALL there on the net.

 

[poynton]

...............This is a nice one i think:

http://www.geocities.com/agalavotti/zerodac.htm

................

Correct URL ?? not working

Andy

 

[tubee]

Try:

ZERO DIY Kusunoki-style DAC For CD Pro Unit

in google search, maybe then? Server at you area offline probably, no problem here.

 

[tmblack]

How do simple transistor I/V compare to passive (R) conversion?

Tom

EE

 

[tubee]

How do simple transistor I/V compare to passive (R) conversion?

Read some older articles about it. Don't know yet, but they say (here on diy) passive is nice for "easy listening" active for dynamical music (jazz/pop) Will try it then i can say more about it.

It could be possible then to choose different parts (clocks, I/V's, OS or not) with particular behaviour (dynamic, analytic, warm sounding) to get the desired sound. Its like cooking!

 

[poynton]

How do simple transistor I/V compare to passive (R) conversion?

Tom

EE

or transformer I/V as per Audio Note?

Andy

 

[poynton]

Read some older articles about it. Don't know yet, but they say (here on diy) passive is nice for "easy listening" active for dynamical music (jazz/pop) Will try it then i can say more about it.

It could be possible then to choose different parts (clocks, I/V's, OS or not) with particular behaviour (dynamic, analytic, warm sounding) to get the desired sound. Its like cooking!

The only measuring tool you need is your ears!
If you like the sound, STOP!

Andy

 

[tubee]

or transformer I/V as per Audio Note?

Have oriented on this, not a cheap solution.

http://www.lundahl.se/

 

[tmblack]

What is the range for the output current of the TDA1541A?
Is it 0 to 4mA or -4mA to 4mA?
Can it survive attaching output pin to -15V?

Tom

EE

 

[Tube_Dude]

What is the range for the output current of the TDA1541A?
Is it 0 to 4mA or -4mA to 4mA?

0 to 4 mA

Can it survive attaching output pin to -15V?

No...I don't think so...but...

http://www.datasheetcatalog.com/datasheets_pdf/T/D/A/1/TDA1541A.shtml

 

[tubee]

Can it survive attaching output pin to -15V?

No, the output will be distroyed then.

 

[tmblack]

OK thanks. I'll be reluctant to put any active device on the DAC output should it fail!

Tom

EE

 

[Zoran]

Passive IV, with a only R at the
output of DAC reversing the phase for 180deg...
but if You add a tube after Riv, the phase is back to normal...
And that is, for my oppinion, one of the best ways to get voltage from
TDA1541A (and PCM63).
For instance of 47ohms IV resistor, which gives a
acceptable distorsion of dac, and 6SN7 tube...
do not use ECC88 this is higher transconductance tube, with vulgar sound
rather go to 6SN7 with very high voltage Va about 400V still is below the maximum, and 5-9mA Ik, with lower value of load resistor 6 to 10K...
The sound is very fast, direct, neutral, and free from distorsion.
With stage gain of about 12-15 output meets the standard values.
Maybee one aproach is better:
All the same, but with diamond single-ended I buffer stage beetwen DAC and Riv...
All techniques does not including capacitor at the path of the signal...

 

[tubee]

I know a few things now: The 1541 is not easy to implement, and the I/V after it is the same story.

But will still try the 6922 with an R for I/V. Have some Philips E88CC + Sovtek 6922 waiting here to be used again. (from my hybrid tube- fet amplifier)

The mains transformer will be:
230 to 12V 20VA for heater + HT
then 10VA 12 to 230V for HT, 12V from first 20VA.
Small transformers of Halogen lights from Ikea, very cheap. Not very sophisticated but will do for first tube I/V experiment.

Have to find some nice I/V resistors (vishay?)