Re: Re: Happy DOS
The only smoke I produced came from my burning fingers (I grabbed the iron when it fell to the ground)
My Wife has very good eyes and is always willing to help.
She does enjoy the big improvements in sound quality also.
Now it´s time for the Decoder PSu.
I will report the improvements latter.
Ricardo
Thank you Ray6h5c said:
Congratulations! Please do report
No smoke? That's excellent, I hope you enjoy it very much.
The only smoke I produced came from my burning fingers (I grabbed the iron when it fell to the ground)
Hi LeeThomo said:
My Wife has very good eyes and is always willing to help.
She does enjoy the big improvements in sound quality also.
Thank you Brent.rowemeister said:Nice one Ricardo
Now it´s time for the Decoder PSu.
I will report the improvements latter.
Ricardo
Hi SimonSimontY said:
Your comments are very welcome.
I really did a very good planning this time so I did know exactly what to do and in what order.
It took me 6 hours work but everything went according to plan.
I experimented some "pad lifting techniques" when removing the opamp caps but I really do not need them anymore.
Ricardo
Glenn2 said:
6h5c said:
Now this is really very interesting.rowemeister said:Ray
When I fitted SPowers on my driver chips I had to short out the fuses to stop voltage drop before the regs. The sound does improve too, the bass tightens and the rhythm becomes more foot tapping
On a side improvement the laser tracks and reads much quicker.
In the CD53 the drivers are fed by +10v unregulated.
Someone has already mentioned usinf LDO to regulate this line.
Some use 9v ... others use 7v.... and I know the CD67 uses 5v...
I am a bit confused
What is the correct voltage to use here (or can I use any voltage from 5 to 10v ???)
Regards
Ricardo
Re: Re: Re: Happy DOS
The fuses indeed add considerable resistance. I'll short those first and do some measurements to see what the motor requires. Probably +/-5V is plenty.
that happened to me also once...
It gave me a few nicely scorched white stripes across my hand
Ray
rowemeister said:Ray
When I fitted SPowers on my driver chips I had to short out the fuses to stop voltage drop before the regs. The sound does improve too, the bass tightens and the rhythm becomes more foot tapping
On a side improvement the laser tracks and reads much quicker.
Brent
The fuses indeed add considerable resistance. I'll short those first and do some measurements to see what the motor requires. Probably +/-5V is plenty.
Originally posted by RCruz
Thank you Ray
The only smoke I produced came from my burning fingers (I grabbed the iron when it fell to the ground)
that happened to me also once...It gave me a few nicely scorched white stripes across my hand
Ray
RCruz said:Now this is really very interesting.
In the CD53 the drivers are fed by +10v unregulated.
Someone has already mentioned usinf LDO to regulate this line.
Some use 9v ... others use 7v.... and I know the CD67 uses 5v...
I am a bit confused
What is the correct voltage to use here (or can I use any voltage from 5 to 10v ???)
Regards
Ricardo
The CD57/67 has different driver IC's, they only need a single +5V. The CD53/63 uses an unregulated supply because this is the cheapest solution
.With big caps the voltage is even higher, more like +/-12V I think, so low-drop regs are not even needed. The motor needs only a few volts to operate, so +/-7V is probably a nice optimum? Maybe 78/7906 or 78/7908?
Did you use 5V Brent?
Ray
SimontY said:
Wasnae me pal... you can get different varieties of 780x with different current ratings. The 1.5A ones are cheap and easily available. 78L is 100mA and 78M is 500ma and to be avoided in this position.
I used LM317T/LM337SP (from ST) and put pots on because I didn't really know what was optimal. The voltages do sag under load, and this may be different depending on whether you have the standard/SE/KI transformer (or a separate one). The negative one seems to dip a lot when you first press play and the disc spins up (on my SE transformer, which actually came from a 67SE) but when music's playing you get at least 10.5V on both rails. Assuming a generous 3.5V overhead I trimmed to 7V (series regs like more overhead when supplying high-current loads). The driver op-amps like a volt or so of headroom too so 7v seemed a good setting. It doesn't matter if the regs drop out of regulation when spinning up, ejecting discs etc. anyway... you only care they're doing their job when the music's playing, so you can go a bit higher to reduce heat.
In this CD63 I'm playing with (my spare, as my 67 is going to be stripped of nice parts and it pretty butchered) I only have the one transformer (SE as I said). I don't know if the benefit is because the servos work much better when regulated, or because it cuts down on the servo noise escaping and getting into the clock and DAC (which it does, as measured by ALW on another thread). If it is the latter and you already have a separate tx for the servo and/or the clock, regulating them may not bring much benefit as you've already isolated this noise source. I simply don't know.
Glenn
The unregulated voltage is around 10-11v.
The drivers are asked to output +/-5v max.
Regulators like 3v headroom on input.
The drivers like >1V headroom between o/p and rails.
Regulating to +/-7V satisfies all these criteria.
It sounds like Ray may be gearing up to try it - why not see what he does. His solution is bound to be more elegant than mine... and even if it isn't, it's sure to look nicer.
Rayregs would be ideal but change the zeners to 6V ones.
Your voltage would be the zener voltage + 1.25V so 7.25v is ideal.
The drivers are asked to output +/-5v max.
Regulators like 3v headroom on input.
The drivers like >1V headroom between o/p and rails.
Regulating to +/-7V satisfies all these criteria.
It sounds like Ray may be gearing up to try it - why not see what he does. His solution is bound to be more elegant than mine... and even if it isn't, it's sure to look nicer.
Rayregs would be ideal but change the zeners to 6V ones.
Your voltage would be the zener voltage + 1.25V so 7.25v is ideal.
