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CD player analogue stage?

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PLease can someone tell me what sort of size transformer they recommend using to supply the output stage of a CD player? I am unsure as to how much current the dual op-amps in my Cd player draw.
Cheers
Tim

Follow Ups:

Re: CD player analogue stage? - Dman 05:36:38 09/19/01 (0)
Typically, the bigger the transformer, the better, in most cases (just ask John Curl!).
I run ICs at 15 volts or so (and some as high as 18v). This leads to better headroom for the output stage, and just sounds more 'in control', robust, or 'gutsy'- but always better than low voltage circuits.
On a related topic, here's a neat 'audiophile' thing for the average musician friend, if you know any.
If they have an 'active' guitar or bass (low impedance pickups with a preamp built in), double the 9 volt batteries up for 18 volts (provided the circuit can take it) and watch your musician be surprised at how much better the instrument sounds!!!!
I did it to my Yamaha Bass, and it took on a new life!!! Clarity, depth (thunderous bottom, was murky and unfocused before), midrange that 'speaks', and a top end that can cut concrete with playing the funk!
Power supply IS the key!!! Everything else is AFTER it!
Dman
Re: CD player analogue stage? - Ryan 04:51:04 09/19/01 (2)
Hi Tim,

I have used up to a 120W (!) transformer here, with 16V secondaries. Of coiurse teh output stage is sitting with +-15V power supply on the op-amps after the regulators.
This tweak makes a big difference, i.e. feeding the op-amps off a separate transformer. That is exactly what NAIM does in its CDP upgrades.
Regards
Ryan
- Re: CD player analogue stage? - Tim Walpole 07:22:00 09/19/01 (1)
  Thanks guys.
  Is it as simple as I think it is? No special grounding requirements?
  I have tried many other tweaks etc but this area is something I've mostly steered clear of.
  Cheers
  - Re: CD player analogue stage? - Ryan 08:45:13 09/19/01 (0)
    Tim,
    I think that this is a very rewarding tweak if you have an op-amp based analogue output stage. Other tweaks are:
    Replace the op-amp power supply decoupling caps (typically 100uF, 25V electrolytics) with tantalums of teh same value. I know people do not like tants for signal path work and I agree with them but for decoupling I think they are great. Something about less ringing during decoupling...
    The audible impact of the tants is to improve the clarity of the bass significantly, especially the very low stuff.
    Another good tweak, which lowers the noise floor, is to bypass the tants with a 10nF, 1nF and 100pF cap.
    Ryan
Re: CD player analogue stage? - M_Anker 04:48:18 09/19/01 (1)
The output op-amps in my cd player run on 5 volts VDC out of a 7805 regulator IC. This is pretty much standard in all CDPs. I don't know why you would want to supply them with a transformer though, this could introduce many problems by itself.
Good Luck!
- Re: CD player analogue stage? - GimmeLPs 07:59:38 09/19/01 (0)
  I assume the original post implies a separate transformer and regulator network to supply the same power req'd (5V, 18V, whatever), rather than a transformer applied directly to the circuit. Because the external new supply circuit it is completely isolated from the rest of the CDP, its power stays cleaner, and the resulting sound output improves.

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