Where to start on CD player mods and other Qs

[Zero One]

Having now collected 2 CD players and a cheap DVD players for modding experiments I am wondering what to address first.

The 2 CD players are Teac 1120s which are supposedly pretty tweakable for little money, my idea is to tweak one and compare to the original as I go as a learning process for better things later.

The Teacs sound quite analogue, except for the bass and that is what I would like to address first. Basically it is a bit aneamic compared to my LP system and shows mild roughness/distortion, it is not particularly tight either. So what changes typically will best address this, better power supply, op amps, chassis damping? I will eventually address it all but I'd rather start with the main problem area first.

And here is a observtion that has me wondering. I burnt a CD copy onto a black Verbatim digital vinyl CD-R and did a back to back comparison with the original for interest, I'd swear the black one sounds nicer, sort of clearer and less grainy though it is subtle, but why? Data is data, one would think. I also tried a regular cheap silver CD-R and it seemed worse than the original.

Bass seems identical in all of them, the difference is in the mid to upper register.

One thing I did notice is that the black one seems to be more accurately balanced, less runout that the original disc or the silver CD copy, can ths possible have an effect, once again I would have thought not as the players are designed to cope with this?

Overall I need to get my son to do a blind test for me so I can be sure it is not a matter of just fooling myself, but it sure seems different at this point.

One other observation that also seems odd, probably because I don't have a good understanding of how CD players really work, if I put the very slightest pressure on the centre spindle on top of the CD while it is playing (the top cover is removed) the highs seem to become a bit smoother, I am not talking about enough pressure to slow it down, rather just to stabilize it. Why?

[Leolabs]

Start from power supply section and analogue output stage section.

[zanash]

read this ............

http://www.zerogain.com/forum/showthread.php?t=9058

[philpoole]

Hi,

I did a lot of modding to a Marantz CD63.
Although different, the main mods are probably the same.

Firstly, if you can, I'd recommend getting a schematic or service manual of the player.

Then the following could be good to try:
removing muting transistors
upgrading output opamps and output passive components
upgrading electrolytic decoupling capacitors
removing unwanted output circuitry (e.g. headphone or digital out - if you don't use them).
Improving voltage regulation and earthing arrangements
Fitting a clock module (like a Kwak Clock).

Plus loads of other things, but that sjould be a start to search and plan for.
Have a look at the CD63 mod thread. Its huge, and has loads of things that *should* be applicable.
Depending on what you're confident enough with doing, you'll be busy for months!

But also, do a mod at a time, and check the difference. Some things are marginal, but they all add up.

Hope this helps.

Cheers,
Phil

[peufeu]

Can you post :

- pictures of the innards (to judge layout)
- dac chips used
- what kind of output stage they use
- what kind of power supply
- schematics ?

[Zero One]

Yes I will take some shots and post them, and thank you to all for your assistance.
Brad.