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Chameleon DAC listening and modifications - Page 28

post #406 of 1144
Originally Posted by MikeW View Post
Wow wood, you are runing at 7v eh? You did not notice any negative effects of this?
I read one guy who claims the TDA1543 sweet spot is 5.6v. Higher voltage gives a more dense sound and lower a more open sound. Another reason for it to be called Chameleon

Hey, snap, I did exactly the same with the trace thing, thought I'd lost the board.
post #407 of 1144
Thread Starter 


yeah, and i would say the same thing if i was selling them.

But I did see an appreciable increase in performance when swapping in the Lundahl from the Pulse. so I expect the same form the AN.

You could only replace the one in the DAC, which is what I did. Damn, now you're going to have me poking around in the CDP again.
post #408 of 1144
Hey, everyone. I've had my dac for two weeks and have done the FIM, coupling caps and pulled the filter caps from the dac board. Can't believe how great it sounds.
I want to pull the Wimas and use them for the FRM. This may sound silly but being a noob to modding this stuff, do you desolder the dac board at the jumpers to remove it, or just slide it out with the main board and let the heat sink compound goop up the bottom of the case? Thanks!
post #409 of 1144
No need to take the dac apart, just parellel the caps and one pair legs on neg and one pair on positive where the power enters the foating board.

Mikes pics here are good


For taking it out, unscrew the dac board screws that pull the chips tight to the case, then slide it all out.
post #410 of 1144
Never mind. Senior moment. Thanks, Wood!
post #411 of 1144
He he, just edited my post after reading yours post properly. So yes Chris you are right, of course, but it comes out easy, you may have to wiggle it a bit, most of the paste stays where it should so no need to worry about repasting it.
post #412 of 1144
Pat, do you think I could get away with 75r (my texas resistor) on that AN coil, their schematic seems to call for 150r?

Audio Note

Guess could just suck it and see.
post #413 of 1144
Thread Starter 
Originally Posted by Wood View Post
Pat, do you think I could get away with 75r (my texas resistor) on that AN coil, their schematic seems to call for 150r?

Audio Note

Guess could just suck it and see.

The primary needs to see 75 but if you are using a transformer then let them talk to each direct and remove the 75 on the primary.

From the schematic I see no other resistor at the secondary.

R106 is on the primary.
Leg #4 on the TX goes to pin 3 and no resistor is on that line.
post #414 of 1144
Thanks again Pat. Hmm its getting tempting!
post #415 of 1144
Thread Starter 

gone and gone

And I think I may nick that 75 off there as well.
post #416 of 1144
imho is it so that the primary needs to see the same impendance as the secondary and the total should match the source impendance, so if you use 110 Ohm for the tranny on the source you should use the same in the DAC. For compatibility 75 Ohm is more convenient but no absolute necessity, at least that is the way I see it.
post #417 of 1144

a question of balance?

So is that 75 to mimic a CDP transformer? Wow I need to do some research on this stuff!
post #418 of 1144
Thread Starter 

not a doctor

If you lock the impedance pre and post then you make the transformer stable, thus the 75ohm on the primary. Remove the resistor you are now dynamic to whatever is upstream. But if your transformer is both 75 ohms the you can let them talk to each other.

Question is what is the impedance on the secondary from pin #3 on rcvr.
I think that they use the 75ohm to lock it in best way they can.

All good. If you have no TX on the transport I would leave that 75R there. But if not and you know your transformer is 75R on the Transport then remove it on the DAC.

This all goes to make the DAC very system dependent. You system, that is.
post #419 of 1144
Ok I have the same type TX on the source, so I'm gonna take of the Texas 75 of the dac, and see what happens. Just waiting for the iron to heat up.

How do we know what the impedence of these transformer are, cant see anything on the datasheet? Please excuse my complete dumbness here guys.

post #420 of 1144
Ok its off.

There is a difference, will have to listen longer but I think its better. Perhaps more transparent but a touch less body, like less pressure!?!?.

Update, yes it different, more relaxed, less in your face. Well there's a thing!

Yep the changes in pace of musical perfomance is more apparent. Less strident. Gives more connection, otherwise there is no detriment I can hear, or no improvement in SQ. Subtle stuff.
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