Hi there,
Just got hold of a Philips CD473, with CDM4 and TDA1541A.
Very surprise to find a volume control to the output signal with remote.
Understand that TDA1541 don't come with attenuation (right ?).
Can someone help to explain how the volume control done in CD473 ?
I would like to bypass it if it was done externally.
thank you very much
Just got hold of a Philips CD473, with CDM4 and TDA1541A.
Very surprise to find a volume control to the output signal with remote.
Understand that TDA1541 don't come with attenuation (right ?).
Can someone help to explain how the volume control done in CD473 ?
I would like to bypass it if it was done externally.
thank you very much
Hi,
Nice to hear that it can be bypass. The vol control board seems complicated at first......
I will find some time to by pass it.
I have been wondering how the vol control is done here.
Looking at the signal flow, immediately after the op-amp filter after DAC, both L/R signal passed thru a MC14051BCP (A digital control analog mutiplexer ??). My guess is that the siganl is divided into 8 part (from small to large) using resistors network, then feed into the multiplexer. Digital volume control then is done by selecting the desired level (3-pin contorl from the spec of MC14051BCP = 8 states).
Any comments ?
I've seen a Philips CD880 that also used TDA1541A S1, but there are 2 sets of output available. 1 set with variable level (vol control) 1 set fixed level at 2 Vrms. Looking at the signal flow, the variable output part passed thru a small board that are very complicated at 1 glance. I think it works the same way as CD473.
Originally, when I get this set, I am only interested in the DAC. Thinking of making a NOS dac (after reading many reports). However after listen to it, I am really surprise to find that it sounds great. Considering the age of the set (>10yrs), the CDM still works well and the sound has certain character that I don't find in my CD67SE or CD6000OSE. So after changing some E-caps and the op-amp, I think it would perform better if the vol control is bypassed ??
Nice to hear that it can be bypass. The vol control board seems complicated at first......
I will find some time to by pass it.
I have been wondering how the vol control is done here.
Looking at the signal flow, immediately after the op-amp filter after DAC, both L/R signal passed thru a MC14051BCP (A digital control analog mutiplexer ??). My guess is that the siganl is divided into 8 part (from small to large) using resistors network, then feed into the multiplexer. Digital volume control then is done by selecting the desired level (3-pin contorl from the spec of MC14051BCP = 8 states).
Any comments ?
I've seen a Philips CD880 that also used TDA1541A S1, but there are 2 sets of output available. 1 set with variable level (vol control) 1 set fixed level at 2 Vrms. Looking at the signal flow, the variable output part passed thru a small board that are very complicated at 1 glance. I think it works the same way as CD473.
Originally, when I get this set, I am only interested in the DAC. Thinking of making a NOS dac (after reading many reports). However after listen to it, I am really surprise to find that it sounds great. Considering the age of the set (>10yrs), the CDM still works well and the sound has certain character that I don't find in my CD67SE or CD6000OSE. So after changing some E-caps and the op-amp, I think it would perform better if the vol control is bypassed ??
Did you ever get this player sorted? I've been looking high (and low) for the service manual so as to remove all the unnecessary things... like volume control.
Hi,
Didn't manage to find the service manual or schematics....
Just referenece to many Philips CD player that used TDA1541A (I have few Philips CD player service manuals that use TDA1541A) .
The schematics are almost the same (I suppose.... 7220B (or A)-->TDA1541A.. the difference will be on 14 coupling caps, some player used po-cap, 473 used SMD cap)
So I removed the volume board, find the singal on the connector and connect it to the output (Anyway it is already buffered, also put in a socket for the buffer)....
BTW, on the board itself, there are some empty space that has some provision routing....
Trace the layout, put 2-3 jumpers/wires you will be able to route the signal all the way to the provision output connector or to find a better place to solder the output signal.
Rgds,
Mark
Didn't manage to find the service manual or schematics....
Just referenece to many Philips CD player that used TDA1541A (I have few Philips CD player service manuals that use TDA1541A) .
The schematics are almost the same (I suppose.... 7220B (or A)-->TDA1541A.. the difference will be on 14 coupling caps, some player used po-cap, 473 used SMD cap)
So I removed the volume board, find the singal on the connector and connect it to the output (Anyway it is already buffered, also put in a socket for the buffer)....
BTW, on the board itself, there are some empty space that has some provision routing....
Trace the layout, put 2-3 jumpers/wires you will be able to route the signal all the way to the provision output connector or to find a better place to solder the output signal.
Rgds,
Mark
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