Philips LHH2000's secret output (versus CD100 & others with TDA1540)

[Richard]

So you like the NOS mod for the TDA1540 or you would rather not use it?

Flavio,

I really like the 1540 in NOS mode, I'm prepared to give up some of the microdetail. I'm reclocking one of the data lines to the DAC and I find the sound to be very natural. As indicated earlier I prefer it to a TDA1541A S1 in my Marantz CD 94 Mk II. The CD 63 may be bulit like a tank, but I'm sure a diyer can do better with some structural mods.

Andy,

You are correct, the board I have is from a Studer A725, schematic is very similar to the output of the Philips LHH2000. I'll take a photo of the board and post it in a day or so.

Oshifis,

I agree with you regarding the ceramic version but Ssshhhh, we don't want all those 1540 fanatics out there hunting down this version to extinction.

Cheers,

Richard

 

[Richard]

Here is a pic of the output baord from a Studer A725, this player used the tda1540

 

[Richard]

and here is the transformer output schematic from the LHH2000

 

[Richard]

and the Studer A725 output schematic. Note that the LHH2000 does not use the additional transistors.

 

[flavio81]

and the Studer A725 output schematic. Note that the LHH2000 does not use the additional transistors.

Isn't the I/V conversion done at the resistor on the feedback of IC11 opamp?? Although the resistor value is unknown!! ("OE"???!?!?!)

 

[QSerraTico_Tico]

Isn't the I/V conversion done at the resistor on the feedback of IC11 opamp?? Although the resistor value is unknown!! ("OE"???!?!?!)

No the IV is not in the picture.

 

[tubee]

I would say, remove the opamp, put in a socket, solder on a socket a THS4032, cool it with a small aluminium sink (with cyanoacrylate glued on) put this smd opamp in the socket, and enjoy your 14 bit downsampling machine. The THS can run on +/- 15V max prepare on that. But you will be astonisched. For coupling cap remove the lytic and wire from the on pcb tracks a motor starter cap from around 5.5 uF.