OP-amp metronom

Operational amplifier for the R2R analogue converters TDA1540 and TDA1541A. CD players usually contain double operational amplifiers with two amplification stages in one housing, following the analog converter. One half is responsible for the voltage conversion of the audio signal, the other half is used for stabilisation with an upstream low-pass filter. However, these very different tasks are performed by identical halves. The OP-amp metronom combines two different individual OPs on one board as a direct replacement.

•  Optimized single op amps for different requirements of each stage
•  Best heat balance compared to double-OPs and conventional adapters
•  improved signal routing with anti-oscillation layout
•  minimal mass change due to new micro pin connectors
•  Plug'n Play replacement for all dual OPs behind R2R analogue converters

OP-amp metronom

•  OP-amp double 825-604 22,-
•  OP-amp double 604-825 22,-
•  OP-amp double 4031-604 22,-
•  OP-amp double 604-4031 22,-
•  OP-amp double 604-604 22,-
•  OP-amp double 825-825 22,-
•  OP-amp double 4031-4031 22,-

Selection criteria
Following the converter I recommend an AD825, then as filter and buffer an OPA604 - i.e. a double OP-amp with different equipment each half. This equipment is suitable for all CD players with double op-amp without any changes in the circuitry as a plug'n'play replacement. If you are able to change the circuitry in the CD player, choose a version with THS4031 instead of AD825. In this case an additional resistor must be added in series to a capacitor, which is located between the converter and the op-amp.

THS4031 I/U stage TDA1541

Example: Marantz CD94MKii

Different connections in CD players can e.g. Use either the first or the second half of a double op-amp first. Most devices require two double op-amps.

2x 825-604
The most common variant with the same wiring per stereo channel. For e.g. all Philips from CD100 to CD304 and also subsequent models such as CD460, CD650, CD880 ...
Grundig CD903, CD8400MKii, CD9000 ... CD9009 has 825-604 but followed by another 3x 604-604 as filters and output drivers, so a total of 8 double OP-amp.

2x 604-825
Some Marantz models use the second half of the op-amp first, such as. the models CD40 and CD50 ...

825-604 und 604-825
Models with different wiring for each stereo channel are e.g. Revox B225 and Sony CDP 337ESD ...

Marantz CD94 MKII first uses 2x 825-825. A subsequent filter section also requires 2x 604-604 and 2x single 604.

single OP-amp
A Philips CD960, Marantz CD94 and some similar models use 4x single op-amps. So two 825 and 604 are required here.

Questions about other models please via email.
OP-amp metronom single

•  OP-amp single 604 12,-
•  OP-amp single 825 12,-
•  OP-amp single 4031 12,-

Operational amplifiers are purchased directly from the manufacturer's distributor. Anyone who purchases such coveted semiconductors from an Asian country where they are not manufactured at prices below those of the manufacturer cannot be helped. If you hear that such an OP-amp sounds like the already installed, you cannot draw any conclusions about the qualities of an original type. In the more harmless cases, it is a differently labeled NE5532/34. But you can still be thankful to get a working standard op-amp - in earlier days there were reports of fakes where the track or parts of the power supply are damaged due to short circuit.

metronom-module V2.0
no oversampling bridge