Sony ta f707es modifications

The German model likely has capacitors in the line signal (RCA jacks) due to the FTZ regulations of the time.
Therefore, compare the schematic with a non-European device and modify your device accordingly.

It's also possible that only the coupling capacitors in the signal paths have dried out.

Thank you I see quite a lot of differences i was wondering if anyone had done the modification in the past and knew what the the main capacitors that needed changing or removing to improve the sound as there seems a marked difference in sound the European model sounds so musical much more forward sounding.

The ceramic capacitors located in the immediate vicinity of the RCA jacks are due to the former FTZ (Telecommunications Technical Center for Telecommunications Equipment in Germany (Radio interference suppression) ). Beyond that, there should be no differences.

Find the Service Manual (SM) for the amp, e.g. search for "Sony TA-F707ES SM PDF" and look up the schematic.

In the schematic you will find described the parts which are different depending on market or model which may need modification.



Main focus should be on the parts near the phono input cinch / RCA, which need to be removed and replaced with one wire.


- Johannes

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The areas marked in blue are added components that can be removed. In case of the input filters, these additional components must be replaced with a wire jumper, one for the left and one for the right channel.

The components marked with a star (and in green underlay by me) have changed values. See tables contained in this schematic. They show three different variants: Two amp models (707 and 808) and the Germany version (according to FTZ regulations in place at that time).

When targeting the phono equalizer, the most important measure is to remove the phono input filter, which is located near the phono RCA jacks on the input board. As described, one wire jumper must be installed per channel after removing the components.

This single measure should have the biggest effect and works very well on many classic amps from this era, across all manufacturers.

Hope this helps.

- Johannes

Thank you will start the modifications I have two ta f707es but one has a blown output transistors but I do have a damaged ta f770es but it does have a good main board are they a straight swap it would save a lot of fault finding and of cause the transistors are unobtainable thanks for your help.

OK, all of these models use the famous VFET output transistors.

What ever you do with these amps, first of all make sure you swap ALL fuse resistors in them against regular resistor types.
These FR are one of the main reasons why so many of the marvelous VFET transistors have died. FR age badly and often change value before finally burning through. Many VFET had to run very hot for long before the FR finally failed.

When exchanging VFET between amps, do it pair-wise. These should be selected pairs to keep distortion low.

Whether it is possible to use a complete PCB from one model in another model, honestly I don't know. The schematic certainly looks very similar.

- Johannes