Modding SR4300 - The Results


Hifi Newbie
After changing some wirings in my SR4300, things did change and it isn't subtle.

1. Replace the analogue audio wires with the Belden 833322. Connect drain wires for shielding.

2. Replace the power socket with a TDK AC noise filter and the wires going to the circuit board with Belden 9583.

3. Replace power lines from main circuit board to transistor circuit board wiht Belden 8719. Connect drain wires for shielding.

4. Wrap the power lines leading to the transformer with shielding foils and connect drain wires.

The sound did change. The level of detail and treble has increase (I have to warn that some might find the treble too bright)

The loudness has also increase. I have to reduce the volume by about 10db to get back the same level as before. I don't know but I do think that lower volume will reduce noise and distortion.

The hissing noise has reduced. I couldn't tell exactly how much but definitely softer.

All these cost me less than 20 pounds (after converion to UK currency).


I'm pretty interested in what you've done, but want to apply it to the 7300. Could you give me a little more detail about what a "drain" wire is amongst other things. Do you plan on putting together a little step by step guide for those not scared of a soldering iron ?
Was the hissing noise what prompted you to do this ?

Thx in advance,


John A.
HiFi Newbie,

Great. Well done! I advised against, but stand corrected! The question remains whether the Marantz design was optimal in their estimation, or whether they were making small savings to the detriment of sound quality.

I once modified my Marantz CD player to remove a spring holding the disc transport down. The spring was pulling the laser head to one side, causing mistracking. I took away the spring and packed the plastic retaining flap with Blu-Tac, so gravity would hold the disc level, instead. It sounded better and has worked like that for 10 years. I could not see what the spring was for, unless it was to allow the player to work upside-down, or else to skim about 100 g or 4 oz off shipping costs.

Anyway, it certainly reads like you now have a much better receiver. Consider sharing precisely what you did, as requested above. I suppose it could be some work and might need photos, though.

Hifi Newbie:

When you say you changed the power socket did you mean the female IEC connector at the back of your reciever for one with a built-in RFI filter? I have read somewhere else that this can be an effective upgrade. Very interested in your conversion can you please explain further? Thanks.

Where do you stand with your warranty now?
Presumably you'd have to swap everything back if you need to return it to a dealer. You said in a previous post that all the cables have got plugs so this can be done.

Sorry, that should be the male IEC connector.

Hifi Newbie
Sorry, I actually mean a grounding wires instead of drain. The wire is connected to the shielding foils to ground it thus the noise thats converted to electrons could the "drained".

As for the power socket, I think its the IEC connector. I didn't know whats the actual term but its that 3 pin power socket (its the same as the computer 3 pin power socket).

The unit does not have a filter for the power. I bought one and fit it in.

I will take pictures and post the links here in order to make things better.

Hifi Newbie:

I was wondering if you were to only change the IEC connector to the one with the built-in RFI filter would that be enough to achieve the performance gains in terms of detail, volume and treble you are experiencing?

Also is their a certain specification required for the new male RFI filtering IEC connector or will anyone do the job? Which model from TDK did you use? Thanks.

Hifi Newbie, Wow :-)
This sounds great, could you please provide links to the materials you used?

Hifi Newbie
I will post the pics and details on how I did the mod shortly (I don't work on Sat and Sun, thus will have the free time to open up the amp to take the pics).

I also did some simple mod to my Jamo E800 which I think makes things sounds better overall. Will post pics of it too.

Any update with the details posted yet?
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