Saturday, March 19, 2011

Marantz PM-45

This little known Marantz was once What Hifi Stereo of the Year 1988 (

Rated at a reasonable 50W RMS per channel into 8ohms, it does pack quite a punch and is barely warm even after continously use for 12hrs! Details specs are available at

The original unit sounds sweet with good details and respectable bass. However my unit required about an hour of running in before the sweetness appears. And there is the off-tone issue as per my original Luxman and Audiolab. Hence it was time to recap.

After I replaced the electrolytics on the power amplifier board, I proceeded to replace the dark green ploy caps in the pre-amp section (aka previously middle of the pix below)  with EPCOS (blue) poly of the same values. That did the job!

From top

Recapping was an easy process as all components are easily accessible with the base plate removed.

The PM-45 is a nicely balanced unit altogether!


  1. Hi I have this AMP and have a problem. The right channel is much quieter than the Left and I am wondering which CAPS I should replace. Can you give me a list of which ones and ID the preamp board and the Power amp board. I do have a copy of the service manual.

    This may of been posted twice as I am not sure that it worked the first time. Thanks, Andrew

    1. Apologies as do not have the list of the caps as did not have the service manual at the time.

      Since you have the service manual, suggest you look for what are known as the "balance caps". These are for maintaining the balance and are usually traceable from the volume knob - small value electrolytic capacitor with low voltage (one for each side).

      Replacing these "balance caps" should normally restore the stereo balance in older units.

  2. I have this amp and there is a problem with the CD/phono Direct button on the RH side. When you switch on the amp the speakers come and go with a lot of crackling and this button crackles when you turn it on and off. Doing this several times quickly seems to help but it is not 100%. Is there something I can do or is it curtains for this lovely amp? No one seems to want to repair it.

  3. I keep trying to post a question..last try. I have this amp and the CD/phono Dorect button RH side is crackling and causing the speakers to come and go. Can anyone advise a non technical person what to do? Is it curtains this lovely amp?

    1. Best for a proper technician to inspect the unit as this unit does not have any grounding cable in the AC power cable,

  4. Hi. Glad to have found this blogpost. I just hooked my fleamarket find up to my b&w cm1s2 and just had to Google it to see of i was the only one into this amplifier. Just ordered the capacitors needed and look forward to restoring this beast to its former glory.
    Kind regards

    1. Do be careful as the older Marantz is well known for crappy soldering points. Some may even loosen if you touch the component by mistake. Just remember which parts you ever touch, reposition etc