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Marantz PM-8 Integrated Amplifier Repair & Restoration

I’ve been very busy repairing and restoring this stunning Marantz PM-8 integrated amplifier.

The Marantz PM-8 integrated amplifier is one of very the amplifiers from the golden era of serious hi-fi equipment. These amplifiers are monsters, massively powerful and massively heavy. They are also massively complex to work on and this one had a massive fault!

Marantz PM-8 Specifications

Power output: 150 watts per channel into 8Ω (stereo)
Frequency response: 5Hz to 100kHz
Total harmonic distortion: 0.01%
Damping factor: 100
Input sensitivity: 0.2mV (MC), 2mV (MM), 150mV (line)
Output: 150mV (line)
Speaker load impedance: 4Ω (minimum)
Dimensions: 416 x 146 x 437mm

More photos and details of the Marantz PM-8 restoration soon. You can find my article about the exploded filter capacitors, here! In the meantime, here’s a video summary of the testing and setup of bias, DC offset and power supply voltage.

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14 thoughts on “Marantz PM-8 Integrated Amplifier Repair & Restoration”

  1. Im going to be the next proud owner of a pm8 mkII. I would like to know how you rate its sound quality next to some of the best in the market.

    1. Hi and well done on acquiring a PM-8. These are excellent integrated amplifiers and potentially sound very nice. How good they sound depends largely on state of service and whether they have been properly overhauled at this age. There are better sounding integrated amps out there but you’d have to go to something like an Accuphase to take that next step. Enjoy!

  2. Thanks for the response.
    Since process of restoration is quite laborious and then sometimes we are NOT truly satisfied with the performance, it would be nice to know a few superior models ….can you numerate some other amps that can be had for near a 1000 dollars (used) that would easily out perform a pm8.

    Also How please guide about the following ?

    Accuphase E 205
    Soulnote 710
    Adcom 555 mkII
    Luxman L550x.
    Sansui AUX 111 mos vintage .
    Quad 303
    Kenwood Supreme 600


    1. No problem, unfortunately I don’t have the time to provide a guide of the type you are looking for here and prices vary according to region. My whole site is devoted to this sort of thing though so have a good look around and try to have a listen to these units where possible. They all sound different and have various strengths and weaknesses. Every amplifier of this age will need overhaul, so this should be factored in to any purchase decision. I’m sure you’ll enjoy the PM-8 anyway!

  3. Hi,

    i recently purchased the PM-8 in excellent condition together with turntable, CD, tuner and speakers. A fantastic setup. However I cannot locate a user manual. Do you have any ideas where I can grab one?

    I have combed the internet with no success


  4. Hi Mike,

    Don’t know if you will read this but I just bought a pm8, it’s absolutely gorgeous.
    I’m having 2 issues so far.

    First the volume control, it makes the right channel crackle if I adjust it too fast.

    Second issue and the really big problem is with the phono stage though.
    It kind of builds up a humming/loading sound and then a loud pop goes of in the left channel (first time it happened I played kind of loud and I guess I’m lucky my speaker didn’t get destroyed).
    This is regardless if I play records or not, it can be quiet for 5-10 minutes then it happens again.

    Also it is on both phono connections. I first thought it was only on the mm/mc connection and when I did hear the disturbance start I gently gently touched the mm/mc selector and it disappeared, but eventually came back.
    I tried switching to only mm connection and played fine for 20 minutes or so. I then stopped playing records and focused on the upcoming wall-mount of my tv so that this beauty can sit on top of the bench, forgetting to switch of the amp the build up of distortion started again and ended with a pop.
    So it’s on both connections.

    Also when I had the volume cranked up a bit and I heard some of this weird noises the first time I lifted the tone arm and the sound went bananas.

    I’ve read somewhere on YouTube about a subsonic filter available on some old equipment preventing bass to feedback through amps.
    I can’t find any user manual for the pm8.
    I’m sure there’s something wrong the amp but I’m curious about this subsonic filter and if it is available on the pm8….there’s a lot of filters/buttons on it.

    I’d be most thankful for any input you could help me with.

    Kind regards

    1. Hi Kim, well done on your PM-8 purchase! I can’t get into great detail here about your amp without seeing it and running through and a fairly extensive list of checks and basic maintenance, but I can say that if it hasn’t received this maintenance in the hands of someone who really knows what they are doing, it will absolutely need it. Finding the right person is the key.

      Beyond that, these are complex amplifiers that need much deeper overhaul work at this age, and attention to various design aspects that collectively combine to create the sorts of issues you’ve described and others.

      Acoustic feedback is a very real thing. The rumble or subsonic filter is not designed to resolve it, though it may help. You need to make sure there is no coupling between the turntable, shelving and equipment supports, speakers and amplifier, or this positive feedback you’ve described will occur and potentially destroy your speakers. Everything needs to be mechanically isolated from everything else, and this is a topic in itself.

      So there’s a bit to consider here. We offer an advisory service for scenarios like this, and you are welcome to utilise it, it’s accessible via the contact page. Keep in mind though that nothing can take the place of a specialist going over your equipment and giving it the care and attention it needs.

      1. Hello again and thank you very much for your input.

        The shop had their guys try to find the problem for some time now and then they eventually sent it away and that guy found a capacitor for the phono preamp that needed to be changed out. He also took a look and cleaned “everything”. The crackling sound when turning the volume control rapidly is unfortunately still unsolved as he said it needs a new potentiometer as he didn’t dare to take it all apart as it is too complex.
        Any chance that you could sell me a replacement?
        We can continue this conversation on email and you send me all the specs so that they can verify that it is the one they need.

        Kind regards

        1. Hi Kim, always a pleasure, I figured you had this sorted as I hadn’t heard back. We don’t offer retail parts sales, so I cannot assist with that, unfortunately. I will say though that, having worked on quite a few of these and just about everything in this series, and based on your description of the fault, it’s unlikely to need a new volume potentiometer and very likely to need only the right maintenance and troubleshooting approach to resolve any remaining issues. One new capacitor in a phono preamp is not going to get this old girl running right unfortunately. I highly recommend you find a local specialist with experience working on these beautiful old amplifiers as they are complex and have many quirks that need attention/consideration. It will also need a complete overhaul at this age. We do offer remote assistance and can help other technicians in certain cases too.

          1. Thanks again for the very fast response. It took quite some time for the shop to search and also send it away and get the riaa fixed but like I said I’m worried regarding the crackling when turning the volume up and down as parts seem to be difficult to find.

            What contact info should I give them if I’m going to continue with this amplifier? Because right now I’m having second thoughts if I dare to buy it without a serious check up and I have no idea whom I can ask but pretty sure that with your help the shop could get it done so then it’s just a matter of if they are willing to.

            Kind regards

            1. No problem, happy to help. Equipment owners and other technicians can book consults via my contact page, but a word of advice – as much as I love helping people with equipment like this, a complex and valuable piece like this should ideally not be with a repairer who needs my help. Again, I suggest you find a really reputable specialist with experience repairing these beautiful old amplifiers, that way you can have everything attended to at the time she visits. Where are you located?

                1. I love Sweden and yes, it’s just a case of finding someone you can trust. My advice in situations like this is to call the best hi-fi store/s in your biggest city and ask who they use for this type of work. You’ll usually be steered in the right direction. Best of luck with this!

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