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  • Carver M-500(t) mkII Restore and Upgrade

       (5 reviews)

    Nelion Audio

    This service is a full restoration and possible upgrade which includes cleaning inside and out, replacement of all consumable parts, reflow of questionable solder, service bulletins, new LEDs (your choice of color) for the meters, new 5-way binding posts, high-quality output relay, and the mkII upgraded components. The mkII upgrade gives your 500(t) a much higher power rating, more headroom, less commutation distortion, better current sourcing and performance into low impedance loads, and tighter bass and transient control.

    We are the only techs authorized to perform this mod. Any other 'pros' out there claiming they can do this upgrade have copied information available on our websites and perform these upgrades without our permission.

    Our prices are well worth every penny. We stand behind our work 100%. If we can impress Bob Carver himself with our work, you can't be disappointed!


    FAQ: Are repairs covered under the restore? Yes. When we say restore, we mean it. It's not a gimmick. We really do tear down and replace all components known to go bad over time. Only extraordinary things like human meddling, corrosion, cracks, etc might not be covered, but only if these problems impede the operation of the unit. We have to cover a 3 year warranty, so we will make sure the unit is as flawless as possible.



    How they look when we get them:



    How they look when we're done:




    Features of Restore:

    - Long life high temp capacitors throughout

    - High performance audio grade capacitors in signal paths

    - Replace all power rectifiers

    - Replace output protection relay

    - Replace meter bulbs with LEDs of your color choice

    - Perform factory service bulletins where needed

    - Calibrate, burn-in and test to specs. I also listen to all the amps I work on. It doesn't leave my bench unless is sounds like it should.


    mkII features:

    - Replace voltage trim pots

    - Replace and upgrade power switching diodes

    - Replace high power switching transistors and drivers in power supply

    - Replace entire pre-drive stage transistors to higher voltage, higher power type

    - Replace input opamp buffer to audio grade device

    - Completely upgrade and rebuild output stage transistors for more linearity, durability and higher power handling

    - Upgrade speaker binding posts to modern 5-way gold or silver

    - m500 models are upgraded with the 't' mod, as recommended by the factory.


    Comes with a 3-year parts and labor warranty.



    Power into 8 ohms:
    Stock: 251 watts  
    MKII: 395 watts 

    Clipping into 8 ohms:
    Stock: 270 watts
    MKII: 410 watts

    Dynamic into 8 ohms:
    Stock: 380
    MKII: 520 watts


    Signal Path Upgrade:

    High grade polypropylene capacitors are installed in critical areas to maintain proper signal conditions while under heavy loads or heat stress. While the amplifier is extremely resistant to trouble caused by noisy or heat stress conditions, this upgrade will take it a step further to increase the amp's performance in demanding circumstances.


    LED options:

    Warm White:







    Cool White:





    All new power output transistors for high linearity and power handling:



    Binding Posts (gold shown) and optional IEC socket




    Although the Dim Switch will still dim the LEDs, The LED driver can be trimmed to your brightness preferences (Driver model 002 shown):





    Base Restore Cost: $380 + shipping

    mkII upgrade add: $150 (includes Gold speaker binding posts and LEDs of your choice)



    IEC socket: $50

    Signal Path upgrade: $65

    Gold RCA jacks: $50

    M500 power switch (added to back of unit): $50

    12V input on/off trigger: $50

    Install 't' Mod on M-500 model: $20

    • Like 2

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    I worked as an electronics restoration tech for many years. I saved a smoke-damaged M500 from a fire, meticulously cleaning it with pressurized DI water and surfactant. 

    I used the amp for years until one day my wife's friend plugged a 3.5mm adapter from the input directly into her phone, cooking the right rail as the phono jack shorted. I fixed the first stage, but as the current came up it cooked again. 

    Greg fixed my baby, making it better than ever. This amp means more to me than any other physical possession. Just do the MKII service--it's cheaper than buying many consumer receivers, and for it you'll get 30 more years from one of Bob Carver's coolest all-around designs. 

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    I have two M500t amps, and had both restored by someone I found on eBay.  I had major/minor problems with both, so I sent them to Greg to look at.  Greg opened them and sent me photos of what he found, and it's clear that someone who does not know electronics can be taken advantage of, as I was to some degree. 

    So, bite the bullet and get your amp done right, by Greg, the first time.  You'll save yourself a lot of time and money.  Looking at the attached "before and after" photo, even to my inexperienced eye I can clearly see the difference between the "'eBay build" and Greg's workmanship. 

    The amps sound fantastic, and I look forward to many years of enjoyment with them. 


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    I came across a M-500 a couple years ago.  The amp was in cold storage for around 18 years.  I plugged it in and it worked but I could tell it needed service.  I did my research and boy did I get lucky when I came across Greg's number.  I sent the unit out to him and paid for as many upgrades as possible, including getting rid of the cheap power cord and replacing it with an IEC.  I used to sell Carver in the 80's so I'm very familiar with the amps and pre-amps.  This M-500 sounds SO awesome after Greg did what he does.  Greg also stands by his work.  A few months ago I had an issue with the right channel.  I called Greg and he sent me a shipping label.  He said send it back and I'll take care of it.  Couple weeks later I hooked it up and I've been listening to it ever since.  Keep up the good, sorry, great work!


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    Years ago I had borrowed my brother's 2 Carver M500t amps with the MKII upgrade (done by Nelion Audio).  I absolutely loved the sweet, powerful sound they put out so recently I purchased 2 Carver M500t amplifiers online with the sole purpose of getting both upgraded to the MKII mod.  When I received the amps I verified they worked and immediately sent them directly to Nelion for the upgrade.   When the upgrade was complete I picked up my amps and installed them in a bridged configuration (1 per channel) in my den.  Now I cannot listen to my new system without a smile on my face.  The mod is well worth the price and the quality is top notch.  I wouldn't hesitate to recommend this upgrade from Nelion Audio.


    2 Carver M500t with MKII upgrade, Parasound P5 Halo preamp, and Definitive Technology BP2000 speakers

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    Just got my C4000 refurb and (2) M500t's w/Mkii upgrades back from Greg ...and they sound Absolutely Fantastic !!   I am fortunate to live in Michigan so I could hand deliver & pick up my equipment thus saving shipping costs.  I strongly urge anyone considering having Carver refurb/upgrade work done to avail yourself of Greg's services. He does exceptional work, stands behind it, and is just a great guy to do business with!  

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