Picked up a huge Marantz receiver (SR8200) at the local donation center for not very much money.


Even though the donation center has a 7-day return policy for non-working electronics, the receiver was worth more than I paid (to me) in parts alone. I quickly discovered that the volume knob was “stuck”. It is a rotary encoder type (not a potentiometer type). The volume setting would barely move when turning the knob,

Thanks to my familiarity with rotary encoders, I quickly recognized this problem as “noisy transitions” within the rotary encoder. In other words, it needed (more) debouncing. What I did was to install some capacitors to the signal pins and viola! it works almost as new. There is still a bit of debouncing problem but does not affect the responsiveness of the rotary encoder. If I experiment with different value capacitors, I would likely solve the problem, but for now this is good enough.


Other than this, the unit seems to be working properly. The only disadvantage is that now I cannot justify gutting it for parts🙂


From the golden era of Made in Japan audio electronics. Things are put together with more screws than seemingly necessary. Plus, this is the first device where I find the use of copper (or some copper allow) screws. The chassis is made of traditional stamped steel.


Nice brushed aluminum front panel (but the knobs are “metal looking” plastic)


The most ELNA capacitors in one place!


One of the last through-hole, hand-crafted audio components…



This receiver, old enough to be powered by a liner supply, is rated at 6x130W (780W for the amplifier section).

It uses a large EI transformer with a copper flux band. These bands are used In order to reduce the radiated flux from the transformer core,  acting as a shorted turn to the leakage flux (only), greatly reducing magnetic interference to adjacent equipment.


There are two 27,000 uF “Marantz” filter capacitors. Incredibly good looking! I believe they are made by ELNA (as every other capacitor is also ELNA). The heatsink behind the capactors is for the bridge rectifier. .

(Update: a reader alerted me that the caps are made by Nippon Chemicon. The logo is in plain sight)




There is space for two additional capacitors. A nice mod would be to add a couple of Panasonic 4-lead capacitors such as these: Panasonic T-HA 10,000-18,000 uF, 63V [link][link] (with care not to blow the fuse due to in-rush current during power-up)


The SR9200 uses 4 capacitors with higher voltage rating but lower capacity as shown in the photo below  [link]



The volume control is provided by two 6-channel Toshiba TC9482N volume control [link]



These devices control up to 8 analog channels (7.1 multichannel) that area available as pre-out but only 6 of them connect to power amplifiers

The input and outputs are buffered by NJM 2068DD opamps [link]. The “DD” grade devices exhibit lower noise specification. Where have we heard about these NJM2068?… From the development of the famous O2 headphone amp [link]

BOTTOM LINE: For those wanting to skip the Tech Section, the conclusions can be summed up as follows:

At gains less than 4X nothing overall could beat the $0.39 NJM2068 in the O2’s gain stage. This is especially true if you’re concerned about power consumption for battery operation.


Current prices of the 2068DD are $0.60 in quantity 1 orders [link]


Stereo D/A board uses CS4396 D/A (3 of them).



A 6-channel module with forced cooling.




Local power supply bypass capacitors. Notice the space for larger size capacitors (the higher model SR9200 uses larger capacitors). Replacing these capacitors with larger ones (a 1000 uF nichicon KW [link] for example -maximum diameter is 16mm) would be an easy mod.


Local PS bypass capacitors in the SR9200


Output transistors: SANKEN A1492 (PNP) and C3856 (NPN)



There is an 8-channel analog input option (7.1 input) that bypasses all the digital processing. They are controlled by the analog volume chips and the output is available through the 8-channel pre-out. Six of those 8 channels are connected to the  6-channel power amplification module. This receiver can be used as a stereo tri-amp setup.



  1. voyager
    January 18, 2015 at 14:52

    Nice teardown, I always wanted to buy a old harman kardon (the black gold ones) and mod the hell out of it🙂 I also upgraded the main filter caps on a very basic harman AVR130 I got for free with a dead channel, but It did not like the bigger caps. On startup sometimes it switches off if the caps are empty. It’s like the protection kicks in and is not expecting the slightly longer time it takes for the voltages to come up.

    • BlgGear
      January 19, 2015 at 00:50

      Thanks. Yeah one has to watch out for inrush current tripping whatever current limit protection it has. It could actually blow the fuse. I’ll have to check the schematics…

  2. John
    January 18, 2015 at 15:03

    I had the same problem with the rotary encoder on a similar Marantz. It turned out that the lubricant they use in the encoder turns into paste over time. The paste makes the encoder hard to turn and it prevented the wiper from making contact with the pads. I took the encoder apart and removed the offending paste. Now it works like new. Who would have thought?

    • BlgGear
      January 19, 2015 at 00:48

      Yeah. I was thinking of taking the encoder out to check it out but after looking at the amount of screws, I decided to try the capacitor mod. In this case I think the problem is due to noise during the transitions. (reflected on the fact that the volume level changes forward and backwards).

  3. Sam5050
    January 18, 2015 at 17:52

    You might want to think about the Elna Silmic II caps to replace those power bypass caps. I’ve really great success in my DAC mod project with them (replacing the Elna’s). There is a link to a couple of capacitor sound quality shootouts (both film and ‘lytic) on my DAC MOd Project thread. http://www.head-fi.org/t/740362/lite-dac60-pcm1704-r2r-tubed-dac-mod-project

    Those big blue Marantz caps are gorgeous! Worth buying for those alone – I’ll keep an eye out at my local thrift shops (always in there looking for LPs)

    • BlgGear
      January 19, 2015 at 00:44

      Thanks. The only limitation is the capacitor footprint. It can only fit <15mm 16mm. Many of the higher value caps are 16 mm 18mm. I'll check the silmic IIs. The existing ones could be Silmic Is

      • Sam5050
        January 19, 2015 at 01:04

        No those in the Marantz are the common Elna’s, although the Silmic II have a similar color – they’re clearly marked on the side. And a very nice step up in sound quality – rich natural tone – the std Elna’s are a bit thin and reedy. My experience is they’re the same size or pretty close. Here is a good source for lot’s of values – they’re hard to find in stock at the regular supply chains like Mouser and Digikey. http://www.partsconnexion.com/capacitor_ele_elna_rfs.html

        The Pannie FCs might be a good choice in high heat areas as they’re rated to 105C. Not a smooth sounding as the Silmic II’s but not bad. Still a step up from the std Elna’s.

  4. Sam5050
    January 19, 2015 at 01:09

    BTW checking on size the same 220uF/ 50V Simlic II’s are exactly 16mm (which I think ou said was max dia there).

    • BlgGear
      January 19, 2015 at 16:59

      It needs 63V like the rest of the PS caps. Those are 18mm. OK fit in most places. But certain locations may require some tricks. Digikey has Silmic II 470uF/63v. Here is a list of possible options:

      Nichicon FG: 330uF, 100V, 16mm: $1.27 Q.10
      Nichicon FG: 470uF, 63V, 16mm: $1.52 Q.10
      Elna SII: 470uF, 63V, 18mm: $2.41 Q.10 (tight fit)
      Nichicon KW: 1000uF, 63V, 16mm: $2.07 Q.10

  5. January 23, 2015 at 13:39

    Hi,those big caps are made by United Chemicon (or Nippon Chemicon during old days).The logo is printed on the caps.

    • BlgGear
      January 24, 2015 at 06:12

      You are right! The logo is in plain sight.

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