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JB Capacitors Polypropylene Capacitors - anybody tried ?

Discussion in 'd.i.y.' started by leeoh, Jun 6, 2016.

  1. leeoh

    leeoh pfm Member

    Hi Folks,

    Following the excellent advice received here in modding my Rotel RCD 955AX CD player, I replaced the two Blackgate 100uf electrolytic capacitors in the analogue output stage after the opamps stage for a couple of metalized polypropylene 4.7uf axial's.

    There was certainly no need for electrolytic's in this position, I guess Rotel fitted them as cheaper than using Blackgate polarized capacitors in this position.

    Anyway I digress, shopping around I found the usual high quality well known polypropylene brands rather expensive just to try this mod and see what the result would be.

    Whilst searching the web, I came across JB Capacitors, a Chinese manufacturer, http://www.jbcapacitors.com/Plastic...ized-Polypropylene-Film-Capacitors-Axial.html I ordered a couple of their Premium capacitors as in the link and they arrive swiftly within a couple of weeks from China.

    After installing them I did notice an increase in clarity and treble response over the Blackgates that were previously installed. Overall very pleased with these capacitors and will not be going back to reinstalling the Blackgates.

    Has anybody else had any experience of using JB Capacitors and what are your thoughts ? There's not a hugh amount of information about them on the web, but what there is, is all very positive and I can add my experience to that.


  2. Mike P

    Mike P pfm Member

    Hi Lee, any half decent polypropylene is going to be an upgrade over an electrolytic. Film/foil are better than metalised film types but tend to be much larger and more expensive. My favourite reasonably priced option are the Ansar Super Sound range which are I beleive a metalised type but with a double thickness metalised layer which makes them superior to most. They're also British made which is nice.
  3. leeoh

    leeoh pfm Member

    Hi Mike thanks, Not heard of these before, seems to be so many options out there. I think I will research these from an interest point of view, I'm not inclined to replace the JB capacitors I've already fitted as they are nice sounding and Rotel have made it a real main to diassemble the player to get access to the underside of the PCB.

    As an aside I've also recently fitted a VA Labs low jitter clock I installed with its own small transformer. This too has made a nice noticeable difference in improving the Rotel sound to warmer and more analogue like.

    cheers !

  4. awkwardbydesign

    awkwardbydesign Officially Awesome

    Did you mean non-polarised?

    Ansar caps are made by Suppression Devices in Clitheroe, and they will make you a pair of caps in your preferred value. I bought two 10uF Kelvin caps from them, and they said I could have them in any reasonable value. Cheap too!
  5. Yomanze

    Yomanze pfm Member

    Another vouch for Ansar Supersounds, they're superb in the signal path.
  6. Mike P

    Mike P pfm Member

    Good work Lee.

    Yes I'd leave the JB capacitors in there. The major difference is in going from electrolytic to film. Any differences between various different brands of polypropylene capacitors will be very minor compared to what you can achieve by doing other modifications.

    How about sharing some pics of your Rotel?
  7. Yomanze

    Yomanze pfm Member

  8. BobMaximus

    BobMaximus pfm Member

    I don't want to start an argument, but as a general statement, this is not necessarily true.
  9. Mike P

    Mike P pfm Member

    Fair enough but it wasn't intended as a general statement.
  10. leeoh

    leeoh pfm Member

  11. leeoh

    leeoh pfm Member

    Oh I should probably add, all mods done included:

    Recap entire player with Panasonic FC and an Elna silmic II
    Replaced PSU diodes with ultra fast type.
    Replaced opamps with better Hifi audio rated - sorry I forget which were some LMExxx ??
    NOS mod made.
    SAA7220 filter +5V rail powered off own dedicated LM317 regulator and transformer.
    TDA1541A DAC +5V rail powered off own LM317 regulator and transformer.
    both regulator's recapped with Panasonic FC.
    VAlabs low jitter clock fitted to replace standard Philips XO.
    DAC decoupling caps replaced to Wima MKS types.

    all thanks to inspiration from this forum :)

    kind regards

  12. Mike P

    Mike P pfm Member

    Hi Lee, those photo links don't work for me.
  13. leeoh

    leeoh pfm Member

    Hi Mike,

    Apologies, been away travelling past few years..

    Hopefully this photo link works. Wish I could just paste an image here but paste is greyed out when I right click...


    Link shows all mods completed. I temp removed the JB caps to drop in some Elna Silmic II I had as an experiment. Certainly doesn't sound worse.

    Curious now to purchase a 6N2 valve output stage off ebay and fit that bypassing the opamp output stage and see what results occur. Though the price of <£30 delivered doesn't inspire me it'll turn the Rotel into a Lector or other beautiful valve CD player...
  14. Dan K

    Dan K pfm Member

    Are you really sure that the new caps sound better than the removed blackgates? You are aware just how good blackgate caps are, and their 2nd hand value? Silmic 2's are a massive downgrade in comparison, I don't use them. TBH that Rotel CD player looks pretty amazing, they must have been sold at a loss!

    Be very careful to check the number on the opamp that you want to bin, some opamps from the Late80's are better than anything that you can buy today.
  15. leeoh

    leeoh pfm Member

    Hello Dan,

    Yes, I'm aware of the BG's sale value on ebay and sold the two in that position for half what I paid for the entire player. I bought the player very cheap at under £45.

    I don't think the Elna's sound worse that the original BG's, but will leave them in place for now whilst I debate whether I want to experiment for fun putting in a 6N2 valve stage coupled direct to the DAC.

    If I decide not to, will put back in place the JB Caps.

    kind regards


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