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Thread: OT, ....New Capaciitor Type.............. for AUDIO Use....

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    Senior Hostboard Member LowOhms's Avatar
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    OT, ....New Capaciitor Type.............. for AUDIO Use....

    "OT" in my "Title" usually stands for " Off Topic", but I want to suggest, in this case, it really means " ON Topic " !!

    This is my first full disclosure on a public Forum of a new film capacitor type, that has profound and serious uses in audio, in my experience and in my OPINION.... both in speakers and amplifiers.

    It is called a Gate-Turn-Off capacitor, and you can read datasheets from people like WIMA, who produce these. I have also seen RIFA " GTOs" and Arcotronics brand " GTOs", which has been merged into Kemet.

    This is a long post and story, be forewarned.

    In April 2016, I befriended a fellow in the Netherlands, an eBay capacitor seller, who, like me, built Single Ended triode amps, he did 300Bs, and I was doing Type 45s then. WE are both amateur enthusiasts.

    My new friend John tells me about his favorite sounding cap, ......an ARCOTRONICS film cap, 5 uF value at 1200 VDC rated. Easily sensing this fellow was legitimate, I ordered some of these capacitors from him, and immediately incorporated them in a second-generation Type 45 SET direct-coupled amp I had designed and was building just THEN, for myself, for VOTTs..

    I ordered many of these, and used two for the shared power supply. This stereo amp used a single L1/C1/L2/C2 B+ filter to the Finals stage. These 5 uF caps were added. as part of a multiple film bypass cap " bunch or bundle ", across C1 and C2, which usually are about 30 uf ( C1 ) and 50 uF ( C2 ) in value.

    I was also FINALIZING my own DIY VOTT 800 HZ crossovers for my speakers, so I included this same type 5 uF Film Caps as part of each " C " position in a 12 dB / 800 hZ, Butterworth Filter. So, it was to employ two ARCOTRONICS GTOs, per crossover.

    In May, 2016, when I fired-up the newly-built 45 amp ( and speakers with new crossovers ), for the first time, it all sounded very good to me. Nice and dynamic.

    By about August, 2016, I go the nerve to disconnect the ground from ONE 5 uF Arcotronics Gate Turn Off cap, bypassing C1. Holly smokes.....the whole system died in Dynamics and sounded very ordinary. I quickly re-connected the C1 5 uF GTO bypass, and have listened that way, religiously, since then.

    I didn't tell too many about this result. In December 2016, I had a USA friend, who I had shown photos to of my DIY VOTT crossovers, call to tell me " he figured out what the cap was, and where to get them ". Lawrence said he ordered some, and installed it in his system, and he was FLOORED. His specific description " It gets the LEADING EDGE of all transients, from the bass on up, UNLIKE anything we have ever heard any wheres in audio ". I truly LIKE his description, after living with these at that point .....for over half a year.

    Lawrence gave me his own unsolicited and unexpected surprise confirmation. So, I re-read the literature on line, in the eBay ad, etc etc to find out more about this device., in December 2016. The spec given by the eBay seller was 1.3 milliohm ESR at 100 khZ, which is very good, and 64 Amps RMS, not too shabby.

    By CHANCE, I notice WIMA made this same type of industrial cap, so I downloaded their datasheet on GTOs. Inside, I found out what I was likely responding to. These caps, besides being supremely low in ESR, ( as are some other caps ) it can ( UN - like other caps ) do INSTANTANEOUS PEAK currents, ( in my size : 5 uF at 1200 VDC ) - in the WIMA datasheet - of " about 1,500 AMPERES PEAK " !!!!!!!!!!!!!!!!!!!!!.

    This instantaneous peak capability, I surmise, it what is now giving us " The leading edge of all musical transients, from the bass on up " as precisely described in November by my copy-cat nice friend Lawrence, who is a good listener.

    In early 2017, I had urged my good personal friends, in audio, to acquire some of these caps for their own use, typically on ALTEC systems, so they are " covered ". The reports from users, are all very positive. In January, I had a St. Louis musician friend add them, in this order : first to his DIY 604 MLTL woofer crossover, then to his crossover's tweeter section, and finally to his amps.

    This was the OPPOSITE of my practical experience in 4-2016, when the amps and speakers got the treatment ALL at one time. His report was very positive, each step. He has also has recently done his upstairs Valencias.

    There is also a ALTEC User, a friend and Forum Member frorm Canada, that has had a similar experience in the last month, with his 604s and his VOTTS. . I asked these friends NOT to discuss this, until I decided to release the information to the audio people up here. Todd, today, thankfully has paved the way !!

    The GTO 5 uF ARCOTRONICS eBay auction, most recent, is here for all to see:

    5uF 1200V MKP Filter Caps GTO LOW ESR HQ arcotronics 2Pcs | eBay


    These 5 uF at 1200 VDC film caps normally will sell in the $50.00 to $80.00 each range, so two for $16.95 is attractive. Kemet, who presently owns ARCOTRONICS, sells the same value part for over $50.00 but has a 50 part minimum.

    Shipping from the Netherlands can be done in packages of up to five or up to thirteen pieces, advantageously. I am pretty sure John in the Netherlands has under 100 pieces left, and I would APPRECIATE IT if someone does NOT buy out all of his stock, so OTHERS can try this out, and we can " share " our results and experiences among more than just a few users. Many of the caps will be scratched and chipped from poor storage and handling. Not usually a factor .

    In a separate post, IF any ( or enough ) folks are interested, I would be happy to cover what I have learned as far as how to most-effectively implement this part. The two mounting bolts I get from McMaster Carr, and they are BRASS, M-8s at 12 mm length, and a 1.25 pitch.

    :-) No no, we do not use 26 AWG magnet wire ever, to connect these caps, .....for obvious reasons. I would be happy to assist any who have an interest.

    In my humble opinion, and Old Guy, its ONLY " my " opinion, from listening for over a year, possibly the first in the USA to do so, this is the future !!


    Thanks, too long a post !!


    Jeff Medwin...... Low Ohms , Low ESR, High Current



    PS, Here is a 6 uF VISHAY GTO, only an example, rated at 7,200 Amperes PEAK current :

    http://www.vishay.com/docs/13094/gto4500.pdf
    Last edited by LowOhms; July 12th, 2017 at 11:58 AM.

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    Senior Hostboard Member drummerwill's Avatar
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    Re: OT, ....New Capaciitor Type.............. for AUDIO Use.

    Yep
    I use them, the Acrotronics 4.5uF 1200v cap the "Hockey Puck"........

    They are the Bomb ! I put them in my 26-26 DC 45 SET stereo amp amp
    the amp transformed into a Dynamic , Clear sounding, Detail monster.

    I just put the GTO's in my Valencia's rebuilt N-1500A crossovers. I've had them in
    for a couple of weeks now. They changed my Valencia's into a sound closer to
    what I've been getting from my 2-way Altec/JBL MLTL system ..... Oh yes
    the 2-way MLTL has GTO's in it's crossovers also..

    Thank you Jeff for the info on these caps.


    Willie
    "And the beat goes on"<br /> Willie

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    Hostboard Member kwingylee's Avatar
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    Re: OT, ....New Capaciitor Type.............. for AUDIO Use.

    Quote Originally Posted by drummerwill View Post
    Yep
    I use them, the Acrotronics 4.5uF 1200v cap the "Hockey Puck"........

    They are the Bomb ! I put them in my 26-26 DC 45 SET stereo amp amp
    the amp transformed into a Dynamic , Clear sounding, Detail monster.

    I just put the GTO's in my Valencia's rebuilt N-1500A crossovers. I've had them in
    for a couple of weeks now. They changed my Valencia's into a sound closer to
    what I've been getting from my 2-way Altec/JBL MLTL system ..... Oh yes
    the 2-way MLTL has GTO's in it's crossovers also..

    Thank you Jeff for the info on these caps.


    Willie
    With the crazy audiophile capacitor prices in mind... I have to ask....How much are they for typical crossover values as I want to build new Hiraga crossovers for my A5 VOTTs.

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    Senior Hostboard Member GM's Avatar
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    Re: OT, ....New Capaciitor Type.............. for AUDIO Use.

    Interesting! Google can't find any info, supplier, just that Kemet apparently owns Acrotronics.

    GM
    Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

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    Senior Hostboard Member SD-50's Avatar
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    Re: OT, ....New Capaciitor Type.............. for AUDIO Use.

    Don?t know how they compare to expensive boutique caps but they are very much superior in all aspects to the PIO they replaced in my A7s &604-8Ks XOs.

  6. #6
    Senior Hostboard Member LowOhms's Avatar
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    Re: OT, ....New Capaciitor Type.............. for AUDIO Use.

    Quote Originally Posted by GM View Post
    Interesting! Google can't find any info, supplier, just that Kemet apparently owns Acrotronics.

    GM
    I forget which USA supplier, but its either Mouser or Digi-Key who handles WIMA... and GTO caps. You can see they LIST them to purchase in various values, but do not stock them.

    DOWNLOAD and review the WIMA GTO datasheet, just for your own information, a reliable source I'd say !!!

    And the 5 uF at 1200 VDC Kemet is prohibitive, in 2017, in the USA, a 50 piece minimum order.

    Nothing we have used before gets the leading edge of the transient like these caps as part of a " bundle " in a key positions in the chain. That is my experience, opinion,. and it corresponds with audio friends who have tried them, last ten months, at my instigation.

    Have fun. I am.

    Low Ohms ...... Jeff Medwin

    - - - Updated - - -

    Quote Originally Posted by drummerwill View Post
    Yep
    I use them, the Acrotronics 4.5uF 1200v cap the "Hockey Puck"........

    They are the Bomb ! I put them in my 26-26 DC 45 SET stereo amp amp
    the amp transformed into a Dynamic , Clear sounding, Detail monster.

    I just put the GTO's in my Valencia's rebuilt N-1500A crossovers. I've had them in
    for a couple of weeks now. They changed my Valencia's into a sound closer to
    what I've been getting from my 2-way Altec/JBL MLTL system ..... Oh yes
    the 2-way MLTL has GTO's in it's crossovers also..

    Thank you Jeff for the info on these caps.


    Willie


    Willie,

    Just for the record, the Arcotronics GTOs we have been using are rated a 5 uF at 1200, not a 4.5 uF value. They often measure close 5.05 uF on my uncalibrated Sencore.

    Low Ohms.....Jeff Medwin
    Last edited by LowOhms; July 14th, 2017 at 12:20 PM.

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    Senior Hostboard Member GM's Avatar
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    Re: OT, ....New Capaciitor Type.............. for AUDIO Use.

    Quote Originally Posted by SD-50 View Post
    Don?t know how they compare to expensive boutique caps but they are very much superior in all aspects to the PIO they replaced in my A7s &604-8Ks XOs.
    Which were?

    GM

    - - - Updated - - -

    Quote Originally Posted by LowOhms View Post
    DOWNLOAD and review the WIMA GTO datasheet, just for your own information, a reliable source I'd say !!!

    Nothing we have used before gets the leading edge of the transient like these caps as part of a " bundle " in a key positions in the chain.
    OK, thanks!

    OK, but if the signal chain the cap is in is 'faster' than the acceleration, decay, BW of the highest ['fastest'] transients, then the signal gets over-damped, which does lead to a perceived higher resolution, so like some of your other preferences is technically harmonic distortion.

    GM
    Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

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    Senior Hostboard Member LowOhms's Avatar
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    Re: OT, ....New Capaciitor Type.............. for AUDIO Use.

    Quote Originally Posted by GM View Post
    Which were?

    GM

    - - - Updated - - -



    OK, thanks!

    OK, but if the signal chain the cap is in is 'faster' than the acceleration, decay, BW of the highest ['fastest'] transients, then the signal gets over-damped, which does lead to a perceived higher resolution, so like some of your other preferences is technically harmonic distortion.

    GM

    LOL. Listen and then decide, don't just think...........listen !!

    RESPECTFULLY !!!

    LOW OHMS

  9. #9
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    OT, ....New Capaciitor Type.............. for AUDIO Use....


    Old Guy's Avatar
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    Re: OT, ....New Capaciitor Type.............. for AUDIO Use.

    LOL Don't just listen, think.

    Mouser page with datasheet links-

    WIMA GTO MKP Series Film Capacitors | Mouser
    Your neighbors called. They like your music.

  10. #10
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    OT, ....New Capaciitor Type.............. for AUDIO Use....


    Phil-G's Avatar
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    Re: OT, ....New Capaciitor Type.............. for AUDIO Use.

    Quote Originally Posted by Old Guy View Post
    Mouser page with datasheet links-
    dang look at the prices. I believe I could have paid less for a real GTO in the 70s
    Sonic Barbarian

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