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vfet

  1. A

    Sony TA-4650 help needed

    Dear all, I inherited a TA-4650 from my dad which had been idle for around 15 years. I used it with great enjoyment for more or less a year before noticing one of the channels was sounding more silent than the other. The difference wasn’t huge, but it was perceptible. Given the reputation of...
  2. MartinAudio

    Sony TAN-5550 Restoration Thread

    Some time ago, a friend of mine inquired about purchasing a VFET amplifier, and was veering towards a Sony TA-N7b. However due to both their expense and rarity, he decided to go with the more common and easily servicable TAN-5550 model. I've worked on a few of these at this point and know the...
    • MartinAudio
    • Thread
    • 5550 death diode rebuild recap restoration servicing sony tan-5550 vfet
    • Replies: 37
    • Forum: Solid State
  3. Connor G

    Sony TA-N7B VFET Amplifier Restoration

    Preface: Hey everyone! It's been a while since I've posted here or on YouTube, so I wanted to share an update about a project I started back in June. Life has been pretty hectic with work and everything else, leaving me little time for any repair or restoration projects. However, I did carve...
    • Connor G
    • Thread
    • amplifier restoration sony ta-n7b vfet
    • Replies: 19
    • Forum: Solid State
  4. G

    Siliconix VM1013 VFET Power VMOS Transistor

    I have a box of Siliconix VFETs model VM1013 Power VMOS transistors in a TO-3 package that I acquired back in the mid 80s. I tried searching for the datasheet but could not find it. My search did lead me to this forum which appears to have a great deal of interest in VFETs. I don't know if...
  5. spaghetti

    Sony TA-N7 maintenance

    I recently pulled the trigger on this amp, I was looking for a new VFET amp to add to the collection, and I was eventually able to find this one for a reasonable price. Unfortunately, since the local European version is generally too expensive for my pockets, I decided to buy the 100V Japanese...
  6. Andyrlb

    Sony TA-5650 Vfet amp & tuner

    I was told how valve like these Sony amps were and that description is spot on .
  7. El Guapo1

    Yamaha B-2 restoration Chicago

    Hello all, I’ve recently come across a Yamaha B-2 in quite nice shape. Everything seems to be working properly as it produces sound (from videos sent to me), and quite good sound at that, as the seller almost had second thoughts. Reading through numerous threads about the B-2 on this forum it...
    • El Guapo1
    • Thread
    • b2 power amp vfet yamaha
    • Replies: 23
    • Forum: Yamaha
  8. AlexHempel

    Sony TA-4650 VFET Amp Restoration

    Greetings all, I purchased a Sony TA-4650 VFET amplifier as a quarantine project and thought I'd start a thread to document my efforts. My Stax headphones go well with warmer, less-fatiguing amps and I left my Pioneer M-22 back in NYC, so this seemed like a good pick-up. Plus, I want to see if...
  9. PE9ZZ

    Replacing VFETs with MOSFETs

    Many people said it couldn't be done so I saw a challenge. On the Audiofreaks forum I documented (in Dutch) my efforts in getting a dud Sony TA-4650 going again without having to resort to tying to get unobtanium 2SJ18/2SK60 SIT transistors. I decided to use IRFP(9)240 instead. Of course the...
    • PE9ZZ
    • Thread
    • 2sj18 2sk1057 2sk60 bias irfp240 ltspice mosfet sony ta-4650 vfet
    • Replies: 79
    • Forum: Solid State
  10. JJ7212

    Yamaha B-2 owner looking for repair shop in Japan

    Hello! First post here. I am an American who has been living in Japan for the past 12 years. I bought a Yamaha B-2 a few years ago. It had LEDs and gold plated speaker terminals on the A channel. I paid about $100 for it junk because one channel had no sound. Deoxit fixed that easily! The...
    • JJ7212
    • Thread
    • dc offset japan repair vfet vintage amplifier yamaha b-2
    • Replies: 2
    • Forum: Solid State
  11. spaghetti

    SONY TA-5550 VFET amp - need help

    I bought recently this amplifier sold as not working, but with clicking relay according to the seller. I did not test it. Right when it arrived I removed the precious VFET transistors, checked them and they're all still OK, so I put them aside. I started replacing the killer diodes, then...
  12. MattiaM

    Sony TA-8650 bias adjustment

    Since there is no unique source of information on the bias for the Sony TA-8650, with no mention of changes from the 125mV in the original Sony Service manual in any service bulletin, and rumors from a Japanese forum of a required new value of 30/40mV, I decided to do a quick and by no means...
    • MattiaM
    • Thread
    • bias adjustement distortion sony vfets ta-8650 vfet vfets
    • Replies: 8
    • Forum: Solid State
  13. MattiaM

    Sony TA-8650 filter cap replacement?

    I got my hands on a beautiful TA-8650 that I bought broken a couple of weeks ago and brought back to life. It's the best example I have ever come across, nobody had ever worked on it, and it was in storage for a very long time (in a very dusty place). It came with 3 of 2SK60 gone and a burnt...
  14. MattiaM

    Sony TA-5650 V-FET high pitch annoying noise

    Hello, I just completed (or so I thought) the restoration of a Sony TA-5650. I am a novice in electronics, and this is one of my first restorations. I replaced the kilelr diodes, added the voltage doubler mod for the power supply, replaced the transistor that control the DC offset, recapped it...
    • MattiaM
    • Thread
    • sony sony ta-5650 sony vfets ta-5650 vfet
    • Replies: 18
    • Forum: Solid State
  15. spaghetti

    SONY TA-4650 first power on

    Hi there, I've just finished refurbishing a Sony TA-4650 VFET amp. First thing I did was remove the VFETs, they all tested fine on the DMM, so I went on replacing the suicide diodes, making the PSU voltage modification in order to center the B+/B- values, and replacing four 1.5K ohm resistors...
  16. Wire Nut

    Sony TAN-5550 Build

    After building the 4650 integrated amp up and hearing it sound so good, I had a hankering to see what more power sounded like. I snagged a 5550 power amp on Ebay that was in pretty good shape. Here is a link to the HFE page on the amp with the owner's and service manuals...
  17. ahess

    Sony TA-4650 Restoration

    I'm glad to be adding something to the forum after having followed so many posts! This is a restoration project for my first-ever audio purchase--a TA-4650 from an enlightened stereo person who brought me into the audiophile world when I was 16. There is a lot of love in this device...
  18. grandpaslab

    VFETs for Sony TA-5650

    I'm sure this has been asked many times before, but does anyone have a line on real VFETs? Specifically 2sk60 / 2aj18, for a TA-5650. I've got a unit with 2 bad VFETs and I'm on the fence about whether to hang on and try to find replacements, or just part the thing out. eBay seems to be chock...
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