Recent content by hobbit

  1. hobbit

    What would you do with these cabinets?

    Ignore the wankers. Audio fora tend to be full of them. If you like them, measure them and look for suitable drivers. I'd be inclined to install tweeters as well as they look to be single full range units, if you plan to use for hi fi. I have a number of old speakers that I bought as blown...
  2. hobbit

    A general transistor matching question

    I'm junking it to be honest. It's a terrible design. The PCB damage goes well beyond where the transistors were mounted. It's delaminating.
  3. hobbit

    A general transistor matching question

    The old transistors are toast. In addition, Technics in their wisdom had a support bracket under the PCB with a hard rubber spacer in contact with the board. This is where it is visibly burnt. On desoldering the transistors the traces and pads detached so badly heat damaged was the board...
  4. hobbit

    A general transistor matching question

    Nearby resistor is running very hot noticeable with the thermal imaging camera . Surface temp of around 100 Deg centigrade. The associated transistors are running at 80 degrees C. Measuring in circuit is giving odd readings , so I need to remove and put on the tester. I think they may well be...
  5. hobbit

    A general transistor matching question

    I'm going to desolder and check but the PCB really is quite heat distressed where they are.
  6. hobbit

    A general transistor matching question

    I'm working on a few old Technics amps at the moment and some transistors in the power amp section look somewhat heat damaged. They are of course unobtanium and most of the eBay units are fakes. I have used on line matching sites and there are a number of alternatives . Looking through them I...
  7. hobbit

    Amp running cooler

    I've just replaced the power supply capacitors in my 1985 Technics SU V10x with a set of Kemet 10000 uf caps from mouser. As well as that I reflowed a lot of dodgy looking solder joints, checked values of other components , but didn't replace as the amp sounded good and the selection I checked...
  8. hobbit

    ? blown trannie

    I had forgotten the double entendre of my original post! Agree with the above re toroidal transformers. Can be a more economical solution. Common in voltage and current hungry PA amps so probably not bad for hi fi
  9. hobbit

    ? blown trannie

    Old thread , but I finally liberated this from the loft The caps beside the fuse had shorted , but unfortunately the transformer was shorted also. I found a cheap eBay replacement with the same specs and replaced it plus the capacitors. No further damage on the boards and the amp is up and...
  10. hobbit

    Electrolytic capacitor reforming

    I think there is a different approach between Europe and USA, much like there used to be with classic cars where the uk/Europe approach was preservation where everything tended to be replaced in USA restorations. One other way is to measure esr in situ and if they are all pretty good it's...
  11. hobbit

    Electrolytic capacitor reforming

    Re recapping I tend to remove a couple from each board ( power amp/ preamp/ tone controls) and test. If they are ok I leave the rest alone unless obvious fluid leak. I'm certain it's not just my ears. They do sound better with use
  12. hobbit

    Electrolytic capacitor reforming

    I know this topic comes up from time to time and the theory of using a variac, or removal from the device to slowly reform old caps. But, recent experience fixing amplifiers that have remained unused for decades makes me wonder if this actually happens anyway. I'm not talking about ancient...
  13. hobbit

    When De-Ox-It just does not cut it

    Deoxit is hard to get where I live. I use servisol 10 and tbh have found it just as good
  14. hobbit

    When De-Ox-It just does not cut it

    Just buy a cheap ultrasonic cleaner , desolder and pop it in the cleaner. They are amazing Great for motorcycle carbs as well
  15. hobbit

    re-capping advice

    Update 11 years later. After leaving the big boys in place all this time , performance clearly dropping Desoldered them Supposed to be 10k uf The 4 are between 6 and 7k uf so new set ordered from mouser. I will keep this amp forever
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