Connect with us

Generic (cheap) Power MOSFETs ?

Discussion in 'Electronic Repair' started by N Cook, May 13, 2007.

Scroll to continue with content
  1. N Cook

    N Cook Guest

    In the same manner that, often for audio power output situations,
    cheap 100V, 15amp TIP3055/TIP2955 with maybe a bit of change of mounting is
    a perfectly servicable replacement for rare/expensive 2SA... / 2SC...
    bipolar pairs.
    Is there anything similarly for the same/similar wide plastic package
    TO3P,TOP3,SOT199,TOP66 >100Volt , 15amp power MOSFET n and p type pairings
    for audio use ?
     
  2. Ray King

    Ray King Guest

    The popular N/P fets in this size in ( TO247) package are IRFP530/IRFP9530
    and IRFP540/IRFP9540 in the ( TO220) package are IRF520/IRF9520 and
    IRF530/IRF9530 and IRF540/IRF9540.
    Ray
     
  3. Ray King

    Ray King Guest

    Sorry,
    Correction
    below.
     
  4. N Cook

    N Cook Guest

    Thanks for the IRFP sugestion, its always the p-ch ones that put the prices
    up.
    I think I'll get a stock of IRFP240
    and IRFP9240, 200V, 12 amp ,TO247 ones which seem to be the best bang per
    buck in the UK.
     
  5. N Cook

    N Cook Guest

    In a similar vein. If an amp needs a rare or expensive or unattainable
    output hybrid block STK..., TA..., Si... I tend these days using a
    relatively cheap for its performance, 100W TDA7294 instead. Small enough to
    place upside down or 2 together for 2 channels, with extra clamping and with
    a strip of matrix board on the new block pins then insulated wires crossing
    over one another to the original pad positions.
    It is usually possible to work out the DC rails, i/ps,o/p, comp, mute lines
    even if a pinout for the original is not available.
     
  6. Ron(UK)

    Ron(UK) Guest

    I do miss those Maplin 150 watt mosfet modules, great for resurrecting
    old stuff like H-H PA amps and the like. There`s nothing quite like them
    now, I must have built over a hundred, and most of them I bet are still
    working.

    Ron(UK)
     
  7. N Cook

    N Cook Guest

    Assuming you put in spring clamps, or such, then cutting off the protruding
    tab of the TDA7294 leaves a block only 20x10x4 mm , so 2 easily go in the
    space of an STK... etc and those are usually quite a bit less than 2x 100W.
    I wonder if they're bridgable, I'll have to dig out the pdf.
     
  8. Arfa Daily

    Arfa Daily Guest

    Ron

    I always used to favour the ILP modules for the same purpose. Remember them
    ? They always used to advertise in Practically Witless magazine. For many
    years, they disappeared, then I tried searching them on the 'net a few years
    back, and I found a piece by the guy that was originally involved with them,
    and it seemed that he was going back into production. I just put it into
    Google again, and it came straight back with the top hit, so it seems that
    they are in production again now. As I recall, these were very 'plug n play'
    also with only + / - power, gnd, in and out connections, and were just about
    bomb proof. Might be worth getting one in just to play with ... ??


    http://www.ilpelectronics.com/index.asp

    Arfa
     
  9. N Cook

    N Cook Guest

    I seem top remember those were dV/dt suceptable to failure (fridge-switch
    syndrome) if you did not limit the i/p dv/dt
     
  10. N Cook

    N Cook Guest

    The pdf shows 2 bridged example but 8 ohm minimum but I've seen 4 of these
    bridged in a high power mixer-amp so presumably 4 ohm in that case.
    I meant SVi not Si, the Technics things
     
  11. Ron(UK)

    Ron(UK) Guest

    Yeah, quite a lot of guitar and bass amps use a pair in bridge mode,
    Carslbro BassBomber springs to mind, tho I dont have a ct diag for one
    offhand.

    They do need sufficient cooling btw

    Ron(UK)
     
  12. Ron(UK)

    Ron(UK) Guest

    Oh cheers, I`ll take a look at those, I built a 200w power amp using
    them way way back.


    Ron(UK)
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-