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output transistors?

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Anonymous
August 18, 2004 1:08:16 PM

Archived from groups: rec.audio.pro (More info?)

I have an old Hafler amp that blew a side. It uses MOSFET transistors I cant
find.
These are in shiny round cans with two wire leads sticking down, and they
screw onto little plastic sheets.
I have a bunch of car radio outputs that look like they will screw down.

Will they work, or will they hurt anything?

More about : output transistors

Anonymous
August 18, 2004 1:08:17 PM

Archived from groups: rec.audio.pro (More info?)

> I have an old Hafler amp that blew a side. It uses
> MOSFET transistors I cant find.

Hafler MOSFETs sometimes show up on eBay.
Anonymous
August 18, 2004 1:16:37 PM

Archived from groups: rec.audio.pro (More info?)

"Sugarite" <not for you> wrote in message
news:p P6dnfiq-5xdyb7cRVn-jg@giganews.com

> I have an old Hafler amp that blew a side. It uses MOSFET transistors
> I cant find.

If you flog some Haffler enthusiast sites and/or contact Hafler, you can
obtain some wisdom about modern replacements.

> These are in shiny round cans with two wire leads sticking down, and
> they screw onto little plastic sheets.

Power transistors mounted on circuit boards.

> I have a bunch of car radio outputs that look like they will screw
> down.

Unlikely that they are MOSFETs, unlikely that they could handle the voltage
in an a large audio power amp, even if they were.

> Will they work,

Highly unlikely.

>or will they hurt anything?

Highly likely.

Fixing power amps isn't like changing spark plugs in a car. Get competent
help!
Related resources
Anonymous
August 18, 2004 1:26:58 PM

Archived from groups: rec.audio.pro (More info?)

In article <pP6dnfiq-5xdyb7cRVn-jg@giganews.com>, Sugarite <not for you> wrote:
>I have an old Hafler amp that blew a side. It uses MOSFET transistors I cant
>find.
>These are in shiny round cans with two wire leads sticking down, and they
>screw onto little plastic sheets.
>I have a bunch of car radio outputs that look like they will screw down.
>
>Will they work, or will they hurt anything?

I'm sorry, this is not funny. This is not funny at all. What have you
done with the real Sugarite?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
August 19, 2004 1:34:53 AM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news:cfvlf2$sli$1@panix2.panix.com...
> In article <pP6dnfiq-5xdyb7cRVn-jg@giganews.com>, Sugarite <not for you>
wrote:
> >I have an old Hafler amp that blew a side. It uses MOSFET transistors I
cant
> >find.
> >These are in shiny round cans with two wire leads sticking down, and they
> >screw onto little plastic sheets.
> >I have a bunch of car radio outputs that look like they will screw down.
> >
> >Will they work, or will they hurt anything?
>
> I'm sorry, this is not funny. This is not funny at all. What have you
> done with the real Sugarite?
> --scott
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

I thought maybe some auto radios used MOSFETs.
Please don't get on me for it.
Anonymous
August 19, 2004 2:29:33 AM

Archived from groups: rec.audio.pro (More info?)

In article <nOydnfqykM0gnrncRVn-gQ@giganews.com>, Sugarite <not for you> wrote:
>
>I thought maybe some auto radios used MOSFETs.
>Please don't get on me for it.

Maybe, but if you don't say what model amplifier you have, and you don't
say what model transistors you have, how can ANYONE expect to even make
a GUESS that they might work. What have you done with the real Sugarite?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
August 19, 2004 3:19:47 AM

Archived from groups: rec.audio.pro (More info?)

"Sugarite" <not for you> wrote in message
news:p P6dnfiq-5xdyb7cRVn-jg@giganews.com...

> I have an old Hafler amp that blew a side. It uses MOSFET transistors I
cant
> find.
> These are in shiny round cans with two wire leads sticking down, and they
> screw onto little plastic sheets.
> I have a bunch of car radio outputs that look like they will screw down.
>


** You need some Hitachi mosfets - probably types 2SJ50 and 2SK135.

No normal transistor can be substited.





............ Phil
Anonymous
August 19, 2004 3:19:48 AM

Archived from groups: rec.audio.pro (More info?)

Phil Allison wrote:

> "Sugarite" <not for you> wrote in message
> news:p P6dnfiq-5xdyb7cRVn-jg@giganews.com...
>
> > I have an old Hafler amp that blew a side. It uses MOSFET transistors I
> cant
> > find.
> > These are in shiny round cans with two wire leads sticking down, and they
> > screw onto little plastic sheets.
> > I have a bunch of car radio outputs that look like they will screw down.
> >
>
> ** You need some Hitachi mosfets - probably types 2SJ50 and 2SK135.
>
> No normal transistor can be substited.

You omit to mention that Hitachi no longer make them.

Close equivalents are available from Semelab and Exicon.


Graham
Anonymous
August 19, 2004 4:59:22 AM

Archived from groups: rec.audio.pro (More info?)

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4123AF6A.CF8082B7@hotmail.com...
> You omit to mention that Hitachi no longer make them.
>
> Close equivalents are available from Semelab and Exicon.

....and available from ProfusionPLC, a UK company but ship very efficiently
to the USA as well.

If the output MOSFETs are blown, then the drivers may well also be blown.
So might the gate resistors.
Anonymous
August 19, 2004 6:57:17 AM

Archived from groups: rec.audio.pro (More info?)

Walter Harley wrote:

> "Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
> news:4123AF6A.CF8082B7@hotmail.com...
> > You omit to mention that Hitachi no longer make them.
> >
> > Close equivalents are available from Semelab and Exicon.
>
> ...and available from ProfusionPLC, a UK company but ship very efficiently
> to the USA as well.

Oh good ! I know them but wasn't sure if they serviced the US market
effectively.

Profusion are a decent company to deal with.


> If the output MOSFETs are blown, then the drivers may well also be blown.
> So might the gate resistors.

I'll beg to differ. That would be a rare condition IMHO.

Hitachi (including other manufactuer similar style ) mosfets usually fail
open-circuit without destructive behaviour.


Graham ( designed quite a few mosfet amps )
Anonymous
August 19, 2004 6:57:18 AM

Archived from groups: rec.audio.pro (More info?)

Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote:
>
>> If the output MOSFETs are blown, then the drivers may well also be blown.
>> So might the gate resistors.
>
>I'll beg to differ. That would be a rare condition IMHO.
>
>Hitachi (including other manufactuer similar style ) mosfets usually fail
>open-circuit without destructive behaviour.

Right, but often blown output devices are a symptom of something else gone
wrong farther up the chain, rather than the original problem. Gate resistors
gone open will take the output stage out with oscillation sometimes, for
example.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
August 19, 2004 8:09:27 AM

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey wrote:

> Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote:
> >
> >> If the output MOSFETs are blown, then the drivers may well also be blown.
> >> So might the gate resistors.
> >
> >I'll beg to differ. That would be a rare condition IMHO.
> >
> >Hitachi (including other manufactuer similar style ) mosfets usually fail
> >open-circuit without destructive behaviour.
>
> Right, but often blown output devices are a symptom of something else gone
> wrong farther up the chain, rather than the original problem. Gate resistors
> gone open will take the output stage out with oscillation sometimes, for
> example.

My own experience has been mainly with failed devices due to overtemperature ( on
C Audio amplifiers that have marginal cooling for example ).

C Audio used to consider the failed devices as *normal* !

They also had poor lifetime on the PSU electrolytics as they stood in the path of
the searing heat from the fan cooling !

Replacement of either / both was considered normal service / repair !

Harman bought C Audio a number of years ago in a classic Harman move that left
the staff that knew the product in Cambridge UK unemployed whilst moving the
inventory to the Soundcraft site some 40 miles south approx.

A friend of mine who worked for Harman UK said at the time that they had a pile
of bits that they had no idea what to do with !

C Audio had just introduced the rather poor GB bipolar series. This eventually
ended up rebadged as the Crown CE series ! Nuff said ?

Does Harman have a death wish ?


Graham
Anonymous
August 19, 2004 10:09:45 AM

Archived from groups: rec.audio.pro (More info?)

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:412408FD.2EEEE5FB@hotmail.com...
> Oh good ! I know them but wasn't sure if they serviced the US market
> effectively.

Very much so. In fact, when I've ordered from them, shipping has been both
cheaper and faster than from most of the US companies I deal with - and I'm
on the west coast. Quite remarkable.


>> If the output MOSFETs are blown, then the drivers may well also be blown.
>> So might the gate resistors.
>
> I'll beg to differ. That would be a rare condition IMHO.
>
> Hitachi (including other manufactuer similar style ) mosfets usually fail
> open-circuit without destructive behaviour.

Our experience differs in that regard, evidently. I would say that the
majority of the MOSFET amps I've fixed have failed short-circuit and about
half have taken out the drivers.

Oscillation might have been the cause in some, but I think not all.
Anonymous
August 19, 2004 11:19:51 AM

Archived from groups: rec.audio.pro (More info?)

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:412419E7.7EE4794E@hotmail.com

> Does Harman have a death wish ?

They do a lot of OEM business in Detoit, or at least they did. Similar
questions are heard around town.
Anonymous
August 19, 2004 12:22:26 PM

Archived from groups: rec.audio.pro (More info?)

Arny Krueger <arnyk@hotpop.com> wrote:
>"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
>news:412419E7.7EE4794E@hotmail.com
>
>> Does Harman have a death wish ?
>
>They do a lot of OEM business in Detoit, or at least they did. Similar
>questions are heard around town.

Harman doesn't need customers. They have investors. Soon they will own
everything in the industry that isn't already owned by EVI.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
August 19, 2004 12:57:14 PM

Archived from groups: rec.audio.pro (More info?)

Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote:
>Phil Allison wrote:
>>
>> ** You need some Hitachi mosfets - probably types 2SJ50 and 2SK135.
>>
>> No normal transistor can be substited.
>
>You omit to mention that Hitachi no longer make them.
>
>Close equivalents are available from Semelab and Exicon.

In TO-3 packages, or do you have to side mount TO-3Ps in there?
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
August 19, 2004 1:58:00 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news:cg2622$kp9$1@panix2.panix.com
> Arny Krueger <arnyk@hotpop.com> wrote:
>> "Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
>> news:412419E7.7EE4794E@hotmail.com
>>
>>> Does Harman have a death wish ?
>>
>> They do a lot of OEM business in Detoit, or at least they did.
>> Similar questions are heard around town.
>
> Harman doesn't need customers. They have investors. Soon they will
> own everything in the industry that isn't already owned by EVI.

...or Bose.

Recoton was about as close as they ever had to competition, and now they are
being broken up.
Anonymous
August 19, 2004 5:02:38 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey"
> Pooh Bear :
> >
> >> If the output MOSFETs are blown, then the drivers may well also be
blown.
> >> So might the gate resistors.
> >
> >I'll beg to differ. That would be a rare condition IMHO.
> >
> >Hitachi (including other manufactuer similar style ) mosfets usually fail
> >open-circuit without destructive behaviour.
>
> Right, but often blown output devices are a symptom of something else gone
> wrong farther up the chain, rather than the original problem. Gate
resistors
> gone open will take the output stage out with oscillation sometimes, for
> example.


** Open gate resistors ???

Such is the logic of a failed recorder mechanic and electronics charlatan.




............... Phil
Anonymous
August 19, 2004 8:26:55 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news:cg283a$fq2$1@panix2.panix.com...
> In TO-3 packages, or do you have to side mount TO-3Ps in there?

The Exicon lateral MOSFETs sold by ProfusionPLC are TO-3; direct drop-in
replacement.

Prices seem to run in the vicinity of US$10-20, more or less depending on
the part. I don't remember which models are the equivalent to the
2SK135/2SJ50.
Anonymous
August 19, 2004 9:05:08 PM

Archived from groups: rec.audio.pro (More info?)

"Walter Harley".
> "Pooh Bear"
>
> >> If the output MOSFETs are blown, then the drivers may well also be
blown.
> >> So might the gate resistors.
> >
> > I'll beg to differ. That would be a rare condition IMHO.
> >
> > Hitachi (including other manufactuer similar style ) mosfets usually
fail
> > open-circuit without destructive behaviour.
>
> Our experience differs in that regard, evidently. I would say that the
> majority of the MOSFET amps I've fixed have failed short-circuit and about
> half have taken out the drivers.


** The subject is Hitachi ( lateral) mosfets - in *** TO3 *** package
( 2SK135, 2SJ50 etc)

Other types are NOT the same.

Other packages do not have fusible wire links inside.

The common IRF ... switching types fail short.



>
> Oscillation might have been the cause in some, but I think not all.
>

** Hitachi lateral mosfets do not fail from oscillations.

The Zobel network may be toast but the mosfets are always fine.




............ Phil
Anonymous
August 19, 2004 11:59:20 PM

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey wrote:

> Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote:
> >Phil Allison wrote:
> >>
> >> ** You need some Hitachi mosfets - probably types 2SJ50 and 2SK135.
> >>
> >> No normal transistor can be substited.
> >
> >You omit to mention that Hitachi no longer make them.
> >
> >Close equivalents are available from Semelab and Exicon.
>
> In TO-3 packages, or do you have to side mount TO-3Ps in there?

TO-3 no problem.

Never really understood why Hitachi dropped the TO-3s - many UK pro amp
manufacturers used them for sure.


Graham
Anonymous
August 19, 2004 11:59:21 PM

Archived from groups: rec.audio.pro (More info?)

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4124F888.F427A350@hotmail.com
> Scott Dorsey wrote:
>
>> Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote:
>>> Phil Allison wrote:
>>>>
>>>> ** You need some Hitachi mosfets - probably types 2SJ50 and
>>>> 2SK135.
>>>>
>>>> No normal transistor can be substited.
>>>
>>> You omit to mention that Hitachi no longer make them.
>>>
>>> Close equivalents are available from Semelab and Exicon.
>>
>> In TO-3 packages, or do you have to side mount TO-3Ps in there?
>
> TO-3 no problem.
>
> Never really understood why Hitachi dropped the TO-3s - many UK pro
> amp manufacturers used them for sure.
>

"The future is plastic".
Anonymous
August 19, 2004 11:59:21 PM

Archived from groups: rec.audio.pro (More info?)

Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote:
>
>TO-3 no problem.
>
>Never really understood why Hitachi dropped the TO-3s - many UK pro amp
>manufacturers used them for sure.

Everybody is dropping TO-3 packages for everything, because they are
expensive to make, and if all you care about is peak power capability
it doesn't buy you all that much over the flat packs. The TO-3 is a big
deal for linear applications with high average power needs, but who does
THAT stuff any more in the modern digital world but a few audio guys?
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
August 20, 2004 1:53:57 AM

Archived from groups: rec.audio.pro (More info?)

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4124F888.F427A350@hotmail.com...
> Never really understood why Hitachi dropped the TO-3s - many UK pro amp
> manufacturers used them for sure.

TO-3 package is awkward for assembly - has to go on the other side of the
heat sink from the wires. One heck of a lot easier to just solder a TO3P or
whatever onto the PCB, and then screw it or clamp it to the heat sink in
final assembly. And the junction-to-case thermal resistance of TO-3 is
*higher* (worse) than TO-263, at least based on looking at a couple of
haphazardly chosen datasheets just now. So it's not obvious why any
manufacturer would prefer a TO-3 over a more modern package.

About the only thing TO-3 has going for it is that it's easier to socket for
repair. The value of that, these days, should be self-evident :-(

Something to consider is that old slow low-beta bipolar power Q's like
2N3055 didn't have stability problems with long leads, so it wasn't a big
problem to run wires from the PCB to the socket. But modern MOSFETs aren't
happy with a bunch of inductance (like a couple inches of wire) connected to
the gate.
Anonymous
August 20, 2004 3:21:04 AM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey"
> Pooh Bear
> >Phil Allison wrote:
> >>
> >> ** You need some Hitachi mosfets - probably types 2SJ50 and 2SK135.
> >>
> >> No normal transistor can be substitute.
> >
> >You omit to mention that Hitachi no longer make them.
> >
> >Close equivalents are available from Semelab and Exicon.
>
> In TO-3 packages, or do you have to side mount TO-3Ps in there?



** Too lazy to do a simple Google search are we now, Dorsey - rather
have a mid air debate instead ???

See : http://www.exicon.com/




............ Phil
Anonymous
August 20, 2004 3:21:05 AM

Archived from groups: rec.audio.pro (More info?)

In article <2ojnv7Fb7ih4U2@uni-berlin.de>,
Phil Allison <philallison@tpg.com.au> wrote:
>
>"Scott Dorsey"
>> Pooh Bear
>> >Phil Allison wrote:
>> >>
>> >> ** You need some Hitachi mosfets - probably types 2SJ50 and 2SK135.
>> >>
>> >> No normal transistor can be substitute.
>> >
>> >You omit to mention that Hitachi no longer make them.
>> >
>> >Close equivalents are available from Semelab and Exicon.
>>
>> In TO-3 packages, or do you have to side mount TO-3Ps in there?
>
>** Too lazy to do a simple Google search are we now, Dorsey - rather
>have a mid air debate instead ???
>
> See : http://www.exicon.com/

Sorry, Phil, I don't even have web access right now. I'm on the road.
So, are these in TO-3 packages, or do I have to side-mount TO-3P types?
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
August 20, 2004 3:58:58 AM

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey wrote:

> Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote:
> >
> >TO-3 no problem.
> >
> >Never really understood why Hitachi dropped the TO-3s - many UK pro amp
> >manufacturers used them for sure.
>
> Everybody is dropping TO-3 packages for everything, because they are
> expensive to make, and if all you care about is peak power capability
> it doesn't buy you all that much over the flat packs. The TO-3 is a big
> deal for linear applications with high average power needs, but who does
> THAT stuff any more in the modern digital world but a few audio guys?

A colleague of mine has been convinced for years that Motorola and
subsequently On Semi are about to drop TO-3. Hasn't happened yet.

I guess there must be significant demand for them outside of audio. The TO-3
can ( being hermetic ) allows the chip to run at a higher junction temp than
plastic - so you can run higher dissipation / device.


Graham
Anonymous
August 20, 2004 4:13:25 AM

Archived from groups: rec.audio.pro (More info?)

Walter Harley wrote:

> "Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
> news:4124F888.F427A350@hotmail.com...
> > Never really understood why Hitachi dropped the TO-3s - many UK pro amp
> > manufacturers used them for sure.
>
> TO-3 package is awkward for assembly - has to go on the other side of the
> heat sink from the wires. One heck of a lot easier to just solder a TO3P or
> whatever onto the PCB, and then screw it or clamp it to the heat sink in
> final assembly. And the junction-to-case thermal resistance of TO-3 is
> *higher* (worse) than TO-263, at least based on looking at a couple of
> haphazardly chosen datasheets just now. So it's not obvious why any
> manufacturer would prefer a TO-3 over a more modern package.
>
> About the only thing TO-3 has going for it is that it's easier to socket for
> repair. The value of that, these days, should be self-evident :-(
>
> Something to consider is that old slow low-beta bipolar power Q's like
> 2N3055 didn't have stability problems with long leads, so it wasn't a big
> problem to run wires from the PCB to the socket. But modern MOSFETs aren't
> happy with a bunch of inductance (like a couple inches of wire) connected to
> the gate.

There's a way of mounting TO-3 that's actually much simpler than any plastic
device and has pretty much none of the disadvantages you mention. I've used it
in many Studiomaster designs.

Have the pcb fitted directly underneath the devices. Fit solderable studs to
the pcb. Studs pass through the heatsink, aligning the assembly. TO-3 device
drops onto the studs from the other side of the heatsink and bolts up - leads
pass through into the pcb and are soldered. Perfectly self-aligning.

In comparison, plastic devices invariably seem to need fiddling to get them to
line up with their mounting holes before you can solder the leads.

I prefer my method with the TO-3s.

Incidentally, On Semi make MJ21193/4 in TO-3 and MJL21193/4 in TO-264 (
presumably same chip ). Same thermal resistance but the plastic versions are
more expensive !
The TO-3 part also is rated at 250W instead of 200W on account of the higher
allowable junction temp.

Graham
Anonymous
August 20, 2004 10:35:33 AM

Archived from groups: rec.audio.pro (More info?)

Stephen Sank wrote:

> Hey, but at least selenium rectifiers never get dandruff.
>
> It is exceedingly rare, in my experience, for any old Hafler amp to fry any output devices.
> About the only way to do it is to bypass the output & supply fuses, turn on the amp with the
> spkr terminals shorted, and crank it up to full power with a 100kHz sqarewave for a few hours.
> Joe Norris used to demonstrate the thermal control on the fan of a DH500 by shorting both spkr
> lines & cranking it up to full power for a while, until the fan kicked up to high gear.
> The later Haflers, post DH500/XL600, did use TO-3P package MOSFETs, some being the
> 2SK1058/2SJwhatever

2SJ192 IIRC

> lateral types that were supposed to replace the 2SK134/135/176 &
> 2SJ49/50/56 laterals, but were discontinued so quickly they're even harder to find the the old
> TO-3 types. The majority of MOSFET's used in current audio are HEXFET types.

They are ? For linear outputs as opposed to PWM ?


Graham
Anonymous
August 20, 2004 2:20:00 PM

Archived from groups: rec.audio.pro (More info?)

Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote in
news:41258DA5.FF5FAA68@hotmail.com:

> Stephen Sank wrote:
>
>> Hey, but at least selenium rectifiers never get dandruff.
>>
>> It is exceedingly rare, in my experience, for any old Hafler amp to
>> fry any output devices. About the only way to do it is to bypass the
>> output & supply fuses, turn on the amp with the spkr terminals
>> shorted, and crank it up to full power with a 100kHz sqarewave for a
>> few hours. Joe Norris used to demonstrate the thermal control on the
>> fan of a DH500 by shorting both spkr lines & cranking it up to full
>> power for a while, until the fan kicked up to high gear. The later
>> Haflers, post DH500/XL600, did use TO-3P package MOSFETs, some being
>> the 2SK1058/2SJwhatever
>
> 2SJ192 IIRC
>
>> lateral types that were supposed to replace the 2SK134/135/176 &
>> 2SJ49/50/56 laterals, but were discontinued so quickly they're even
>> harder to find the the old TO-3 types. The majority of MOSFET's used
>> in current audio are HEXFET types.
>
> They are ? For linear outputs as opposed to PWM ?

Yup - The BSS EPC780 amps (commonly packaged with Turbosound
Flashlight/Floodlight speakers)
use IRF840/11P20 outputs (18 of each per channel)in a very conventional
linear fashion.
M
Anonymous
August 20, 2004 3:00:01 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news:cg2d5j$6u5$1@panix2.panix.com...
> In article <2ojnv7Fb7ih4U2@uni-berlin.de>,
> Phil Allison <philallison@tpg.com.au> wrote:
> >
> >"Scott Dorsey"
> >> Pooh Bear
> >> >Phil Allison wrote:
> >> >>
> >> >> ** You need some Hitachi mosfets - probably types 2SJ50 and
2SK135.
> >> >>
> >> >> No normal transistor can be substitute.
> >> >
> >> >You omit to mention that Hitachi no longer make them.
> >> >
> >> >Close equivalents are available from Semelab and Exicon.
> >>
> >> In TO-3 packages, or do you have to side mount TO-3Ps in there?
> >
> >** Too lazy to do a simple Google search are we now, Dorsey - rather
> >have a mid air debate instead ???
> >
> > See : http://www.exicon.com/
>
> Sorry, Phil, I don't even have web access right now. I'm on the road.
> So, are these in TO-3 packages, or do I have to side-mount TO-3P types?

To-3

although they also have To-3p versions available if you want ....
Anonymous
August 20, 2004 3:03:38 PM

Archived from groups: rec.audio.pro (More info?)

"Sugarite" <not for you> wrote in message
news:nOydnfqykM0gnrncRVn-gQ@giganews.com...
>
> "Scott Dorsey" <kludge@panix.com> wrote in message
> news:cfvlf2$sli$1@panix2.panix.com...
> > In article <pP6dnfiq-5xdyb7cRVn-jg@giganews.com>, Sugarite <not for you>
> wrote:
> > >I have an old Hafler amp that blew a side. It uses MOSFET transistors I
> cant
> > >find.
> > >These are in shiny round cans with two wire leads sticking down, and
they
> > >screw onto little plastic sheets.
> > >I have a bunch of car radio outputs that look like they will screw
down.
> > >
> > >Will they work, or will they hurt anything?
> >
> > I'm sorry, this is not funny. This is not funny at all. What have you
> > done with the real Sugarite?
> > --scott
> > --
> > "C'est un Nagra. C'est suisse, et tres, tres precis."
>
> I thought maybe some auto radios used MOSFETs.
> Please don't get on me for it.
>

Well yes they do - a lot of car Audio Amplifiers use variations of the D
class output and having switching mosfets on the output - these are
different to Lateral mosfets .

Regards
Richard Freeman
Anonymous
August 20, 2004 6:04:36 PM

Archived from groups: rec.audio.pro (More info?)

"Stephen Sank" <bk11@thuntek.net> wrote in message
news:cg3r13$6eu$1@reader2.nmix.net...
> Hey, but at least selenium rectifiers never get dandruff.
>
> It is exceedingly rare, in my experience, for any old Hafler amp to fry
any output devices.
> About the only way to do it is to bypass the output & supply fuses, turn
on the amp with the
> spkr terminals shorted, and crank it up to full power with a 100kHz
sqarewave for a few hours.
> Joe Norris used to demonstrate the thermal control on the fan of a DH500
by shorting both spkr
> lines & cranking it up to full power for a while, until the fan kicked up
to high gear.
> The later Haflers, post DH500/XL600, did use TO-3P package MOSFETs, some
being the
> 2SK1058/2SJwhatever lateral types that were supposed to replace the
2SK134/135/176 &
> 2SJ49/50/56 laterals, but were discontinued so quickly they're even harder
to find the the old
> TO-3 types. The majority of MOSFET's used in current audio are HEXFET
types.
>
Well, that's it. It kept blowing, so I bypased the fuze, but the line
transfomer itself had a dead short.
I actually checked that, but the range switch on my meter was defective.
How's that for bad luck.
Anonymous
August 20, 2004 6:13:48 PM

Archived from groups: rec.audio.pro (More info?)

In article <JK2dnfAA1pyooLvcRVn-uQ@giganews.com>, Sugarite <not for you> wrote:
>
>Well, that's it. It kept blowing, so I bypased the fuze, but the line
>transfomer itself had a dead short.
>I actually checked that, but the range switch on my meter was defective.
>How's that for bad luck.

What makes you think that?
You can't check a transformer with a DC meter.

A transformer is supposed to reflect the impedance of the secondary,
through a static ratio. If the transformer secondary has a dead short
across it, the transformer primary will behave like it has a dead short
across it.

Transformers don't fail often. Rectifiers and output stages fail all
the time.

Disconnect the transformer secondary and try again. The transformer
will almost certainly not be the problem.
--scott

Oh, yes, and don't bypass fuses, ever, under any circumstances. THAT
is how transformers get damaged. What did you do with the real Sugarite?
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
August 20, 2004 10:06:46 PM

Archived from groups: rec.audio.pro (More info?)

"Pooh Bear"
> Stephen Sank wrote:
>
> > Hey, but at least selenium rectifiers never get dandruff.
> >
> > It is exceedingly rare, in my experience, for any old Hafler amp to fry
any output devices.
> > About the only way to do it is to bypass the output & supply fuses, turn
on the amp with the
> > spkr terminals shorted, and crank it up to full power with a 100kHz
sqarewave for a few hours.
> > Joe Norris used to demonstrate the thermal control on the fan of a DH500
by shorting both spkr
> > lines & cranking it up to full power for a while, until the fan kicked
up to high gear.
> > The later Haflers, post DH500/XL600, did use TO-3P package MOSFETs, some
being the
> > 2SK1058/2SJwhatever
>
> 2SJ192 IIRC


** You recall incorrectly.


>
> > lateral types that were supposed to replace the 2SK134/135/176 &
> > 2SJ49/50/56 laterals, but were discontinued so quickly they're even
harder to find the the old
> > TO-3 types. The majority of MOSFET's used in current audio are HEXFET
types.
>
> They are ? For linear outputs as opposed to PWM ?


** Yes - very common in US made products.

The IRFP240 and IRFP9240 being a favourite pair.




........... Phil
Anonymous
August 21, 2004 5:22:54 AM

Archived from groups: rec.audio.pro (More info?)

Phil Allison wrote:

> "Pooh Bear"
> > Stephen Sank wrote:
> >
> > > The later Haflers, post DH500/XL600, did use TO-3P package MOSFETs, some
> being the
> > > 2SK1058/2SJwhatever
> >
> > 2SJ192 IIRC
>
> ** You recall incorrectly.

Ah yeah - 2SJ162 - got one number wrong. Been a while since I used them.


> > > lateral types that were supposed to replace the 2SK134/135/176 &
> > > 2SJ49/50/56 laterals, but were discontinued so quickly they're even
> harder to find the the old
> > > TO-3 types. The majority of MOSFET's used in current audio are HEXFET
> types.
> >
> > They are ? For linear outputs as opposed to PWM ?
>
> ** Yes - very common in US made products.
>
> The IRFP240 and IRFP9240 being a favourite pair.

Interesting. How well do they match for bias ? That seems to a classic problem
with vertical FETs.


Graham
Anonymous
August 21, 2004 2:39:05 PM

Archived from groups: rec.audio.pro (More info?)

"Pooh Bear"
>
> Phil Allison wrote:
>
> >
> > ** Yes - very common in US made products.
> >
> > The IRFP240 and IRFP9240 being a favourite pair.
>
> Interesting. How well do they match for bias ? That seems to a classic
problem
> with vertical FETs.
>


** Matched sets *are* required ( plus ballast rsistors) - which makes
later repairs interesting.




............. Phil
!