# Generic (cheap) Power MOSFETs ?

N

#### N Cook

Jan 1, 1970
0
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 ?

R

#### Ray King

Jan 1, 1970
0
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

R

#### Ray King

Jan 1, 1970
0
Sorry,
Correction
below.
The popular N/P fets in this size in ( TO247) package are IRFP130/IRFP9130
and IRFP140/IRFP9140 in the ( TO220) package are IRF520/IRF9520 and
IRF530/IRF9530 and IRF540/IRF9540.
Ray

N

#### N Cook

Jan 1, 1970
0
Ray King said:
Sorry,
Correction
below.

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.

N

#### N Cook

Jan 1, 1970
0
Ray King said:
Sorry,
Correction
below.

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.

R

#### Ron(UK)

Jan 1, 1970
0
N said:
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.

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

Ron(UK)

N

#### N Cook

Jan 1, 1970
0
Ron(UK) said:
I do miss those Maplin 150 watt mosfet modules, great for resurrecting
old stuff like H-H PA amps and the like. Theres nothing quite like them
now, I must have built over a hundred, and most of them I bet are still
working.

Ron(UK)

--
Lune Valley Audio
Hire Sales Maintenance
www.lunevalleyaudio.com

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.

A

#### Arfa Daily

Jan 1, 1970
0
Ron(UK) said:
I do miss those Maplin 150 watt mosfet modules, great for resurrecting old
stuff like H-H PA amps and the like. Theres nothing quite like them now,
I must have built over a hundred, and most of them I bet are still
working.

Ron(UK)

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

N

#### N Cook

Jan 1, 1970
0
Arfa Daily said:
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

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

N

#### N Cook

Jan 1, 1970
0
N Cook said:
enough and

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.

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

R

#### Ron(UK)

Jan 1, 1970
0
N said:
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.

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)

R

#### Ron(UK)

Jan 1, 1970
0
Arfa said:
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

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

Ron(UK)

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