Hafler DH-220

gcohen · 3rd September 2006, 12:38 PM

Hello all,

I have an Haflar DH-220 with burnt output mosfets.
Since these are quite expensive I wonder if someone have tried
to put an IRF devices, e.g., IRF240 and IRF9240 instead of the
2SK134/2SJ49 .

Thanks in advance,
Guy

anatech · 3rd September 2006, 01:18 PM

Hi Guy,
Won't work. The bias characteristics are different. The IRF devices are completely different beasts.

-Chris

edl · 3rd September 2006, 01:19 PM

Quote:

Originally posted by gcohen
Hello all,

I have an Haflar DH-220 with burnt output mosfets.
Since these are quite expensive I wonder if someone have tried
to put an IRF devices, e.g., IRF240 and IRF9240 instead of the
2SK134/2SJ49 .

Thanks in advance,
Guy

Hi,

don't even try these IRF devices.
Let's use the 2sk1058/2sj162 pair.

Regards,

Dick West · 3rd September 2006, 02:49 PM

gcohen,

Did you test and check your present Lateral Hitachi MOSFETs? How do you know they are burnt? These are very rugged devices. Tell us more.

But, the other posters are correct, you can't use vertical MOSFETs (IRF devices) to replace Lateral MOSFETs (Hitachi).

Profusion (UK) sells replacements for Hitachi devices. Go here:

http://www.profusionplc.com/static/subsites/exicon.htm

But, they must be matched ±10% on Vgs and matched pairs can get expensive.

jackinnj · 3rd September 2006, 05:49 PM

Hitachi doesn't make the Lateral MOSFET's anymore -- they're done by Renesas -- http://www.tech-diy.com/LATFET.htm -- shameless plug

gcohen · 3rd September 2006, 07:06 PM

Hello all,

Thanks for your help. I was affraid that the IRF parts will not
work. There is a guy who says that he did such a modification
in his SCS amp, please see here:

http://aga.rru.com/TechTips/disp.cgi...owerFETRepl.tt

I know that one of my 2SK134 in my Hafler is burnt since it
is shorted between source and gate.

Surprisingle, I do not find any other shorted component.

Thanks again,
Guy

Roar Malmin · 3rd September 2006, 07:22 PM

I have 50 pairs of 2SK175 / 2SJ55 Hitachi MOSFET`S. They are the same, only difference is higher voltage rating and higher current capability. These are new and unused, and they are all from the same batch, so there is no need to match them.
Roar

anatech · 3rd September 2006, 07:24 PM

Hello Guy,
I've tried on different amps with varing results. I'll rephrase my earlier statement.

As best, they do not work properly, worst case they will go into thermal runaway and cook themselves to death.

Don't do it. Jackinnj gave you a workable solution.

-Chris

gcohen · 4th September 2006, 08:06 AM

Hello all,

Thanks again for your help.

If I will buy replacements, I will buy a 2SK135/2SJ50 and not
2SK134/2SK49 - This will force me to buy four transistors.
and to accept the differences between the two channels (since
the other channel is original 2SK134/2SK49).

The price of two matched pairs start to be very close to the
price of buying another Hafler DH-220 in ebay!

So, I will see what to do. Thanks anyway.

Guy

edl · 4th September 2006, 10:32 AM

Hi,

You can use the buz900/buz905 or the buz901/buz906 pairs too.

Good luck,

3rd September 2006, 12:38 PM	#1
gcohen diyAudio Member Join Date: Feb 2006 Location: Israel	Hafler DH-220 Hello all, I have an Haflar DH-220 with burnt output mosfets. Since these are quite expensive I wonder if someone have tried to put an IRF devices, e.g., IRF240 and IRF9240 instead of the 2SK134/2SJ49 . Thanks in advance, Guy

3rd September 2006, 07:06 PM	#6
gcohen diyAudio Member Join Date: Feb 2006 Location: Israel	DH-220 Hello all, Thanks for your help. I was affraid that the IRF parts will not work. There is a guy who says that he did such a modification in his SCS amp, please see here: http://aga.rru.com/TechTips/disp.cgi...owerFETRepl.tt I know that one of my 2SK134 in my Hafler is burnt since it is shorted between source and gate. Surprisingle, I do not find any other shorted component. Thanks again, Guy

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3rd September 2006, 01:18 PM	#2
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Guy, Won't work. The bias characteristics are different. The IRF devices are completely different beasts. -Chris

3rd September 2006, 02:49 PM	#4
Dick West diyAudio Member Join Date: Aug 2004 Location: Illinois	gcohen, Did you test and check your present Lateral Hitachi MOSFETs? How do you know they are burnt? These are very rugged devices. Tell us more. But, the other posters are correct, you can't use vertical MOSFETs (IRF devices) to replace Lateral MOSFETs (Hitachi). Profusion (UK) sells replacements for Hitachi devices. Go here: http://www.profusionplc.com/static/subsites/exicon.htm But, they must be matched ±10% on Vgs and matched pairs can get expensive.

3rd September 2006, 05:49 PM	#5
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	Hitachi doesn't make the Lateral MOSFET's anymore -- they're done by Renesas -- http://www.tech-diy.com/LATFET.htm -- shameless plug

3rd September 2006, 07:22 PM	#7
Roar Malmin diyAudio Member Join Date: Jul 2006	I have 50 pairs of 2SK175 / 2SJ55 Hitachi MOSFET`S. They are the same, only difference is higher voltage rating and higher current capability. These are new and unused, and they are all from the same batch, so there is no need to match them. Roar

3rd September 2006, 07:24 PM	#8
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hello Guy, I've tried on different amps with varing results. I'll rephrase my earlier statement. As best, they do not work properly, worst case they will go into thermal runaway and cook themselves to death. Don't do it. Jackinnj gave you a workable solution. -Chris

4th September 2006, 08:06 AM	#9
gcohen diyAudio Member Join Date: Feb 2006 Location: Israel	Hello all, Thanks again for your help. If I will buy replacements, I will buy a 2SK135/2SJ50 and not 2SK134/2SK49 - This will force me to buy four transistors. and to accept the differences between the two channels (since the other channel is original 2SK134/2SK49). The price of two matched pairs start to be very close to the price of buying another Hafler DH-220 in ebay! So, I will see what to do. Thanks anyway. Guy

4th September 2006, 10:32 AM	#10
edl diyAudio Member Join Date: Oct 2004	Hi, You can use the buz900/buz905 or the buz901/buz906 pairs too. Good luck,

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