DH-220 Outputs

DreadPirate · 22nd April 2011, 02:17 PM

Are there different output transistors used on this model number Hafler? And if so, are there originals and/or substitutes available for them at reasonable prices (as in $10 or less each) or are they rare and expensive?

lineup · 22nd April 2011, 02:26 PM

Here is service manual with schematics
Hafler - Tech Support

jaycee · 22nd April 2011, 02:37 PM

Exicon ECF10N16/ECF10P16 MOSFETs are suitable replacements. I dont know how expensive they are though. Lateral MOSFETs are usually expensive and no longer widely manufactured. The original Hitachi devices are long obsolete.

You cannot substitute more easily obtainable "HEXFET" devices as they will not work correctly.

Tajzmaj · 27th April 2011, 12:24 AM

Hafler used closely matched 2sk/2sj mosfets.....i think that 2sk135/2sj50 is exact code.......I am on vacation at the moment but i think that I have still some of these at home. But used of course. But genuine hitachi.......bla bla. If you want to play with them and try to make some pairs I'll be glad to get rid of them and send a package to you.....for free. Be aware that amp of yours won't play nice if you won't match them. And it will produce more heat than music...he he. If you are not able to make some measurements I can do it for you. For free again. Just to get rid of them.
Best regards
Taj

Tajzmaj · 27th April 2011, 12:26 AM

Btw how many transistors you need? I think thare was 4 at each channel..2 2sk+2 2sj...?
If you once start to repair such amp it is also wise to replace electolytic caps.....bias trimpots and than you need to readjust unit....
Regards

DreadPirate · 27th April 2011, 12:20 PM

Thanks for the offer, Tajzmaj, but I won't be needing any parts as I'm not going to purchase the DH-220 with the bad channel. I also found that the BUZ900/905 mosfets may work, as well as the Exicon's mentioned previously.

Tajzmaj · 28th April 2011, 08:47 PM

Well just an offer
Regards

22nd April 2011, 02:17 PM	#1
DreadPirate diyAudio Member Join Date: Jan 2006 Location: Northern Virginia, USA	DH-220 Outputs Are there different output transistors used on this model number Hafler? And if so, are there originals and/or substitutes available for them at reasonable prices (as in $10 or less each) or are they rare and expensive?

22nd April 2011, 02:26 PM	#2
lineup diyAudio Member Join Date: Dec 2005 Location: the north	Here is service manual with schematics Hafler - Tech Support __________________ lineup

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22nd April 2011, 02:37 PM	#3
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	Exicon ECF10N16/ECF10P16 MOSFETs are suitable replacements. I dont know how expensive they are though. Lateral MOSFETs are usually expensive and no longer widely manufactured. The original Hitachi devices are long obsolete. You cannot substitute more easily obtainable "HEXFET" devices as they will not work correctly.

27th April 2011, 12:24 AM	#4
Tajzmaj diyAudio Member Join Date: Mar 2011 Location: Ljubljana	Hafler used closely matched 2sk/2sj mosfets.....i think that 2sk135/2sj50 is exact code.......I am on vacation at the moment but i think that I have still some of these at home. But used of course. But genuine hitachi.......bla bla. If you want to play with them and try to make some pairs I'll be glad to get rid of them and send a package to you.....for free. Be aware that amp of yours won't play nice if you won't match them. And it will produce more heat than music...he he. If you are not able to make some measurements I can do it for you. For free again. Just to get rid of them. Best regards Taj

27th April 2011, 12:26 AM	#5
Tajzmaj diyAudio Member Join Date: Mar 2011 Location: Ljubljana	Btw how many transistors you need? I think thare was 4 at each channel..2 2sk+2 2sj...? If you once start to repair such amp it is also wise to replace electolytic caps.....bias trimpots and than you need to readjust unit.... Regards

27th April 2011, 12:20 PM	#6
DreadPirate diyAudio Member Join Date: Jan 2006 Location: Northern Virginia, USA	Thanks for the offer, Tajzmaj, but I won't be needing any parts as I'm not going to purchase the DH-220 with the bad channel. I also found that the BUZ900/905 mosfets may work, as well as the Exicon's mentioned previously.

28th April 2011, 08:47 PM	#7
Tajzmaj diyAudio Member Join Date: Mar 2011 Location: Ljubljana	Well just an offer Regards

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