Musical Fidelity P170 Blown Transistors

rigel9999 · 16th September 2007, 07:48 AM

Would welcome any suggestions for alternatives for replacing blown Transistors, which are no longer available, in a 1988 Musical Fidelity P170 power amp.

Thanks

AndrewT · 16th September 2007, 08:00 AM

Hi,
I seem to recall these were Lateral FETs.
Can you confirm type numbers?

PMik · 16th September 2007, 09:15 AM

The original Hitachi 2SJ81/2SK226 (2SJ82/2SK227) is no where to find and this has been a fact for more than a decade ..., solution use Hitachi 2SJ162/2SK1058 notice these FET's have different housing (TO-3P)

AndrewT · 16th September 2007, 10:05 AM

Hi Rig,
is Pmik correct?
Are 2sj81/k226 the original fitment?

These are 2bolt Fpack packages.
The To247 Renases replacement are single bolt fixing and should be a straight swap. The Pin order is identical, but you'll need to move them sideways to align with one of the existing tapped fixing holes
2sj161/k1057 are the 140V equivalent.
2sj162/k1058 are the 160V equivalent, these are available from Rapid.

PMik · 16th September 2007, 10:30 AM

Andrew
Yes they are the original ones
I have had so many of the MF P series in my hands ..., sure i know

ANTHONY2181 · 16th September 2007, 03:19 PM

I have some New 2SK343 and 2SJ99 pairs which look pretty similar in specs + they are the same package.

Regards

Anthony

jaycee · 16th September 2007, 05:46 PM

Look at the Exicon range of mosfets from Profusion PLC

These are excellent replacements for the Hitachi originals. The ones in the TO-247 packaging should do.

rigel9999 · 18th September 2007, 09:50 PM

Hi Andrew T,

I can confirm the originals are Hitachi 2SJ81/2SK226 (2SJ82/2SK227.

Thank you PMik and everyone else who took time to reply.

Rigel9999

rigel9999 · 18th September 2007, 09:50 PM

Hi PMik,

I still have one set of MOSFETS which are still intact. Should I purchase and replace the one blown pair or do you advise i replace both sets with the Hitachi 2SJ162/2SK1058?

Thank you

PMik · 18th September 2007, 11:39 PM

I would strongly advice you to change both pairs of MOSFET's to the 2SJ162/2SK1058 this to insure equal performance betwin the chanals

An interesting detail regarding the 2SJ162/2SK1058 is the fact that the pair are equal to the 2SJ50/2SK135 pair
The 2SJ50/2SK135 where used in the MF B200, P140 and P150
Class AB standing current should be set for at least 100mA and imho for best sonic performance 200mA

16th September 2007, 07:48 AM	#1
rigel9999 diyAudio Member Join Date: Sep 2007	Musical Fidelity P170 Blown Transistors Would welcome any suggestions for alternatives for replacing blown Transistors, which are no longer available, in a 1988 Musical Fidelity P170 power amp. Thanks

16th September 2007, 08:00 AM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, I seem to recall these were Lateral FETs. Can you confirm type numbers? __________________ regards Andrew T.

16th September 2007, 09:15 AM	#3
PMik diyAudio Member Join Date: Mar 2004 Location: Fort Lauderdale, FL	The original Hitachi 2SJ81/2SK226 (2SJ82/2SK227) is no where to find and this has been a fact for more than a decade ..., solution use Hitachi 2SJ162/2SK1058 notice these FET's have different housing (TO-3P) __________________ Mod is fun

16th September 2007, 10:05 AM	#4
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi Rig, is Pmik correct? Are 2sj81/k226 the original fitment? These are 2bolt Fpack packages. The To247 Renases replacement are single bolt fixing and should be a straight swap. The Pin order is identical, but you'll need to move them sideways to align with one of the existing tapped fixing holes 2sj161/k1057 are the 140V equivalent. 2sj162/k1058 are the 160V equivalent, these are available from Rapid. __________________ regards Andrew T.

16th September 2007, 10:30 AM	#5
PMik diyAudio Member Join Date: Mar 2004 Location: Fort Lauderdale, FL	Andrew Yes they are the original ones I have had so many of the MF P series in my hands ..., sure i know __________________ Mod is fun


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16th September 2007, 03:19 PM	#6
ANTHONY2181 diyAudio Member Join Date: Jul 2002 Location: HERTFORSHIRE UK	I have some New 2SK343 and 2SJ99 pairs which look pretty similar in specs + they are the same package. Regards Anthony

16th September 2007, 05:46 PM	#7
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	Look at the Exicon range of mosfets from Profusion PLC These are excellent replacements for the Hitachi originals. The ones in the TO-247 packaging should do.

18th September 2007, 09:50 PM	#8
rigel9999 diyAudio Member Join Date: Sep 2007	Hi Andrew T, I can confirm the originals are Hitachi 2SJ81/2SK226 (2SJ82/2SK227. Thank you PMik and everyone else who took time to reply. Rigel9999

18th September 2007, 11:39 PM	#10
PMik diyAudio Member Join Date: Mar 2004 Location: Fort Lauderdale, FL	I would strongly advice you to change both pairs of MOSFET's to the 2SJ162/2SK1058 this to insure equal performance betwin the chanals An interesting detail regarding the 2SJ162/2SK1058 is the fact that the pair are equal to the 2SJ50/2SK135 pair The 2SJ50/2SK135 where used in the MF B200, P140 and P150 Class AB standing current should be set for at least 100mA and imho for best sonic performance 200mA __________________ Mod is fun

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