Alternatives to 2SD669 and 2SB649 transistors

Si992 · 14th April 2005, 05:09 PM

Hi, just a quick question, are there any available alternatives to the 2SD669 and 2SB649 transistors used in Randy Sloanes designs? There seems to be some issues regarding wether its best to look hard and seek some out or to replace them with an alternative. Does anyone have any opinions, alternatives or help in what to look for when trying to choose a replacement?
Si

hienrich · 14th April 2005, 05:45 PM

the nearest to thier specs:

MJE340/MJE350

same pin configs. and pkging.

AndrewT · 14th April 2005, 06:24 PM

Hi,
340/350 are only 500mA. and rarely specified for Ft.
2sa1930/c5171
2sa1606/c4159 only 15w & 100MHz
2sa1507/c3902 only 10w & 120MHz
2sa1535/c3944 only 150v 15w 1a
2sa985/c2275 only 120v
The 1930 fully meets spec the others as listed don't quite meet it.
There are some ultra definition video drivers that exceed your spec but they are expensive.
Report back on your findings.

hienrich · 14th April 2005, 06:42 PM

I don't know why they dont specify FT's to this, either
ON or Fairchild

what about 2SC2344 and 2SA1011?

rodolfo · 15th April 2005, 03:34 AM

Quote:

Originally posted by Si992
Hi, just a quick question, are there any available alternatives to the 2SD669 and 2SB649 transistors used in Randy Sloanes designs? There seems to be some issues regarding wether its best to look hard and seek some out or to replace them with an alternative. Does anyone have any opinions, alternatives or help in what to look for when trying to choose a replacement?
Si

I have 25 of each one

B Cullingford · 15th April 2005, 03:36 AM

Available from ampslab.com
never ordered from them and know nothing about them - just found with goggle

rodolfo · 15th April 2005, 03:42 AM

they are hitachi but they come marked alone with the b649a and d669a but are the same

jpnascim · 15th April 2005, 10:44 AM

Hello,

I am also buidling a Slone Amp and I had the same problem your are having in finding those devices. As far as I know Hitachi doesn't manufacture them anymore.

Doing a lot of search here I saw a recommendation to use Fairchild's KSA1220 and KSC2690 (alternatives for the 2SA1220/2sc2690) which have very close specifications. I bought a number of them (easy to find even here in Brazil) but I haven't finished the amp so I couldn't test. Simulation tests indicate very similar performance to the 2Sd669 and 2sb649 with no problems with amp stability.

Best regards,

João Pedro

Si992 · 15th April 2005, 11:06 AM

cheers, thanks for the help, wheres the best place to order transistors from in the uk?
Si

Netlist · 15th April 2005, 11:14 AM

2SC3117/2SA1249 if you can find them.

/Hugo

14th April 2005, 05:09 PM	#1
Si992 diyAudio Member Join Date: Feb 2005 Location: Loughborough	Alternatives to 2SD669 and 2SB649 transistors Hi, just a quick question, are there any available alternatives to the 2SD669 and 2SB649 transistors used in Randy Sloanes designs? There seems to be some issues regarding wether its best to look hard and seek some out or to replace them with an alternative. Does anyone have any opinions, alternatives or help in what to look for when trying to choose a replacement? Si

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14th April 2005, 05:45 PM	#2
hienrich diyAudio Member Join Date: Dec 2004 Location: City of Gentle People	the nearest to thier specs: MJE340/MJE350 same pin configs. and pkging.

14th April 2005, 06:24 PM	#3
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, 340/350 are only 500mA. and rarely specified for Ft. 2sa1930/c5171 2sa1606/c4159 only 15w & 100MHz 2sa1507/c3902 only 10w & 120MHz 2sa1535/c3944 only 150v 15w 1a 2sa985/c2275 only 120v The 1930 fully meets spec the others as listed don't quite meet it. There are some ultra definition video drivers that exceed your spec but they are expensive. Report back on your findings.

14th April 2005, 06:42 PM	#4
hienrich diyAudio Member Join Date: Dec 2004 Location: City of Gentle People	I don't know why they dont specify FT's to this, either ON or Fairchild what about 2SC2344 and 2SA1011?

15th April 2005, 03:36 AM	#6
B Cullingford diyAudio Member Join Date: Mar 2005 Location: California	Available from ampslab.com never ordered from them and know nothing about them - just found with goggle

15th April 2005, 03:42 AM	#7
rodolfo diyAudio Member Join Date: Jan 2005 Location: tamaulipas	they are hitachi but they come marked alone with the b649a and d669a but are the same

15th April 2005, 10:44 AM	#8
jpnascim diyAudio Member Join Date: Nov 2004 Location: S.J. Campos - SP	Hello, I am also buidling a Slone Amp and I had the same problem your are having in finding those devices. As far as I know Hitachi doesn't manufacture them anymore. Doing a lot of search here I saw a recommendation to use Fairchild's KSA1220 and KSC2690 (alternatives for the 2SA1220/2sc2690) which have very close specifications. I bought a number of them (easy to find even here in Brazil) but I haven't finished the amp so I couldn't test. Simulation tests indicate very similar performance to the 2Sd669 and 2sb649 with no problems with amp stability. Best regards, João Pedro

15th April 2005, 11:06 AM	#9
Si992 diyAudio Member Join Date: Feb 2005 Location: Loughborough	cheers, thanks for the help, wheres the best place to order transistors from in the uk? Si

15th April 2005, 11:14 AM	#10
Netlist diyAudio Moderator Emeritus Join Date: Jan 2003	2SC3117/2SA1249 if you can find them. /Hugo