Alternatives to 2SD669 and 2SB649 transistors

[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

 

[hienrich]

the nearest to thier specs:

MJE340/MJE350

same pin configs. and pkging.

 

[AndrewT]

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]

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

what about 2SC2344 and 2SA1011?

 

[rodolfo]

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]

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

 

[rodolfo]

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

 

[jpnascim]

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]

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

 

[Netlist]

2SC3117/2SA1249 if you can find them.

/Hugo

 

[jpnascim]

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

Have you tried Farnell website ?(www.farnell.com)

Best regards,

João Pedro

 

[Greg Erskine]

or here....

http://www.tech-diy.com/smallsignal.htm

.....may not be in the UK.

 

[UltimateX86]

What is the Randy Sloanes designs ?

 

[Spirtos]

Randy Slone designs mostly mosfet power amps according his famous books: "The audiophile's project sourcebook" and "High power audio amp guidebook" Take a look:http://www.amazon.co.uk/s/ref=nb_ss...l=search-alias=aps&field-keywords=randy+slone

He mostly prefers 2sk1058/2sj162 power mosfets.
His "Totem Pole " is a very nice amp design.

http://www.diyamp.net/ or his personal brand name http://www.zusaudio.com/

 

[synonymous]

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.

Toshiba is replacing the 1930 with and lists the replacement as the
TTA004B,Q

Ft 100MHz for the TTA004B,Q
Ft 200MHz 2sa1930
Ft 175MHz KSA1220
Ft 140MHz 2SB649