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Rarkov 19th September 2002 12:23 PM

Equiv. Parts: 2SD669, 2SB649
Does anyone know of equivilent part numbers for the following:

* Hitachi 2SD669
* Hitachi 2SB649

BTW, the package is a TO-192...

Here is a link to the datasheets.

The circuit designer, Randy Slone, told me that some people replaced them with components from the MJE series but he couldn't remember the part numbers. I believe they are made by motorola but I cannot find any datasheets.

Any help would be GREATLY appreciated!
Thanks in advance!!!

jackinnj 19th September 2002 01:27 PM

I have these for sale
they are a little hard to find in the US, contact me at if you are interested.

A number of the Motorola products are now manufactured by On Semi -- this was most of the discretes part of Motorola, spun out of the company about 3 years ago. Their web-site is

Rarkov 19th September 2002 01:36 PM

It seems to be even harder in the UK!!! Can you ship to the UK?

jackinnj 19th September 2002 02:18 PM

No problem
I use USPostal Service "Global Priority Mail" which is $4 and usually arrives in 4 to 7 days. Contact me off-list at

Tube_Dude 19th September 2002 03:10 PM

Hei RarKov

The only equivalents quoted in my book are:



Not to much help! :(


Jorge Santos

soundboy 19th September 2002 05:23 PM

have u tried the onsemi website, they seem to have an intuitive competitor cross reference page,,4291,,00.html

the results show mje344 is a suitable substitute for 2sd669 and the mje350 for the 2sb649.

I'm also very interested in Randy Slone's Mosfet designs, and would like opinions on sound and any mods if any of you out there have built them :)

Rarkov 19th September 2002 06:49 PM

Well done!!! I didn't see that...

The reason I went for this design is:


(The Audiophile's Source Book pg172)Finally, we come to Fig. 6-21, which is my favourite audio power amplifier design of any type .

and I'm sure he's built alot of amplifiers! THD+N is 0.04% but usually more like 0.005% and BW is 3Hz to 120kHz! The SNR is over -115dB...I don't claim to understand what Signal to Noise Ratio is when measured in dB...I thought that a ratio had no units but there you go!

Anyway...I'll have a look for UK suppliers of the MJE344 and MJE350...


Christer 19th September 2002 10:04 PM


I have only checked what is available from swedish suppliers, but the closest match I have found are the Toshiba devices 2SA1837
and 2SC4793, which I think should work fine.

I recommend against the suggested Motorola/ON devices
MJE344 and MJE350. Compared to the orignal devices, 2SB649
and 2SD669, they seem quite inferior.
1) A min. fT of only 15MHz, compared to 140MHz
2) Max. IC is 500mA, compared to 1.5A
3) Wider spread in hFE and much lower min hFE
4) They seem not even to be complementary devices.
They would probably work in any of Sloanes amplifiers, but so
would problably a number of other BJTs having similar specs.

Why do you want a replacement, BTW? Admittedly 2SB649 and
2SD669 tend not to show up in every suppliers stock, but
decent replacements seem at least as rare, in my experience.
If you search for the part numbers with Altavista or Google, you
will find quite a number of European suppliers of these devices,
some of them most certainly in the UK.

BTW, Spice models for 2SB649 and 2SB669 would be most

bawang 20th September 2002 06:33 AM

I used BD139/140, if the lower fT of these devices (as compared to the 649/669 devices) is not a problem.

bawang 20th September 2002 06:46 AM

......oh, nearly forget.... and lower voltage too....

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