Equiv. Parts: 2SD669, 2SB649

Free Model Generator

A free DOS-based demo device model generator is available from Intuisoft www.i-t.com. You feed in as much data as you can from a datasheet and the program estimates the remainder. It will do diodes, zenners. BJT, J-FETs, and M-FETs.

This is a demo and I can't get the results to print or to be saved to an ascii file. However, you can simply write them down carefully and type them into an ascii file. They are not that long. Supossedly the program allows PrintScreen but not, appearently, in my XP setup. If I fiddle enough, I may get those glitches worked out.

Over the next couple of days I'll plug in the 2sd669/2sb649 results. I can't make any guarantee that they are accurate and you may have to add or modify the headers for your SPICE version.
 
[B]Close Fairchild Substitute[/B]

Look at www.fairchild.com. Search for KSA1220 and KSC2690. Per the data sheets they look incredibly close to the 2sd669/2sb649. In fact they look like they could be upgrades.

Bad news they seem to be unavailable from US catalog suppliers (which frustrates me as Fairchild Corp HQ in about a 30 minute drive from here!).

Good news for Rarkov: They seem to be the same as 2sa1220 and 2sc2690 available in the EU from Donberg.

Best news: you can downloadspice models from Fairchild!
 
DIY Spice models

Since Spice models seem not available for the 2SB649 and
2SD669 I embarked on some Spice model DIYing a while ago.
The models are based on a combination of semiconductor
physics and empirical tweaking to match the datasheets. As
far as I can see it is usually theoretically as well as practically
impossible to match Spice models closely to all relevant diagrams
for most BJTs, so these models are a compromise not matching
any diagram perfectly but neither matching any very badly. Use
at your own risk. I also attach my DIY models for the potential
replacements 2SA1837 and 2SC4793. Suggestions for
improvements of the models are welcome.

.model 2SD669 NPN (IS=5p NF=1 BF=250 ISE=5p NE=1.5 IKF=3 VAF=150 RB=1 RC=0.25 RE=0.25 TF=1.14ns CJC=50p )
.model 2SB649 PNP (IS=5p NF=1 BF=250 ISE=10p NE=1.5 IKF=3 VAF=75 RB=1 RC=0.25 RE=0.25 TF=1.14ns CJC=50p )
.model 2SC4793 NPN (IS=0.1p BF=130 NF=1 ISE=0.1p RB=1 RE=0.1 RC=0.2 VAF=500 IKF=3 TF=1.6ns CJC=100p )
.model 2SA1837 PNP (IS=0.1p BF=130 NF=1 ISE=0.1p RB=1 RE=0.1 RC=0.2 VAF=500 IKF=3 TF=2.28n CJC=150p )
 
better price in NJ

Jack there at tech-diy will sell those Hitachi pairs at a MUCH better price than I've found anywhere else. It was like $1.40 or $1.50 a pair. At Fry's I shamed myself by paying something like $1.60 or $1.80 each...and that was for the NEC clones...which worked fine, by the way.
 
I have just used Christer's home brew spice models for the 2sd669/2sb649 in a SIMetrix model of one of Slone's amps. I substituted the models for 3 or four other types previosly discused as substitutes. I use SIMetrix's FFT facility to look at the predicted 2nd, 3rd, 4th ... harmonics. If the models are to be trusted, it makes very little difference which of the alternative transistors are used. I didn't need to be too precise in reading the graph to see that in all the casaes the THD was going to calculate out with riduculously many leading zeros after the decimal!

I seem to recall that Slone says in one of his books that he designs with the intent that only ordinary components are required to get the performance levels claimed. For instance, he even suggests that 5% carbon film resistors are good enough.
 
To Jackinnj,

In your checking keep an eye out for 2SA1220/2SC2690 as well. I think (but I'm not sure) that hey are nearly/virtually the same as as the 669/649's. Fairchild makes some in Korea except that the "2" prefix is replaced by "K".

Neither seem to be available in North America except in large quantities direct from Fairchild.
 
.model 2SD669 NPN (IS=5p NF=1 BF=250 ISE=5p NE=1.5 IKF=3 VAF=150 RB=1 RC=0.25 RE=0.25 TF=1.14ns CJC=50p )
.model 2SB649 PNP (IS=5p NF=1 BF=250 ISE=10p NE=1.5 IKF=3 VAF=75 RB=1 RC=0.25 RE=0.25 TF=1.14ns CJC=50p )
.model 2SC4793 NPN (IS=0.1p BF=130 NF=1 ISE=0.1p RB=1 RE=0.1 RC=0.2 VAF=500 IKF=3 TF=1.6ns CJC=100p )
.model 2SA1837 PNP (IS=0.1p BF=130 NF=1 ISE=0.1p RB=1 RE=0.1 RC=0.2 VAF=500 IKF=3 TF=2.28n CJC=150p
Are these models used for Multisim? I use Orcad.
Who can tell me the site to download multisim 2001 free:( ?
 
CF amplifier from Slone-Seal Elect.

To Sound Boy

I just to let you know that I built two monoblock vesions of
Mr. Slone's CF amplifier.
Only to say that this the most sensational amplifier that I ever
built, and there are many!...
I'm a tube sound lover and I have several amps that I built/
rebilt but let me tell you Mr. Slone's design as far as the sound
goes is very, very comparable to the tube sound.
The two monoblocks I built are the best SS amplifiers I own.
The sound is smoot, detailed and the bass are powerful the
mid and treble are detailed with no harshness whatsoever.
 
" Mr. Slone's design as far as the sound goes is very, very comparable to the tube sound"

If you read the intro to his Amplifier Construction book you might conclude he would be diappointed or even a little insulted by such praise. He would never say so himself, of course, except in the kindest and most diplomatic manner.:D