fairchild semi, new audio output devices

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#61
Thanks for the company suggestion, Jacco.

Alex, thank you for your view on why the 2SC2330/sa1016 is a better part. I came to about the same views as you and Syn08, but am always interested in other people's views. Especially as you have measured these BJTs and compared to my favorite low power BJT pair, the 2SC2240/sa970.

I have ordered 500+500 pcs from Profusion.

I try to use the best parts I can find, but sometimes it is hard to keep track of 'em all.

Sanyo's video transistors are an amazing piece of work. Some of the best for VAS work.


SIgurd

jacco vermeulen said:
Then just order original Sanyos by the 100 from Profusion, which is also cheaper.
Click to expand...
 
#62
homemodder said:


a) I dont know about beta though i have some gain group g s which measure close to 500 and 2 or 3 group h which measure around 780 on my fluke meter. The h are near impossible to find though. I have a batch of some hundred 2sa970 the highest was group bl at 460.
<snip>
I also see my favourite driver is sold at profusion, its another sanyo. 😀 😀 😀 . Pity about vas transistors.
<snip>
They have some transistors manufactured by unisonic, anybody know if these are as good as original japanese ????.
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Funny enough, I can't buy here any 2SC2362/2SA1016 that are better than the F beta class (that is, 160-320). These parts have a measured Early voltage of about 60-100V (which also matches what you can extract from the Ic-Vce curves in the datasheet). Anything else (G and H class) are simply not available through the retail channels (even www.bdent.com stocks only F class). However, I can get unlimited amounts of 2SC2240/2SA970 from Toshiba in the BL beta class (300-700 and they mesure all around 740!). Of course the Early voltage is lower, but the product beta*Va is remarcably similar between the Sanyo and the Toshiba devices.

I don't need anything better than 2SC3601/2SA1407 as VAS and pre-drivers, but they are rather expensive. Unless absolutely required, I prefer to use KSC3503/KSA1381 which I can get here literally for pennies here, from Mouser.

For drivers, I use only 2SC5171/2SA1930 from Toshiba, you can't beat these devices. They are also rather on the expensive side.

Unisonic is BS, don't mess with.
 
#63
I can also get SC2240/SA970 with BL grade from www.elfa.se.

Not sure what grade I will get from Profusion on the SC2362 / 1016. I will let you know.

Yes, the SC3601/2SA1407 are as good as it gets as far as I know.
If there are any better ones, I surely would like to know.

The 2SC5171/2SA1930 pair is superb. I bought plenty, but I think that most are fakes.....


Alex - what are those Sanyo VAS transistors?



Sigurd

syn08 said:


Funny enough, I can't buy here any 2SC2362/2SA1016 that are better than the F beta class (that is, 160-320). These parts have a measured Early voltage of about 60-100V (which also matches what you can extract from the Ic-Vce curves in the datasheet). Anything else (G and H class) are simply not available through the retail channels (even www.bdent.com stocks only F class). However, I can get unlimited amounts of 2SC2240/2SA970 from Toshiba in the BL beta class (300-700 and they mesure all around 740!). Of course the Early voltage is lower, but the product beta*Va is remarcably similar between the Sanyo and the Toshiba devices.

I don't need anything better than 2SC3601/2SA1407 as VAS and pre-drivers, but they are rather expensive. Unless absolutely required, I prefer to use KSC3503/KSA1381 which I can get here literally for pennies here, from Mouser.

For drivers, I use only 2SC5171/2SA1930 from Toshiba, you can't beat these devices. They are also rather on the expensive side.

Unisonic is BS, don't mess with.
Click to expand...
 
#65
Re: 2SA1209/2SC2911

Edmond Stuart said:

Has anyone experience with 2SA1209/2SC2911 as a replacement for 2SA1407/2SC3601.
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Yes, I have successfully tried them in designs with a loop gain Fu under 1-2MHz, over that something better is required. Look in the datasheet under the switching parameters (Ton, Toff and Tstorage) to understand why.

They are not among my favourites, though. No reliable Spice models, I'm afraid.
 
#66
Ive used 2sa1209|2sc2911, they good using them as output transistors on buffers ect, they much better than bd139 mje253s and the like used by so many as vas and drivers. Ive got tons of them purchased as complementary matched pairs from factory, 90 percent match dead on for vbe and hfe. I wish all transistors manufacturers would do this.

2sa1407, now thats a excellent vas transistor, although i use 2Sa1406. Just a lower power version but with even less cob and higher ft at lower Ics where typical vas currents are used.

As driver i prefer 2sa1507|2sc3902 but these are yet again very hard to get. When i can find them i use 2sb1144|2sd1684 which now thanks to jacco i have a reliable source for. The 2sa1930 are great transistors too, they can handle higher powers.

Alex
 
#67
Syn08

I dont purchase mine through the usual retail channels 😀 but actually managed to find in the smallest imagenable shop here in portugal a supplier that sold me their stock of 300 pairs at 8 cents a piece. group g, hfe s around 500.

Alex
 
#71
Alex - you can get the
2sb1144|2sd1684
at www.bdent.com
, too.


Sigurd

homemodder said:
Ive used 2sa1209|2sc2911, they good using them as output transistors on buffers ect, they much better than bd139 mje253s and the like used by so many as vas and drivers. Ive got tons of them purchased as complementary matched pairs from factory, 90 percent match dead on for vbe and hfe. I wish all transistors manufacturers would do this.

2sa1407, now thats a excellent vas transistor, although i use 2Sa1406. Just a lower power version but with even less cob and higher ft at lower Ics where typical vas currents are used.

As driver i prefer 2sa1507|2sc3902 but these are yet again very hard to get. When i can find them i use 2sb1144|2sd1684 which now thanks to jacco i have a reliable source for. The 2sa1930 are great transistors too, they can handle higher powers.

Alex
Click to expand...
 
#76
Thanks Jacco for the info on extracting Early from the graphs.

But what about some answers to my other questions?
Wiki tells me nothing about Early's effect on circuit operation, or when It is deleterious to performance and when it can be tolerated.
 
#77
Sorry I thought that this would be clear then.

Let me answer you in your own way 😀

What happens with the VCE in a long tailed pair with applied input signal?

What can you do to keep VCE constant?

Look at the IC/VCE-plot: where is the effect smallest?

Have fun , Hannes😀
 
#78
AndrewT said:
Thanks Jacco for the info on extracting Early from the graphs.

But what about some answers to my other questions?
Wiki tells me nothing about Early's effect on circuit operation, or when It is deleterious to performance and when it can be tolerated.
Click to expand...

Andrew,

Wiki has comments regarding the impact of the Early voltage on the large and small signal models, so it all boils down to the impact of these models on an amp performance.

Imagine a common emitter amp stage. You inject a sine current in the base and you are looking at the collector current. In an ideal world, Ic will follow Ib as in Ic=Beta*Ib. The Early effect says that unfortunately Beta is a function of Vce (look into Wiki on how). As Vce also varies with Ic (because of the stage load), the net result is that beta depends on Ic. Which makes the nice linear relationship between Ic and Ib simply untrue. Net result - distortions.

The obvious solution is to keep the common emitter gain stage Vce constant. How? Usually by cascoding the gain stage.
 
#80
Early

Hi Andrew,

My previous answer was a bit short and needs further explanation.
No matter if the Early effect is a linear or a nonlinear function of Vce, in most cases it will add to distortion.

In case of a fully complementary input stage however (that was I was thinking of, see the BT thread) then a linear function and equal for both "genders", will not add to distortion.
But in case of nonlinear (but equal) functions, the terms of even degree will not be canceled and will contribute to distortion.

Cheers,
Edmond.
 
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