Drivers for Sanken 2SA2922/2SA1216

[Kees]

Hi,

I want to build an amp using Sanken 2SA2922/2SA1216 in the end stage. The current amplifier will have 3 stages.

Does anybody know which driver transistors can be used and are easy to get (maybe from Schuro in Germany). I was first thinking of ON semiconductor MJE340/350 for the 1st stage, ON semiconductor MJE15028/15029 for the second stage and Sanken 2SA2922/2SA1216 in the last stage.
I can imagine the Japanese may have better transistors than ON semiconductor.
Any good suggenstions?

Kees

 

[diyman]

Drivers

I've used 2SA968 and 2SC2238 successfully.

ckt

 

[capslock]

The MJE150xx series do have pretty low gain at low current. If you measure them with a multimeter, you get gains on the order of 20. Gains gets better at intermediate levels before it drops off again at several A. I wonder if this causes a problem when the transistor just starts to conduct.

Also, these devices are not exactly fast, with an f_T of 30 MHz. The Sankens you want to use have about 50 MHz.

Sanyo makes TO-126 video transistors, the older series having 150 MHz, the newer about 400 MHz. Current gain is very flat from 0-1 A. Should make nice VAS stages, too. The part numbers are in the thread "new law".


Eric

 

[peranders]

MJE340/350 as input transistor seems a little bit not . I would use some low noise small signal transistor like BC5xx series. If the power supply voltage is high, use a cascode.

Gain Hfe >300
fT >100 Mhz
Ic 300 mA
Uce 20-50% more than you have as power supply voltage.

BC546/47/48/49/50 NPN

BC556/57/58/59/60 PNP

Or the excellent and cheap BC847BS/BC857BS, see picture below

http://home5.swipnet.se/~w-50719/hifi/qsxm2/layout_qsxm2.html#Anchor-47857

 

[dshortt9]

The 340, 350 are not as good as the 2sa1837, 2sc4793 which have a flatter beta for drivers. For the front end try 2sa1016, 2sc2362.

 

[Kees]

Thanks for the suggestions.
Do you have a good source for these 2SA... and 2SC... transistors?
I live in the Netherlands. I believe Schuro in Germany might have them but they don't answer to emails or faxes and are hard to get hold on. I want to place 1 or 2 orders for all components in order to avoid minimum order and freight charges.

However I noticed that Schuro is about to introduce their Millenium XP Amp that uses the Sanken transistors, see
http://www.schuro.de/preisl-mill-xp.htm
Let's see what will be the drivers in that design.

Thanks for the help!

 

[capslock]

Kees,

try www.reichelt.de. They have all kinds of Japanese parts. Problem with them: they won't tell you the gain grade...

Eric

 

[Kees]

data sheets for 2SA968 and 2SC2238

Hi,

I found out that transistors 2SA968 and 2SC2238 are good available.
However I cannot find a data sheet. I believe these are from Toshiba but there is nothing on their web site.

Does anybody have a PDF ?

 

[JensRasmussen]

Drivers

Hi,

Toshiba make som great new drivers to replace 968/2238.

They have ft= 70 Mhz (less than the old ones) but are reated to 230 V

I have PDF's of all types

2sa1837 and 2sc4793

\Jens