For vas use I find 2sa1406 to be the best option, its a bit pricey and not so easy to get. At 10ma ft is 300 and still rising and it can handle higher power.
I have a little problem with 2sa1360, during some actual real time testing for early effect these didnt perform as good as 2sa1145, so much for it to be that but in TO220 case. Performance is about in same class as 2sa1381, actually worse as 1381 can easily be had with much higher gain. Second source 1360 datasheets as supplied by KEC is a more realistic view of its performance, far from the 1406 and 1145.
2sa1381 is very cheap and easily available, there are 3 manufacturers of this part, 1360 also cheap but not so easily available in europe.
I have a little problem with 2sa1360, during some actual real time testing for early effect these didnt perform as good as 2sa1145, so much for it to be that but in TO220 case. Performance is about in same class as 2sa1381, actually worse as 1381 can easily be had with much higher gain. Second source 1360 datasheets as supplied by KEC is a more realistic view of its performance, far from the 1406 and 1145.
2sa1381 is very cheap and easily available, there are 3 manufacturers of this part, 1360 also cheap but not so easily available in europe.
roender said:
Many fakes out there of a1360/c3423 pair
I'd rather suggest a1381/c3503!
http://www.datasheetcatalog.org/datasheet/sanyo/ds_pdf_e/2SC3503.pdf
Janneman I used a testing scheme similar as can be seen in renardsons site to test how good the transistors were. The best results obtained were with 2sa1406, 2sa1145 and the bf422. The latter 2 in TO92 cant stand as much current though, but I think it cannot be taken as a rule about the packages, 2sa1406 is TO126 and when doing the test were fairly even with 2sa1145. If the power rating of 2sa1145 is enough its a very good choice, havent found anything beter and its cheap. The difference to 1360 and 1381 is more noticeble when measureing for this but sonically the difference is minute, I can only pick up these diferences with high quality headphones. With cascodes used I have tried trannys with ft of 1,2Ghz in vas and ltp, these have cob of less than 1pf. I heard a very high end amp uses this type of transistor and I can see and hear why but this is not for everyone as it sounds very clean and I notice people seem to like some type of coloration.
janneman said:
Of course it is The Rule.
There are limits for different packages.
Two very nice packages with many good transistors in past were the metal case TO-18 and TO-39.
They are probably better than corresponding plastic packages, like often used TO-92 and TO-126.
Generally any TO-92 will beat the speed and capacitance of TO-126. (BD139/140, MJE350/340).
Same way generally any TO-126 will beat any TO-220 (MJE15030/31).
There are not many transistors made in TO-18 no more.
TO-71 is like one dual TO-18.
http://www.linearsystems.com/ makes high quality LSK389 dual monolitic JFET in TO-71 metal package
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I did this a while back, they are rf transistors. I experimented with 3 or 4 different ones, cant remember their numbers, I ordered from either fairchild or onsemi. The ones I looked at were RF but having higher gain than usual rf types. Vce was either 30 or 40 volts with very low cob figures.
If I recall one was bf240 or bf260, something in that line.
If I recall one was bf240 or bf260, something in that line.
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