My Fairchild BC560C have Bf=780 at 14.6Vce but 600 at 7.6Vce. Think about it, Vaf is the voltage at which Bf doubles (About 23 for this transistor). Transistors with a low Early voltage will have a Bf that rises greatly at high Vce. This is not shown in the datasheet, surprisingly.
I have done some checking and it seems my Vaf test rig really is reporting Vaf correctly. Have you guys measured Bf at say 40Vce? Because it should be very high.
I have done some checking and it seems my Vaf test rig really is reporting Vaf correctly. Have you guys measured Bf at say 40Vce? Because it should be very high.
This thread is a gem in many ways. And so is Toni's amplifier. One of the particularly impressive things I found was the way the amp rejects intermodulation between PSU ripple and signal. Note that this CAN be very different to PSRR - i have seen amps with great PSRR provided zero signal i/p, but once you subject the amp to PSU ripples AND inject a signal, 100hz sidebands to the fundamental can be significant.
I simmed Toni's amp like this (with suitably long sample capture to increase resolution in the FFT) and came away VERY impressed by the clean output - no sidebands visible at all even with 1V ripples! I tried this again removing the FE filter caps (pretty evil test i know) and again the sidebands were extremely low.
This one goes on my build list for this year
I simmed Toni's amp like this (with suitably long sample capture to increase resolution in the FFT) and came away VERY impressed by the clean output - no sidebands visible at all even with 1V ripples! I tried this again removing the FE filter caps (pretty evil test i know) and again the sidebands were extremely low.
This one goes on my build list for this year
See attached data files. This is, what the DCA75pro software allows to export. Have data converted from dos2unix.
Unfortunately DCA75pro isn't able to test Ft...
Thx for sharing!
BR, Toni
Attachments
For a first look see schematic pictures 2 and 3 of the first post of this old thread:
http://www.diyaudio.com/forums/chip...ing-only-bridged-8-ohms-only.html#post3220966
... there are some extra features (and schematics) missing like mute using speaker output relais, remote power on/off using 12V signal, configuration of remote control using MCU TTL RS232 TX/RX port and so on.
Cool!...
This one goes on my build list for this year
BR, Toni
... does this mean you can use that data for your needs? If so then I will provide you the data for the other 3 parts. Maybe also extra data for the different BC5x0C variants I have (Fairchild, Onsemi)
BR, Toni
... some more data ...
2SC/2SA-types:
UTC = Unisonic
TOS = Toshiba
BC-Types:
FC = Fairchild Semi
ON = OnSemi
Have fun, Toni
Attachments
If you imagine Vcesat doesn't exist, then a transistor with Vaf=20 and Bf=300 at 0Vce will have an Hfe of 600 at 20Vce. You can see in the Fairchild BC560C charts that if the slope continues to about 30V Hfe will have doubled.
Obviously if Vaf is 900 and Bvceo is 180V, you can't operate the transistor outside of it's voltage range, but you know that Hfe will change only about 20% across it's voltage range.
In most datasheets Hfe is measured at 1Vce-5Vce, so it's close enough to 0 that the relationship is still pretty close.
Obviously if Vaf is 900 and Bvceo is 180V, you can't operate the transistor outside of it's voltage range, but you know that Hfe will change only about 20% across it's voltage range.
In most datasheets Hfe is measured at 1Vce-5Vce, so it's close enough to 0 that the relationship is still pretty close.
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Hi Tony,
Lots of $ invested in this hobby. Even going for the premium 200V devices, planning on some high rail voltages?
I used the alf16n(P)16W (one pair) with the LME49830, set the bias at 150mA, needed more HS for bias higher. it was opc latfet amp, with a few mods. Put them in a old sansui G-7500 and a Pioneer SX-1050 PS. I can pump it into the 120W range. Works, sounds great and measures okay, fast at 600ns rise/ 650ns fall times, no ringing.
what is the rise/fall time of your amp with bjt?
Good luck with the fets, I am sure you will like them but will ponder if the extra expense is worth it. Waiting ...
Lots of $ invested in this hobby. Even going for the premium 200V devices, planning on some high rail voltages?
I used the alf16n(P)16W (one pair) with the LME49830, set the bias at 150mA, needed more HS for bias higher. it was opc latfet amp, with a few mods. Put them in a old sansui G-7500 and a Pioneer SX-1050 PS. I can pump it into the 120W range. Works, sounds great and measures okay, fast at 600ns rise/ 650ns fall times, no ringing.
what is the rise/fall time of your amp with bjt?
Good luck with the fets, I am sure you will like them but will ponder if the extra expense is worth it. Waiting ...
Jup - here we call it Euro.
Currently no real plan to use higher rail voltages. Maybe a bridged / balanced high power variant of SA2014-circuits delivering 1000W@8R for my 3-way active crossover mono block tower amplifier...
What you don't know - there exists also a SA2012 - a high power LME49830 MOSFET based 4 channel amplifier which I made 2012. Capable to drive 190W@8R continuous using 3pairs IRFP240/IRFP9240. Sounds very good and is my fallback, if SA2014 will produce holy smoke ...
Have fun, Toni
Attachments
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SA2013, SA2014, SA2015 housekeeping circuits
I've been asked several times mostly via PM to provide more information about the housekeeping circuits which I've developed and used in most of my current amplifier projects. If there's enough positive response here, I will think about providing gerbers and maybe firmware for programming the pic16f690 and the newer replacement pic16f1829...
Got these very nice votes - many thanks. Maybe there is some more positive feedback out there ... as it is a lot of work to prepare the data...
Have fun, Toni
I've been asked several times mostly via PM to provide more information about the housekeeping circuits which I've developed and used in most of my current amplifier projects. If there's enough positive response here, I will think about providing gerbers and maybe firmware for programming the pic16f690 and the newer replacement pic16f1829...
... This one goes on my build list for this year
Got these very nice votes - many thanks. Maybe there is some more positive feedback out there ... as it is a lot of work to prepare the data...
Have fun, Toni