Just restarted the work. Was down due to a small accident.
I should get one board ready very soon. Been trying to make the board so that I can try a few variations on the same board. If it works out well I'll make the second board. Not a very good layout but should do it's job. Should be ready this weekend I think.
I should get one board ready very soon. Been trying to make the board so that I can try a few variations on the same board. If it works out well I'll make the second board. Not a very good layout but should do it's job. Should be ready this weekend I think.
I want to try also looks promising of what stated by Gaborbela the sound quality. Please update once you've done. Thanks
Regards,
Boyet
Hello
I did it and sounded horrible!
I tested several power transistor and driver - not even come close to the cheap TIP142/147 etc from ST..
In case you do not believe fell free to test any built up darlington but first test it with BDW83C/84C or TIP147/142 so you get some information about these little amp!
there is a matching schematic from Wahab for the Darlingtons I think that would work.
I'm off for a while because I separated some cash close to a $1000 to finish some of my project and now I do not find that money.
Until I do not find that fund I afraid to take more money from the rest which I need for living.
I do live on disability support (to understand my situation), also live in a apartment where the supper has access to enter to my apartment.
I do not say he stole it but if I do not find that fund, who knows...
I did search for it several days with out finding it, I do remember clearly I did separated that fund and I kept in a different location.
These situation sucks.
Greetings G
Hello
TIP142/147 from ST one of the best you can get today.
When you look at the data do not look for TO247 package because it used to be in a TO218 package.....
A few years back the switched to TO247 so they didn't changed the full data on the net.
Actually both package is the same transistor.
ST is a great transistor, I did tried other type for BDW like ISC and blew up after few minutes but never the ST!
I still have them in both package, no performance difference between.
What do you use for drive?
BF no longer recommended, made in India and the performance only shadow of the orig what I used 20 years a go.
I recommend MJE234/235 but you have to take care the offset because huge Hfe differences between the PNP/NPN.
I WILL HELP THAT WHEN YOU THERE!!
Some famous amplifier used these driver (like Naim Chrome Bumper) and it surprised me when I tested.
Yes I did tested many other driver from ON semi MJ's from NEC, Philips BD139/140 etc. I will stick with the MJE until I'll get something better.
Sometimes more important the driver transistor has to match the power transistors...
For input please use BC550C/560C or you can use JFet 2SJ74BL/2SK170BL just turn (rotate) then 180 degree..
For example if the bi polars mounted face to face the JFet has to be back to back.
Use a PC. of heat shrink on them for thermocouple them.
I used to use that meting glue on the top or between them if they are mounted back to back to feel up the gap.
That glue has great thermal conductivity.
Please use large heatsink, do not under estimate because that will lead a thermal run away 100%.
I do want finally someone test these amp!.
Soon I will test the lateral version to but first I must find my $$$ was separated for DIY purpose..
Greetings
Right. But these are the parts I have with me and will use them now otherwise it will delay the test further and might just slip further .......
I do remember having a +/- 35 V supply but can't find it ! Will look for it till I get down to testing the board.
Most that can happen is a blown amp ! The speakers are protected.
I do remember having a +/- 35 V supply but can't find it ! Will look for it till I get down to testing the board.
Most that can happen is a blown amp ! The speakers are protected.
Djk: Thanks for pointing it out. I didn't actually look at the power . In any case I wouldn't be using this at clipping or anywhere near that. I just want to confirm that it is stable. I'll be switching the power transistors to Lat Fet's later.
I'd probably get about 50 watts unclipped into 8 ohms taking into consideration voltage loss due to supply sag and the ripple on the cap , Vce sat. loss and R(emitter). Might get about 40 watts into 4 ohms at +/- 33 V. It isn't a stabilised power supply. Just an average transformer. Should be OK I think.
Cheers.
I'd probably get about 50 watts unclipped into 8 ohms taking into consideration voltage loss due to supply sag and the ripple on the cap , Vce sat. loss and R(emitter). Might get about 40 watts into 4 ohms at +/- 33 V. It isn't a stabilised power supply. Just an average transformer. Should be OK I think.
Cheers.
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