So Osscar, I have not built a stereo pair yet to listen to in my system. I will compare the A40 to the AB100 when I do. I have had the A40 for over 10 years and it is the best amp I own right now. I also have the Honeybadger and it is a close second. I need the power though for running maggies.
Sorry for late answer, but as NP said (if I remember correctly), darlington transistors with lower value internal resistors are better ...higher driver current - less distortion...obsolete Lambda PMD parts even better...
Would like to discuss what it would take to replace the Darlington output stage with just a power BJT. Particularly looking at Sanken devices. Will the existing driver stage have enough gain to drive this? Or will it take another driver stage after the existing. I have no idea if what I'm asking will work or not.
@Eugene L. - Singapore (I don't remember your nickname),
please send me a PM, your boards are back to me (incorrect / Insufficient shipping address)
@manniraj,
that lets hope!
please send me a PM, your boards are back to me (incorrect / Insufficient shipping address)
@manniraj,
that lets hope!
Oh so his has reached back but mine no trace of it so far. Lets hope if it reaches me and unfortunately I will be in Frankfurt for a week or 2 in the 2nd week of October. So if mine as well returned within that time frame then surely can request you to ship it to FK.
Thanks
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So my thoughts on replacing the Darlington stage are aimed at building a 300W/chan power amp to drive magnepans. they are very inefficient as everyone knows. I'm currently pushing a little over 200W/Chan with the four 142/47. That puts it just over the SOA of the outputs. So what I was thinking was using BJT outputs rated higher and still using just 4 pair so that I can utilize the same board as is. Looking at rails between 50-60vdc.
If they are not darlingtons, then you will need follwer driver transistors, as the
current gain of big power transistors is less than 100, and the front end is
good for whatever its DC bias point is, 20 mA or so.
current gain of big power transistors is less than 100, and the front end is
good for whatever its DC bias point is, 20 mA or so.
So then the question becomes are there Darlingtons with higher output capabilities so that I can use just four still. In my search I haven't come across them. Sankens aren't any higher that I can see. Anybody know of any.
Take a look at MJ11015/MJ11016
https://www.onsemi.com/pub/Collateral/MJ11012-D.PDF
I don't know if it is OK to use it in this project, I know some DIY-ers used it in the A40 as a replacement for the Lambada.
https://www.onsemi.com/pub/Collateral/MJ11012-D.PDF
I don't know if it is OK to use it in this project, I know some DIY-ers used it in the A40 as a replacement for the Lambada.
AB100 is an exercise in getting maximum watts per dollar. Its TIP142/7 output transistors are half the price of comparable Sanken devices (2SB1647) and one ninth the price of the massive, brutal 300W TO-3 devices (MJ11033). If you want to increase AB100's output by a factor of N, increase the number of TIP142/7 devices by that same factor of N. Or design a new amplifier with different goals.