Now that my F5T will soon replace my F5 ,I intend to reuse my F5 chassis, heatsink & psu for Aleph J. So a few questions
--If I omit C1 will I have to jumper the C1 cap pads?
--I have 2 Silmics ,so better to use them @ C3 . Can someone tell me the voltage rating @C2, I have some 220uF 16v,25V
--If I use BC550/560 do any of the resistor values need change. Also will my bias current go down?
That's all I can think of now 🙂
Thanks
--If I omit C1 will I have to jumper the C1 cap pads?
--I have 2 Silmics ,so better to use them @ C3 . Can someone tell me the voltage rating @C2, I have some 220uF 16v,25V
--If I use BC550/560 do any of the resistor values need change. Also will my bias current go down?
That's all I can think of now 🙂
Thanks
-- yes
--for C3 16V is plenty enough , for C2 35V is tight , 50V means peaceful sleep
--just use them and do not worry
Thank you Aleph Angel 😀, all the boys have moved on to shinier stuff the Aleph still seems to be your precious 😛
The feet will take a bit longer, but for as far as I know I do not need to set the bias on this amp. In thought the bias was determined by the circuit. There is nothing to adjust (no trimpots). Am I missing something?
I do not totally agree.
Several of us, including me, found a bias current as high as 1.2 to 1.3 amps per leg using stock values.
1 amp per leg (2 amps total) is enough though. (think about dissipation)
By curiosity, you should measure the bias current on your amp.
Anyway, your amp is running a little too warm IMO.(You tell 33 above ambient)
Several of us, including me, found a bias current as high as 1.2 to 1.3 amps per leg using stock values.
1 amp per leg (2 amps total) is enough though. (think about dissipation)
By curiosity, you should measure the bias current on your amp.
Anyway, your amp is running a little too warm IMO.(You tell 33 above ambient)
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there are 2 trim pots on my aleph J, one for biasing and one for dc-offset
but for Albert, don't worry too much right now, just enjoy you new amp 🙂
but for Albert, don't worry too much right now, just enjoy you new amp 🙂
I don't know how to measure the bias (is probably mentioned somewhere in this long, long thread) but I don't have any trimpots anyway. Any adjustment would have to be by taking out (or adding) resistors. I think I will leave it as is for now
I finally got the feet on today. Metalwork is not easy for someone in an electric wheelchair
, I can tell you.
The amp is sitting on the bench and has been cooking for a bit under an hour with the top plate in place. DC offset is at 39mV (and still slowly decreasing) at speaker outputs (input shorted) and temperature is 59 Celsius (ambient + 33) at the hottest point I can find on the heatsinks. Seems OK to me 🙂
I will leave it for another hour and check again. If it is still OK I hope to be able to test the sound tomorrow.
Thanks again everyone for all your help, and of course a big thank you to Nelson
for your generosity. It makes it possible to build and own such beautiful amps!
Albert
PS It is quite possible that I will be asking simple questions in other threads in the future, as I think I may have been infected by a diy-amp virus that is prevalent on this forum!
I finally got the feet on today. Metalwork is not easy for someone in an electric wheelchair
, I can tell you. The amp is sitting on the bench and has been cooking for a bit under an hour with the top plate in place. DC offset is at 39mV (and still slowly decreasing) at speaker outputs (input shorted) and temperature is 59 Celsius (ambient + 33) at the hottest point I can find on the heatsinks. Seems OK to me 🙂
I will leave it for another hour and check again. If it is still OK I hope to be able to test the sound tomorrow.
Thanks again everyone for all your help, and of course a big thank you to Nelson
for your generosity. It makes it possible to build and own such beautiful amps!Albert
PS It is quite possible that I will be asking simple questions in other threads in the future, as I think I may have been infected by a diy-amp virus that is prevalent on this forum!
if you find it little on hot side , you can always arrange something like this :
http://www.diyaudio.com/forums/pass-labs/186554-babysitter-papas-koan.html?highlight=babysitter
http://www.diyaudio.com/forums/pass-labs/186554-babysitter-papas-koan.html?highlight=babysitter
Albert, why wait for tomorrow? or is it past midnight in Holland?
you know what they said, midnight listening is best, until your wife calls you that's is 🙂
ZM, that babysitter is one of the fuglyest I ever seen..ha ha, might need one for my hot SIT
you know what they said, midnight listening is best, until your wife calls you that's is 🙂
ZM, that babysitter is one of the fuglyest I ever seen..ha ha, might need one for my hot SIT
It is quite possible that I will be asking simple questions in other threads in the future, as I think I may have been infected by a diy-amp virus that is prevalent on this forum!
There is no known cure 😀
There is no known cure 😀
There is no hurry but, for info again:
One measures voltage across source resistors of the power mosfets.
Knowing voltage and resistor gives current when applying the ohm's law.
As there are two output pairs, the current found is to multiply by two.