Hello All,
finally finished my Aleph 5
. Well almost, but at least it makes some music and not even bad at all.
Tested the first channel yesterday evening and got about 11A of bias wich was a bit to much for the fuse I used (good thing those fuses). After looking for a while at my printed circuits I found I had made a little mistake while designing the printed circuit mirrored for the left and right channel
Well now the connections to the plus and minus supply don´t look so nice for one channel and I´ll have to make a new board.
The rest works fine, I get 32.5volts before the chokes from a 25v transformer with a 2.8A bias current. After the choke it´s 31.5 volts with a 10mV ripple. DC-Offset is 48mV left and 23mV right.
Temperature is a bit high with 70° C measured directly next to the fets but this will be allright when I´ve corrected the bias to about 2A (don´t really know why it´s so high, any suggestions?)
Output is about 30V at 8 ohms with symmetrical clipping, humm is only noticable with my ear next to the speaker.
I´ve only heard it on my small "upstairs" system with small dynaudio speakers but it sounds like I hoped it would. Very natural but detailed without any harshness, good bass (on this speaker). I´ll try it on my downstairs system when I´ve reset the bias and finished the casing (wouldn´t like my 3 year old daughter to test how well I´ve isolated the mains....)
Here´s a picture if the right channel,
finally finished my Aleph 5
. Well almost, but at least it makes some music and not even bad at all.Tested the first channel yesterday evening and got about 11A of bias wich was a bit to much for the fuse I used (good thing those fuses). After looking for a while at my printed circuits I found I had made a little mistake while designing the printed circuit mirrored for the left and right channel
Well now the connections to the plus and minus supply don´t look so nice for one channel and I´ll have to make a new board.
The rest works fine, I get 32.5volts before the chokes from a 25v transformer with a 2.8A bias current. After the choke it´s 31.5 volts with a 10mV ripple. DC-Offset is 48mV left and 23mV right.
Temperature is a bit high with 70° C measured directly next to the fets but this will be allright when I´ve corrected the bias to about 2A (don´t really know why it´s so high, any suggestions?)
Output is about 30V at 8 ohms with symmetrical clipping, humm is only noticable with my ear next to the speaker.
I´ve only heard it on my small "upstairs" system with small dynaudio speakers but it sounds like I hoped it would. Very natural but detailed without any harshness, good bass (on this speaker). I´ll try it on my downstairs system when I´ve reset the bias and finished the casing (wouldn´t like my 3 year old daughter to test how well I´ve isolated the mains....)
Here´s a picture if the right channel,
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