Rev A vs C
Sorry, was away for the weekend... Russ is correct.
I did stop supplying the "RevA" parts (only a single capacitor) as it was just confusing people. The other differences are part omissions and a few alternate placements.
If you stuff the boards with the parts supplied, you have a RevC. The part(s) with RevC on the labels are just older labels (trying to use them up
).
Sorry, was away for the weekend... Russ is correct.
I did stop supplying the "RevA" parts (only a single capacitor) as it was just confusing people. The other differences are part omissions and a few alternate placements.
If you stuff the boards with the parts supplied, you have a RevC. The part(s) with RevC on the labels are just older labels (trying to use them up
).Finally, I have finished My Ref Rev A. Hope it is not a bit late for me to write this.
The Amp is wonderful and the sound is good and clear. Some of my friends said that the power is a bit more powerful than Pass A5. (of course i dont' think so). I played the 1812 and hopeful it was passed by most of my friends
Howver, I met something happening strange and want someone could help me. It is that the sound will, somethimes, be mute for a second or a "ti" sound. I wonder if the LM3886 was overheated or something was wrong? This happened when it played loud.
(my english is poor, hope you maybe understand)
The Amp is wonderful and the sound is good and clear. Some of my friends said that the power is a bit more powerful than Pass A5. (of course i dont' think so). I played the 1812 and hopeful it was passed by most of my friends
Howver, I met something happening strange and want someone could help me. It is that the sound will, somethimes, be mute for a second or a "ti" sound. I wonder if the LM3886 was overheated or something was wrong? This happened when it played loud.
(my english is poor, hope you maybe understand)
Banned
Joined 2002
It sounds like one of the folowing is true:
1) Your heatsink is too small
2) You are driving a very low impedance load
3) You are driving the amp too hard for your heatsink/speaker load (see 1 and 2)
4) Your rail voltages are too high
5) There is something wrong with your amp
From the datasheet (page 17):
SPiKe Protection: The LM3886 is protected from instantaneous
peak-temperature stressing by the power transistor
array. The Safe Operating Area graph in the Typical Performance
Characteristics section shows the area of device
operation where the SPiKe Protection Circuitry is not enabled.
The waveform to the right of the SOA graph exemplifies
how the dynamic protection will cause waveform distortion
when enabled. (see attached pic).
1) Your heatsink is too small
2) You are driving a very low impedance load
3) You are driving the amp too hard for your heatsink/speaker load (see 1 and 2)
4) Your rail voltages are too high
5) There is something wrong with your amp
From the datasheet (page 17):
SPiKe Protection: The LM3886 is protected from instantaneous
peak-temperature stressing by the power transistor
array. The Safe Operating Area graph in the Typical Performance
Characteristics section shows the area of device
operation where the SPiKe Protection Circuitry is not enabled.
The waveform to the right of the SOA graph exemplifies
how the dynamic protection will cause waveform distortion
when enabled. (see attached pic).
Attachments
You, Brian and troystg, all are right. I have not made holes for venting from bottom and will improve it later.
I cannot find out what the problems are. But in fact, such things were happened once.
Yesterday, I tried it and make it loud for half an hour but no such happened again. But I remember I opened the case like that!!
The sound image is good.
I am now trying to add 100K in parpella with the 100k (R13, R36)... and seems good. Am I right for more low frequency?
I cannot find out what the problems are. But in fact, such things were happened once.
Yesterday, I tried it and make it loud for half an hour but no such happened again. But I remember I opened the case like that!!
The sound image is good.
I am now trying to add 100K in parpella with the 100k (R13, R36)... and seems good. Am I right for more low frequency?
