Salas hotrodded blue DCB1 build - Page 119 - diyAudio
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Old 30th July 2011, 02:39 PM   #1181
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Quote:
Originally Posted by johnwmclean View Post
Builder Brad, for your reference if your considering Tent Labs you might want to check these guys out, much cheaper...

Dantimax (elektronik) - Kits
bump on Dantimax. It's a part time job for Mikkel, so he sometimes misses posts on his forum, but direct email is responsive. Quality is good and Mikkel is great guy to work with.
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Old 30th July 2011, 02:54 PM   #1182
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Default 470r carbon resistor

Quote:
Originally Posted by AndrewT View Post
The carbon film , just like metal film, is usually cut to form a helix. Both will have the same inductance if the number of turns in the helix is the same and the diameter of the helix is the same.
Carbon composition does not have a helical form.
Confused now. The BOM says carbon FILM, but if I interpret what Andrew said above and Salas said in post #900 it should be carbon COMPOSITION. Is the BOM right or wrong?
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Old 30th July 2011, 02:58 PM   #1183
Salas is offline Salas  Greece
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Not a real issue. All will work.
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Old 31st July 2011, 01:51 PM   #1184
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Hello Salas, is it possible to use 202k for the 220k (get lot of foil SFnice around) Something must take care with a lower value?
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Old 1st August 2011, 02:30 PM   #1185
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I am working on heat sinking for a stage 2, 600mA version.
  • Option 1) Use the case bottom as the heatsink, assuming a roughly 12x12x1/4" plate of aluminum with the MOSFETs bolted to them from the bottom of the PCB
  • Option 2) a single 140x190x32mm horizontal finned plate, mounted fins down in the case, with the PCB mounted on the back.
  • Option 3) A pair of 140x81x44mm vertical finned plates on each side of the PCB, MOSFETS mounted above board and bolted to the heatsink.
  • Option 4) As above, 250x100x55mm
Anybody successful at 600mA with any of these approaches?
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Old 1st August 2011, 02:31 PM   #1186
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dvb-projekt:

What current are running with your SK-36 heat sinks?
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Old 1st August 2011, 03:03 PM   #1187
Salas is offline Salas  Greece
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Quote:
Originally Posted by Praudio View Post
Hello Salas, is it possible to use 202k for the 220k (get lot of foil SFnice around) Something must take care with a lower value?
Yes, if you will not use a pot higher than 20K. Else, it will twist its log curve.
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Old 6th August 2011, 01:53 AM   #1188
cersepn is offline cersepn  United States
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I fired everything up last night and it was working wonderfully!! Much more 3D, sound is more organic and alive than my previous pre. But after about 30 odd minutes and no music was playing, my speakers suddenly started humming real loudly and the overheat/protect red LEDs were flashing (i'm using active monitors).

I immediately turned off the speakers - the amp's heatsink at the back was really hot. I turned it back on and tried playing some music using my old preamp. Seems to work fine. But the volume output seems to be much lower. I left it for the night and got back to it today again. The volume output is still quite low. I'm wondering if any permanent damage was done to my speakers?

More importantly, i'm not sure what happened to the dcb1 and why it happened. I re-measured the voltage levels, dc offset and resistor voltage levels and they are all same as before, which is fine. Any help on what troubleshooting i should be doing now?
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Old 6th August 2011, 01:57 AM   #1189
Salas is offline Salas  Greece
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Does not sound like you had DC, but you may had an oscillation between the two components? Long cables? Is the speakers amp AC coupled by the way? Leave the DCB1 on but not connected for an hour and check if for some reason develops DC offset also. If your actives don't sound as loud, there is damage done to them most possibly.
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Old 6th August 2011, 02:11 AM   #1190
Salas is offline Salas  Greece
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Quote:
Originally Posted by cersepn View Post
More importantly, i'm not sure what happened to the dcb1 and why it happened. I re-measured the voltage levels, dc offset and resistor voltage levels and they are all same as before, which is fine. Any help on what troubleshooting i should be doing now?
Its highly possible nothing happened to the DCB1 itself. If all offset sampling will measure OK after long in power, then its OK. Tell us more about your source and active speakers, also type and length of interconnects.
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