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Old 28th March 2012, 02:48 PM   #12081
kroyin is offline kroyin  India
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Gentlemen a little help please. Here is my situation (i only have one channel now).
--All Chinese Boards
--80mF capacitors/channel
--Biased with input shorted,o/p open
---Steady bias of .48mV across R11/R12, 3.5V across R3/R4, offset bias 2mV
---Heatsink extremely cold (as if there is no heat exchange)

Connected all my sources & i have to literally hold my ear to the speaker (tried 3 types) to listen to sound (it is playing though).

Are my mosfets fried? But if they are, will everything be so honky dory.
Thanking you all
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Old 28th March 2012, 03:01 PM   #12082
kroyin is offline kroyin  India
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And rails are 26VDC
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Old 28th March 2012, 03:03 PM   #12083
Zen Mod is offline Zen Mod  Serbia
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problems:

- IP stealer's boards
- no pictures , sch with important points tested and written down
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Old 28th March 2012, 03:09 PM   #12084
kroyin is offline kroyin  India
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Thank you sir...yes not very proud of the boards .
Only one question - Can the o/p mosfets be fried even though the bias is right/steady and i can hear the output although extremely low?
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Old 28th March 2012, 03:13 PM   #12085
fdlsys is offline fdlsys  South Africa
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Quote:
Originally Posted by kroyin View Post
.48mV across R11/R12
If it's 0.48mV than no wonder that:
----> Heatsink extremely cold (as if there is no heat exchange)

Quote:
Connected all my sources & i have to literally hold my ear to the speaker (tried 3 types) to listen to sound (it is playing though).
What are the sources? Are you using a preamp? What is the input (into F5) signal voltage ?
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Old 28th March 2012, 03:21 PM   #12086
kroyin is offline kroyin  India
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Eeps sorry, it would read as .48V.

No preamps, tried my PS3 (analog output). HTPC
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Old 28th March 2012, 04:20 PM   #12087
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Hi Kroyin,
I think,you will need a preamp for F5.

Regards,
Sachin
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Old 28th March 2012, 04:35 PM   #12088
kroyin is offline kroyin  India
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Is that a absolute necessity...I'm in the process of B1...you know that :-)
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Old 28th March 2012, 05:26 PM   #12089
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Quote:
Originally Posted by kroyin View Post
Is that a absolute necessity...I'm in the process of B1...you know that :-)
No but you wont get a lot of volume unless speakers are fairly (90dB and up) efficient. With 85-86 dB speaks I can get listening levels at full volume with B-1....not real loud but ok.

Russellc
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Old 28th March 2012, 05:36 PM   #12090
kroyin is offline kroyin  India
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Well I have troel gravessen's nomex..should be 90db (if I have beuilt them right)...the cold heatsinks are bothering me...it did not get even warm after 1 hour
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