here some thing I found out .................. One thing after u download the file plz change the extension to .pdf
PDF
regards
aniket
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regards
aniket
Cs800s
Well, to answer my own question, eserviceinfo.com has got a Peavey CS800S schematic dated 1995. Since the 1976 version B available on diyaudio, they have added speaker disconnect relays, and put transformers for sensing around the speaker leads. I would guess they would be current transformers, as I suggested I was thinking about in a previous post as being a non-invasive way to check up on what is going out. There are thermistors on the heatsink leading to a complicated circuit that controls the fan and what else? The rails have decreased from 81v to 76 volt, and the ten quasi-complementary output transistors on the 1976 version have changed into eight fully complimentary bipolar output transistors, providing fuel for another thread that am not qualified to fully follow.
Well, to answer my own question, eserviceinfo.com has got a Peavey CS800S schematic dated 1995. Since the 1976 version B available on diyaudio, they have added speaker disconnect relays, and put transformers for sensing around the speaker leads. I would guess they would be current transformers, as I suggested I was thinking about in a previous post as being a non-invasive way to check up on what is going out. There are thermistors on the heatsink leading to a complicated circuit that controls the fan and what else? The rails have decreased from 81v to 76 volt, and the ten quasi-complementary output transistors on the 1976 version have changed into eight fully complimentary bipolar output transistors, providing fuel for another thread that am not qualified to fully follow.
in my country there was plenty of CS 800 of various versions The company that sold them was the second big in all the country so it makes sense that we had plenty of those
now this amplifier is actually built as idiot proof very hard to fail beyond that psu caps get leacky after all these years and may be i ventilator never had to replace anything on them ...
Phoenix87's Jun 11 circuit looks as if it detects output too close to the rails, and pulls a relay to the output if so. That is if d11, d12, d13,d14 are actually zener diodes whose values are a little less than the split supply rails. (schematic diagram is not shown as zeners.) This would have a similar effect as the more common diac-triac crowbar circuit, only it disconnects the speakers instead of shorting the output and blowing the power supply fuse fuse. The 2u2?? capacitor seems to act as a time delay circuit.(Every continent seems to label capacitors differently). This would protect speakers somewhat against a shorted output transistor, something that happens frequently I believe. This circuit would not protect the output transistors against speaker wire shorted to return or shorted speakers. It would need speaker fuses for that.
I like the CS800S circuit better, that measures the speaker current with current transformers and does calculations with a microprocessor on the results before pulling the speaker relay. But programming a microprocessor is too complicated for most individuals like me on a one-off project. Finding and repairing a blown up pro amp that has a protection microprocessor already built in is more my speed. My CS800S wasn't even blown, just part of a $1000 package that nobody else needed all the parts of. (2 SP2 speakers, amp, 12 input 4 output mixer, dual frequency equalizer (main+monitor), digitech 4 channel effects processor, 100' 20 pair snake cable.) Individually I would have had to pay about $1300 and been johnny on the spot with the cash to get those prices.
I like the CS800S circuit better, that measures the speaker current with current transformers and does calculations with a microprocessor on the results before pulling the speaker relay. But programming a microprocessor is too complicated for most individuals like me on a one-off project. Finding and repairing a blown up pro amp that has a protection microprocessor already built in is more my speed. My CS800S wasn't even blown, just part of a $1000 package that nobody else needed all the parts of. (2 SP2 speakers, amp, 12 input 4 output mixer, dual frequency equalizer (main+monitor), digitech 4 channel effects processor, 100' 20 pair snake cable.) Individually I would have had to pay about $1300 and been johnny on the spot with the cash to get those prices.
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I take neways to mean "No-way"? I don't believe this circuit protects the output transistors against speaker wire shorts, but I am assuming the diodes are say 50 v zeners on a 56 V rail. I am not the world's most experienced linear circuit designer or repairman, I just am the first to see your post. Best of luck. For speaker circuits the relay contacts had better be silver or gold, copper contacts would corrode up and make noise after a while.
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