Greetings.
I would like to ask if anyone knows a reliable circuit for an amp, that would be used for live monitor speakers. I think 300 w would be plenty per channel. I would build two of them in old enclousores of old pa amps. It has tk be a reliable circuit with thermal and output protection, that doesnt fail in harsh environmental conditions for pa and touring.
The trkck is o need something for My band and due Tot e corona virus and such we dont have alot of money,but i have some old enclousures transformers of reasonable power (700 VA+) and smoothing caps 22000 uf probably around 40 of those and some output transistors like 2sc5200 and 2n6259... And massive massive heatsinks
Thanks for help in advance!
I would like to ask if anyone knows a reliable circuit for an amp, that would be used for live monitor speakers. I think 300 w would be plenty per channel. I would build two of them in old enclousores of old pa amps. It has tk be a reliable circuit with thermal and output protection, that doesnt fail in harsh environmental conditions for pa and touring.
The trkck is o need something for My band and due Tot e corona virus and such we dont have alot of money,but i have some old enclousures transformers of reasonable power (700 VA+) and smoothing caps 22000 uf probably around 40 of those and some output transistors like 2sc5200 and 2n6259... And massive massive heatsinks
Thanks for help in advance!
If you need 300 W/ch you are going to need more output transistors than 1 pair shown above. 3 pair I guess. That means bigger drivers than a 7 watt bd130/140. MJE15031/32 is the best bargain these days, extremely tough. Use heat sink on drivers & VAS.
The +-35 v rail of above would be suitable only for 4 ohm speakers. +-41 is more usual for 2 pair OT amps like M-2600 or PV-4c. Those are 100 w/ch. +-60v is on 400 w/ch amps with 8 ohm rating.
Thermal protection old fashioned is a snap action NC switch on the heat sink series the transformer. More modern is a NTCR on the heat sink pulling up the gate of a nfet. Fixed resistor pulls the gate down to source. Size of fixed resistor determines turn on temperature; experiment with metal plate & hair dryer. Nfet turns on input of relay.
Really with the requirement for speaker DC protection, I don't see why you don't just rebuild the PA amps you have already. Maybe leave out the 4th and 5 pair of OT's since you don't need 400 W/ch. 2sc5200 are lower soa than MJ15024/25 and 2n6029 from central has no soa rating at all. So maybe 4 pairs would be safer @ 300 w/ch. I wouldn't use 2n6029 on 60 v rails, it is 100 v Vceo.
The +-35 v rail of above would be suitable only for 4 ohm speakers. +-41 is more usual for 2 pair OT amps like M-2600 or PV-4c. Those are 100 w/ch. +-60v is on 400 w/ch amps with 8 ohm rating.
Thermal protection old fashioned is a snap action NC switch on the heat sink series the transformer. More modern is a NTCR on the heat sink pulling up the gate of a nfet. Fixed resistor pulls the gate down to source. Size of fixed resistor determines turn on temperature; experiment with metal plate & hair dryer. Nfet turns on input of relay.
Really with the requirement for speaker DC protection, I don't see why you don't just rebuild the PA amps you have already. Maybe leave out the 4th and 5 pair of OT's since you don't need 400 W/ch. 2sc5200 are lower soa than MJ15024/25 and 2n6029 from central has no soa rating at all. So maybe 4 pairs would be safer @ 300 w/ch. I wouldn't use 2n6029 on 60 v rails, it is 100 v Vceo.
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