Minion
Well-known member
Hi Guys, I have a pretty simple question here for you folks and I think I allready know the answer but just need someone to confirm my thoughts...
Here is the situation:
I am designing and Building a Guitar amp based arround the LM3886 Power amp IC....This design also has a preamp stage useing the OPA2134 which runs off of 15v Rails but the LM3886 needs at least 18v but preferably higher (voltages from 18v up past 35v) but it doesn"t need to be regulated...
The problem is I don"t want to build a Supply that uses 4 regulators (+/-15v & +/-18v) because of space concerns and because the LM317/337 regulators have a max amperage of 1.5amps and this supply will be delivering more than 1.5amps (Useing a 18v-0v-18v 100vA 2.4amp torroid)....
What I was thinking of doing was takeing the voltage off of the supply rails for the LM3886 after the filtering Caps but before the Regulators to give me an unregulated aprox 22v DC for the Power amp and take the 15v after the regs for the preamp.....
So my question is will this work properly?? are there some unforseen problems I might encounter??
I think this should work fine but I was thinking that maybe when the power amp is at max power it might cause a voltage drop which would cause the 15v regs to recieve less Voltage than needed to regulate to 15v??
I also though it should still work OK as the OPA2134 can run at lower voltages than 15v....
This amp should deliver 35w to 50w into 8 ohms and up to 68w into 4 ohms but I can"t seem to find any info that will tell me if my 100vA Torroid will be strong enough to power this amp...
Do you guys know if 100vA is enough for a 50w amp, If it isn"t enough will it just mean that the amp won"t go as loud when cranked to full or will it mean that it will only work up to a certain volume level and any higher will just produce distortions??
Also Heatsinking the IC is very important so I was thinking of simply attaching a Heatsink from a CPU and Power the 12v fan off of the 15v power rails through say a 150r resistor to lower the voltage a bit...
Will that work ok or will I need a bigger heatsink?? Do I ground the heatsink??
Thanx a Lot for any help you can Give.....
Cheers
Here is the situation:
I am designing and Building a Guitar amp based arround the LM3886 Power amp IC....This design also has a preamp stage useing the OPA2134 which runs off of 15v Rails but the LM3886 needs at least 18v but preferably higher (voltages from 18v up past 35v) but it doesn"t need to be regulated...
The problem is I don"t want to build a Supply that uses 4 regulators (+/-15v & +/-18v) because of space concerns and because the LM317/337 regulators have a max amperage of 1.5amps and this supply will be delivering more than 1.5amps (Useing a 18v-0v-18v 100vA 2.4amp torroid)....
What I was thinking of doing was takeing the voltage off of the supply rails for the LM3886 after the filtering Caps but before the Regulators to give me an unregulated aprox 22v DC for the Power amp and take the 15v after the regs for the preamp.....
So my question is will this work properly?? are there some unforseen problems I might encounter??
I think this should work fine but I was thinking that maybe when the power amp is at max power it might cause a voltage drop which would cause the 15v regs to recieve less Voltage than needed to regulate to 15v??
I also though it should still work OK as the OPA2134 can run at lower voltages than 15v....
This amp should deliver 35w to 50w into 8 ohms and up to 68w into 4 ohms but I can"t seem to find any info that will tell me if my 100vA Torroid will be strong enough to power this amp...
Do you guys know if 100vA is enough for a 50w amp, If it isn"t enough will it just mean that the amp won"t go as loud when cranked to full or will it mean that it will only work up to a certain volume level and any higher will just produce distortions??
Also Heatsinking the IC is very important so I was thinking of simply attaching a Heatsink from a CPU and Power the 12v fan off of the 15v power rails through say a 150r resistor to lower the voltage a bit...
Will that work ok or will I need a bigger heatsink?? Do I ground the heatsink??
Thanx a Lot for any help you can Give.....
Cheers