Nice Battery Powered 10 Watt Amp
I made a small stereo amp using a pair of OPA-548,s in Bridge mode. with 8 ohm and above Loudspeakers I have used 6 ohm ratt shack LS-5's at one time and it worked but the Hammond 1455 series exturded aluminium case got real warm almost hot. The case also serving as a common heatsink for all (4) OPA-548's. The reproduction is alot better than the Car stereo IC power Amp Chips, althought the Car IC's do power lower impedance loads better.
Topology wise the OPA-548 is more akin to your nomal Op Amp than the Car stereo IC that most often has rail to rail single supply and an all NPN output stage. The OPA-548 on the other hand uses a true differential Input and Complimentry Output Emitter follower output stage both of these i am strongly in favor of and the Complimentry output stage of the OPA-548 is a futher Bonus in Bridged applications where Both the Advantages of an ALL NPN output stage and Complementry symmectrical output stage transistor Pairs all in one.
The attractive aspect of the OPA-548 vs your typical Car stereo IC is First a Bridged stereo amp will have about 80 mA quesent curent and work op to 30 volt supplys. The Car stereo IC stereo Amp will require about 300 mA. The low voltage operation is similar to car stereo IC's with a 7-8 volt min. however, the Max on the 548 is about twice that of a Car IC @ 30 Volts.
In coclusion I am happy with its use as a small light weight High Quality Stereo Amplifier. would also be great in Powered loudspeakers desireing Battery opation.
I made a small stereo amp using a pair of OPA-548,s in Bridge mode. with 8 ohm and above Loudspeakers I have used 6 ohm ratt shack LS-5's at one time and it worked but the Hammond 1455 series exturded aluminium case got real warm almost hot. The case also serving as a common heatsink for all (4) OPA-548's. The reproduction is alot better than the Car stereo IC power Amp Chips, althought the Car IC's do power lower impedance loads better.
Topology wise the OPA-548 is more akin to your nomal Op Amp than the Car stereo IC that most often has rail to rail single supply and an all NPN output stage. The OPA-548 on the other hand uses a true differential Input and Complimentry Output Emitter follower output stage both of these i am strongly in favor of and the Complimentry output stage of the OPA-548 is a futher Bonus in Bridged applications where Both the Advantages of an ALL NPN output stage and Complementry symmectrical output stage transistor Pairs all in one.
The attractive aspect of the OPA-548 vs your typical Car stereo IC is First a Bridged stereo amp will have about 80 mA quesent curent and work op to 30 volt supplys. The Car stereo IC stereo Amp will require about 300 mA. The low voltage operation is similar to car stereo IC's with a 7-8 volt min. however, the Max on the 548 is about twice that of a Car IC @ 30 Volts.
In coclusion I am happy with its use as a small light weight High Quality Stereo Amplifier. would also be great in Powered loudspeakers desireing Battery opation.
ppl
Yes- although this is an old thread, I just posted on the 548 & was encouraged by your info. I had not dissected the internals of TI's product, but I can say with certainty that the 3886T is a quasi-complementary beastie. I have not been impressed W/ the sound, tube like or not. The TI does cost more money, BTW.
I am led to wonder about a car circuit that could produce -(that's minus) 14.2V, which is a running car, +/-. It could be ballasted by a small batt (to say nothing about boomer caps) and the result would be decent at 4 ohms without bridging. These chips could be paralled for reliability, and heat-sinkery.
I realize this puts us into the murky world of mosfet switchers , but can't the folks here come up with just about anything?
Yes- although this is an old thread, I just posted on the 548 & was encouraged by your info. I had not dissected the internals of TI's product, but I can say with certainty that the 3886T is a quasi-complementary beastie. I have not been impressed W/ the sound, tube like or not. The TI does cost more money, BTW.
I am led to wonder about a car circuit that could produce -(that's minus) 14.2V, which is a running car, +/-. It could be ballasted by a small batt (to say nothing about boomer caps) and the result would be decent at 4 ohms without bridging. These chips could be paralled for reliability, and heat-sinkery.
I realize this puts us into the murky world of mosfet switchers , but can't the folks here come up with just about anything?
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