Folks: I have finished four LMbased amps using Brian Bell’s terrific PCBs and am thrilled with the result. But as I follow the various threads. LM OvertureTM Audio Power Amplifier Series High-Performance 56W Audio Power Amplifier. The is a high-performance audio power amplifier capable of. Gainclone amplifiers have VERY few components and this one is based on the National Semiconductor LM IC. The PCBs and components are very simple .
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The jacks had a tendency to loosen up.
Moving magnet phono pre-amplifier – 1. The amp is DC coupled straight through. Other details remain off the official record to this day: I prefer two bridge rectifiers, but one bridge or 4 individual soft recovery diodes can be substituted. The tube preamp just didn’t sound right.
My collection of gear exceeds size of my listening room and stray pieces are being stashed throughout the house. This gives the stated nine part circuit.
LM3875 Gainclone Power Amplifier
I preferred the two big bridges, which sounded more open and powerful, but clearly there is room to experiment. Horns and percussion are great. A 50 kOhm volume potentiometer could be substituted.
So how did it measure? The transformer should be rated to around VA and be either a torroid, R-core or C-core type with dual secondary windings of 16 VAC. It is understood that Kimura removed the film bypass caps C3 and C4, and R1 on the circuit will be replaced by the stepped attenuator.
If that is not enough, you only need three resistors and a couple of reasonable line caps uF will do to build a high end amplifier. My original design had the heat sink on the bottom of the amp chassis and during hard use it kept shutting down. Headphone amplifier is small enough to fit in Altoids tin box, and thanks to low power consumption may be supplied from a single 9V battery.
However this will cause the heat-sink to be at the -ve supply – not a problem for my current set-up since the amplifier is housed in a wooden enclosure. After listening to the tube-chip combination for a while, I really would have loved to have this quality of sound reproduction at any time in the past.
It easily surpasses everything I’ve owned except for my modified K Tube Amp kit. I conclude from my experiences that carbon film is the right choice for the R2-R4, AB carbon composition sounded too noisy and fuzzy, metal oxide too grainy, and from a different circuit metal film too, uh, metallic and zingy.
The first version fortunately no photo as it would be just too embarrassing was a collection of parts sprawled on a shelf with the rest of my gear. I hate working in tight spaces but I am pretty good at it. It’s small, power efficient, yet customizable through onboard 2 x 7 perfboard that can be used for connecting various sensors and connectors.
With many nights of pre-design trials I finally brought it all together. Created 24 April The chips are bolted to the sides of the case so cooling is not optimal. No smoke or fire, so I popped in a CD. Like I said earlier, I didn’t believe everyone when they said uF would be enough.
The umbilical cord is heavy duty with two of the four wires supplying earth. Amplifier schematic Figure 1 shows the amplifier schematic one channel only – two ICs are required for stereo.
Separate position attenuators for each channel. All material is provided “as is” with no guarantees or warranties, either express or implied.
The “Beast” – LM Chip Amplifier (Gainclone) Kit –
Conclusion I haven’t heard sound this good before. It came from an odd place. From stereophile Z in data. DC offset was about 80mV on one channel and about 40mV on the other.
So how did it sound? I tried replacing my two 50A bridge rectifiers with 4 discrete diodes. It just sounded cleaner and was easier to listen to. There was a lot of deliberation on the type of transformer to get, particularly the secondary voltages. I believe km3875 worked although I can’t point to any data that supports it. Created 16 December That l3m875, a single integrated circuit based on an operational amplifier op amp on a single substrate of silicon.
Typical operation, from the LM datasheet: That is always a concern when something is powered by a watt transformer. There are no filter capacitors. My ears said something in the order of dB.
Everything fit like I planned.
56W Audio Power Amplifier Using LM – Circuit Ideas I Projects I Schematics I Robotics
Diodes should be rated to at least 5A. Figure 1 shows the amplifier schematic one channel only – two ICs are required for stereo. But being a bit of a conservative guy translation, I like to do things cheaply if I can I couldn’t find a suitable enclosure for the project.
Well in short, glue smokes like crazy when you try to solder through it. The meter is a perfect addition to any power supply, battery chargers and other electronic projects where voltage and current must be monitored.