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JLH 10 watt, class A amps


Marvel

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This will be a long process, but the two boards have finally made it from Shenzhen, CN to the U.S. We'll see how long before they get to my house. I will then figure out the PS and heatsinks, case, etc., before connecting them to anything. I am looking forward to trying these out. Nelson Pass even has an article on these (he made some mods). If these are made well, they should work great for the compression drivers in the active setup I hope to someday have working.

 

Bruce

 

 

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Waiting on the porch when I arrived home. I put a Hershey's kiss in the pic to show the size. These will need heat sinks added to the aluminum angle, case and power supply. I think I want to make these as little monoblocks. At around 10 watts output, the 3055s should only be dissipating approx. 40 watts or so. They are rated to 150.

 

Bruce

JLH_1969.jpg

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1 minute ago, Marvel said:

Waiting on the porch when I arrived home. I put a Hershey's kiss in the pic to show the size. These will need heat sinks added to the aluminum angle, case and power supply. I think I want to make these as little monoblocks. At around 10 watts output, the 3055s should only be dissipating approx. 40 watts or so. They are rated to 150.

 

Bruce

JLH_1969.jpg

Interesting.  Let us know what you think of em after you have had some tiem with them.   What did they run you if I may ask? 

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$47... I will probably spend way more than that for the power supply and cases, etc.

 

He designed the original in 1969, updated the circuit in '96, as some of the transistors were no longer available. Others have made changes, Nelson Pass for one. He said it was/is a nice amp. Very simple class A that still holds its own. There are better spec amps, but these are not costly at all.

 

It will be a while, with Christmas and traveling.

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  • 2 weeks later...

No, those have some of the addon circuitry for the power supply (I think... that's where the extra TO-3 comes in). I may be in over my head with this. There were no directionsbor docs at all . These only have  single connection for power where the circuit I have seen have a + - 22vdc connections. I probably would have been better off to breadbord one first and go from there.

 

Bruce

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It could be that these will simply go up in smoke when I try them. I don't know if I can follow the circuit enough on these boards. We'll see. I could do with half the the power as I was thinking of these as tweeter drivers.

 

I also have to replace one of the terminal screws. Not a real good sign.

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