I will give it the 92% isopropanol and toothbrush treatment. I will be firing up via variac. What should I monitor voltage wise as I power up?
Russellc
Russellc
You’ve tested the PSU by itself, yes? If that’s good attach the Burning OpAmp boards and adjust offset as mighty ZM says.
I will fire them up not hooked to any thing, RCA or volume pot, should I short inputs, or just fire up and set offset? I guess if LEDs light and offset can be set to zero it is good to go.
Russellc
Russellc
Boom
BigBadaBoom!
You Joking or am I doing something way stupid for 18 millionth time causing big Badda Bang?😱
Russellc
Always must check....with my "experience" or lack there of, many big picture items are often missed.😱
Russellc
How should off set be. Just brought up and only cooked 20 minutes or so. Either channel seems to get down to .4 mv or so, then up to 4-8 mv, drifting around.
What should I check? Little nervous with that much on preamp output.... input not shorted, does it need to be shorted to prevent off set swings?
Russellc
What should I check? Little nervous with that much on preamp output.... input not shorted, does it need to be shorted to prevent off set swings?
Russellc
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0.4mV ? That is to say, 0.0004 of one V?
I wouldn’t be overly concerned... 😀
That said, look at your offset and blow on the boards, if it moves much it’s going to be much more stable when it’s in a box.
I wouldn’t be overly concerned... 😀
That said, look at your offset and blow on the boards, if it moves much it’s going to be much more stable when it’s in a box.
well, .4 isn't much, but it will go up to 10 mv, then drift down to .4, lower, lower then start climbing negative numbers, then back down, and back up the positive numbers.
I will try it with shorted inputs, then try with boards in a box of some sort. Failing that, off to ZM's OPLDF. I will take the board off for lower shipping costs.
Russellc
I will try it with shorted inputs, then try with boards in a box of some sort. Failing that, off to ZM's OPLDF. I will take the board off for lower shipping costs.
Russellc
That much drift is inconsequential, and did you blow on it? If it’s temp related it will get much more stable once it’s in a box and can stay temp stable.
If it really bugs you, put a cap on the output.
If it really bugs you, put a cap on the output.
Most of my amps have some sort of cap on the input somewhere........ I don't think F5 does.
Russellc
Russellc
Out of curiosity, how is the off set on those who have built this? One channel is a few mv, the other I cant help but think could be lower. It floats from acceptable under 1 mv, to 11 or 12 mv. I know I could put a cap on the output, but seems like it should be lower.
I guess this is an acceptable level, but I would feel better if it were lower. Maybe I just need a comfort level adjustment! Nightmares of speaker frying.
Russellc
I guess this is an acceptable level, but I would feel better if it were lower. Maybe I just need a comfort level adjustment! Nightmares of speaker frying.
Russellc
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