Hi blackdod,
thank you for pictures, I don't believe uploaded schematic applies to your version of the board. If you are worried about those lifted tracks check for continuity with DMM to be sure , however I don't expect problems there. Cleaning the flux from the board with some alcohol wouldn't hurt either. If you feel confident and you are good at desoldering change input ceramic cap to 1uF film type, not sure if WIMA would fit here because lack of space, if not try Panasonic ECQ-V series. If all goes well replace two Zener diodes on the board each with 4x1N4148 connected in series, observe the polarity it is opposite to the zeners.
Regards
Marko
thank you for pictures, I don't believe uploaded schematic applies to your version of the board. If you are worried about those lifted tracks check for continuity with DMM to be sure , however I don't expect problems there. Cleaning the flux from the board with some alcohol wouldn't hurt either. If you feel confident and you are good at desoldering change input ceramic cap to 1uF film type, not sure if WIMA would fit here because lack of space, if not try Panasonic ECQ-V series. If all goes well replace two Zener diodes on the board each with 4x1N4148 connected in series, observe the polarity it is opposite to the zeners.
Regards
Marko
Thanks Max but I can´t accept that. Let me pay you the plate and sending.I will change the input ceramic capacitors and some bridges because are rusty only by test.
Regards
This is why I love this forum so much, indeed a true DIY spirit.
Regards to you Max
Marko
If output coupling caps are added to protect the headphones from the output dc offset, is there any reason to aim for 0V dc offset upstream of the cap?
I have a pair of ASC GLY513 600uf fim caps that I'm mounting in a separate enclosure with 6.35mm stereo in and out to allow me to use these caps with any headphone amp I'm using. With these film caps it won't damage anything if the offset is positive or negative, but I wondered if setting the offset to +1vdc (making the signal vary from 0-2vdc in normal use) would be best.
In the meantime I have a pair of black gate 1000uf 16v standard polar caps at the output, so setting the offset to +1vdc keeps the polarity of the signal correct for the polar cap.
Any thoughts?
I have a pair of ASC GLY513 600uf fim caps that I'm mounting in a separate enclosure with 6.35mm stereo in and out to allow me to use these caps with any headphone amp I'm using. With these film caps it won't damage anything if the offset is positive or negative, but I wondered if setting the offset to +1vdc (making the signal vary from 0-2vdc in normal use) would be best.
In the meantime I have a pair of black gate 1000uf 16v standard polar caps at the output, so setting the offset to +1vdc keeps the polarity of the signal correct for the polar cap.
Any thoughts?
If you use a capacitor at the output , it might be better to use a single supply circuit. That would bias the output cap at 1/2 Vcc. Electrolytics with no dc voltage across them aren't really operating in a comfort zone. Even a non polar electrolytic might not be the best solution here.
Like oz7aff said. Try out the way you want to do it and see how it sounds. It finally depends on if the sound is acceptable to you.
Have fun !
Like oz7aff said. Try out the way you want to do it and see how it sounds. It finally depends on if the sound is acceptable to you.
Have fun !
Well actually, you only want as much DC across a 'lytic as is necessary to keep it in good working order. At higher voltages, distortion actually increases, as Cyril Bateman found. Introducing some DC offset should be easy in the JLH, as it requires some offset trimming anyway.
Basically the largest disadvantage of using coupling caps is their size. Ideally you're looking at something like 1000µF per channel.
Basically the largest disadvantage of using coupling caps is their size. Ideally you're looking at something like 1000µF per channel.