maybe it,s mentioned but this is too big thread to find it.how much is the input impedance of these boards?any buffer recommendations if needed?
i just received a pair l25d's.where is speaker output and +-voltage?is gnd common for speaker and psu?
Here you go.
http://img03.taobaocdn.com/imgextra/i3/36508936/T2LQBAXaBMXXXXXXXX_!!36508936.jpg
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http://img03.taobaocdn.com/imgextra/i3/36508936/T2LQBAXaBMXXXXXXXX_!!36508936.jpg
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Yes. Sorry I meant to post the image for the L25D but the connection layout is the same
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Sent from my HTC Amaze 4G using Tapatalk
So i have modded my L25D amp with upgraded caps and resistors on the boards, and i added a tube buffrer. But i ran into a little problem, i have a weak transformer hum in the speakers. But it dissapears when i connect rca plugs. Any ideas?
Zero volt line from what? from the transformer? (50 - 0 - 50) Just take the to wires that make the Zero and connect them to my earth?
I usually take a wire from the input signal zero volts to the earth.
But the star ground point would be good too.
But the star ground point would be good too.
Should i then remove the Zero volt from the PSU and just earth them? Or should i have them in the PSU and take a wire from there to my earth?
Hmm.. My psu has 4 inputs from the torodial. it makes the 0 in the PCB, Then should i just solder on a 2 to 1 cable to earth from the two ac that makes the Zero?
Made a bad drawing in paint.. hope its understanable.
Made a bad drawing in paint.. hope its understanable.
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Ground
Remove the wire from Earth to AC2 and AC3 twist the speaker cables very tight, connect your negative speaker cables to the star ground connection ( Yours are inverted BTW , but it's an inverting amp , so understandable but that are the wires connected to your red speaker terminals ). Your wiring from the RCA's to the Tube preamp could use more tight twisting , so does the wiring from the preamp to the Class D do .
And , VERY important , keep those speaker wires as far away as possible from your preamp (and preamp wires) !
The positive thing is , Looks pretty cool ! Hope it sounds good !
Enjoy and Cheers ,
Rens
Remove the wire from Earth to AC2 and AC3 twist the speaker cables very tight, connect your negative speaker cables to the star ground connection ( Yours are inverted BTW , but it's an inverting amp , so understandable but that are the wires connected to your red speaker terminals ). Your wiring from the RCA's to the Tube preamp could use more tight twisting , so does the wiring from the preamp to the Class D do .
And , VERY important , keep those speaker wires as far away as possible from your preamp (and preamp wires) !
The positive thing is , Looks pretty cool ! Hope it sounds good !
Enjoy and Cheers ,
Rens
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I dont have a ground from AC2 and AC3 atm, i was asking Nigel if that was what he ment. My grounds are as follow:
- Psu is grounded from its own marked ground (right in the drawing)
- Speaker protect is grounded
- Mains is grounded.
- Speaker terminals is grounded in amp boards
- Amp boards is grounded in PSU
- Rca grounded in amp boards.
And the L25D is inverted so i have the speaker terminals inverted.
- Psu is grounded from its own marked ground (right in the drawing)
- Speaker protect is grounded
- Mains is grounded.
- Speaker terminals is grounded in amp boards
- Amp boards is grounded in PSU
- Rca grounded in amp boards.
And the L25D is inverted so i have the speaker terminals inverted.
Ground-loop...
Could you please get rid of those horrible blue Leds... I prefer red light-areas 😀
OK that is clear ,
My mistake , didn't read it well enough , but ground your speakers and amps at the star point , and take care of the other stuff I mentioned .
If that doesn't work , try to isolate your star ground from the chassis .
Cheers ,
Rens
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