Mainline Resistance Question [solved]
- Thread starter isldkid
- Start date
Hi guys, in the interest of bandwidth efficiency if you all don't mind, will answer all three question in this post , also have a question for P.B..
Grainger, yes posted image with I-Pad.
Adam and Paul B, yes the 90 degree Neutric XLR is the 4 pin.
According to Justin of JE they were not available last year, he did not say when it was put on the market.
Question for Paul B.: The bias voltages on the Mainline's output tubes have stabilized, however one tube has a lower audio output.
Have checked this by switching channels, low audio output follows the one tube, also no light up on two of four LEDs on C4S board on the low channel. (The two unlit LEDs follows the low output tube)
Also the bias voltage adjustments switches sides along with he tubes.
Suggestions please.
Best,
Francis
Grainger, yes posted image with I-Pad.
Adam and Paul B, yes the 90 degree Neutric XLR is the 4 pin.
According to Justin of JE they were not available last year, he did not say when it was put on the market.
Question for Paul B.: The bias voltages on the Mainline's output tubes have stabilized, however one tube has a lower audio output.
Have checked this by switching channels, low audio output follows the one tube, also no light up on two of four LEDs on C4S board on the low channel. (The two unlit LEDs follows the low output tube)
Also the bias voltage adjustments switches sides along with he tubes.
Suggestions please.
Best,
Francis
Hello Francis,
I'd suggest leaving the Mainline on for a few days to cook the tube. What is the the bias voltage on the offending tube? (OB or OA, look for the white wire leaving and heading to the sockets containing the iffy tube)
It may be that a little cooking time will help with this, but knowing the bias voltage will provide some clues.
-PB
I'd suggest leaving the Mainline on for a few days to cook the tube. What is the the bias voltage on the offending tube? (OB or OA, look for the white wire leaving and heading to the sockets containing the iffy tube)
It may be that a little cooking time will help with this, but knowing the bias voltage will provide some clues.
-PB
Hi Paul,
The bias voltages have recently both held at 145.
However switching the tubes gives these bias readings:
The low output ( offending tube) will read 130 and the other (good?) tube's reading will be 167, and will take about four complete revolutions of the trimmer adjusting screw to bring them both back to 145, one going clockwise the other counterclockwise.
Where ever the offending (low output) tube is the two LEDs out of the four are hardly lit, and only read 130 always on the B side, all the rest of the LEDs will read 266, this condition occurs halmost exactly the same on both channels when the tubes are switched.
Will try leaving unit on for a couple days and see what happens.
Thanks again,
Francis
The bias voltages have recently both held at 145.
However switching the tubes gives these bias readings:
The low output ( offending tube) will read 130 and the other (good?) tube's reading will be 167, and will take about four complete revolutions of the trimmer adjusting screw to bring them both back to 145, one going clockwise the other counterclockwise.
Where ever the offending (low output) tube is the two LEDs out of the four are hardly lit, and only read 130 always on the B side, all the rest of the LEDs will read 266, this condition occurs halmost exactly the same on both channels when the tubes are switched.
Will try leaving unit on for a couple days and see what happens.
Thanks again,
Francis
Sorry, I should've specified that the bias voltage comes off the center PC board. I'd expect it to be between 0.8V and 2V.
-PB
-PB
