Power Amp Meter Lights?

[cougit25]

Hi guys. I recently picked up an additional 402 and I'm running them mono parallel at 800 watts per channel!!!

Sounds like I got new speakers, but more on that later.

My only issue is the meter lights on the 2nd 402 are significantly brighter than the ones on the first. I did a search but could find no info on adjusting the brightness on the 402 or other Mac amps.

Can the brightness be adjusted and if so how is it done? I understand that the meters use led lighting and I'm quite surprised at the difference in light output of the two units. Both 402 are only about 3 years young.

Any and all information you hare to share on this subject would be greatly appreciated.

Thanks!

[Formerly YB-2]

Are the stock lights in the MC402 LEDs? If not, and you purchased your second MC402 used, there is a chance that it was upgraded with an LED light kit. The MA6600 is LED and I prefer the brighter, deeper blue of the LEDs to any of the previous bulb illuminated meters.

[cougit25]

Originally Posted by Formerly YB-2

Are the stock lights in the MC402 LEDs? If not, and you purchased your second MC402 used, there is a chance that it was upgraded with an LED light kit. The MA6600 is LED and I prefer the brighter, deeper blue of the LEDs to any of the previous bulb illuminated meters.

To my knowledge the 402 has always had led lighting, but I'm not 100% sure of that.

[j3brow]

yes, LED lights stock on MC402 (mine purchased early 2008)
there is a thread here, somewhere, that discusses how to adjust the brightness on meters and nomenclature. it involves removing the glass faceplate. i believe Bob (vintage tube) posted photos. Or was it Dan?

btw, did you notice any improvement in sound quality after installation of the 2nd 402 at a given volume level, say around 4 watts?? obviously A LOT more power going mono bridged. Looking forward to your thoughts.


Jason

[cougit25]

Originally Posted by j3brow

yes, LED lights stock on MC402 (mine purchased early 2008)
there is a thread here, somewhere, that discusses how to adjust the brightness on meters and nomenclature. it involves removing the glass faceplate. i believe Bob (vintage tube) posted photos. Or was it Dan?

btw, did you notice any improvement in sound quality after installation of the 2nd 402 at a given volume level, say around 4 watts?? obviously A LOT more power going mono bridged. Looking forward to your thoughts.


Jason

Jason...I found a few posts on adjusting meter brightness on Mac source components but not on the amps.

As far as sound quality with the additional amp all I can say is "WOW!" I'm still listening and trying to put into words what I'm hearing. I'm having so much fun that this has got to be illegal!

[T-3G]

I find it interesting that both brightness and color on the blue meters are inconsistent across different units, even if they're the same model. I find this to be true at dealership showrooms as well. They should have a way to keep the color/brightness consistent, or make it easier for users to adjust them when necessary.

[cougit25]

Originally Posted by T-3G

I find it interesting that both brightness and color on the blue meters are inconsistent across different units, even if they're the same model. I find this to be true at dealership showrooms as well. They should have a way to keep the color/brightness consistent, or make it easier for users to adjust them when necessary.

+1

[jdandy]

Harold.......If you remove the cover behind the meters you will see a long narrow circuit board that goes from one meter to the other. This is the circuit board has the four LEDs for each meter mounted on each end. On this circuit board you will also find four adjustable trim potentiometers (trim pots) which will be labeled L-Green, L-Blue, and R-Green, R-Blue. By adjusting the left and right green and/or blue trim pots you will see the meter change color and the brightness will be altered slightly. By adjusting these trim pots you should be able to match the other amp's meters in color and brightness.

[cougit25]

Thanks Dan.

I had to replace the end caps on a MC252 once which required the removal of the front glass from the amp. I assume the same is required on the MC402 in order to access the pots. Am I correct or is there an easier way?

Also, I like the brightness of the 2nd amp. Is it possible to raise the brightness of the 1st amp or is it wiser to lower the levels of the second?

[jdandy]

Harold.......I do not have an MC402. I was able to get the information I gave you from the service manual schematic. I believe you will be able to access the trim pots without removing the front glass. As a starting point I would remove the metal cover from behind the meters to see if I could locate the trim pots. I have a feeling they will be located there. To remove this cover, remove the two screws on top, and two screws from each end.

I did not see an adjustment for LED brightness. The voltage for all LED's is set at 12 volts, so it looks like only the color can be adjusted. You may want to adjust the brightest amplifier, and see if fine tuning green and blue will achieve the same color and brightness as the dimmer amp.