Bottlehead Kits > Mainline

Channel imbalance [resolved]

(1/2) > >>

NightFlight:
After not listening for about a month or so... (yikes) I came back fresh and immediately noticed a channel imbalance which sweeps right to left in the fine volume attenuator as the attenuation is decreased. Obvious once you are aware of it.  Anyone else notice?

 

Doc B.:
You can measure the resistance of each step on each channel. Try doing that and report back any differences you measure between left and right. The most likely cause would be swapping resistors on one side.

NightFlight:
Hey thanks Doc. Finally got around to checking it out.  As it turns out my one 1372F (13.7K) is reading 8.86K.

NightFlight:
Checking the my coarse attenuator with reference to ground:


* Points 12/6 - 139 ohms
* Points 11/5 - 390 ohms
* Poitns 10/4 - ~1.1k/1.07k     ohms
* points   9/3 - ~3.15k/2.89k   ohms
* points   8/2 - ~8.9k/6.87k     ohms
* points   7/1 - ~25.12k/8.86k ohms
The labelling all seems right.

My 16.2 is reading around 8K on the one side (across points 1,2). The 5.76K reads 4.7K (across points 2,3). The 2.05K reads about 100ohms low across points 3,4. Everything on the other channel seems fine.

Very weird. I'm flummoxed as to what might have done this. I'm fairly certain I metered them during the build.

Paul Birkeland:
Try turning the fine attenuator all the way up, then recheck.

With the fine attenuator all the way up (and nothing plugged into the RCA jacks), you should be able to measure the resistors a bit better.

For what it's worth, we do not carry a 4.7K RN55D resistor in our inventory, so I suspect something else is messing with the readings. 

Navigation

[0] Message Index

[#] Next page