Ever since I viewed this AMA I been meaning to conduct this maintenance on my Son's 2014 MAZ 38 NR Head.
I finally got the time to do so.
Powering down the AMP while powered On (non Standby mode) will allow the tubes drain the capacitors, to reduce hazardous voltage.
After power down, and metering B+ voltages, measurements were near zero.
I did loosen the POTS and Jacks to ensure DeoxIT will seep between the chassis and component, prior to retightening.
While inspecting all solder connections I found the PI Plate connection on pin 1 with a degraded solder joint.
Previously I had a LPS PI tube go bad and begin induce hum, possible cause of excessive Plate current draw.
My Son had just played two Christmas Eve performances to a crowd of 3000. This was a failure about to happen.
Before Repair
After Repair
Utilizing my Android phone sound meter app. 1/2 inch from speaker grill, with all knobs at noon (nothing connected to the Amp input).
Before PM: 47-49 dB idle noise floor.
After PM: 42-43 dB idle noise floor.
I use the sound meter as a baseline reference to detect future changes (possible tube degrade) in idle state.
These AMA tips are great, utilizing the Head cabinet as a support while conducting the PM task.
Very helpful. Thanks Doc.
Here is the 2104 MAZ 38 NR Gut shot, note the quality of construction and lead forming. No slap together construction here. Top shelf.
Not only the Z Amp has rich sound quality, but the internal components are high quality too.
As the Z owners know and talk about on this fourm.
2014 Maz 38 NR Gut Shot
Tip of the hat...