(Added Video Files of meter's working , unable to load in the original Red Plating Post)
Tim Mellow - 25W OTL Tube Amplifier Build / Progress Just got some more kit that I may use for this Amp.
All holes for Tube bases Done.
Chassis now formed using my home made sheet metal bender.
Seen this Double VU Meter with driver board on Ebay , ooh, thought I'll incorporate it in the design. Original design had 2 x 1Amp meter's for biasing only, no VU Meter's. I have read in some of the forums these meter's were replaced by resistors and not fitted after initial set up. I'm going to use a switch were I can switch between the resistors and meters so as to check the biasing now and again when needed. Trying to fit the 1 Amp meters any where on the chassis just did not look aesthetically right.
Hole cutout for the Meter, took about an hour to complete , took extra care not to mark the chassis as this will be in full view when complete.
Deciding were the I/P'S and O/P'S are going.
Final Placement Decided on this layout in the end.
I ordered a pair of these with driver board some time ago to go with the Boyuurange A09
No Lamp adjustment with this PCB
Dam Big Holes to drill in the Face Plate
Made the mistake of measuring the resistance of all the meters and testing their deflection. 2 Pairs and I Double all varying resistances and deflections with the same current.The only consistency with parts from China is the Inconsistency. Best use these as "Indication Only" as they look like 20-30% variation between then. Having in the past calibrated Medical equipment these would be a nightmare to calibrate correctly and would be scraped but we'll use just to show some indication.
Tested using another PCB with lamp adjustment
Low level adjustment
High level adjustment
Blue meter's Illuminated
Added Some Tape for better affect
Chassis Size comparison to the Boyuurange A09
Giving the Meters workout
Take Care and have fun. Will.