Those 220 Ohm are really hard to get at with the test leads, as they are each sandwiched between two heat-sinks, voltages were at just over 11, was able to adjust them to 14.88 and 14.90, that's good enough for now. Do they sell longer (the metal part) test leads for the DT-830B?
12-13V is originally recommended / determined by ear (but NOT set) by Indeed. 15.5V (IRF) is determined by ear (Mike) and measurements (based on equal clipping properties, maximum output power and LM317 behavior).
You can set it to whatever value you prefer or thinks it sounds best to you. I encourage to simply experiment with both voltages and hear fo yourself.
On last week the amp broke. It start to generate a noise, similar to working on low rotations tractor engine and then became silent.
Symptoms: Red and blue LEDs not lights up. One of mosfets seriously overheats, the second one is warm. Anode voltage jumps(permanently changes) between 1v to 7v. Filter capacitor (6800µF 25v) was broken down. BTW, I tried to replace it and the new one broke too.
Any suggestions or diagnostic methods? Thanks a lot.
Hi folks. I have two Bravo V3s, one the original which developed a hum in the left channel and then two, the replacement. Both are 6922EH equipped. Wrote the factory about the first and they said pretty much what you folks have said. Adjust the trim on the bias. I just now gotten the first unit hooked up to a VOM. I used the inboard resistor legs as test points. The voltages checked 21V (R)and 11V (L) approximately). The voltages do not seem to vary as I move the pots. There is still audible noise in the left channel. I have the caps 2200 gold and LRF510 FETs but I think I must get rid of the noise first. The Indeed 3 seems to be a more sturdy build with larger heat sinks etc. What to do, what to do...
Well PATIENCE is what to do! I found a position on the potentiometers where both voltages were within a small fraction of a volt. And just slightly over 12V. The noise is still there when turned down to almost off (or the volume of the signal is low). Hey, nothing is perfect right?
I really don't fancy your chances, most of that size are DAC & HP amp together. The only possibility that springs to mind is a Deltec (DPA) "Little Bit" or "PDM x" DAC obtained second hand. The Bravo is still smaller but would look quite neat sitting on top.
videoguy: Hi Jon: I am in Florida & am in frequent contact w Alex Kethel. Am in need of some single ripple eater boards. Wpuld you mind giving me the address of the pcb manufacturer; as I need ten boards. Thank You in advance. Bill Wilson
Dec 2, 2019 1:54:46 GMT