Question, if I see the 50hrtz on all the gates of the output transistors, drive is present. Withing a few seconds gain is all the way down the high side output transistors heat up, I tested all the driver transistors, in tester and with ohms for leaking. Would it be the torrid, one looks raised? Or the octacouplers?
No perry if I look at say the drive signal on power supply it is no. It's clean. Most output signals. I just look at them like that.
1. If you look at any other signals in the audio section, do you get the same noise?
2. If you probe the audio ground, do you get the noise?
3. Did you check the signals in differential mode?
2. If you probe the audio ground, do you get the noise?
3. Did you check the signals in differential mode?
Yes perry differental mode, and the noise starts at the a/v Jack's, it's possible it's from the main ground.? If I test the DC voltages at the output placements. high side I get 6.51vdc on the gate
80vdc source
3.45vdc on drain.
Low side
Gate -71.6vdc
Source 3.45vdc
Drain -78.4vdc
80vdc source
3.45vdc on drain.
Low side
Gate -71.6vdc
Source 3.45vdc
Drain -78.4vdc
Could use help, the driver transistors heat up quickly as well. The a1277, c3228. Replaced them still the same. The noise is only on this amp.
I did get the octacouplers u suggested perry.
And a new set of irfp264.
I pulled one leg of all the gate resistors and tested them and the diodes, all within tolerence.
I did get the octacouplers u suggested perry.
And a new set of irfp264.
I pulled one leg of all the gate resistors and tested them and the diodes, all within tolerence.
Does your scope give the same really noisy signals on the class D output section of other amps or is it just a problem with this amp?
Confermed the noise is only on this soundstream amplifier. Went to the shop and tested the audiopipe class d amp and it's perfect clear 50hrtz on the pads with no output transistors. So it's not the scope.
Does anyone know of a similar amplifier that uses this same driver /design I can purchase to figure out what is going on with this one?
Many amps use this basic design. There are fewer that use the board with the TO-220 drivers. The Planet Audio BB2400.1 uses this driver board. I don't know of any manufacturer that will sell the boards. You may find some on ebay.
The forum member jacampb2 may have something that you can use for testing.
The forum member jacampb2 may have something that you can use for testing.
That should be fine perry just going to order a working unit to make comparisons to. I used the octocouplers you suggested and they worked. It stopped the small signal drivers from over heating. But the high side output transistors still heatup within 10 sec of turning on the amplifier. Same noise appears right at the RCA? I found that someone repaired the underside of the rca grounding leg with soder. So I reworked that connection. Still the noise persists
