This thread is for discussions about everything to do with the many possible Burning Amplifier configurations.In general, there are two output board types. BA-1 and BA-2
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Dear all
Not sure if this is the right thread to discuss my issue with the single ended output stage. I do have an issue while building my BA consisting of a BA-3 gain stage and a single ended bias and output board (BA-1). The BA-3 works as expected and I could successfully bias it as described in the build guide (and as I did on my F5 before).
But as soon as I connect one of the output boards to the power supply, the bulb tester turns fully bright. So, it looks like a short. Both output stages behave the same. So, the error is at least consistent (part selection, build, wiring).
Here's some information about my setup:
- PS is the Universal PSU V3.0 from the store. And it's exactly the same as I used in my F5 for about a year now. I threw out the F5 boards and replaced them with the BA. So, we can rule out the PS. Not sure if the toroid is beefy enough, though (300VA, 2x18V => +/- 24V output).
- I installed a bulb in series with the mains input.
- With only the gain stage connected, the bulb turns bright and slowly dims to zero within a couple of seconds. This seems to work perfectly.
- Both channels of the gain stage are now biased to about 0.8V (80%). P3 is set to equal resistance. The MOSFET's turn warm.
- With either one or both output boards connected to the power supply, the bulb first behaves the same (dims from fully bright to zero) but after about one second, it turns fully bright again. The speaker protection board never switches "on" (meaning it never switches the speaker signals).
- The MOSFET's on the output board stay cold.
- I measure about 8 V DC between V+ and V- on the output boards. Not sure if that's of any relevance.
- The potentiometer P202 is meant to dial the DC offset, right? Wasn't sure about that.
I'm actually not sure if there's a problem at all. But I don't want to remove the bulb unless I'm sure that there's not an issue. But I'd appreciate it a lot if someone could have a look at the pictures.
Thanks,
Daniel
Not sure if this is the right thread to discuss my issue with the single ended output stage. I do have an issue while building my BA consisting of a BA-3 gain stage and a single ended bias and output board (BA-1). The BA-3 works as expected and I could successfully bias it as described in the build guide (and as I did on my F5 before).
But as soon as I connect one of the output boards to the power supply, the bulb tester turns fully bright. So, it looks like a short. Both output stages behave the same. So, the error is at least consistent (part selection, build, wiring).
Here's some information about my setup:
- PS is the Universal PSU V3.0 from the store. And it's exactly the same as I used in my F5 for about a year now. I threw out the F5 boards and replaced them with the BA. So, we can rule out the PS. Not sure if the toroid is beefy enough, though (300VA, 2x18V => +/- 24V output).
- I installed a bulb in series with the mains input.
- With only the gain stage connected, the bulb turns bright and slowly dims to zero within a couple of seconds. This seems to work perfectly.
- Both channels of the gain stage are now biased to about 0.8V (80%). P3 is set to equal resistance. The MOSFET's turn warm.
- With either one or both output boards connected to the power supply, the bulb first behaves the same (dims from fully bright to zero) but after about one second, it turns fully bright again. The speaker protection board never switches "on" (meaning it never switches the speaker signals).
- The MOSFET's on the output board stay cold.
- I measure about 8 V DC between V+ and V- on the output boards. Not sure if that's of any relevance.
- The potentiometer P202 is meant to dial the DC offset, right? Wasn't sure about that.
I'm actually not sure if there's a problem at all. But I don't want to remove the bulb unless I'm sure that there's not an issue. But I'd appreciate it a lot if someone could have a look at the pictures.
Thanks,
Daniel
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Hope you have moved this query to the correct forum, this behavior is normal when the fully biased amp makes the rig glow very bright...i assume you are using 60W or less powered bulb for this rig...the voltage across +V and -V will show very low since the amp is drawing most of the power...the relays won't latch because they are expecting a certain voltage to activate, which did not happen...but I have moved ahead already
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