Anyone have knowledge on this amp?
Yesterday there was 77v dc on the output but I applied a 4 ohm speaker and the voltage went away and it played music fine. Then I tapped the middle of the amp and it started to have static and buzz come out of the speaker. I instantly removed power and opened it up
There was a swollen cap 80v2200uf cap near the rca input that I replaced.
So when powered up with no load on the output there is 55v dc. When I applied a 4 ohm speaker it drops to 2v roughly.
There is 2 amps idle current with or without the load applied.
Also a little side note, without remote the protection light if faintly lit.
Yesterday there was 77v dc on the output but I applied a 4 ohm speaker and the voltage went away and it played music fine. Then I tapped the middle of the amp and it started to have static and buzz come out of the speaker. I instantly removed power and opened it up
There was a swollen cap 80v2200uf cap near the rca input that I replaced.
So when powered up with no load on the output there is 55v dc. When I applied a 4 ohm speaker it drops to 2v roughly.
There is 2 amps idle current with or without the load applied.
Also a little side note, without remote the protection light if faintly lit.
These amps typically have no DC feedback so there can be DC on the output that doesn't really have any drive.
Did you measure the 2v on the 4 ohm load directly across the speaker terminals?
The cap doesn't look swollen.
Did you measure the 2v on the 4 ohm load directly across the speaker terminals?
The cap doesn't look swollen.
I measured it at the speaker output terminals on the amp itself. That picture is after I replaced it.
Did you find the intermittent problem that was seen when you tapped on the amp?
What are you using for a 12v power supply on the bench?
What are you using for a signal source on the bench.
What are you using for a 12v power supply on the bench?
What are you using for a signal source on the bench.
12v battery and a jvc headunit I use for music in the garage. But that 2 volts is without rca cords even plugged in.
I questioned the 2v because you stated that there was no difference in current draw with or without the load. 2v across 4 ohms would cause a slight increase in current.
Did you find the intermittent problem that was seen when you tapped on the amp?
Did you find the intermittent problem that was seen when you tapped on the amp?
No. I cannot see anything burnt/lose. I touched up some joints on the card nearest to the power inputs which would be near the center of the amp. So whatever caused that could or could not be fixed
I'm going to go check DC Voltage on the speaker again and I'll let you know what I find out
So I went through and touched up all the t220 joints. Touched up some other questionable joints. Checked all for shorts or solder bridges.
When I hook up a 4 ohm speaker I still get 3vdc that declines to 2.3v~ I
replaced the other sides cap to see If there was any change but still having the same symptoms.
I forgot to mention when I replaced the 80v2200uf cap I'm pretty sure I put in backwards and did power the amp up with it like that.
Did I cause this by doing so?
Do you have any rough idea what would cause it? I do not have a scope. 😕😕
Connecting the cap backwards will generally cause excessive current flow as voltage is applied with reverse polarity. The caps may survive is reconnected properly. Initially, there may be higher than normal current draw but that generally rectifies itself as the dielectric reforms.
Does the amp produce audio?
Not having a scope makes this much more difficult.
Does the amp produce audio?
Not having a scope makes this much more difficult.
I tried last night to check if it did. I cannot confirm that it plays music but current draw did go up as if it was. I'll go confirm here in a while though.
I was kinda going off of speaker movement but with what the amp is doing all I can see is as soon as it powers up the speaker pushes outward.
So it does still play music. But it kinda scratchy while playing and the 3.2v is still present while playing
Black probe on main ground terminal. What is the DC voltage on the positive and negative speaker terminals?
When you power down, which speaker terminal has a voltage that increases significantly?
When you power down, which speaker terminal has a voltage that increases significantly?
So from what I can see neiter the pos or neg of the speaker terminals jump when power down.
Negative terminal claims to a max of 15v them rests at 12v
Positive maxes out at 13v then rests to 11.5v.
Test Was done with the 4 ohm speaker
Would you like a video to see whats going on? Its very visible. Its on a little 6.5 door speaker. Are you kinda lost on what it could be also?
I just wanted to say I really do appreciate the help you have gave me to far. And you helped me fix another amp also in the past. Thank-you very much and happy Easter
I don't do video or audio files.
You haven't provided enough information to make any sort of a conclusion.
Is the noise clearly audible through a subwoofer?
Does it sound like this:
http://www.bcae1.com/temp/cooleditmixedoscillator01.wav
You haven't provided enough information to make any sort of a conclusion.
Is the noise clearly audible through a subwoofer?
Does it sound like this:
http://www.bcae1.com/temp/cooleditmixedoscillator01.wav
You know when I just got them numbers for you I though I heard a climbing high pitch squeal but now that you asked I definitely did. I'll provide you with anything you ask for. I'm just not 100% sure what to provide you with unless asked specifically.
Some people call that nose static. Is that what you were calling static?
Is the noise clearly audible through a subwoofer?
Is the noise clearly audible through a subwoofer?
I would not call that static. High pitch whine is more or less what I'd describe that as. But no that's not the original noise I heard. I'm thinking that static was due to a solder issue or the swollen cap. I've tried multiple ways to get the static to happen again and cannot re-create it.