Got, two Orion 2500Ds in, both with similar reports of a high pitched sound at the speakers, without input signal. Powered up both and confirmed.
Without audio, the amplifiers power up ok and the relay clicks on. There's an audible sound, it starts off around 1khz and slowly increases in freq until it stops. It takes roughly 3 mins before it goes away.
I found two threads below which seem similar but don't seem to have a resolution. I haven't poked around due to workload, but anyone has a solution to this?
https://www.diyaudio.com/community/...ng-orion-2500d-amp-high-pitched-sound.381353/
https://www.diyaudio.com/community/threads/orion-2500d-sound-like-horn-at-speaker.362443/
Without audio, the amplifiers power up ok and the relay clicks on. There's an audible sound, it starts off around 1khz and slowly increases in freq until it stops. It takes roughly 3 mins before it goes away.
I found two threads below which seem similar but don't seem to have a resolution. I haven't poked around due to workload, but anyone has a solution to this?
https://www.diyaudio.com/community/...ng-orion-2500d-amp-high-pitched-sound.381353/
https://www.diyaudio.com/community/threads/orion-2500d-sound-like-horn-at-speaker.362443/
If it's due to unsynchronized oscillators, there probably isn't a resolution.
Do you have a two-channel scope?
Do you have a two-channel scope?
Set it up to use ch1 as the trigger channel and monitor the PS waveform with that channel. Then use ch2 to monitor the output carrier waveform. The PS waveform should be locked. The output waveform will be at a higher frequency. Is it locked in sync with the PS waveform? Or does it drift left/right?
This is caused beat or phase noise and it's essentially the difference in the frequency of the two oscillators. Unless the two are supposed to be synchronized, there isn't much you can do.
Is the noise audible with the subs in the vehicle?
Is the noise audible with the subs in the vehicle?
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I belive I came across this in a Memphis 16-1000d I recently worked on.
I’ve been using this Jbl schematic for most of the f16/b52 type amplifiers. This seems to have the same sync circuit.
I’ve been using this Jbl schematic for most of the f16/b52 type amplifiers. This seems to have the same sync circuit.
In the Memphis amps, the sync circuit sometimes causes the amp to draw excessive current on startup. I've never had one here that I had time to troubleshoot so I'm not sure of the cause. On the forum, there may have been a couple that the sync transistor was pulled to solve the problem.
Does your amp have the part locations in the board that you could fill to enable the synchronization?
Was the sync circuit installed in the 24001?
Does your amp have the part locations in the board that you could fill to enable the synchronization?
Was the sync circuit installed in the 24001?
In the Memphis I worked on, it didn’t cause any problems, as you mentioned it with the drawing I remember I saw a transistor connected to pin 5 of the 494 whilst tracing around.
I’ve never worked on any Jbl 24001 to date, I pulled the schematic as it’s helped a lot with crossfire and similar amplifiers.
I’ll trace around the circuit on this Orion and get back to you.
I’ve never worked on any Jbl 24001 to date, I pulled the schematic as it’s helped a lot with crossfire and similar amplifiers.
I’ll trace around the circuit on this Orion and get back to you.
I had a look and poke around on this Orion, the Sync is not connected.
Pin 5 of the TL494 goes to C9 to ground, the trace splits and goes to Q5, but Q5, R29/R30/C17 are unpopulated.
Pin 4 of the MC14060 is connected to pin 7 of its respective daughterboard and this connects to the open pad C17 of the PS daughter board.
I've attached a pic of this area of the PS DB.
Pin 5 of the TL494 goes to C9 to ground, the trace splits and goes to Q5, but Q5, R29/R30/C17 are unpopulated.
Pin 4 of the MC14060 is connected to pin 7 of its respective daughterboard and this connects to the open pad C17 of the PS daughter board.
I've attached a pic of this area of the PS DB.
Attachments
There may be a reason that they don't use the sync circuit. It may have been causing the problem that the Memphis 1000 was having.
Were these amps doing this the entire time that they have been installed?
Were these amps doing this the entire time that they have been installed?
The owner had one amplifier first and was playing it without the noise until early this year.
He went and purchased the second unit and this too has the noise as the first.
He went and purchased the second unit and this too has the noise as the first.
Well, you'll have to make the executive decision whether to risk causing the amp to fail.
I'm assuming that you've confirmed that the amp is working perfectly, other than the noise.
I'm assuming that you've confirmed that the amp is working perfectly, other than the noise.
yes sir both amps are working correctly except for the noise.
I'm gonna set these aside until I get some time to further troubleshoot.
I'm gonna set these aside until I get some time to further troubleshoot.