More Testing
Wow, it's nice to see people are starting to make progress with their builds and hopfully this will inspire others.
I'm going for the simple build, psu > amp and no facy bits, just an on/off switch...
Got a few connector blocks just to make testing a little easier/safer. This time I've tried out the amps connected to the dps-600's and bias set to 400mA. No probles to report so far. Next step is to assemble a pre-amp then I can test it with music
Wow, it's nice to see people are starting to make progress with their builds and hopfully this will inspire others.
I'm going for the simple build, psu > amp and no facy bits, just an on/off switch...
Got a few connector blocks just to make testing a little easier/safer. This time I've tried out the amps connected to the dps-600's and bias set to 400mA. No probles to report so far. Next step is to assemble a pre-amp then I can test it with music
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I'm sorry this happened to you. I want to help but do not have enough information to understand what happened. it is strange that a smd caps is gone.
what is now the state of the DPS-600? (disconnected from the amp)
in what circumstances did this happen?
LME voltage regulators, have fuse 1R on board.
Hi AP2, thanks for the offer. The DPS-600 starts up and the main power section is working as normal. Just no power on the LME section, not had time to find out what's wrong but am positive I'll be able to fix it
Not sure what happend fully myself yet. Think it was C71 on the amp that went POP but not checked it. A short somwhere??? Replace parts and start again...
Not sure what happend fully myself yet. Think it was C71 on the amp that went POP but not checked it. A short somwhere??? Replace parts and start again...
Hi AP2, thanks for the offer. The DPS-600 starts up and the main power section is working as normal. Just no power on the LME section, not had time to find out what's wrong but am positive I'll be able to fix it
Not sure what happend fully myself yet. Think it was C71 on the amp that went POP but not checked it. A short somwhere??? Replace parts and start again...
Hi,
see location of res-fuse on pcb.
I set 1R, in agreements with Opc, (lme current is in range of 30mA).
replace fuse (not use wire please).
..before blow, it sound?
if res-fuse are open, is better that you check well and change smd caps on wire-amp.
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Looks like the two 1R res-fuses have gone, neither measure 1 Ohm. Will make sure everything else is ok before using.
The Wire's output volume was very, very low, the lme was getting hot [could still touch it, just] and the fets were cold, then POP. Something not right for sure... the hunt begins...
Might completely strip the amp and get everything new just incase...
The Wire's output volume was very, very low, the lme was getting hot [could still touch it, just] and the fets were cold, then POP. Something not right for sure... the hunt begins...
Might completely strip the amp and get everything new just incase...
Hi BuildMeSomething,
Can you post exactly what variant you're building, and what capacitors seem to have exploded?
It's quite strange that it would happen so suddenly like that. My best guess from what you described is that some solder had shorted over to the top ground plane and didn't actually short until the voltage was high enough to arc. Sometimes checking for continuity with a meter misses stuff like that.
I once had a massive explosion on an SMPS I was working on, and it turned out the top ground plane was shorting through the shrink wrap on the electrolytic caps to the can of the cap itself. Everything looked fine with a DMM, but when 400V was on there, it was enough to arc between the capacitor can and the PCB. In the end, each cap needed a Mylar disk to protect it.
Some close-up pics of your board could help too!
Cheers,
Owen
Can you post exactly what variant you're building, and what capacitors seem to have exploded?
It's quite strange that it would happen so suddenly like that. My best guess from what you described is that some solder had shorted over to the top ground plane and didn't actually short until the voltage was high enough to arc. Sometimes checking for continuity with a meter misses stuff like that.
I once had a massive explosion on an SMPS I was working on, and it turned out the top ground plane was shorting through the shrink wrap on the electrolytic caps to the can of the cap itself. Everything looked fine with a DMM, but when 400V was on there, it was enough to arc between the capacitor can and the PCB. In the end, each cap needed a Mylar disk to protect it.
Some close-up pics of your board could help too!
Cheers,
Owen
Think I found the root problem, got the Zener Diode mounted the wrong way... Then probably shorted something trying to figure out why I wasn't getting any sound...
R39/46 are shot & will replace C71/81, one or both of these went poof... and reorientate the zener. Hopefully everything else is ok...
Oh Yeah... my The Wire's first test. One channel might be in need of repair, but the other is singing sweetly. Crapy futage was recorded on my phone, sorry... will use my DSLR next time
Excellent!!!
I'm very glad to hear you identified the problem and got the other channel up and running!
For the first amp, I would replace all the parts in the Mute circuitry as most of them were probably damaged by the high voltage. If you are lucky, the LME might have survived, but I think that pin might be sensitive to over-voltage as well.
Give it a try as is, but be mindful that it may need to be replaced.
Everything else looks really good, and let us all know when you both channels going
Cheers,
Owen
I'm very glad to hear you identified the problem and got the other channel up and running!
For the first amp, I would replace all the parts in the Mute circuitry as most of them were probably damaged by the high voltage. If you are lucky, the LME might have survived, but I think that pin might be sensitive to over-voltage as well.
Give it a try as is, but be mindful that it may need to be replaced.
Everything else looks really good, and let us all know when you both channels going
Cheers,
Owen
Andrew,
I'd like more information on this screech ... have you got any information on the nature of the oscillation that you describe? Owen described a soft noise during turn off at less than 1V RMS or something from memory, which he was certain posed no risk to tweeters or fragile drivers. Maybe something else is wrong? I haven't seen anyone else describe behaviour like this, though I haven't followed this thread as closely as some.
Regardless, I am working on a design for an automation board for the LME49830 Wire amps that is mostly aimed at DPS600 SMPS and setting a pre-selected high/low bias level. One thing I would like to set is a delay in power off after pressing the momentary switch on front panel, this would allow the mute function of the LME49830 to be asserted automatically before powering down the amp via a relay, this may help tame some of these turn off transients perhaps? Depends on what is causing your screech I guess.
Cheers,
Chris
I'd like more information on this screech ... have you got any information on the nature of the oscillation that you describe? Owen described a soft noise during turn off at less than 1V RMS or something from memory, which he was certain posed no risk to tweeters or fragile drivers. Maybe something else is wrong? I haven't seen anyone else describe behaviour like this, though I haven't followed this thread as closely as some.
Regardless, I am working on a design for an automation board for the LME49830 Wire amps that is mostly aimed at DPS600 SMPS and setting a pre-selected high/low bias level. One thing I would like to set is a delay in power off after pressing the momentary switch on front panel, this would allow the mute function of the LME49830 to be asserted automatically before powering down the amp via a relay, this may help tame some of these turn off transients perhaps? Depends on what is causing your screech I guess.
Cheers,
Chris
Hi Andrew,
I have tested start-up and shutdown behavior pretty extensively here, with some 30 screenshots from four different SMPS supplies and a linear supply, and I have never once seen any sign of oscillation. Granted, the SMPS supplies do cause some low level thumps as the SMPS UVLO kicks on and off, but the amp can hardly be blamed for that. Even still, it's less than 1V and very short duration which will not damage anything unless you're direct driving a very low impedance ribbon, and in that case, this is not the right amp.
What you're describing must be somehow related to your PSU arrangement or the specific way you've decide to setup the amp or your grounding. I know you were using a 10R resistor between GND planes which I specifically recommend against doing, and it could have to do with that.
This is a complex build, and if people deviate from the instructions provided, then they had better know exactly what they're doing. I have provided safe and tested arrangements and PSU suggestions that I know work well (and have provided measurements to that effect) but if you decide to use something else, then you really can't come back here and complain it's not working.
As qusp mentioned, if anyone else is having this issue, please let us know and maybe we can single out exactly what might be causing it. Also, Andrew, if you could post a very detailed schematic of exactly how you have things set up, then maybe we can track down the problem.
BuildMeSomething:
You just got your amp up and working... are you seeing this issue at all (high frequency oscillation on shutdown)?
Cheers,
Owen
I have tested start-up and shutdown behavior pretty extensively here, with some 30 screenshots from four different SMPS supplies and a linear supply, and I have never once seen any sign of oscillation. Granted, the SMPS supplies do cause some low level thumps as the SMPS UVLO kicks on and off, but the amp can hardly be blamed for that. Even still, it's less than 1V and very short duration which will not damage anything unless you're direct driving a very low impedance ribbon, and in that case, this is not the right amp.
What you're describing must be somehow related to your PSU arrangement or the specific way you've decide to setup the amp or your grounding. I know you were using a 10R resistor between GND planes which I specifically recommend against doing, and it could have to do with that.
This is a complex build, and if people deviate from the instructions provided, then they had better know exactly what they're doing. I have provided safe and tested arrangements and PSU suggestions that I know work well (and have provided measurements to that effect) but if you decide to use something else, then you really can't come back here and complain it's not working.
As qusp mentioned, if anyone else is having this issue, please let us know and maybe we can single out exactly what might be causing it. Also, Andrew, if you could post a very detailed schematic of exactly how you have things set up, then maybe we can track down the problem.
BuildMeSomething:
You just got your amp up and working... are you seeing this issue at all (high frequency oscillation on shutdown)?
Cheers,
Owen
Thanks Owen, I'll order a spare LME when I put in my order with digi-key for the other bits, including the ones from the mute circuit. Hopefully the LME is ok though, it'll be a pain to remove from the pcb. If it is dead, I could just cut all the pins though...
Going to have a dedicated listening room for this sysrem, the room is 3m x 3m and I'll be using a nearfield position. Not decided on speakers yet, but like the idea of the Full Range Frugel Horns [FE126eN drivers], or maybe some from XTZ.
Turning on the amp by its self [nothing connected] I get no start up noise [that I can recall]. With the O2 [used as preamp] and cd player connected I get some mid/hf noise until all devices are on*. Probably just a grounding issue while nothing is in a chassis. [*This only happens if I turn the amp on before the others...]. Plus, there is a slight LF oscillation on power down, but it only lasts for a couple of seconds.
None of this worries me at the moment, on mine it's all low[ish] volume stuff and I can't see it damaging a speaker.
Edit; couldn't we use diyAudio's Soft Start & Speaker Turn-On Delay and DC Protector Boards if things get out of hand due to individual setups?
So far I'm very happy with the level of detail I can hear and things should improve again when I replace the O2 with The Wire SE-SE HPA as a pre amp. Detailing is certainly close to what I'd expect to hear from my HD650's when using the O2 amp. Better speakers than the Mission ones will help hear also
Going to have a dedicated listening room for this sysrem, the room is 3m x 3m and I'll be using a nearfield position. Not decided on speakers yet, but like the idea of the Full Range Frugel Horns [FE126eN drivers], or maybe some from XTZ.
Turning on the amp by its self [nothing connected] I get no start up noise [that I can recall]. With the O2 [used as preamp] and cd player connected I get some mid/hf noise until all devices are on*. Probably just a grounding issue while nothing is in a chassis. [*This only happens if I turn the amp on before the others...]. Plus, there is a slight LF oscillation on power down, but it only lasts for a couple of seconds.
None of this worries me at the moment, on mine it's all low[ish] volume stuff and I can't see it damaging a speaker.
Edit; couldn't we use diyAudio's Soft Start & Speaker Turn-On Delay and DC Protector Boards if things get out of hand due to individual setups?
So far I'm very happy with the level of detail I can hear and things should improve again when I replace the O2 with The Wire SE-SE HPA as a pre amp. Detailing is certainly close to what I'd expect to hear from my HD650's when using the O2 amp. Better speakers than the Mission ones will help hear also
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Hi, just in perfect harmony with the topic, I should mention that the DPS-600 when using the remote control, in the duration of the OFF phase, is completely inactive (dead). You can see below the PCB, 2 small diodes connected to the NC 2Pin (remote control). the instant that the contact is closed, pwm and power stage is disabled. output voltage decrease linearly dependent on the load. any small oscillations are due to the transition in the AMP. these are not dangerous, but if someone wants to, we can take action to disable the amp when the voltage rail drops below 15V.
regards
regards
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