LC ZAPpulse Amplifier Q & A

Status
Not open for further replies.
Jump to Latest
#122
Unsolder one end, or remove it, and then use an ohmeter to check it's value. I think resistors tend to fail closed so an ohm meter on any range might read zero. Or it may be dependant on what type of resistor it is as well. So you could find out it's value and tolerance and see if it's in spec.

It may be also be visibly screwed, take any discoloration as a bad sign.
 
#124
classd4sure said:
Unsolder one end, or remove it, and then use an ohmeter to check it's value. I think resistors tend to fail closed so an ohm meter on any range might read zero. Or it may be dependant on what type of resistor it is as well. So you could find out it's value and tolerance and see if it's in spec.

It may be also be visibly screwed, take any discoloration as a bad sign.
Click to expand...
Do you think my problem (72,5V DC ) out on the speaker terminals could depend on that resistor?
 
#125
Hi,

I'm just guessing but I don't think so.
With the hum you describe and the voltage at the terminals, I think you blew your mosfets. What's your rail voltage, 72.5V?

That's just my guess though, if you're trying to troubleshoot, maybe you can remove your mosfets and test them with an ohmeter, make sure they aren't cooked.

I also dont' know if there's any kind of warranty on it though, or if they'll charge you more to repair it if you played around with it like that, I'll leave that up to you.

Best Regards,
Chris
 
#126
classd4sure said:
Hi,

I'm just guessing but I don't think so.
With the hum you describe and the voltage at the terminals, I think you blew your mosfets. What's your rail voltage, 72.5V?

That's just my guess though, if you're trying to troubleshoot, maybe you can remove your mosfets and test them with an ohmeter, make sure they aren't cooked.

I also dont' know if there's any kind of warranty on it though, or if they'll charge you more to repair it if you played around with it like that, I'll leave that up to you.

Best Regards,
Chris
Click to expand...
Yes the rail voltage is 72.5 V i have mailed them and they will replace it if it`s broken.Strange thing it happens twice and on the right channel.I have measured the power supply and there is no strange there.Another strange thing about this is a "clipping" sound from the softstart when i don´t play music it dissapered when i removed the broken module but the sound was there long before both the module crashed.Now i play on the left channel,using it to drive a sub and the only strange thing is for now the amplifier shuts down if i play a little bit loud for a while.
 
#127
I think I had a similar problem once.
Then it was a fault V4P PSU. If my memory is correct, it was a fault gate driver. I had +60 V out.
Maybe your gate driver is defunct on the modules?
Your guess is as good as mine.
I have blewn 3 woofers with the zappulses. All of them really expensive.
 
#129
bambadoo said:
I had a couple of mudules that burned that resistor.
It was clearly visible.
In fact I noticed a small flame when fireing up the zappulse modules.
Click to expand...


Be very carefull with that resistor, if that resistor has burned out, I think it becomes an open (I had one burned out).

This is potentially very dangerous. If that resistor is gone, the zobel network will not work. If you then operate the amp without any load, the output voltage after the LC filter can become very high (hundreds of volts, enough to kill you) once the amp is fed with a signal close to the resonance frequency of the LC filter (about 150kHz) or when it oscillates for some reason at that frequency.

I saw a warning like this in maybe a class D tutorial from IR????

SO be very carefull as this resistor easily blows out when you are experimenting.

Best regards

Gertjan
 
#130
vroum90 said:
hello,

it is not encouraging :xeye:

I have received 2 zaps 2.3SE this week... I hope that my loudspeaker will not burn...

Best regards

Seb
Click to expand...
Be very careful when you solder the cables and look more than twice that everything is in the right place.And never change RCA or speaker cables when there is still even little power left in the module.Beside this things they sound very good when they are working.
 
#131
This burning of woofers also worries me a bit (or a lot). I plan to use the Zappulse in an active system with two Lambda Acoustics SB12 speakers. It took me many, many days to build the enclosures (90 kilos each) and the units cost $200 a piece, excluding more than $300 shipping and import taxes. Besides, they cannot be replaced anymore (because Nick stopped building them).

What can I do to protect my investment?

Is it sensible to use a good relay, such as this one
An externally hosted image should be here but it was not working when we last tested it.


However then there must still be some sort of detection circuit to operate the relay. A DC detection circuit + detection of high voltage perhaps (but how?)

Maybe LCaudio can implement a good circuit..... (Lars???)
 
#132
Duck-Twacy said:
This burning of woofers also worries me a bit (or a lot). I plan to use the Zappulse in an active system with two Lambda Acoustics SB12 speakers. It took me many, many days to build the enclosures (90 kilos each) and the units cost $200 a piece, excluding more than $300 shipping and import taxes. Besides, they cannot be replaced anymore (because Nick stopped building them).

What can I do to protect my investment?

Is it sensible to use a good relay, such as this one
An externally hosted image should be here but it was not working when we last tested it.


However then there must still be some sort of detection circuit to operate the relay. A DC detection circuit + detection of high voltage perhaps (but how?)

Maybe LCaudio can implement a good circuit..... (Lars???)
Click to expand...


There seems to be a good protection circuit avaialable at

http://www.wnaudio.com/

Look in their products section and you will find it

Best regards

Gertjan
 
#133
That White noise protection circuit sure looks interesting. It has all the feautures I could wish.

How thus such a circuit work by the way? Will such a protection circuit have a negative impact on the sound quality (apart from the theoretical drawback of a relay, but I don't worry about that). Especially the DC voltage detection. Thus that impact the signal?

Btw it is triggered by DC voltage exceeding 1.2V (or -1.2V). Will it not be triggered by the normal music signal, when playing loud?
 
#135
One question about the White Noise speaker protection:

LSPRO.jpg

http://www.wnaudio.com/lspro.html

The loudspeaker protection module ( LPM ) is intended to preserve your loudspeakers from amplifier switch on ( "thumps" ) or off ( "squawks or squeals" ) transients , to protect them from damage in the event of an amplifier fault, and optionally to prevent any consequential amplifier damage after an initial fault condition. The LPM is intended for use with amplifiers having a directly coupled output ( i.e. no output coupling capacitor ) and split power supply rails ( i.e. power supplies with positive, ground, and negative connections ). Most modern amplifiers are of this type. The LPM can be used with bridged amplifiers but you'll need two per amplifier channel, one connected to each output.
The LPM performs three separate functions. (1) When power is first applied the power amplifier output is not connected to the loudspeaker until a few seconds have elapsed. This eliminates the switch on thump generated by most amplifiers as their operating point stabilizes immediately after switch on. At power off the LPM disconnects the amplifier from the loudspeaker before the amplifier has ceased to operate. This mutes any power down noises that the amplifier may produce. (2) If a dc voltage of greater than 1.2V or less than -1.2V appears on the output of the power amplifier then the loudspeaker is immediately disconnected from the power amplifier to save the bass drive unit from damage.(3) When an amplifier fault exists continued application of power can cause further damage to the power amplifier. The LPM has an open collector dc fault output ( DCF ) which can be used to shut down the amplifier power supply if it has a suitable control input. The White Noise Active Power Supply has a shutdown input which can be connected to the LPM DCF output. Loudspeaker protection is not essential but is a very wise precaution. Ths LPM pcb measures 76mm x 48mm.
Click to expand...

Regarding the highlighted text: is it suitable for the Zappulse?? (sry, noob question I guess, but I'm just a kit builder, not an electronic expert)
 
#136
I think you will be fine as long as there is no signal present to the input of the amp when switch on or off. This is because the ZAPpulse amp does not like to see no load on it's output and you can possibly blow the filter capacitor if no load is connected and the output is trying to play music. This has been fixed in ZAPpulse 2.3.
 
#138
Hey,

There is no problem with the 2.3SE modules. I`ve have 2, and can plug and unplug all with full signall, turn the power on and off, and so on with no problems/noise at all 🙂

As soon I got my cabinet finish I`ll write about the projekt.

Venlig hilsen Jan Jensen
 
#139
richie00boy said:
I think you will be fine as long as there is no signal present to the input of the amp when switch on or off. This is because the ZAPpulse amp does not like to see no load on it's output and you can possibly blow the filter capacitor if no load is connected and the output is trying to play music. This has been fixed in ZAPpulse 2.3.
Click to expand...
That probably is a problem (for the 2.2). Of course if the protection is triggered by high DC voltage there is already a problem with the Zappulse. However the function to surpress poweroff noises will be used every time. It is impossible to guarantee that no input signal is present at that time. Such a thing is bound to happen.

Would it help if the relay would connect to an 8 ohm power resistor (50 watt at least) in stead of no load (don't know if that is possible)?
 
#140
Got mail from LCAudio my module was "burned" and i will get a new one.They told me not to start the amp without speaker cables connected????That is no problem with the 2.3SE i think they should change or modify for free the 2.2 SE modules to work like that.Strange thet they don`t tell with very large text on the module this problem.Every amp i have owned in my whole life i could start without speaker cables connected even amps from early sixties.But ok i get a new one for free and i know the problem,a little strange anyway.
 
Status
Not open for further replies.
Top Bottom