Turn on/off thump with "others" D amps...how it is managed? - diyAudio
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Old 15th March 2005, 04:33 PM   #1
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Default Turn on/off thump with "others" D amps...how it is managed?

Hi, i am wondering how the turn on/off thump is managed on other modules like UCD or ICE modules. Do they have thump might be the initial question.
If not, how the design permit a direct connection from the LC filter to the speaker?

As an example, my IR redisign uses a mute relay because upon turn on, there is a dead time forced to charge the bootstrap cap. I know UCD or ICE module differ a lot, i am just wondering because it looks like there is no relay at all.


thanks.
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Old 15th March 2005, 05:04 PM   #2
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Pat,

Indeed in the UcD modules we do not have any relay. We switch ON/OFF the currentsource of the two PNP differential input transistors. Please check the schematic from the UcD what is yet public known.

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Jan-Peter
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Old 15th March 2005, 05:08 PM   #3
Pierre is offline Pierre  France
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Is there a link for that schematics? Or you refer only to the UcD patent?

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Old 15th March 2005, 05:11 PM   #4
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Pierre,

Please check this http://www.diyaudio.com/forums/attac...amp=1110300548

Jan-Peter
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Old 15th March 2005, 05:15 PM   #5
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Ok, so there is absolute no turn on/off thump?

How is the current source turned on/off, with a constant simple delay, microprocessor controled, manualy??
Is it totaly self contained?

Is there some active protection on these UCD modules?


thanks.
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Old 15th March 2005, 05:23 PM   #6
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Indeed there is only silence when you switch the UcD amp on.....

(however to be honest, when you put your ear in front of the loudspeaker you will hear a very small "thick")

We wait for one second so that the bootstrap capacitor can be fully charged, and the we switch the current source on.

We use this ON/OFF part to switch OFF the UcD when there is an overvoltage. In the first version of the UcD180/400 we used a piek current protection hereby was also this mute section used.

However we use now a constant current limiter in the UcD modules, this works in a different way and is confidential.......

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Jan-Peter
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Old 15th March 2005, 05:31 PM   #7
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Thanks.
Sorry to ask, how can the bootstrap cap be charged if Vout=0?
In my understanding, it have to be -vcc as long as it needs to be charged?
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Old 15th March 2005, 05:37 PM   #8
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Sorry, confidential.......

But it works

Jan-Peter
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Old 15th March 2005, 05:41 PM   #9
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Ok, i think i get it anyway....while i was playing with the PB12 module, i was "forcing" the bootstrap cap to be charged...it is grounded by the speaker resistance then, so...

thanks very much.
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Old 16th March 2005, 02:24 AM   #10
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Quote:
Originally posted by pat allen
Ok, so there is absolute no turn on/off thump?

How is the current source turned on/off, with a constant simple delay, microprocessor controled, manualy??
Is it totaly self contained?

Is there some active protection on these UCD modules?


thanks.

As Jan-Peter said, only a very small thump when you put your ear close to the speakers. I have these modules directly connected to my tweeter, midranges and woofers (active system). Very well on/off switching behavior. No relay needed in between amps and speakers.

Gertjan
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