UCD 180 boxed

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JP,
Made an UCD180 boxed version but when I switched on the amp. it will give -18V on the output.
On my 400 boxed version I have the ON wire connected to ground. It switches on OK. But when I do this with the 180 it wont switch on. I have to ground it later than on switch on.
Is there any cap. I can take off at the logic gate to have it immediately switched on(when connected to ground) without an additional delay circuit?
thx, Bert
 
Bgt said:
JP,

Made an UCD180 boxed version but when I switched on the amp. it will give -18V on the output.
On my 400 boxed version I have the ON wire connected to ground. It switches on OK. But when I do this with the 180 it wont switch on. I have to ground it later than on switch on.

Seems to be a problem related to some UcD180 v2. I've the same problem here with my UcD180 v2. The v1 I previously used do not have this problem.

It's an UcD's initialization problem (wrong startup process). This appends only when no speaker is connected to the output. The -18V (to -22V) no longer exist when a speaker is connected.

Add a delay of 3 seconds before connecting the MUTE to ground with a small temporized circuit. With this, you'll be sure to have a good startup in any case.
 
Bgt said:
Problem is I use an output relay, DC offset sensing, so when the output does not connect because of sensing a -18V it will never close. A bit of a nuissance this "ON"circuit.

I had the same problem on my project. Just add a transistor or an opto-coupler to your DC protection circuit to connect MUTE to ground, and switch ON the MUTE at the end of the start cycle.

The problem is not the MUTE (this is good to have a MUTE) but that the current implementation seems a little buggy.

Please post your DC circuit diagram here. I'll show you where to add the MUTE circuit.
 
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