DC on outputs

[farflungstar]

Quick question. When measuring for DC on amp outputs is it DC milliamps or DC millivolts to check for?

I'm reading 156ma / 0.01mv.

Hmmm

[Blackdog]

It is DC mV that you measure. Measuring mA will cause you to short the outputs of your amp. DON'T do this.

[farflungstar]

It is DC mV that you measure. Measuring mA will cause you to short the outputs of your amp. DON'T do this.So, I'm measuring DCmV... which shows 00.1... with multimeter set at 200. Is this okay or should I worry - obviously this readout changes depending on the setting - how can I be sure this isn't 1volt of DC - which is a lot.

[CageyH]

If it was 1V, the decimal point would be in a different place.

[farflungstar]

Here's the reading on one channel, the other is the - on V.
same...https://uploads.tapatalk-cdn.com/20180304/2f162f4e6a39c8bddd231006487583af.jpg


On 200m it's.....

https://uploads.tapatalk-cdn.com/20180304/ea4be7a2dcdc896084b82416dedb2b92.jpg

[CageyH]

Knock it down to the 20v range for better accuracy, and then down to the 2000mV range. You will soon see if it is 1v.

[farflungstar]

Ok will put each setting...

https://uploads.tapatalk-cdn.com/20180304/6c523c1d116ef102c07ad786e6406472.jpghttps://uploads.tapatalk-cdn.com/20180304/fdb16ec06a320b0b806b40f60388fbe7.jpg
https://uploads.tapatalk-cdn.com/20180304/3b0f2499123190161e0905c153809376.jpg

[Firebottle]

Yes you have 180 mV there, or 0.18 Volts.
I would consider that a bit high, prefer to see less than 50mV. What amp is it?

[farflungstar]

Yes you have 180 mV there, or 0.18 Volts.
I would consider that a bit high, prefer to see less than 50mV. What amp is it?The Hiraga, as the ref 75 is still in for service and they're waiting for parts from ARC I thought I'd fire it back up - no music is bad. But I don't want to switch on if it might damage the Tannoys.

[Firebottle]

Are the readings with the speakers connected or without?

I'm probably being a bit cautious here, even with 0.18V on the speakers the actual power dissipated in the speakers is only 4 milliwatts, which is of no concern at all.

[farflungstar]

Are the readings with the speakers connected or without?

I'm probably being a bit cautious here, even with 0.18V on the speakers the actual power dissipated in the speakers is only 4 milliwatts, which is of no concern at all.Without speakers.

This was the subject of a thread a long time ago and my techie was supposed to collect and sort the Hiraga but he's been overloaded. I'm going a bit crazy without music while the 75 is being fixed and would love to hook it up and play some tunes.

[StanleyB]

Nothing to worry about as far as the speakers are concerned. Some amps can have as much as 1VDC on the speaker outputs before their speaker protection relays kick in.
The manufacturer's service manual would normally specify what the amp's maximum voltage offset should be. Amps with discrete output stages tend to have a preset to adjust the DC offset to as close to 0 as possible. But that value should only be read after the amp has warmed up under no signal condition for 5 to 10 minutes at least. If you are reading the output at switch-on and from cold, then the reading is not accurate as far as the procedure of measuring the voltage is concerned.

[farflungstar]

Nothing to worry about as far as the speakers are concerned. Some amps can have as much as 1VDC on the speaker outputs before their speaker protection relays kick in.
The manufacturer's service manual would normally specify what the amp's maximum voltage offset should be. Amps with discrete output stages tend to have a preset to adjust the DC offset to as close to 0 as possible. But that value should only be read after the amp has warmed up under no signal condition for 5 to 10 minutes at least. If you are reading the output at switch-on and from cold, then the reading is not accurate as far as the procedure of measuring the voltage is concerned.No I've given it 15 mins warm up.