Roland Cube 60 has 50 mV of DC offset.... What is considered too much?

[1ampman]

I have 50 mV with or without the speaker connected using an 8 ohm speaker. Is this acceptable? The original owner replaced the stock 8 ohm speaker with a 4 ohm. Is 50 mV going to heat the voice coil??

[Jazz P Bass]

I. Is 50 mV going to heat the voice coil??

Not much.

But the 4 ohm speaker is going to pull roughly twice the power of an 8 ohm.
This in itself is cause for concern. More so than the feeble dc offset.

"IF" you play the amp full bore, flat out.

[1ampman]

Thx Jazz Bass.... I thought 50mv was acceptable for guitar amps. I'm installing the correct speaker. Well that's good news!

[Enzo]

Figure it out. 50mv through 8 ohms is 6ma of current. And that is 0.3 milliwatts.

You would have three tenths of one milliwatt of voice coil heating. A milliwatt being 1/1000th of a watt.

Rubbing your hands together and blowing on them would cause more heat.

[1ampman]

So what would be considered too much dcv on an output for guitar amps. ??? When you consider it repair time.....

[Enzo]

When it tells my amplifier-zen all-amp-oneness that it is a sign of trouble.

If I see a half a volt offset even under load, I am curious to know why it is there. SOlid state amps are so heavily fed back on themselves there really ought to be no offset. But a few millivolts are probably inevitable now and then. But that half a volt? If the amp sounds OK and shows no signs of trouble, I am not likely to know it is there in the first place. And certainly if it hits a volt or volts, then there is something wrong. Even a half volt won;t hurt the speaker, but to me it is an omen.