UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Mullard 5-10 amplifier

ajgriff · 18th Jun 2019, 4:35 pm

Just been studying the oscilloscope noise image and wondering about the 80mV figure. The peak to peak value of most of the noise signal seems to be about 80mV. However, the variable sensitivity control appears to be turned to maximum ie, at least 2.5 times the set value. Presumably the x5 magnifier is not activated (knob pulled out) and a x1 probe is being used. Also I'm not quite sure how the RMS value of the noise signal can be evaluated and compared with GJ's 1.6mV calculation. Just thinking aloud really.

I'd still be interested to know whether or not the hiss is audible at anything like normal volume settings and listening distance. I accept that this may be of no interest to anyone else.

Alan

18th Jun 2019, 4:35 pm	#74
ajgriff Nonode Join Date: May 2004 Location: Halifax, West Yorkshire, UK. Posts: 2,587	Re: Mullard 5-10 amplifier Just been studying the oscilloscope noise image and wondering about the 80mV figure. The peak to peak value of most of the noise signal seems to be about 80mV. However, the variable sensitivity control appears to be turned to maximum ie, at least 2.5 times the set value. Presumably the x5 magnifier is not activated (knob pulled out) and a x1 probe is being used. Also I'm not quite sure how the RMS value of the noise signal can be evaluated and compared with GJ's 1.6mV calculation. Just thinking aloud really. I'd still be interested to know whether or not the hiss is audible at anything like normal volume settings and listening distance. I accept that this may be of no interest to anyone else. Alan