I have just hacked a Roberts R404 radio (1965-68)  And it seems lacking in power. My previous hack , a Roberts R606-MB is a total power house running from 6 c size batts. The 404 has 2 pp9 batts ( 18v) and is much quieter! It does use a 25 ohm speaker tho and the components are an older vintage. I came across the 404 without the radio part working.

Any one notice big differences in power output? The 606 is maybe 1970ish so different parts.

I have just spotted a Grundig RR640 professional tape/radio in a charity shop which could be worth looking at . its volume pot is a side on turning wheel ( not a slider!). Any one come across these?

Any help , comments appreciated.

Andysound