hello everyone,
anyone out there built a NDFL amp from E. Cherry's NDFL design/article which appeared in an edition of ETI UK back in the early 80s?
it seems that the Cherry received a patent for his NDFL concept which he subsequently sold to Pioneer Japan.
regards,
kenlow
anyone out there built a NDFL amp from E. Cherry's NDFL design/article which appeared in an edition of ETI UK back in the early 80s?
it seems that the Cherry received a patent for his NDFL concept which he subsequently sold to Pioneer Japan.
regards,
kenlow
I built a 60watt version as it appeared in the Canadian edition of "Electronics Today International" back in the 70's or early 80's.
It used the same output transistors and power supply as a SWTPC Tiger Amp that I had. So I rebuilt the Tiger into an NDFL. There was a major improvment in quality.
I still have the amp and sometimes still use it when I need dual 60 watts. I have both the construction articla and the accompanying theory article.
The amp also had compesation for the feedback cap that kills the DC gain. It can pass a low frequecy square wave intact. Cherry mentions that this feature can be used on any amp but I have never seen any one else use it.
It used the same output transistors and power supply as a SWTPC Tiger Amp that I had. So I rebuilt the Tiger into an NDFL. There was a major improvment in quality.
I still have the amp and sometimes still use it when I need dual 60 watts. I have both the construction articla and the accompanying theory article.
The amp also had compesation for the feedback cap that kills the DC gain. It can pass a low frequecy square wave intact. Cherry mentions that this feature can be used on any amp but I have never seen any one else use it.
I built a pair of these back in the 80s, which served me well for many years. They were 60W modules which featured 2 nested differentiating feedback loops designed by Professor Cherry. The article appeared in the the Australian version of ETI as well....if I can find it I will post the schematic for interest.
From memory, they were pretty good at the time (I still have them but haven't pulled them out for a long time)
From memory, they were pretty good at the time (I still have them but haven't pulled them out for a long time)
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