#1 Surprised by solid improvement in my SE DHT amp
Posted: Thu Nov 14, 2019 2:28 pm
When I got into amp building a few years ago I did a lot of reading before I got around to building anything. I took away from that reading an aversion to the coupling cap which has until now strongly influenced my amps.
Last weekend I changed my DHT SE amp to cap couple V2 (71A) to V3 (300B). The interstage transformers were removed (Tribute Finemet), I subbed a LL1667 choke as anode load for V2, grid leak resistor for V3 and a cap between the two. The grid leak were 88K 2W Allen Bradley while the caps were inexpensive 1uF (Cornell).
Against all expectations the sound is significantly better. More solid and musical throughout the range, much better sound stage ... The word Geoff and I kept coming back to was "immense".
Just goes to show how important it is to challenge your own assumptions, which for me at least is a large part of the pleasure of DIY. I think the improvement will be coming from the choke, which gives 200H compared to the 60H of the Tribute primary. Looking forward to doing the same with V1 (26) to V2.
I can barely wait to bring this to Owston, I need some independent feedback. Anyone near South Yorkshire fancy a listen? I'll provide food and beer.
Last weekend I changed my DHT SE amp to cap couple V2 (71A) to V3 (300B). The interstage transformers were removed (Tribute Finemet), I subbed a LL1667 choke as anode load for V2, grid leak resistor for V3 and a cap between the two. The grid leak were 88K 2W Allen Bradley while the caps were inexpensive 1uF (Cornell).
Against all expectations the sound is significantly better. More solid and musical throughout the range, much better sound stage ... The word Geoff and I kept coming back to was "immense".
Just goes to show how important it is to challenge your own assumptions, which for me at least is a large part of the pleasure of DIY. I think the improvement will be coming from the choke, which gives 200H compared to the 60H of the Tribute primary. Looking forward to doing the same with V1 (26) to V2.
I can barely wait to bring this to Owston, I need some independent feedback. Anyone near South Yorkshire fancy a listen? I'll provide food and beer.