PDA

View Full Version : Tube rolling a Croft 25R - unexpected result



worrasf
20-08-2010, 22:31
I am avery happy owner of a Croft 25R that Glenn kindly built incorporating my own (original) TESLA E83CC's gold pins in line stage and Telefunken ECC801s (1959 Ulm) in the phono stage. I left the 2 ecc83's supplied by Glenn in the regulator circuit and as I say have been very happy with it feed in my Croft 4s. being somewhat bored this evening I decided to swap out these latter valves (turned out to be nasty new production JJ Tesla ecc803s') for a matched pair of 1960's Brimar ecc83's - just for the heck of it and not expecting much as this was not part of the line/phono circuit. OMG! what an amazing difference :stalks: The whole soundstage opened up and everything just seemed to come into focus. Bass was deeper, way deeper and tuneful, highs shimmer and sparkle and there is real 3D soundstage :)- but why? :scratch: It's just the regulator circuit.

Not a tweak as such but most interesting.

Just for the record after much tube rolling in the 4s it now I have settled on the following:
Telefunken EL519's (pair)
GE 6550A's (quad)
RCA black plate 12BHA's (pair)
JAN GE 5751's (2 pair)


Steve