AndrewR
pfm Member
Well that's what I'm calling it
My latest project. A unique valve amplifier design all of my own - with a nod towards the interstage push-pull 6B4G design on the Meta-Gizmo site. But it's rather more than just that...
It's two stages of an ECC99 directly coupled together, the last of which has an interstage transformer on the anode that splits the signal in two for the pair of 6B4G grids.
What does that mean? Well it does not use any capacitors in the signal path for starters. Also the interstage transformer neatly divides the signal to the class A push-pull stage.
The power supply is also most interesting, and designed in a way that increases the agility of amplifiers handling of the music over the spectrum. Here I'm calling it Hyperdrive technology - something that would give marketing guys wet dreams. Basically it uses descending values of supply caps, which works a treat! Sadly I think the use of motor run capacitors (from Ducati!) was a bit of a wrong-turn, and are probably difficult to take out.
However I am loving the BHC capacitors - IMHO a far better and more practical choice than Black Gates (from previous project). Works well with the tantalum resistors too The iron is from Sowter.
The end result is superb! Very open and rythmic with plenty of bottom end welly. It has the capability of grabbing attention (in a positive way) even with 8W running into 85dB/W/m Katans.
Andrew Randle
My latest project. A unique valve amplifier design all of my own - with a nod towards the interstage push-pull 6B4G design on the Meta-Gizmo site. But it's rather more than just that...
It's two stages of an ECC99 directly coupled together, the last of which has an interstage transformer on the anode that splits the signal in two for the pair of 6B4G grids.
What does that mean? Well it does not use any capacitors in the signal path for starters. Also the interstage transformer neatly divides the signal to the class A push-pull stage.
The power supply is also most interesting, and designed in a way that increases the agility of amplifiers handling of the music over the spectrum. Here I'm calling it Hyperdrive technology - something that would give marketing guys wet dreams. Basically it uses descending values of supply caps, which works a treat! Sadly I think the use of motor run capacitors (from Ducati!) was a bit of a wrong-turn, and are probably difficult to take out.
However I am loving the BHC capacitors - IMHO a far better and more practical choice than Black Gates (from previous project). Works well with the tantalum resistors too The iron is from Sowter.
The end result is superb! Very open and rythmic with plenty of bottom end welly. It has the capability of grabbing attention (in a positive way) even with 8W running into 85dB/W/m Katans.
Andrew Randle