nrgrecording
Well-known member
Hey guys.
Today we did it. Yes, we wound our first homebrewed trannie. We used an old Siemens Telephone transformer for bobbin and core.
We decided to go with an 2:1 ratio with around 5 Henry primary inductance to use with jakobs SRPP tube output stage.
So we had to find out the AL value of the core. For this reason
we wound 11 turns of wire around the existing windings. The
resulting inductance for this 11 windings was 600µH.
AL= L/N² = (600µH/11²)
AL= 4958,7 nH
The required amount of turns for a 5 Henry input primary inductance is then calculated by:
N = 1004 turns
We decided to go with 2 primary sections, 500 turns each both
enclosing the secondary section (also 500 turns)
Test winding for calculating AL value.
No hacksaw needed at all.. only two screws to remove. :green:
The AUMANN atomic coil winder.
Ready to go!
Done.
Measurements:
low frequency response is -3dB@4,7Hz with 50ohm source impedance,-3dB@22Hz with 600ohm source impendance
hi frequency response is flat up to 300 KHz, peaks around 5dB@436KHz
measurements with 10kOhm load
Not bad so far :green:
Damn, we have no SRPP stage around at the moment to do some listening tests. We will post our impressions later these days.
Steffen and Frank.
Today we did it. Yes, we wound our first homebrewed trannie. We used an old Siemens Telephone transformer for bobbin and core.
We decided to go with an 2:1 ratio with around 5 Henry primary inductance to use with jakobs SRPP tube output stage.
So we had to find out the AL value of the core. For this reason
we wound 11 turns of wire around the existing windings. The
resulting inductance for this 11 windings was 600µH.
AL= L/N² = (600µH/11²)
AL= 4958,7 nH
The required amount of turns for a 5 Henry input primary inductance is then calculated by:
N = 1004 turns
We decided to go with 2 primary sections, 500 turns each both
enclosing the secondary section (also 500 turns)
Test winding for calculating AL value.
No hacksaw needed at all.. only two screws to remove. :green:
The AUMANN atomic coil winder.
Ready to go!
Done.
Measurements:
low frequency response is -3dB@4,7Hz with 50ohm source impedance,-3dB@22Hz with 600ohm source impendance
hi frequency response is flat up to 300 KHz, peaks around 5dB@436KHz
measurements with 10kOhm load
Not bad so far :green:
Damn, we have no SRPP stage around at the moment to do some listening tests. We will post our impressions later these days.
Steffen and Frank.