Saya kupi paste dari TubeCad Jurnal ya. lagi males ngetik hihihi.
Also known as the Anode Follower, the Plate Follower is in many ways the
inverse of the Cathode Follower. The Cathode Follower preserves the phase of
the input signal; the Plate Follower, inverts. The Cathode Follower's output
is taken at the cathode; the Plate Follower's output, at the plate. The
Cathode Follower's input impedance is extremely high; the Plate Follower's
input impedance, relatively low, as it is equal the value of resistor R1.
And finally, where the Cathode Follower can only aggressively pull the
output more positively; the Plate Follower, can only aggressively pull the
output more negatively.
Still, the Plate Follower makes a fine buffer and boasts some very
desirable features: a ground potential input, adjustable gain, and low
heater-to-cathode differentials. The need for a coupling capacitor or a
connection to a high voltage input is eliminated in the Plate Follower, as
the grid is, in DC terms, at the ground voltage. Unlike the Cathode
Follower, whose gain always falls short of unity, the Plate Follower can
achieve unity gain output, or if desired, less than unity or more than unity
gain. This is a great help when cascading stages and just a bit more gain is
needed. Because the cathode is not floating at some high voltage, the issue
of maintaining a low heater-to-cathode voltage difference does not arise.
The negatives for this buffer are that its bandwidth is compromised by the
low pass filter created by resistor R1 working into the Miller Effect
capacitance of the triode and the this same resistor defines the input
impedance of the circuit and serves to load down the previous stage.
Increasing the value of R1 unburdens the previous stage, but worsens the
high frequency response. Additionally, the circuit requires three extra
resistors and, potentially, a bypass capacitor for resistor Rk as well.
From: [email protected] [mailto:[EMAIL PROTECTED] On
Behalf Of Yustinus
Sent: Friday, November 21, 2008 8:33 AM
To: [email protected]
Subject: [ELPOP-Audio] beda anode follower & cathode follower
dear sahabat milisers,
good morning.
sebelum pekerjaan mulai menimpuki diriku, kulempar dulu pertanyaanku ke
milis, barangkali ada yang bisa dan berkenan menjelaskan sedikit soal anode
follower dan cathode follower di rangkaian tube preamp. Kenapa bisa ada dua
jenis ini, dan apa keunggulan/kerugian dari masing2 topologi ini?
sekian aja dulu.
selamat bekerja kembali.
salam,
yus
