looking at a Zener diode can drive some circuits into oscillation
Hello
I`ve also build an Aleph P1.7 a time ago.
It had hum with PC worser than with CD Player.
Seems that this are oscillations.
Put in a 221Ohm resistor at the input like in BOSOZ R18/19
solved the problem.
In the BOSOZ article is this:
Also note that if you do not use Zener diodes for input protection, you
will not need R18 and R19, and they may be replaced by wire. Their
function is to ensure stability for the circuit driving the input, since
directly looking at a Zener diode can drive some circuits into oscillation.This is also why we use R7 and R8, and R9 and R10.
The input at BOSOZ and ALPEH P looks similar
But Aleph P dosn`t have 221Ohm input resistors but the problem is the same-> circut looks at input directly at Zener and maybe drive crazy???
Is it possible that Pass use this resistors but they are not in schematics?
or is that problem solved at another way?
(Used friendly Zeners that dont annoy other circuts
)
Maybe Pass himself can give a hint he must know it best
(For fun i tested my Bosoz without R18/19 an problem is the same i had hum/oscillations with R18/19 hum was gone)
Hello
I`ve also build an Aleph P1.7 a time ago.
It had hum with PC worser than with CD Player.
Seems that this are oscillations.
Put in a 221Ohm resistor at the input like in BOSOZ R18/19
solved the problem.
In the BOSOZ article is this:
Also note that if you do not use Zener diodes for input protection, you
will not need R18 and R19, and they may be replaced by wire. Their
function is to ensure stability for the circuit driving the input, since
directly looking at a Zener diode can drive some circuits into oscillation.
The input at BOSOZ and ALPEH P looks similar
But Aleph P dosn`t have 221Ohm input resistors but the problem is the same-> circut looks at input directly at Zener and maybe drive crazy???
Is it possible that Pass use this resistors but they are not in schematics?
or is that problem solved at another way?
(Used friendly Zeners that dont annoy other circuts
)Maybe Pass himself can give a hint
he must know it best(For fun i tested my Bosoz without R18/19 an problem is the same i had hum/oscillations with R18/19 hum was gone)
Hello, I want to ask one question. Two years ago I started making Aleph P1.7 with some changes in the configuration. I put the relay shunt type attenuator at the input and output goes directly from output capacitors. Did I made a worse solution knowing that the preamp sensitive to the impedance next level if it is not loaded symmetrically?
I didnt found a common theme for P1.7 so I asked the question here.
I didnt found a common theme for P1.7 so I asked the question here.
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