CD-to-Phono Damage
Rick
I recently purchased an integrated amp (Plinius 8150) that has a
built-in phono stage. While hooking everything up, I accidentally
plugged my CD player into the phono inputs and pushed Play. I noticed
my mistake about 5 seconds later and stopped the CD player, changed
inputs, and the CD player came through its proper inputs as normal.
However, I just got around to checking the phono inputs out this
weekend. I connected my turntable setup to the Phono inputs, switched
the selector to Phono, and was greeted with a fairly loud static-like
noise. I tried playing a record, and the music seemed to come through
relatively normally, but the noise is really noticeable.
I have played around with the setup, such as unconnecting ground,
completely unconnecting the phono inputs, etc. Lifting the ground
introduces a loud hum, but it is not related to the noise.
Disconnecting the inputs has no effect on the noise.
So - should this mistake have caused damage to the phono input stage?
Because I never tested the phono inputs before making the mistake, I
don't know if it is likely that it was like this when I got it, or
whether I have fried it myself.
TIA,
Rick
Michael Montanari
don't here the noise, than it's you phono player. I don't think youl kill
the line amps. I'v run non phono stuff into those inputs before...MIKE
"Rick" <burnsr...@hotmail.com> wrote in message
news:1a79864a.0201...@posting.google.com...
Kalman Rubinson
>So - should this mistake have caused damage to the phono input stage?
>Because I never tested the phono inputs before making the mistake, I
>don't know if it is likely that it was like this when I got it, or
>whether I have fried it myself.
It's possible. The phono stage expects signals in the mV range while
line level inputs, like a CD player, are about a volt. Contact
Plinius.
Kal
Jamie Hanrahan
Sure, but it's a volt into about 50 kohms. If the phono stage is really
so touchy that forcing a mere 1 volt and 20 microamps into it will damage
it, the designer (I use the term loosely) should be sent back to
Electronics 101. Especially since it isn't exactly rare for folks to make
this mistake.
--- jeh
Phil Allison
The static noise has NOTHING to do with the incident with the CD player.
You have a bad conection somewhere with the RCA leads, phono cartridge pins
or maybe the plug (if any) under the tone arm base.
Make sure also that the ground part of the RCA plugs are actually tight
enough to connect to the female on the amp.
Regards, Phil
Arny Krueger
"Jamie Hanrahan" <j...@cmkrnl.com> wrote in message
news:2m5a4u05qndf905bd...@4ax.com...
That's the way I feel about it.
Richard Crowley
> >>So - should this mistake have caused damage to the phono input stage?
> >>Because I never tested the phono inputs before making the mistake, I
> >>don't know if it is likely that it was like this when I got it, or
> >>whether I have fried it myself.
Kalman Rubinson <k...@nyu.edu> wrote:
> >It's possible. The phono stage expects signals in the mV range while
> >line level inputs, like a CD player, are about a volt. Contact
> >Plinius.
"Jamie Hanrahan" <j...@cmkrnl.com> wrote
> Sure, but it's a volt into about 50 kohms. If the phono stage is really
> so touchy that forcing a mere 1 volt and 20 microamps into it will damage
> it, the designer (I use the term loosely) should be sent back to
> Electronics 101. Especially since it isn't exactly rare for folks to make
> this mistake.
True, but the 50K (actually 47K) is the load resistor in PARALLEL with the
input. I agree that it isn't likely that the input terminator resistor could
be damaged even by large speaker levels far in excess of nominal line level.
It seems far more likely to me that the input device (transistor, op-amp,
whatever) or subsequent circuitry may have been toasted by the amplified
over-spec input signal. Not unprescedented.
RC