[NJARC] Hi, Guys. What am I looking at here?

Sun Mar 15 10:40:07 EDT 2009

Dave,
Apparently you didn't listen to John presentation at Fridays meeting...

Sal

-----Original Message-----
From: John Ruccolo <jr6v6gt at yahoo.com>
To: njarc at mailman.qth.net; Dave Sica <davesica at juno.com>
Sent: Sun, 15 Mar 2009 10:27 am
Subject: Re: [NJARC] Hi, Guys. What am I looking at here?

Just remember
Reply = Poster
Reply All = Everyone

_________________________________________________________

Hi Dave,

I have several suggestions:

1) Tell the young lady to forget it and buy an Ipod! (like everyone 
else her
age)
Just kidding....

2) Does the behavior change when you reverse the AC line plug? That's 
an old
trick with anything that's AC/DC powered (or "transformerless").

3) It may be that the volume control just needs more cleaning. Give it 
a spritz
of cleaner (like the stuff that John T. had at the meeting that I 
forgot to buy
a can or two of) and work it back and forth.

4) Is there a preamp stage (like a 12AV6 or something) before the 50C5?
I might suspect that area, or maybe:

5) Possibly the cartridge wiring? But I'm sure Darrin chacked all 
that....

6) Try swapping out each tube one-at-a-time -- I wonder if you could 
have
heater/cathode leakage somewhere? If there was a H/K *short*, however, 
I would
expect a LOT more HUMMM.

Just throwing some ideas out. Trying to fix things via email can be 
tough. ;-)
=0
D
As a vinyl collector for over 30 years, are you telling me now I have 
to compete
with people MUCH LESS than half my age? Sigh....no wonder I'm not 
finding
anything at the local second-hand store.

Later,

JR

--- On Sun, 3/15/09, Dave Sica <davesica at juno.com> wrote:

> From: Dave Sica <davesica at juno.com>
> Subject: [NJARC] Hi, Guys. What am I looking at here?
> To: njarc at mailman.qth.net
> Date: Sunday, March 15, 2009, 12:53 AM
> Just remember
> Reply = Poster
> Reply All = Everyone
>
> _________________________________________________________
> Virtual repair clinic anyone?
>
> You may recall my post a few weeks ago about "Looking for a
> phonograph
> for a young person" or something to that effect. I spent
> today working on
> the record player I picked up from Darrin Hoffman at the
> club meeting
> yesterday. He had done a wonderful electrical and
> mechanical
> refurbishment and the thing plays like the day it was new.
> The girl we're
> giving it to is coming over tomorrow to pick it up (she
> spent today at
> the Princeton Record Exchange stocking up!) and I spent
> today sprucing up
> the cosmetics.. (I hadn't ever "restored" a set with that
> leatherette/painted paper covering and it was a learning
> experience!) It
> now looks like 999,000 bucks. (I would have said it looked
> like a
> million, but to be honest, there are at least a million
> paint speckles20I
> didn't deal with. The future owner probably has more
> patience than me
> anyway.)
>
> Anyway, here's my predicament. After running this thing off
> and on all
> day and marveling at how nice it sounds, late this evening
> it apparently
> decided to get noisy.  There was always a bit of hum,
> about what you'd
> expect from the 35W4-powered 50C5 amp.  But now it's
> got more hum, I'd
> say a fair amount of hum. Maybe still acceptable. Possibly
> even still the
> same as it was this morning except that now I'm paying
> attention. What
> caught my attention was a new noise, a buzz. Sounds a lot
> like
> interference from a fluorescent light, but it only appeared
> at night and
> I've got most of the lights in the house turned off. Even
> stranger, the
> buzz is most noticeable when the volume control is down,
> GOES AWAY (!?!)
> when you advance the volume control slightly and then
> RETURNS and
> strengthens (along with the hum being amplified) as you
> advance the
> volume control further. I don't recall ever hearing about
> that type of
> symptom before.
>
> I'm the farthest thing from a competent electronics
> engineer, but I can't
> imagine this high frequencly damped wave buzz is coming
> from inside the
> record player. But then again, I can't figure out where it
> might be
> coming from. Or why it behaves the way it does when I
> fiddle with=2
0the
> volume control And why only now after it's been running for
> a while? 
>
> I've posted photos of the noise as seen on my scope at
> www.njarc.org/phono_noise. Can anybody figure out what's
> going on here?
>
> Thanks,
> --Dave Sica
> ____________________________________________________________
> Digital Photography - Click Now.
> 
http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTDvmSDoFcYunilkg9b54YqPiYZpu5ziKnvpSHHWfEtDt62lQHWdKg/
> ______________________________________________________________
> NJARC mailing list
> Home: http://mailman.qth.net/mailman/listinfo/njarc
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:NJARC at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

______________________________________________________________
NJARC mailing list
Home: http://mailman.qth.net/mailman/listinfo/njarc
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:NJARC at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html