$5500 10 years ago? that's 2 month's salary

這部L-1000T 約7-8年前在中環二手鋪見過, 但他說不是賣的, 相信是店主自已留番玩.

MCM: My L1000-D is still in excellent running order.

transistor tuners can last forever coz there are numerous spare parts......dunno about tube/IC tuners

To metal and all high hand,

What is FM de-emphasis function?

I got a Pionner TX-9800, with the "FM de-emphasis selection" which have 25, 50, 75 selection. Which value should I select?

Also there have a "Touch Sensor", with High or Low selection. What is the function of that switch?

Thank you for your help.

REASON FOR PRE/DE-EMPHASIS IN FM MODULATED TRANSMISSION SYSTEMS
In the transmission of FM modulation there is more noise at the higher audio frequencies than there is at the lower audio frequencies. To compensate for this unbalance and make the noise more uniform over the audio spectrum, the Broadcasting industry developed some standards for Pre-emphasis and matching De-emphasis. In a modulator the audio is boosted with Pre-emphasis prior to modulation. In the receiver, De-emphasis is used after demodulation to recover a flat audio frequency response. This results in a much improved Signal-to-Noise Ratio for any given FM transmission system.

The standard in the USA for FM Radio is 75 microseconds. BE aware that some countries have standardized on 25 or 50 microseconds and International Satellites use what is called the J-17 standard as well as others

manbor mentioned in the previous post that Hong Kong is 50us

akaik low selection is for audiophile (wide IF), high selection is for dx'ers (narrow IF)

wow!

Tunafish:

what is the audible difference when choosing different de-emphasis timing?

very obvious.........but I like switching it to 75 coz it sounds "thicker"

great!! thanks

but switched to 50 became more "airy"!! very interesting

echo, reverb...not as precious as thickness

maybe that's why those US tube tuners sound thick

High Hand metal,

Thank you for your help.

I am just a new hand in tuner. I need the help from high hand like you ah.

By the way, since I cannot set up the stereo function up to now. So I don't find any different between 25, 50 and 75 yet.

When I find a suitable antenna, I will check the sound quality in detail.

Thank you for your help again.

High Hand sm,

Thank you for your help.

highhands:

please help

if a FM tuner has 2 outputs called "multiplex audio" does that mean stereo? does it need a FM multiplex decoder?

thanks

highhands:

when I was turning the tuning knob, the station point (needle) did not silde, I took a closer look, it seems that the string (connecting the needle and the variable capacitor) lost friction with the turning knob, what could I do?

stringing problem, any highhand good in re-stringing?

this is from audioasylum:



You need to examine the large round metal(or plastic) plate the string wraps
around. It connects to the large multi-section rotating RF capacitor shaft,
used to tune the different stations. This is where the strings two ends are
attached, usually one has a spring on it. If the spring is stretched and
still under tension, you need to pull on the string ahead of it to let the
spring remove the slack.

Usually this is not the case though. You need to remove a little bit of
string so the spring is back under tension. I usually do this by removing
the *other* string end connection (without spring) and tie a knot in the
string, very close to the end. If this doesn't do it, tie another knot.
Usually works great. Advanced techniques involve removing the string,
cleaning it, and reversing it so the wear area (where it contacts the small
dia. tuning knob shaft) is moved. So then a fresh part of the string
contacts the knob shaft. If you do this, take good detailed notes
beforehand, as it can get a little tricky on reassembly. All the repair
manuals have the stringing diagrams, though. I have rejuvinated quite a few
dial strings in the last few weeks and it can really make a difference in
the "feel" of the tuner when tuning in a weak station. The tube Sherwoods
seem especially susceptible to wear.