Pioneer TX-6800
Stereo FM/AM High
Fidelity Tuner
Improved
Performance-to-Cost Ratio Gives You Lower Tuning Error for Lower Price in This
new Pioneer Model.
Clean Audio Output:
Flat 20 Hz to 15 kHz +0,5 dB, -1,0 dB.
Extra-Long Tuning
Dial with LEDs
Straight-Rule Twin
Tuning Meters
Pioneer-Exclusive
ICs with Automatic Pilot Canceller.
A Very Clean Audio
Output
When designing the
TX-6800 stereo FM/AM tuner, Pioneer put sound quality first on the list of
objectives. We made sure the audio output is as clean as possible – free of
distortion and noise. Our goal was achieved the frequency response reaches from
the almost inaudible low of 20 Hz to the upper reaches of your hearing at
15,000 Hz. Plus 0,5 dB, minus 1,0 dB or better. Special ICs developed
exclusively for Pioneer are used throughout, wherever it was possible to
eliminate bulky discrete parts without harming performance quality. In fact,
these special ICs anable us to reduce cost and improve performance quality, not
only in this model but in our most expensive tuners and receivers as well.
FM
Front-End Section – FET Assures
High Sensitivity.
Radio-frequency
signas entering the tuner via the antenna are passed throughthe front end. It
is here that the broadcast signal to which you have tuned on the 3-gang
variable capacitor (via the tuning system) is sorted out fromall the others.
Pioneer has employeed an FET in this section to see that the signal selected is
stripped of noise and distortion, this permits us to step up the sensitivity of
the sectionto achieve more “reach”. The usable sensitivity in FM mono, for
instance, is a respectable 10,8 dBf (1,9 uV). At the same time, the spurious
response ratio is improved to 70 dB.
The
FM IF Section – The First Pioneer
Exclusive IC
A one-stage buffer
amplifier and the Pioneer developed IC No. PA-3001A team up here to amplify the
IF or Intermediate Frequency. The special advantage of the IC here is low-noise
performance; the signal-to-noise ratio obtained is an excellent 80 dB (mono) or
74 dB (stereo).
Phase-Linear Ceramic
Filters
Also, in the IF
section, a pair of phase linear ceramic filters are put on line amomg the IC
and IF amplifier. Without them, the high frequencies in the final audio output
would be far less clean and clear. A further advantage is that the ceramic
filters offer excellent interference rejection characteristics.
Our New Quadrature
Discriminator.
We
call this new circuit a “One-Pack
Phase Shifter” because it packs
the conventional micro inductor and the discriminator with new bobbin material
in one shielded case. The benefits include the following:
Positive
protectionagainst distortion
Improvement of input
vs. distortion characteristics
reduction of noise
for a better S/N
Increased stability
against temperature/humidity changes.
FM Stereo Section
in the multiplex
section of the TX-6800, we use a microelectronic integarted circuit (the
Pioneer exclusive IC No. PA-1001A) which contains a throughly reliable PLL or
Phase-Locked Loop circuit. Unlike the old-fashioned “demodulators” which were
subject towide errors in performance depending on outside influences like
temperature and humidity, our PLL is entirely error free. Always-stable, very
wide stereo separation in FM is the result.
A Built-In Pilot
Canceller Circuit.
The
multiplex “switching signal” mentioned erlier is a 19 kHz signal which is
broadcast along with the two stereo channels. Its only function is to “trigger”
the multiplex section to separate the left and right channels; once that
function is done, it must be removed entirely lest it interferes with the audio
signals processed in the following sections of the tuner. Old-fashioned tuners
used a low-pass filter for removing that “switching signal”, now called the
“Pilot”. But such filters tend to “chop off” desired audio frequencies, too. We
ve avoided this with the use of a built-in Automatic Pilot Signal Canceller,
quite different in concept and operation from the “active filter” type another
advantage is an improvement of carrier leakage by 20 dB over conventional
types. Also, it should be pointed out that this Automatic Pilot Signal
Canceller is incorporated within the PA1001A itself and thus enjoys the same
high reliability and protection from outside influences.
AM Fidelity Is
Improved
Better Frequency
Response - A high-density IC (HA-1138) is used in the AM section of the Pioneer
TX-6800 to contribute greatly to improved frequency response, permitting a
flatter, more faithful reproduction over a wider range.
AM Distortion
Reduced - The IC likewise serves to reduce the sound- spoiling distortion in AM
reproduction especially in the very low frequencies around 100 Hz.
Variable Capacitor -
Our use of a 2-gang system in the variable capacitor for AM permits liner
tuning and higherlinearity. AM sound you might once have thought to be “lo-fi”
is received and reproduced with more pleasant results.
Still More
Advantages
Extra Long Tuning
Dial - It's unusual to find a tuner in this price range with such a good tuning
“feel”. The major contribution to more convenient and accurate station
selection in the Tx-6800 is its long (300 mm) tuning dial for AM/FM. The FM
band, by the way, is “frequency linear” - divided into equidistant sections.
Srtaight-Rule
Meters – The Twin Tuning Meters on
this model reflect Pioneer's policy of providing maximum readability and
impeccable accuracy. The staraight-rule scales of the Signal meter (for AM/FM
signal strength) and the Tuning meter (for FM center-of-channel) are calibrated
for easy reading and finished in Pioneer blue for eye appeal.
FM Muting Switch -
This front-panel feature permits you to cut out inter-station tuning noise
while tuning FM stations. in the Off/Mono position the muting circuit is taken
off line to permit tuning of distant/weak stations; reception mode is then
switched to monophonic.
LED Indicators -
These long-life Light Emitting Diodes let you know tuner status for AM, FM and
Stereo FM at a glance.
Function Switch -
Select FM or Am ; a special back-up circuit prevents pop noise as the switch is
used.
Specifications
FM Section
Usable
Sensitivity: 10,8 dBf (1,9 µV) [Mono]
50 dB Quieting
Sensitivity:
Mono : 15 dBf (3,1 µV) / Stereo
: 38 dBf (44 µV)
Signal-to-Noise
Ratio:
Mono : 80 dB / Stereo : 74 dB
Distortion:
At
100 Hz : 0,1% (mono) / 0,2% (stereo)
At
1 kHz : 0,1% (mono) / 0,2% (stereo)
At
6 kHz : 0,15% (mono) / 0,25% (stereo)
Frequency
Response: 20 – 15,000 Hz +0,5 dB, -1,0 dB
Capture
Ratio: 1,0 dB
Alternate
Channel Selectivity: 60 dB
Spurious
Response Ratio: 70 dB
Image
Response Ratio: 60 dB
IF
Response Ratio: 80 dB
AM
Suppression Ratio: 55 dB
Muting
Threshold: 17,2 dBf (4,0 µV)
Stereo
Separation: 40 dB (1 kHz) / 35 dB (30 – 15,000 Hz)
Subcarrier
Ratio: 50 dB
SCA
Rejection Ratio: 50 dB
Antenna
Input: 300 Ω balanced, 75 ohm unbalanced
AM Section
Sensitivity:
300 µV/m (IHF, ferrite antenna) / 15 µV (IHF, external antenna)
Selectivity:
35 dB
Signal-to-Noise
Ratio: 50 dB
Image
Response Ratio: 40 dB
IF
Response Ratio: 70 dB
Antenna:
Buil-in ferrite loopstic antenna
Semiconductors: 1 FET; 3 ICs; 8
Transistors; 15 Diodes
Power Requirement: 120 -240 V, 50/60
Hz
Power
Consumption: 14 watts
Dimensions
(W x H x D): 451 x 151 x 284 mm (17-3/4” x 5-15/16” x 11-3/16”)
Weight:
5,3 kg (11 lb 11 oz) net
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