Akai GXC-310D cassette deck

Double Capstan Drive Cassette Stereo Tape Deck

Professional Wow&Flutter characteristics with closed loop double capstan drive system

 

The employment of the refined tape drive system of this model is usually limited to a few professional type open reel models. However, Akai decided to include this feature in a discriminating number of our cassette models for matchless cassette performance when combined with the other quality mechanisms incorporated in these models.

With this system, the recording/playback head is positioned in the center between two capstan and pinch rollers. This not only results in better head-to-tape contact, but also provides constant tape tension and the section of the tape between capstans is kept free of vibrating interference which may occur outside of the closed area during tape travel.

Functioning integrally with this system is an anti-vibration hysteresis synchronous motor for reduced wow and flutter, modulation interference, and tape speed variation as well as two unusually stout flywheels and flat belts for capstan drive. (When compared with the usual flywheel and V belt system, wow and flutter is small, but rotating energy is increased). Further, the revolutions detector for automatic stop is an electro-magnetic system control lead switch so that the load applied to the reel table is small for even better wow and flutter characteristics.

Thus, these features result in incomparable tape travel stability and constant tape tension and speed with an amazing wow and flutter specification of 0,07% WRMS

 

Like all Akai cassette machines, the GXC310D features the Dolby Noise Reduction System to reduce tape hiss to a virtually inaudible level, give a bigger frequency response Akai's ADR (Automatic Distortion reduction) system which varies the equalisation at high input levels to cut distortion and extend the dynamic range at high frequencies,

Its many other features include a peak Level indiator Automatic Stop Limiter switch, Mic/Line Input Selector for a wider dynamic margin and less noise. Pause Control, output Level Control for perfect matching with any amplifier input, Tape Run indicator, Memory Rewind and Index Counter direct function change controls and a bias equalisation switch for low noise, CrO₂ or ferrichrome tape.

Again, there's a specially designed perspex dust cover (DC310) as an optional extra.

 

Specifications

Track System:  4 track, 2 channel stereo

Tape Speed:  1-7/8 ips

Wow and Flutter:  less than 0,007% WRMS

Frequency Response:

Low Noise Tape :  30 to 14,000 Hz ±3 dB

CrO₂ Tape :  30 to 16,000 Hz ±3 dB

Fe-Capture Ratio Tape :  30 to 17,000 Hz ±3 dB

Distortion:   less than 1,5% (1,000 Hz "0" VU)

Signal-to-Noise Ratio:  better than 50 dB (with Dolby up to 60 dB) above 5 kHz

Bias Frequency:  100 kHz

Erase Ratio:  better than 70 dB

Heads:GX Recording/playback and Erase head

Motor:  4-pole hysteresis synchronous outer-rotor motor

Fast Forward and Rewind Time:  75 sec. C-60 cassette tape

Output Jacks:

Line :  0,775 V ("0" VU). Required load impedance; more than 10 k Ω

Phone :  30 mV/8 Ω

Input Jacks:

Microphone :  0,3 mV/5 k Ω

Line :  60 mV/100 k Ω 

DIN jack :

Output :  0,4 V

Input :  2 mV

Dimensions (W x H x D):  440 x 142 x 300 mm (17,3 x 5,6 x 11,8 inch)

Weight:  8,6 kg (18,9 lbs)

Akai GXR-82D 8-track deck

Stereo Cartridge Deck

Amazing GX head performance can now be yours with a compact stereo cartridge deck. Besides Akai's long lasting superior high range frequency Glass & Sigle X'tal GX head, automatic stop and continuous playback, pause control, and a highly efficient induction motor are included is the features of this easy-to-operate finger-tip control unit.

 

Glass & X'tal GX Head

This model employs Akai's GX recording and playback head for better Signal-to-Noise Ratio, extended high range frequency and a more dynamic range. These features are contributable to the characteristics of Akai's amazing focused-field recording system. The core of the GX Head consists of a single crystallized element which is mounted and set in glass of the same hardness characteristics. The gem "single crystal" has no composite particles to eventually separate and cause head gap damage as the tape passes the head surface, thus enabling Akai engineers to focus the magnetic field system eliminates un due equalization, minimizes high frequency loss and achieves a wider dynamic range. And GX performance is not just temporary. It's fully maintained for lasting new machine performance.

 

8-Track cartridge stereo system

This model employs an 8-track 2-channel cartridge stereo system. The tape has a total of 8-tracks, two of which are used at a time for stereo performance. When the first channel terminates, the second channel is automatically set to position for continued operation. Thus, a 300 ft. Cartridge tape accommodates one hour of continuous performance. Desired channel or program can be easily selected by manually operating the Program Selector Button.

 

Specifications

Track System:  8-track, 2-channel stereo

Tape Speed:  3-3/4 ips (±1,5%)

Wow and Flutter:  less than 0,25% rms at 3-3/4 ips

Equalization:  Correct equalization for playback of tapes recorded to the NAB curve

Frequency Response:  40 Hz to 17,000 Hz (±3 dB) at 3-3/4 ips

Output Power:  16 W total Music Power (8 W/8 W) at 8 Ω 

Signal-to-Noise Ratio :  better than 47 dB

Erase Ratio:  better than 65 dB

Cross-Talk:  better than 45 dB (stereo)

Heads:  2 - Recording/Playback GX head, Erase head

Motor: two-speed 2/8 pole induction motor

Fast Forward and Rewind Time:  Within 230 secs. Using a 300 ft tape

Recording Capacity:  One hour stereo recording using a 300 ft. Cartridge tape

Output Jacks:

Line :  1,23 V ("0" VU) / 100 Ω  (Required load impedance:  more than 20 k Ω )

Phone :  30 mV/8 Ω

Speaker:  8 W /8 Ω  each

Input jacks:

Microphone :  0,5 mV/4,7 k Ω

Line :  50 mV/500 k Ω

DIN Jack:  0,5 V/5 mV

Power Requirements:  100 V - 240 V AC, 50/60 Hz

Dimensions (W x H x D):  346 x 135 x 255 mm (13,6" x 5,3" x 10,5")

Weight:  8 kg (17,6 lbs)

 

Pioneer SX-2500 receiver

 

Auto-tuning , solid state AM/FM stereo receiver.

The AM/FM auto-tuning feature of this outstanding receiver is really convenient - one touch of the button sends the tuning needle on to the next station, where it will lock onto the signal with uncanny accuracy. It's a center-tuning system exclusive with Pioneer. Another convenient feature is the remote control unit for auto-tuning and volume control, operable up to 7 meters. With a tremendous 340 watts of power, the SX-2500 can drive any type of speaker system easily, even low-efficiency designs. The tuner employs 5 ICs and 2 crystal filters to ensure an excellent sensitivity of 1,6 µV, bringing in even weak or distant stations clearly. All in all the very advanced technology and finest quality parts of the SX-2500 make it Pioneer's top-of-the-line stereophonic receiver.

 

Convenient and precise Auto-Tuning servo-mechanism system

Just touch the button and the tuning needle will travel along the dial, lighting up and stopping precisely at the next station, with the help of a center-tuning meter and servomechanism, exactly where the signal is strongest. When the needle reaches the end of the dial scale, it will "turn around" automatically.

The biggest problem in auto-tuning systems has always been in centering the needle accurately. In conventional systems, the inertia of the needle motor carries it a bit beyond the exact spot, but in the SX-2500 Pioneer has solved the problem electronically with the servo-mechanism, and the needle is neither slightly to the right of left of the correct position - it's right on. The discriminator supplies a point "0", and the needle locks onto this "0" position precisely and almost instantaneously. This auto-tuning, center-tuning system is the only truly accurate one, and it's exclusive with Pioneer. When the needle moves inn the auto-tuning mode, the muting switch turns on automatically to cut out inter-station noise.

 

Specifications

Audio Section

Music Power Output

208 watts (IHF Rating) at 8 Ω

340 watts at 4 Ω

Continuous Power Output (Each channel driven)

84 W / 84 W at 8 Ω  (1 kHz, T.H.D. 0,5%)

120 W / 120 W at 4 Ω  (1 kHz, T.H.D. 0,5%)

Continuous Power Output (Both channel driven)

72 W / 72 W at 8 Ω  (1 kHz, T.H.D. 0,5%)

90 W / 90 W at 4 Ω  (1 kHz, T.H.D. 0,5%)

Total Harmonic Distortion :  less than 0,5% (at 1 kHz, Continuous Power Output)

Damping Factor:  40 (at 8 Ω , 1 kHz)

Frequency Response:  20 Hz to 70 kHz ±2 dB

Power Bandwidth:  8 Hz to 40 kHz (IHF rating)

Hum and Noise:

Phono Mag :  better than 80 dB

Aux :  better than 100 dB

Input Sensitivity/Impedance (at 1 kHz, continuous power)

Phono 1 (MC) :  110 µV/30 Ω  (with PP-402)

Phono Mag :  2,7 mV/50 k Ω

Phono Cer/Crystal :  60 mV/100 k Ω

Aux :  200 mV/100 k Ω

Tape Monitor :  200 mV/100 k Ω

Main Input :  500 mV/120 k Ω

Output Jacks and Terminals

Speakers (A, B) 4 - 16 ohms

Stereo Headphone Jack

Tape Recording jack

Tape Rec/Power Bandwidth Connector (DIN type)

Remote Control Connector (4 P)

MC Transformer Connector (* P)

Equalization Curves:  Phono RIAA

Controls

Bass :  +12 dB -9 dB at 100 Hz

Treble :  +9 dB -12 dB at 10 kHz

Filters Low :  Cut 8 dB at 50 Hz

Filters High :  Cut 10 dB at 20 kHz

Loudness Contour:  Switchable to On-Off +13 dB (at 50 Hz), +6 dB (at 10 kHz), with Volume control set at -40 dB

Semiconductors:  2 FETs; 36 Transistor; 18 Diodes; 2 Thermistors

FM Tuner Section

Frequency Range:  87,5 MHz to 108 MHz

IHF Sensitivity:  1,6 µV (at 98 MHz)

Capture Ratio:  1,0 dB  (at 98 MHz)

Selectivity:  65 dB  (at 98 MHz)

Image Rejection:  90 dB  (at 98 MHz)

Signal-to-Noise Ratio:  better than 70 dB (IHF rating)

Antenna Input:  300 Ω  balanced; 75 Ω  unbalanced

FM MPX Section

Channel Separation:  40 dB (at 1 kHz)

Total Harmonic Distortion :  0,5% (at 1 kHz)

AM Tuner Section

Frequency Range:  525 kHz to 1605 kHz

IHF Sensitivity:  8 µV

Image rejection:  83 dB (at 1,000 kHz)

Antenna Input:  Built-in ferrite loopstick antenna

Semiconductors:  5 ICs; 3 FETs; 34 Transistors; 35 Diodes

Miscellaneous

Power Requirements:  110, 120, 130, 220 240 V, 50/60 Hz

Power Consumption:  220 VA

Dimensions (W x H x D):  489 x 146 x 384 mm (19-1/8" x 5-3/4" x 15-1/8")

Weight (net):  15 kg (33 lb)

Denon PRA-1100 pre-amplifier

Stereo Pre-Amplifier

 

Specifications

Equalizer Amplifier (Phono In - Rec Out)

Input Sensitivity/Impedance:

Phono MC :  0,2 mV/100 Ω

Phono MM :  2,5 mV/47 k Ω

Phono Variable Input Capacitor:  200 pF - 600 pF

Max. Input Level

Phono MC :  13 mV/ 1 kHz

Phono MM :  160 mV/ 1 kHz

Max. Output ? Rated Output:  10 V / 150 mV

Total Harmonic Distortion :  less than 0,001% (1 kHz, 7 V output)

RIAA Deviation

Phono MC :  20 Hz - 100 kHz ±0,3 dB

Phono MM :  20 Hz - 20 kHz ±0,2 dB

Signal-to-Noise Ratio

Phono MC :  79 dB (A -weighted) at 0,5 mV Input

Phono MM :  96 dB (A -weighted) at 5 mV Input

Gain

Phono MC :  57,5 dB / 1 kHz

Phono MM :  35,6 dB / 1 kHz

Phono Subsonic Filter:  16 Hz, 12 dB/oct

High-Level Amplifier (AUX In - Pre Out)

Input Sensitivity/ Impedance:

CD, Tuner, Aux 1, 2; Tape 1, 2 :  150 mV / 47 k Ω

CD Direct :  1 V/ 10 k Ω

Max. Output/Rated Output:  10 V / 1 V

Total Harmonic Distortion :  less than 0,003% (20 Hz - 20 kHz, 5 V output)

Frequency Response:

1 Hz - 300 kHz +0,2 dB -3 dB

10 Hz - 100 kHz ±0,2 dB

Signal-to-Noise Ratio :  105 dB (A -weighted)

Tone Control:

Bass :  ±8 dB at 100 Hz

Treble :  ±8 dB at 10 kHz

Muting:  PRE Out Off and Headphones circuit muting (indication by LED)

Gain :  16,5 dB

Output Impedance:  10 Ω

General

Power Requirements:  AC 220 - 240 V 50/60 Hz

Power Consumption:  15 W

DC Output:  15 V x 2 (1 mA)

Dimensions (W x H x D):  434 x 119 x 302 mm (17-3/32" x 4-11/16" x 11-57/64")

Weight (net):  5,0 kg (11 lbs 1 oz)

 

Denon POA-800 power amplifier

Stereo-Monaural Power Amplifier

 

 

Specifications

Rated Power Output

Stereo

50 W per channel, min. RMS, at 8 Ω  from 20 Hz to 20 kHz with no more than 0,05% T.H.D.

90 W + 90 W (4 Ω , 1khz, T.H.D. 1%)

Monaural

120 W channel, min. RMS, at 8 Ω  from 20 Hz to 20 kHz with no more than 0,08% T.H.D.

150W (4 Ω , 1khz, T.H.D. 1%)

Dynamic Power

Stereo

130 W + 130 W at 4 Ω

150 W +150 W at 2 Ω

Monaural

180 W at 4 Ω

190 W at 2 Ω

Total Harmonic Distortion (-3 dB at rated output , 8 Ω ) 

Stereo :  less than 0,008%

Mono :  less than 0,007%

Intermodulation Distortion (60 Hz/7 kHz : 4/1 at rated output , 8 Ω )

Stereo/Mono :  less than 0,03%

Power Bandwidth:  10 Hz - 50 kHz (8 Ω , T.H.D. 0,1%)

Frequency Response:  1 Hz - 100 kHz +0 -3 dB at 1 W

Input Sensitivity/Impedance: 

Stereo :  1 V/ 25 k Ω

Mono :  0,85 V/ 25 k Ω

Output Impedance:  0,1 Ω  (1 kHz)

Signal-to-Noise Ratio (A weighting)

Stereo :  120 dB

Mono :  114 dB

Output Terminals

Speakers :  4 Ω  Min.

Power Requirements:  AC 110, 120, 220, 240 V 50/60 Hz

Power Consumption: 150 - 160 W (3 A in USA, Canada)

Dimensions (W x H x D):  434 x 120 x 300 mm

Weight:  6,8 kg

 

Harman/Kardon 50+ receiver

Designed in the Citation tradition is, perhaps, the fundamental statement we make as we articulate our approach to product. During the past years, Harman/Kardon has rededicated itself to that perspective and to that commitment.

Our new line of multichannel products is a vivid extension of that philosophy. Clearly, these are products that stretch the state of the art. And products that establish new frontiers of engineering, integrity, creativity, and performance.

 

Special Features

Provision for double-power stereo or four channel. Special rear panel switch selects mode of operation.

Newly designed FM front end utilizes low noise transistors which provide amazing sensitivity with highest rejection of unwanted stations

Separate pushbutton on/off switch permits user to turn receiver on and off without upsetting careful positioning of controls

Large illuminated meter permits tuning of AM and FM stations with precise accuracy.

Tilting AM antenna permits user to position antenna for optimum signal strength

Heavy counter-weighted flywheel tuning provides smooth tuning action

Stereo/quad headphone receptacles permit user to employ stereo or quad head phones for personal listening. Special resistive padding prevents accidental overload.

Heavy duty, ultra-wideband output devices permit receiver to extend several octaves above and below the normal range of hearing for clean, totally transparent sound.

Prevision to monitor stereo or quad tapes

Sharply illuminated dial scale provides high visibility.

Provision for mono, stereo, SQ matrix, conversion of stereo-to-quad, discrete and discrete phono quad. (Discrete phono quad requires special adapter).

Gold plated escutcheon, blackout dial scale area and gold anodized aluminum knobs give the 50+the look of luxury.

 

Specifications

Continuous Power

Stereo :  25 watts RMS per channel into 8 Ω  at 1 kHz

Quad :  4 x 12,5 watts, RMS, per channel into 8 Ω  at 1 kHz

Total Harmonic Distortion :  0,3% at 1 kHz

Intermodulation DIstortion :  0,5% (40 &4,000 Hz) 3 dB down in power

Frequency Response:  18 - 74,000 Hz ±1 dB

Power Bandwidth:  28 - 30,000 Hz , 3 dB down

Matrix Phase Differential:  0° to ±6°

Matrix Overload:  4 volts, RMS, 20 - 20,000 Hz

Matrix Frequency Response:  20 - 20,000 Hz (uniform amplitude)

Hum and Noise: 

Phono :  -60 dB

Aux :  -63 dB

Damping Factor:  20 into 8 Ω

Controls

Bass  :  ±12 dB at 50 Hz

Treble  :  ±12 at 10 kHz

FM Sensitivity:  2,8 mV, IHF

FM Total Harmonic Distortion :  0,9%

Ultimate Signal-to-Noise Ratio :  62 dB

Capture Ratio:  3,0 dB

IF Rejection:  60 dB

Spurious Response Rejection:  60 dn

Stereo Separation:  30 dB

AM Sensitivity:  30 mV

Image Rejection:  40 dB

Dimensions (W x H x D):  15-5/8" x 4-3/4" x 12-3/4"

Weight:  18 pounds

 

Hafler DH-200 power amplifier

Both ears and instruments attest to the excellent quality of the DH-200 power amplifier. It has both superior test specifications and the listening quality to satisfy the most critical listeners, including those for whom price is not a limitation.

The DH-200 follows in the path of the widely acclaimed DH-101 preamplifier which has had highly laudatory reviews and wide spread consumer acceptance. Like the preamplifier this 100 watt per channel amplifier is available either in easy-to-assemble kit form or factory assembled. Either way it is a highly reliable piece of equipment which can satisfy the most hyper-critical listener, including the audiophile with the most difficult loudspeaker load. And, in kit form the DH-200 provides a significant cost saving for a pleasant few hours of assembly time, using factory pre-assembled and tested audio modules.

Two completely assembled and fully tested amplifier modules comprise all of the kit's active circuitry, leaving just a handful of parts for the builder to complete the mechanical assembly and power supply wiring. This makes your job simpler and faster, and assures that your finished kit will easily meet all of its specs, and provide the ultimate in listening pleasure.

The DH-200 employs a unique circuit configuration using all discrete transistors, operating the very latest output devices, power MOSFET's in a conservative array. The result is that the benefits of Class A output stages are obtained - such as high speed, minimal crossover distortion, and decreasing distortion at lower signal levels - without the disadvantages of high cost, high heat, low efficiency and thermal instability that are a part of conventional Class A operation. Like the Hafler preamplifier, this power amplifier has a completely symmetrical, mirror-image complementary push-pull circuit from input to output.

Exceptionally low distortion is apparent on reading the specifications, but such figures cannot detail the unit's true capabilities. The significance of achieving orders of magnitude reduction in Total Harmonic Distortion and Intermodulation DIstortion lies in the correlative elimination of other distortion products. The footnote at the end discusses this in detail.

 

The DH-200's characteristics of vanishing distortion at lower signal levels, and minimal indication of any forms of transient distortion, such as slew induced distortion, as observed at all power levels of square waves, tone bursts and pulse tests, will , we are confident, maintain its superiority as new standards and tests become applicable.

T.H.D. and Intermodulation Distortion (both SMPTE and CCIR measurements) are below the threshold of the finest test equipment - from one-tenth of a watt to beyond 70 watts. Measured with the Sound Technology Model 1701A analyzer, typical mid-band distortion at full power into 8 ohms averages 0,0015%

Another limiting factor in correlating sound quality to measured performance is that conventional amplifiers may measure well on the standard resistive test loads, but exhibit distortion when confronted by the complex reactive loads of the loudspeaker and its crossover network. The Hafler DH-200 has the power reserves to handle mismatched loads (it can deliver 150 watts into 4 ohms, and 100 watts into 2 ohms), but more important, it can handle the back - EMF from the loudspeaker cone without generating interfacing distortion components.

With no need for special protective circuits which may compromise sonic performance, the self-protective design of the DH-200 output stage prevents the thermal runaway which is a threat to other designs.

For applications requiring extraordinary power, the DH-200 may also be bridged to convert it to 300 watt (at 8 ohms) monophonic amplifier, with similar distortion specifications. As a modestly priced, versatile "no frills" design, operating premium quality components conservatively for extended life, this new Hafler amplifier is the audio perfectionist's answer to state of the art. Performance at affordable prices.

 

Specifications

Power Rating:  less than 0,02% T.H.D. at any power level up to 100 watts continuous average power per channel into 8 Ω  at any frequency between 20 Hz and 20 kHz with both channels driven.

Intermodulation DIstortion (SMPTE): less than 0,005% from 1 watt to 100 watt into 8 Ω

Typical Total Harmonic Distortion at 100 wats into 8 Ω :

1 kHz :  0,0015%

10 kHz :  0,005%

20 kh :  0,012%

Frequency Response (into 8 Ω ):

-3db, 1 Hz to 100 kHz at 1 watt

±0,5 dB, 10 Hz to 40 kHz at 100 watts

Typical Channel Separation:

20 Hz :  66 dB

1 kHz :  66 dB

20 kHz :  60 dB

Signal-to-Noise Ratio (Unweighted): better than 100 dB at 100 watts into 8 Ω

Input Impedance:  22,000 Ω

Input Sensitivity:  1,5 volts rms for 100 watts into 8 Ω

Damping Factor:

150 to 1 kHz into 8 Ω

50 to 10 kHz into 8 Ω

Rise Time:  10 kHz, 60 volts peak to peak square wave, 10% to 90% :  2,5 µs

Slew rate:  10 kHz, 60 volts peak to peak square wave :  25 V/µs

Semiconductors:  26 Transistors; 8 Power MOSFETs; 24 Diodes; 4 Zener Diodes; 1 Diode Bridge

Power Consumption:  Quiescent 100 VA, 100 watts into 8 Ω  ; 370 VA

Dimensions (W x H x D): 16" x 5-1/8" x 10-1/2"

Weight: 26 lbs net

 

Hafler DH-100 preamplifier

 The preamplifier functions as the control center of your component music system. It is the interface between the audio sources and the basic power amplifier. It provides appropriate switching, and adjustment of the volume, balance and tonal correction, as well as the additional amplification and frequency compensation required for magnetic phono cartridges. Given the wide choice of preamplifier designs, a price range of ten times or more, some laden with features, and others burdened with notable complexity, there is a natural tendency for you to expect that the highest performance will necessarily be achieved with the most costly designs. This need not be true. The David Hafler Company has a tradition of maintaining a very high level of quality while achieving substantial cost reductions in our products. In the DH-100 we have state of the art. Performance in a handsome unit which is very modest in cost.

Our philosophy has always been to produce maximum performance at minimum cost, offering exceptional value in every one of our designs. The ability to achieve this is based on our expectation that the merits of each product will be so well recognized that demand will enable us to produce it in substantial volume, with the attendant economies in purchasing and manufacturing. Some of the design features which contribute to this value factor are:

Elimination of frills, such as unnecessary inputs, loudness controls, and the like, while we provide all the important features

Careful component selection and painstaking distillation of each circuit to its essentials delivers unsurpassed performance.

We develop a physical arrangement which enables reliable, reproducible performance with easy low cost assembly techniques.

We expend a large amount of engineering time to make our designs conform to close standards, without the need for time-consuming adjustments.

A further benefit of these factors is that our designs can be supplied as kits with ease of assembly and assurance of success for the builder, with additional savings.

 

While the DH-100 exemplifies the "no-frills" path to ultimate economy, it is replete with subtle features which are not apparent at first, but which make a significant contribution to its superior performance:

Low impedance power supply maintains that characteristic out to the highest audio frequencies.

A delay circuit provides muting to eliminate surges and "pops" at turn-on

Unused inputs are isolated to prevent feedthrough and consequent distortion from unselected sources

Precision RIAA phono equalization and a balanced tone control circuit assure flat response.

Sufficient line output enables the use of high impedance headphones for direct listening, as an alternate to the power amplifier connection.

 

A  goal of the lowest possible distortion is axiomatic. The conventional harmonic and intermodulation distortion of the DH-100 are almost unmeasurable. But further, we determined to make some of the more obscure forms of distortion equally inoffensive. Outside of conventional audio band it is possible for signals to intermodulate, producing distortion products inside the listening range. This ultrasonic intermodulation is an insidious form of distortion that is not shown in conventional specifications. Some engineers try to reduce it by rolling off the response of the unit so that out-of-band signals are not being reproduced. Our method is to make a very wide band design which can handle high frequency signals cleanly, so that they will not create intermodulation or transient distortion which might be audible.

 

We have paid special attention to maintaining stereo separation out to the highest frequencies so that phase information remains accurate between the two stereo channels. This provides a stable and sharply defined stereo image.

In selection circuit components, we used special listening tests based on amplified bridge comparisons, so that we could identify those items which adversely affected sonic quality. This LED to the exclusive use of polypropylene and polycarbonate capacitors in the signal path, because their superior quality justified the higher cost. Like the circuit design, the parts which comprise it were selected for the most accurate sound quality attainable.

 

Specifications

Phono preamp Section

Rated Output: 3 V rms

Max. Output:  8 V rms

Total Harmonic Distortion :  less than 0,005%

RIAA Frequency Response :±0,25 dB (20 Hz - 20 kHz); ±0,1 dB (40 Hz - 20 kHz)

Sensitivity:  10 mV (for 1/2 volt at Rec Out)

Max. Input:  180 mV at 1 kHz

Gain:  34 dB at 1 kHz

Input Impedance:  47,5 k Ω  in parallel with 130 pF

Signal-to-Noise Ratio better than 100 dB (A-weighted)

Line Amplifier Section

Rated Output:  3 V rms

Max. Output:  8 V rms

Total Harmonic Distortion :  less than 0,005%

Frequency Response:  ±0,25 dB (20 Hz - 20 kHz)

Gain:  20 dB

Input Impedance:  better than 35 k Ω

Signal-to-Noise Ratio :  better than 100 dB  (A-weighted)

Crosstalk:  down 80 dB

Separation:  better than 70 dB (at 1 kHz); 55 dB (at 10 kHz)

Controls

Bass ;  ±10 dB at 20 Hz (Moving inflection type)

Treble :  ±10 dB at 20 kHz (shelving type)

General Specifications

Semiconductors:  7 ICs; 5 Diodes; 1 LED

Inputs:  Phono, Tuner, Aux, Tape

'outputs:  Record, Line

Power Requirements:  AC Supply Voltage 95 - 130 V or 190 - 260 V 50/60 Hz

Power Consumption:  less than 5 watts

AC Outlets:  2 switched

Dimensions (W x H x D):  13-9/16" x 3 " x 10"

Weight:  7 lbs net

Adcom GFP-555 preamplifier

 Preamplifier A remarkable combination of exceptional performance, flexibility and value

The GFP-555's musical performance is outstanding - by any measurement or listening criterion. For example,… one of the most satisfying preamps around in terms of overall tonal balance. You can go back to it after a few weeks and still feel it to be basically right; it reveals most associated equipment as more colored than itself.

At the same time, the GFP-555 is surprisingly affordable.

Superb construction, incorporating regulated power supplies with large filter capacitors, provides superior performance no matter how widely the musical signal or AC line voltage may fluctuate.

As for flexibility, you can listen to any source while taping from another. There's an unusual number of inputs and outputs, plus adjustable phono gain and capacitance.

Outstanding performance

The GFP-555's musical performance is outstanding - by any measurement or listening criterion - and at the same time it offers a full array of meaningful controls and features.

What's more, the GFP-555 does it all at a surprisingly affordable price. Surprising, that is, only to those who aren't yet familiar with the Adcom approach to design and performance Musical performance, in particular.

Gai path - simple and direct

The GFP-555's gain path is simple and direct from input to output. The use of a minimum number of components - each of the highest quality - means low waveform distortion and less phase shift

The gain stages employ the most innovative state-of-the-art. Linear amplifiers ever used in high fidelity components. These individually selected instrument-grade devices are in a class by themselves.

The speed of the gain stages is almost fifty times faster than CD or LP signals.  And the noise and distortion measurements are incredibly low. Direct coupling makes possible a frequency response from below 1 Hz to beyond 400,000 Hz

 

Specifications

Total Harmonic Distortion:  0,005%

Intermodulation Distortion:  0,005%

Signal-to-Noise Ratio

Phono :  better than 85 dB (re 0,5 V output)

Tuner, CD, Tape :  better than 100 dB (re 2 V output)

Tone Controls

Bass :  ±9 dB at 40 Hz

Treble :  ±9,5 dB at 15 kHz

Contour:  =6 dB at 50 Hz

Frequency Response:  1 Hz - 100 kHz ±0,1 dB

High Filter:  -2,5 dB at 20 kHz (6 dB/octave)

Low Filter :  -5 dB at 20 Hz (6 dB/octave)

Input Sensitivity for 0,5 V output

Phono High MC/MM :  0,4 mV

Phono Low MMC :  0,13 mV

High :  40 mV

Maximum Output Level :  10 volts

Input Impedance

High MC'/MM :  47 Ω

Low MC :  100 Ω

Output Impednce:  470 Ω

Phono Overload (at 1 kHz High MC/MM):  140 mV

Phono Input Capacitance:  10 pF, 175 pF, 275 pF (adjustable)

Line Voltage:  120 V 60 Hz (available in 230 V /50 Hz)

Dimensions (W x H x D):  432 x 83 x 324 mm (17" x 3-1/4" x 12-3/4")

Weight:  6,4 kg (14 lbs)