McIntosh C27 Specifications

The World Wide LeaderIn State Of The ArtHigh Fidelity TechnologyEngineered and Manufacturedin the United States of AmericaMclntosh Laboratory Inc.2 Ch

Output Transformersin TransistorPower Amplifiersby Sidney Corderman*Output transformers can make tran-sistor power amplifiers more reliable,more flexi

The impedance ratio required betweenprimary and secondary has been re-duced by a factor of four-to-one com-pared with the conventional arrange-ment. I

Fig. 5 - McIntosh MC 2205 output stage and transformerdred to one. With transistor outputstages, a ratio of only about 4 to 1 isrequired. In tube ampl

be mated to a specific amplifier cir-cuit. We went through dozens of de-velopmental samples in the case of ournew MC 2205 amplifier. What weended up w

provided for reactive loads.To Sum It All UpThe points we've tried to make arerelatively few, but they spell the differ-ence between a McIntosh o

You are Mclntosh protectedsix ways with the newMclntosh amplifiers.PROTECTION1. The patented Mclntosh Sentry Monitoring circuitconstantly monitors the

PERFORMANCE GUARANTEEDPerformance limits are the maximumdeviation from perfection permitted for aMclntosh instrument. We promise you thatwhen you purc

FIER PERFORMANCE LIMITSMC 2255MC 2250MC 2155MC 2120MC 502250 Watts PerChannel500 Watts20 Hz to 20 kHz0.02%1, 2, 4, 8 W1/2, 1, 2, 4, 8, 16 W0.02%+ 0, -

THE McINTOSH C 27STEREO PREAMPLIFIERSTATE-OF-THE-ARTPERFORMANCE WITHFLEXIBILITYPERFORMANCE LIMITS and RATINGSFREQUENCY RESPONSE:+ 0, -0.5 dB 20 Hz to

PRODUCTANALYSISTHE McINTOSH C 27STEREO PREAMPLIFIERFig.1 - Front viewMANUFACTURER'S PUBLISHEDLIMITS (SPECIFICATIONS):PERFORMANCERated Outputs: Ma

works a bit differently from that contained in the C 32.The user is instructed to set the volume control formaximum (lifelike) listening levels while

back curve measured via the phono inputs and shownas photographed from the face of our spectrum ana-lyzer's CRT tube. Mclntosh has wisely elected

92 dB with an "A" weighting network inserted, bothfigures exceeding published limits of Mclntosh. Volumecontrol tracking was found to be acc

McINTOSH c 29SOLID STATESTEREOPREAMPLIFIERPERFORMANCE LIMITS and RATINGSFREQUENCY RESPONSE:+ 0 -0.5 dB 20 Hz to 20,000 Hz.DISTORTION:.02% maximum at r

IF YOU DESIGNED A PREAMPLIFIER THAT HAD THEFLEXIBILITY YOU WANT WITH THEPERFORMANCE YOU NEEDIT WOULD LOOK LIKE THIS...C 33 shown in optional walnut ve

• Signal Processor input and output for both LISTENand RECORD circuitsExternal signal processors can be connected tomodify the program when recording

PERFORMANCE LIMITS and RATINGSPREAMPLIFIER SECTIONFREQUENCY RESPONSE+ 0, -0.5dBfrom20Hzto20,000HzMAXIMUM VOLTAGE OUTPUT10 volts from 20Hz to 20,000HzT

McINTOSH MR 75AM-FM STEREO TUNERThe Mclntosh MR 75 AM-FM Stereo Tuner is asuperb tuner using the latest high technology cir-cuits. This fine tuner wil

15 YEARS OF BASIC CIRCUIT AND CONCEPT RESEARCHHAS DEVELOPED THE TECHNOLOGYNECESSARY FOR A TRULY LOW DISTORTIONFM TUNER WITH VARIABLE SELECTIVITY . . .

The MR 78 tuner uses linear phase filters at theNORMAL and the NARROW positions of the SELEC-TIVITY switch settings.LINEAR PHASE BRIDGE DISCRIMINATORT

YOU SHOULD OWNMcIntoshBECAUSETABLE OF CONTENTSPower Amplifiers:MC 2500, MC 2255, MC 2250, MC 2155, MC 2120,MC 502 2-16PreAmplifiers:C 33, C 29, C 27,

PRODUCTANALYSISTHE McINTOSH MR78FM/FM STEREO TUNERFig. 1 — Front viewMANUFACTURER'S PUBLISHEDLIMITS (SPECIFICATIONS):PERFORMANCETuning Range: 88

illuminated over a portion of its length. Also located withinthe dial opening are symmetrically positioned center-of-channel and signal-strength meter

variable output jacks. The power supply section consists ofa 24-volt regulated supply which uses electronic filteringand supplies power to all signal

if he could have heard FM the way we heard it over theMac MR 78.There was only one instance where we found it necessaryto use the SUPER-NARROW positio

THE MOST FLEXIBLE CONTROL SYSTEMEVER FOR A DIGITAL DISPLAYPROFESSIONAL FM TUNERThe Mclntosh MR 80Engineering direction dictated a tuner designgoverned

as the detector coupled with a broadband limiter toproduce unmeasurable noise and distortion.The heart of the multiplex section is a new thirdgenerati

THE McINTOSH MR 80DIGITAL FM/FM STEREO TUNERMANUFACTURER'S PERFORMANCE LIMITS:Sensitivity: 9.3 dBf (1.6 uV) for 35 dB of quieting;14.7 dBf (3 uV)

separate closely spaced signals in our listening area.We have been told by some of our friends and col-leagues, however, that there are some areas of

the de-emphasis switches, an electronically switch-ed filter circuit is used to reduce out-of-phase noisewhen receiving weak signal stereo. The filter

The spectrum analyzer plots of Fig. 4 illustratesfrequency response and separation characteristicsof the tuner measured with selectivity set to the&qu

THE NEWMCINTOSH AMPLIFIERSMclntosh leadership in research and bipolarepitaxial transistor technology has producedstartling new advances in safe, cool,

COMPACT, FLEXIBLE - MASTER CONTROLWITH SUPERIOR AM/FM TUNINGTHE MCINTOSH MX 117AM-FM STEREO TUNER-PREAMPLIFIERMatch the Mclntosh Stereo Tuner-Preampli

separation—noise reduction control circuit. Whenlistening to weak or distant FM stations, optimumstereo separation and signal to noise ratio isautomat

Electronic Laboratories'THE MCINTOSH MX 117AM/FM TUNER-PREAMPLIFIERMANUFACTURER'S PUBLISHED SPECIFICATIONS:FM Tuner Section:Usable Sensitivi

Rear Panel ControlsStereo pairs of input jacks and a chassis groundterminal are located at the extreme right of the rearpanel of the MX 1 1 7. Inboard

phone jack. A turn-on delay circuit using a light-emitting diode/light dependent resistor network thattransmits no signal for two seconds after power

division in this and all other 'scope photos. At 1 kHz,separation measured an impressively high 55 dB fasopposed to Mclntosh's conservativel

reference 0.5 volts output, and this too correspondsexactly to the 250 mV spec called for by Mclntoshfor their referenced output level of 2.5 volts.Fi

Fig. 14 —Phono signal-to-noise plot, referred to 5 mVinput, 0.5 volts outputtained. Spectral distribution of the noise, in one-thirdoctave bands, is p

THE MAC 4100A HIGH QUALITY, HIGH POWERAM/FM STEREO RECEIVERAUTOMATIC POWER TURN ON/TURN OFFPower to the entire stereo system can be control-led from e

loudness compensation accuracy is dependenton many variables such as speaker efficiency,amplifier gain and differences in input level. Theloudness con

YOU ARE PROTECTED FROMLISTENING TO AMPLIFIERPRODUCED DISTORTIONWITH MCINTOSHPOWER GUARDPlus:• Mclntosh Output Autotransformer delivers fullpower outpu

A CONSUMER'S GUIDENewEquipmentReportsPreparation supervised byRobert Long, Harold A Rodgers.and Edward J. FosterLaboratory data (unless otherwise

Very little of the receiver's special quality is immediatelyapparent from the outside, though in hooking it up you get aclue from the convenience

range of the signal-strength meter is well chosen as an aid inantenna orientation for best reception of problem stations.The amplifier section, loo, e

HERE IS PERFORMANCE ONCE ONLY OBTAINEDWITH SEPARATE PREAMPLIFIERSAND POWER AMPLIFIERSTHE McINTOSH MA 6200STEREO PREAMP-AMPLIFIERHere's Mclntosh p

THE MCINTOSH CUSTOMEQUALIZER ELIMINATESTHE LAST MAJOR SOURCEOF DISTORTION IN YOURSTEREO---YOUR ROOMA Mclntosh Environmental Equalizer:• Adjusts for mu

The continuous improvement of its products isthe policy of Mclntosh Laboratory Incorporated,who reserves the right to improve design without notice.Pr

THE MCINTOSH POWER GUARDThe Power Guard waveform comparison circuitdetects minute amounts of waveform difference be-tween the output signal and the in

The meters have extremely fast rise time, about500 microseconds for 90% accuracy. A tone burst of500 microseconds is almost inaudible even at fullpowe

test reports"Reprinted with permission from the June 1982 issue of STEREO REVIEW magazine.Copyright © 1982 Ziff-Davis Publishing Company. All rig

STEREO REVIEWtest reportsto the two input phono jacks is a switch thatsets the input sensitivity to either 0.75 or 2.5volts for full output depending