rek-o-kut RE-EQUALIZER III User manual

OPERATING MANUAL
FOR
REK-O-KUT
RE-EQUALIZER III
PRICE: $5.00

INSTRUCTIONS FOR OPERATION OF REK-O-KUT RE-EQUALIZER III
INTRODUCTION:
Modern preamps are designed for today's microgroove RIAA recordings. In the 1950's, many had
TURNOVER and ROLLOFF switches. Turnover refers to the boost applied to compensate for
diminishment of bass during disc cutting to avoid groove crosscutting. Rolloff refers to treble reduction to
compensate for treble boost applied during record cutting. The latter reduces surface noise during play.
Before 1954 there were a variety of recording characteristics, such as AES, LP, NAB and FFRR. Before
1940 most, but not all, records were cut flat with only a low frequency turnover below 300 Hz or 500 Hz.
This also applied to radio transcriptions and disc recordings used for cinema. Playing most 78 rpm
records made prior to 1950 through a modern preamp is effectively using a filter that begins at 2200 Hz.
This accounts for the lack of highs and muffled voices experienced with these records.
A graphic equalizer is not accurate. Modifying your modern preamp may spoil the cosmetics of your
$3,000 preamp. There is also the problem of what to do with digital and tape recordings of vintage discs
made off of an RIAA preamp. They will have the RIAA response imbedded in them, and they cannot be
played through a properly equalized phono preamp.
The RE-EQUALIZER III solves this problem. It is used at line level, after the RIAA phono stage, and
connects to the system like a common graphic equalizer. Thus it will provide proper equalization to any
signal source. The RE-EQUALIZER III allows the use of any modern RIAA phono amplifier and will not
degrade the performance of any audiophile unit.
CONNECTION:
Here are some examples for connection. The RE-
EQUALIZER III can be connected to the stereo system
like other sound processing components. De-clickers,
such as the Packburn 323 or Esoteric Sound
SURFACE NOISE REDUCER, must always precede
the RE-EQUALIZER III.
If an audio recorder is not used, connect the RE-
EQUALIZER III in the tape monitor path. To listen,
operate the “Monitor switch.” If audio recording is used,
connect the RE-EQUALIZER III in the tape monitor
path (Fig. 1) and use a "Y" connector to feed its (or
associated equipment's) output to an unused "Aux"
input. After recording, playback can be via this "Aux"
input. If not recording, the processed sound can be
listened to via the amplifier’s ”Monitor switch.”
If your preamp/amp/receiver does not have a separate
"Aux" input, eliminate the "Y" connectors and connect
directly to the recorder, and connect the recorder's
output to the amp's "Tape In." For listening to
processed sound, use the amplifier’s Monitor switch to
hear the sound through the audio recorder with the
recorder’s "Monitor" switch set to "Source."
The labeling of many panel and input/output connectors used on amplifiers and recorders can be be quite
different. So, connections may vary. Last resort: Use an outboard preamp with the RE-EQUALIZER III,
and feed an unused AUX input on your amplifier.
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CONTROLS:
Bypass Switch - provides a hard wire connection from input to output with no intervening circuitry. When
switched to “IN,” the two inputs are mixed together via the Blend control providing optimum mono
operation. This reduces noise and facilitates recording on stereo recorders or sound cards.
V/L Switch - facilitates the play of vertical cut disks, such as Edison, Pathe’ and early Okeh.
Blend - Normally set to the center position. It is used to compensate for stereo cartridge imbalance,
unequal preamp channel gains, and tilted cutter heads. You can set it by ear, or use the V/L switch to set
it very close. Set full left or full right to hear only that groove wall.
Turnover (FLAT) - Can be used with acoustical records and cylinders. Then use graphic EQ for best
sounding bass. Acoustic recording bass compensation is highly subjective. Start with RIAA (500).
Turnover (300 Hz) - This is used for Columbia brand and manufactured electrical 78 records, London
FFRR 78s, BBC broadcast transcriptions, many pre-WWII records and transcriptions, and early Western
Electric products. Also, it is useful for improving bass on acoustical records.
Turnover (400 Hz)(AES) - Some post-WWII 33s, 45s, 78s using the AES characteristic.
Turnover(RIAA) (500 Hz) - Most post-1935 US 78s, broadcast transcriptions and also for Orthoacoustic
and NAB transcriptions.
Turnover (LP)(500 Hz, modified) - For early Columbia, Columbia manufactured, and some other LPs.
Turnover (629 Hz) - Used with some early electrical 78s, some 1931 vintage Victor LPs.
Turnover (800 Hz) - Used mostly by RCA for early RCA-Victor 1950s LPs and 45s.
Turnover (1000 Hz) - Used with many old 78s, 45s, BBC microgroove LPs, provided there is a sharp
rumble filter.
Rolloff (FLAT)(0dB) - For acoustical records and all early (pre-1938) electrical 78s and transcriptions. A
low-pass (scratch) filter is useful in conjunction with this setting.
Rolloff (-5 dB) - This is for a -5 db drop at 10 KHz. Used for some post-1938 78's, FFRR 78s, or to soften
noise on early recordings.
Rolloff (BBC) - A setting for late 1940s, early 1950s BBC transcriptions. Nice effect for acoustic records.
Rolloff (-8dB) - This is for a -8 db drop at 10 KHz. Mostly for early RCA-Victor LPs.
Rolloff (-10 dB) - Used for some post-1938 78s, early LPs, such as London.
Rolloff (-12 dB)(AES) - This is used for some post WWII records employing the AES characteristic.
Rolloff (RIAA)(-13.7 dB) - For most modern records.
Rolloff (NAB)(-16 dB) - For early Columbia LPs and all NAB and Orthoacoustic transcriptions.
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RECOMMENDED SETTINGS (see tables on pages 6 through 10)
These are recommendations, but not written in stone. As documentation of recording curves is difficult to
track down, some experimentation may be called for. Be particularly observant of matrix numbers
surrounding the label area and record labels for dating records.
Tables for record compensation settings were published in most early hifi magazines, such as “Dialing
Your Discs” in High Fidelity, but are often fallacious. These turn up occasionally and may be consulted. In
"Conversations With Toscanini," by B. H. Haggin, many subjective suggestions are given for playback of
Toscanini discs.
HINTS ON USE:
One advantage of the RE-EQUALIZER III is the ability to use it on recordings of vintage records made with
RIAA equalized preamps. Do not trust all transcription and record labels. Also, many small recording
company and radio station engineers seemingly didn't understand the technology and often employed no
pre-emphasis on recordings labeled as NAB. This has been found to occur even on discs cut in the
1960's! Many pre-WWII radio shows which were recorded with flat highs were re-syndicated again in the
late 40's and 50's. As original masters were normally used, the re-release will require a flat Rolloff even
though the label states NAB or Orthoacoustic! This is also true for post-WWII 78s, and LP reissues. Use
the Flat Rolloff position and you may be in for a pleasant surprise.
You may find many discs that do not fit the tables or are ambiguous. For these, you will have to let your
ear be your guide. Western Electric, Columbia, and non-US companies tended to use 300 Hz Turnover.
Listening to the material will often suffice to guide you whether to use 300 Hz or 500 Hz. Once the low end
is determined, try various Rolloffs. Almost all early electrical recordings were recorded with flat response.
If noise proves a problem, try more than the recommended Rolloff.
When playing older or abused records that require less Rolloff, i.e., Flat, -5, -8, a significant increase in
noise level will often be noticed due to surface noise. In these cases, a high frequency, lo-pass, hi-cut, or
"scratch" filter is recommended. Don't forget that when playing a flat cut record with an RIAA preamp, you
are actually effectively using a scratch filter that is some 13.7 db down at 10 KHz. With these types of
records, a 7.5 KHz scratch filter and the RE-EQUALIZER III set to FLAT, you will be gaining in highs
between 2.2 KHz and 7.5 KHz. Significantly more highs than with a standard RIAA preamp and no filter.
The Blend control can either be left at center, or can be set by ear for best sound. This may be easier: To
play common, lateral cut records, set the Vertical/Lateral switch to Vertical and adjust the Blend control for
least sound. Then return to Lateral, and play. When playing vertical-cut records, such as Edison or Pathe,
do the just the opposite. Also, the Blend can be set to full left or right to play either groove wall.
Most commercial, pre-RIAA records had matrix numbers that were of larger, often cursive fonts, and were
raised from the surface. Their characters appeared to be made with punches. Most RIAA discs had
smaller, more Arial fonts and appeared to be etched into the surface. You can use a toothpick and
magnifying glass to help determine this.
LONDON/DECCA OLDER MATRIX LONDON/DECCA NEWER MATRIX
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The photos above are of British London/Decca LPs made circa 1954. The left matrix number has the
raised, large font commonly associated with RIAA/-10 dB equalization. The right matrix number, ARL-
1425, would ordinarily indicate an earlier equalization; however, it has the engraved into font associated
with RIAA/RIAA equalization. Also, note the “R.” That signifies remastered for RIAA.
US DECCA OLDER MATRIX US DECCA NEWER MATRIX
US Decca has a similar distinctive matrix identification. Note the higher “Take Number,” or “Stamper
Number,” (T7). Usually, lower Take Numbers are associated with pre-RIAA records. The (T3) record on
the left requires 800/-8 dB equalization in order to make it sound like the RIAA on the right.
US COLUMBIA OLDER MATRIX US COLUMBIA NEWER MATRIX
US Columbia follows similarly. Note that both matrix numbers are the same. The RIAA issue, however,
has a smaller Arial font, and also higher Take Numbers.
US COLUMBIA OLDER MATRIX (Version 2) US COLUMBIA NEWER MATRIX
Sometimes font characterization is not enough. Above, only the take number and label are different.
Labels can tell a lot about a record’s age.
These US Decca labels are from the
same recording of show music. On the
left is the earlier, pre-RIAA version. On
the right is the later, RIAA version.
However, this is not a guarantee of a
record’s age, but one of several
indicators. It was the Matrix Numbers that
confirmed this equalization choice.
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Although the label on the left is the older
label, only one side of this record is pre-
RIAA. The matrix number font and Take
Number was the give away. With US
Decca, one can expect pre-RIAA only up
to and including T3.
Below are two common Columbia LP
labels. Both of these labels have
appeared on records that were either “LP
curve” or RIAA. The blue label was almost
exclusively used during the pre-RIAA era.
The “6-Eyes” label appeared as Columbia
switched to RIAA. Almost all are RIAA.
You will sometimes find records with LP
EQ on one side and RIAA on the other.
You must check the
matrix number for
absolute certainty.
During the Columbia
transition to RIAA, they
reissued records with a
“HIFI Plus” sticker
to indicate an RIAA release. The labels
were often the old blue at the left. The
transition to RIAA was “gradual,” possibly
stretching into 1955.**
Lastly are a pre-RIAA RCA label on the left
and an RIAA label on the right. However,
you must check matrix numbers. The
remaining records in this Beethoven set
were all RIAA. This set was issued during
RCA’s transition to RIAA. Try to find
preponderance of EQ indicators.
SPECIFICATIONS:
Max input signal level: 3.5 volts (+12 dbm)
THD at max output : 0.02%
Frequency Response (RIAA compensation): 20 - 20 KHz + .5 db
Gain: 1
Signal-to-Noise relative max out: 85 db
World power supply: 100-240 VAC, 50/60 Hz
HELP SET THE RECORD STRAIGHT
If you have any additional equalization information, please bring it to our attention so that it can be
included in future updates.
**** WARRANTY ****
This unit is warranted to perform properly for one year from date of purchase. All parts and labor are
covered. Should the unit malfunction, return it properly packed, along with payment of $17.00 to cover
return postage, and it will be repaired and returned as soon as possible.
Foreign purchasers are requested to remove the RE-EQUALIZER III from its cabinet (if purchased) and
return it properly packed, along with payment of $60.00 to cover return shipping. We will return the unit
via economy shipping.
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PHONOGRAPH RECORD EQUALIZATION COMPENSATION SETTINGS
MANUFACTURER SPEED BASS (TURNOVER) TREBLE (ROLLOFF)
==============================================================================================
Acoustic records* All 300 FLAT
AFRS Transcriptions 33 RIAA FLAT
1944 Some or if NAB Stated RIAA NAB
12" Transcriptions 1000 FLAT
Allegro 33 Lp NAB
Allied 33 RIAA NAB
American Recording Society (<E2KP9607) 33 RIAA -12
Angel (2XEA213-392/XAX561-817)(1N,2N) 33 RIAA FLAT
Arizona (up till 1955) 33 400 -12
Artist 78 RIAA NAB
Atlantic 33 RIAA NAB
Audiophile 33 RIAA -12
78 400 FLAT
Autograph (Marsh electrical) 78 1000 FLAT
Audio Fidelity (901-903) 33 RIAA NAB
Bach Guild (501-529) 33 Lp NAB
Balkan 78 500 -5
Banner (up to 10002) 33 Lp NAB
Bartok 33 Lp NAB
(301-307, 309, 906-920) 33 629 NAB
Berliner* 71.29 300 FLAT
BBC Transcriptions (1930-1949)(<50000) All 300 FLAT
(1949-1953)(>70000) All 300 BBC
(“P” matrix) (1954-1956) 33 400 -10
(“R”matrix)(<1961)(<105403)LP-cut 33 1000 FLAT
Bluebird All See RCA-Victor See RCA-Victor
Blue Note 33 400 -12
Boston (up to B202) 33 Lp NAB
Brunswick (1925) 78 300 FLAT
(1946-1954) 78 629 -12
(up to MG4400)(w/raised matrix)** 33 800 -8
Caedmon 33 629 -12
(1001-1022) 33 629 NAB
Canyon (to C6160) 33 400 -12
Capitol<1954 78 800 -10
<1954 45 800 -12
(FDS) (up to P8155) 33 400 -12
(1953,FDS>8156) All RIAA RIAA
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MANUFACTURER SPEED BASS (TURNOVER) TREBLE (ROLLOFF)
=================================================================================================
Capitol-Telefunken 78 RIAA FLAT
Capitol-Cetra (up to A-50155)(9/53)# 33 400 -12
Cetra-Soria 33 Lp NAB
Colosseum 33 400 -12
Some Long Operas 33 1000 -5
Columbia-1925 78 300 FLAT
Columbia-1938 78 300 -5
Columbia-1948 78 300 NAB
Columbia-1948* 45 RIAA NAB
Columbia-1948 (up to ML4895, XLP3200)# 33 Lp NAB
Columbia-1954 (after XLP3200 matrix)# All RIAA RIAA
Columbia with “HIFI+” sticker ** All RIAA RIAA
Columbia(English) (1925-53) 78 300 FLAT
1949-1953 (XA561-XAX817-1N,2N only) 33 RIAA FLAT
Contemporary 33 400 -12
Concert Hall 78 RIAA -5
(XTV matrix to 20383)(low take nos) 33 Lp NAB
(E0 matrix) 33 800 -8
(E1KP/E2KP matrix) 33 RIAA -12
(CH matrix?) 33 RIAA -10
(E2RP>4095/E2KP>9607) 33 RIAA RIAA
Contemporary (3501, 2501/2/5/7, 2001/2 33 400 -12
(2504) 33 RIAA NAB
(after AP121) 33 RIAA RIAA
Cook 33 RIAA -12
(binaural-inside band) 33 RIAA FLAT
Coral (1946-1954) 78 629 -12
(up to MG4400)(w/raised matrix)** 33 800 -8
Cylinder records* All FLAT FLAT
Decca (US)(pre 1946) 78 300 FLAT
(1946-1954) 78 629 -12
(up to MG4400)(w/raised matrix)** 33 800 -8
Decca-English 78 300 FLAT
FFRR(1944)(<DR8485-2) 78 300 -5
FFRR (after 6/50)*** 33 RIAA FLAT
(>ARL1186-1B)*** 33 RIAA -10
(>ARL2530-2A)***# 33 RIAA RIAA
DGG (Deutsche Grammophon) 33 Lp -10
78 300 -5
Dial 33 Lp NAB
45/78 Lp NAB
Edison 80 FLAT FLAT
Elektra (2-15, 18-20, 24-26) 33 629 NAB
(17, 22) 33 400 -12
(16, 21, 23, 24) 33 RIAA RIAA
Electrical 78's (general) (1925-1938) 78 300 FLAT
1932-1938 78 300/RIAA FLAT
1938-1946 78 300/RIAA FLAT, -5
1947-1954 78 RIAA NAB
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MANUFACTURER SPEED BASS (TURNOVER) TREBLE (ROLLOFF)
=================================================================================================
Electrola 78 800 -10
EMI (1931-53) 78 300 FLAT
1949-53(2XEA213-392/XAX561-817)(1N,2N) 33/45 RIAA FLAT
7/17/53 33/78 RIAA RIAA
EMS 33 400 -12
Epic 33 Lp NAB
Esoteric (ES500, 517, EST5, 6) 33 400 -12
(E2KP to 9607) RIAA -12
(>E2KP9607) (ES533) 33 RIAA RIAA
European 78's (general) 78 300 -5
Festival 33 Lp NAB
Folkways 33 Lp NAB
Fraternity Records (up to F-1013) 33 RIAA FLAT
Good Time Jazz (3, 9-19) 33 400 -12
(1, 5-8) 33 RIAA -16
Gramophone Company 78 300 FLAT
Handel Society 33 Lp NAB
Haydn Society (<XTV20383, HS3062, HS80)# 33 Lp NAB
Hit Of The Week 78 RIAA -5
Home recordings 33/78 RIAA -5
HMV(English)
1925-1953 78 300 FLAT
1949-1953 (2XEA213-392 -1N,2N only) 33 RIAA FLAT
HMV(American-1951) 33 RIAA -12
Improved Record (Eldridge R. Johnson)* 71.29 FLAT FLAT
Kapp (100-103,1000,1001) 33 800 NAB
Kendall 33 RIAA NAB
Keynote 78 RIAA FLAT
King 78 RIAA NAB
Linguaphone 78 300 FLAT
L'Oiseau-Lyre (up to OL50018)# 33 Lp -10
London (pre 1944) 78 300 FLAT
FFRR (1944)(<DR8485-2) 78 300 -5
FFRR (after 6/1950)*** 33 RIAA FLAT
(>ARL1186-1B)*** 33 RIAA -10
(>ARL2530-2A)***# 33 RIAA RIAA
Lyricord (before 1953)(E0-E3 matrix) 33 400 -12
(XTV matrix) 33 Lp NAB
(If 629 listed on jacket) 33 629 NAB
Majestic 78 RIAA NAB
Page #8

MANUFACTURER SPEED BASS (TURNOVER) TREBLE (ROLLOFF)
=================================================================================================
Marsh Laboratories (electrical) 78 1000 FLAT
Mercury (MG10000 series-approx fit) 33 500 -10
(thru 10/54, <MG50026, 7000)# ALL 400 -12
MGM (up to E3071)# All RIAA -12
Montilla 33 RIAA -12
Musicraft 78 800 RIAA
NAB/NARTB transcriptions 33/78 RIAA NAB
vertical transcriptions 33/78 400 NAB
New Records (similar to URANIA) 33 RIAA -12
Nocturne (LP 1-3, 5, XP 1-10) 33 400 -12
Oceanic (up to XTV20383)(low take nos) 33 Lp NAB
Odeon 33 300 -10
some early electrical 78 800 FLAT
pre-1953) 78 300 FLAT
Okeh(electrical) 78 300 FLAT
Orthacoustic transcriptions 33/78 RIAA NAB
Overtone (up to XTV20383)(low take nos) 33 Lp NAB
Oxford 33 Lp NAB
Pacific Jazz (1-13) 33 400 -12
Parlophone
1925-1953 78 300 FLAT
1949-1953 33 500 FLAT
Period (up to 576)# 33 RIAA NAB
Philharmonia 33 400 -12
Polydor 33 300 -10
78 300 -10
Polymusic 33 RIAA NAB
binaural-inside band 33 RIAA FLAT
Rachmaninoff Society 33 Lp NAB
RCA-Victor
Early Acoustics* 71.29 300 FLAT
Later Acoustics* 76.59-78 300 FLAT
1925 78 300 FLAT
1931(Program Transcription) 33 800 FLAT
1935 78 300/RIAA -5
1938-1954 78 RIAA -8
1954 (New Ortho only) 78 RIAA RIAA
1930-50 (European) 78 300 FLAT
1949 (D9 to EOLRC3980)# 33/45 800 -8
1950-8/52 (>E0LRC3981)# 33/45 RIAA -12
8/52(New Orthophonic)(>E2RP4094) 33/45/78 RIAA RIAA
Remington (up to 199-135)# 33 RIAA NAB
Page #9

MANUFACTURER SPEED BASS (TURNOVER) TREBLE (ROLLOFF)
=================================================================================================
Riverside 33 400 -12
Renaissance 33 Lp -12
Stradivari 33 Lp NAB
Supraphone 78 400 FLAT
Technichord 78 800 -12
Telefunken 78 400 -5
Tempo 33 RIAA NAB
Transcriptions(many pre-WWII) 33/78 RIAA FLAT
(vertical-old) 33 300 -5
(vertical-NAB) 33 400 NAB
Transradio 33 Lp NAB
Ultraphone 33/78 400 FLAT
Urania-old (to XTV21093**)(low take nos) 33 Lp NAB
(up to E2KP9607) 33 RIAA -12
(up to XTV20383)(low take nos) 33 Lp NAB
Vanguard (411-422, 6000-6018, 7001-7011, 33 Lp NAB
8000-8004,(up to XTV20383)
Vox (up to XTV20386**), PL8400)# 33 Lp NAB
War Department-Special Services - 12" 33 800 -5
Weathers (Acoustimetric) 33 RIAA RIAA
Spectrumax 33 400 -12
Westminster (EO matrix) 33 800 -8
(up to E2KP9607) 33 RIAA -12
(up to XTV20383)(low take nos) 33 Lp NAB
Victor All See RCA-Victor See RCA-Victor
Vitaphone(motion picture) 33 300 FLAT
Vocalion(electrical) 78 300 FLAT
Western Electric(early transcripions) 33 300 FLAT
Zonophone 78 300 FLAT
(early)* 71.29 300 FLAT
RIAA, Ortho, New Ortho, New NARTB, New All RIAA RIAA
AES used on recordings since 1955
NOTES:
* On some recordings with very thin bass, such as 45 rpm EP's and acoustics, 629,800 or
1000 Hz Turnover may be used with appropriate rumble filter.
** Sometimes,one side has an old matrix number, the other new; two Eqs. Also, the first known matrix for the sticker is
ZLP31315/6-3G/1G, a 7 inch disc. Columbia pressed other record labels, and they too may vary in RIAA introduction date
and (XTV) matrix numbers.
*** Only for non-“R” matrix with punched, large-font, raised matrix numbers.
# These are approximate record numbers circa adoption of RIAA
Page #10

SOURCES:
Many suggestions, data, and techniques from John M. Kaar, and Peter Copeland.
Letter from E.C. Forman to John M. Kaar, 1935.
Drawing KRD-1384, from letter of H. I. Reiskind of RCA to John M. Kaar, 12-10-49.
Personal correspondence from Emery Cook, 1987.
Letter from V. C. Houk of RCA to John M. Kaar, 10-26-48.
Letter from H. I. Reiskind of RCA to John M. Kaar, 4/11/50.
Personal correspondence and articles from Peter Copeland, 2002.
Evolution of a Recording Curve, R. C. Moyer, Audio, 1953.
McIntosh Laboratory, C-8, C-22 Manuals.
High Fidelity Magazine, Dialing Yor Discs, 1953-57.
Fisher Master Audio Control 80-C operating manual.
Pickering Record Compensator manual.
Packburn 323A operating manual.
Source Engineering Specialist Preamplifier operating manual.
Western Electric 9A reproducer manual.
RCA Universal Tone Arm And Filter Kit MI-11870 manual.
Radiotron Designer’s Handbook
ARSC Journal, Vol 37, No.1, article by Powell, Stehle, Powell.
The Recording and Reproduction of Sound, Oliver Read, 1952.
Radio & Television News, Charles Boegli, 1953.
Getting the Best from Records, Wireless World, February, 1940, P. G. A. H. Voigt.
Preamplifier Switching and Equalizing Unit for Critical Listening, M. V. Kiebert, Audio, 1952.
Professional Equalizing-Preamp Suitable for Home Use, K. W. Betsh, Audio, 1957.
FREQUENCY RESPONSE OF RE-EQUALIZER III FOR VARIOUS SETTINGS OF TURNOVER AND ROLLOFF
Esoteric Sound
1608 Hemstock Ave.
Wheaton, IL 60189
630-933-9801
E-Mail: [email protected]
Page #11