MANLEY LABORATORIES, INC. OWNER'S MANUAL MANLEY TAPE HEAD PREAMPLIFIERS MANLEY LABORATORIES, INC. 13880 MAGNOLIA AVE. CHINO, CA. 91710 TEL: (909) 627-4256 FAX: (909) 628-2482 EMAIL: emanley@manleylabs.com www.manleylabs.
CONTENTS MANLEY TAPE HEAD PREAMPS USER and TECHNICAL MANUAL 3) INTRODUCTION (mostly hype but you can quote us) 4) IMPORTANT (read this even if you hate manuals) 5) WARNINGS (because we have to) 6) TECHNICAL DETAILS (for the person who has to plug it in) 7) ALIGNMENTS (for the person adjusting it daily) 8) PLAYBACK HEADS (yes, you now need special heads) 9 & 10) ALTERNATIVE VERNIER CALIBRATION (cool trick) 10) OTHER LITTLE HINTS(more hints for the cable builder) 11 & 12) EQ ( tech talk) 13) REPL
INTRODUCTION THANK YOU!... for choosing the Manley and congratulations on your purchase of MANLEY LABS TUBE TAPE PREAMP. This product is the result of continual evolution from the era when all tape machines were vacuum tube based to the present with refinements and improvements virtually every year. This preamp was designed to meet the extreme requirements of Mastering Engineers and Audiophile Record Labels.
IMPORTANT Do NOT connect or disconnect the POWER SUPPLY CABLES with the power on. Disconnect the mains plug first. Wait 3 minutes after powering off to remove the power supply cable. This allows various capacitors to discharge. We do not want anybody electrically shocked. The power supply cable carries about 470 VAC and 17 VAC. Several reasons less important than safety exist for the above warning.
WARNINGS WATER & MOISTURE As with any electrical equipment, these preamplifiers should not be used near water or moisture. If liquid enters the preamplifier, it must be immediately returned to your dealer or the factory for servicing. SERVICING The user should not attempt to service the preamplifier beyond that described in the owner's manual. Refer all servicing other than biasing and tube replacement to Manley Laboratories SPECIAL NOTES Tubes may become loose during transit.
TECHNICAL DETAILS The tape inputs are unbalanced however the POLARITY switch governs which XLR pin is used for “positive” signal from the “floating” head coil. Normally Pin 2 is signal, Pin 1 and Pin 3 are grounded but if the switch is set “180” then Pin 3 is signal and Pin 1 and Pin 2 are grounded. The input impedance is variable from 4K to 250K depending on the setting of the VHF control. Notice that “loading” the head affects its hi frequency response. The EXT inputs are unbalanced.
ALIGNMENTS ALIGNMENTS Let us assume that the head has been properly mounted and the cables have been installed and the preamps are solidly mounted. Let us also assume you have access to an alignment tape or the reel to be played has well recorded tones with 50Hz, 100Hz, 1KHz, 10Khz and 15Khz or 20Khz. 1)With the power off - Demag and clean the heads and tape path. Verify input, output and power cables are correctly attached then turn the power on and wait 5 minutes for the preamp to be well warmed up.
Playback Heads Manley Playback Heads are custom manufactured new heads of a better quality than can be obtained in any stock tape machine of any vintage. They are manufactured by JRF Magnetics. We strongly recommend that you only use playback heads supplied by Manley Labs or those under licence from Manley Labs. The reason for this is that these are vacuum tube based units designed for "high impedance" playback heads typically 500mH (mili-Henrys).
ALTERNATIVE VERNIER CALIBRATION Some mastering engineers have found that the following procedure helps with their day to day use of these preamps. The procedure essentially gives a reference vernier setting that shows them immediately if todays tape is “unusual”. It simply involves “moving” the verniers so that a typical tape will read “50” on each dial. This is easy on all but the LF control where a reference setting of “30” may be needed simply to have sufficient range of this control.
ALIGNMENT, CONTinued 8) Verify that each vernier freely adjusts from “0” to “100”. Hopefully they should. If one doesn’t its because the pot is at the end of its travel. If this is the case either decide that a number other than ”50” is OK or that it is unlikely that the extreme setting is will ever be needed. 9) Power off, Wait a few minutes, Slide the top back on. The front panel has a notch to accept the perf panel and it is sometimes a bit tricky to get it in right.
EQ There is a fair amount of confusion amongst engineers regarding record and repro eq curves. The most important fact is that all repro heads have a frequency response characteristic that rises at 6 dB per octave. The prime EQ curve of any head preamp is the inverse of that rising response. A preamp “first” has to have a characteristic that falls in a straight line at 6 dB per octave. This translates to over 50 dB more gain at 20 Hz than at 20 kHz (AES 30 IPS).
MORE EQ We have these variable trims on all tape machine repro cards to further modify those “standard” curves to align a tape machine to another machine’s reality. Different manufacturers have different ways of accomplishing this. Some vary the repro characteristic curves by making some of the components involved variable. Others have fixed standard curves and add a basic high and low shelving EQ stage after the first network.
REPLACING TUBES How long will these tubes last? We can't say for sure. Some die prematurely and some tubes last more than 30 years. The average for the tubes in the Manley Tape Head Preamps seems to be 4 to 5 years depending on useage. As with all tubes, their quality degrades with age. This is due to decreasing cathode emission, a natural process found in all tubes.
WARRANTY All Manley Laboratories equipment is covered by a limited warranty against defects in materials and workmanship for a period of 90 days from date of purchase to the original purchaser only. A further optional limited 5 year transferrable warranty is available upon proper registration of ownership within 30 days of date of first purchase.
WARRANTYREGISTRATION We ask that you please fill out this registration form and send the bottom half to: MANLEY LABORATORIES REGISTRATION DEPARTMENT 13880 MAGNOLIA AVE. CHINO CA, 91710 USA OR you fax it in: +1 (909) 628-2482 OR you many go to the Service Form in the Tech Support section of our website and do your registration electronically at www.manleylabs.com Registration entitles you to product support, full warranty benefits, and notice of product enhancements and upgrades.
