C.A.T. JL7 Black Path Edition User manual

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TABLE OF CONTENTS
Unpacking Your Amplifier 3
Turning on the Amplifier 3
OptiBias™ 3
Replacing your Power Tubes 3
New Power Tubes 4
NOS Driver Tubes 4
Mechanical Grounding 4
Tube Dampers 4
Power Conditioners 5
Special Power Cords 5
Break In 5
Warm up 5
Use of Output Taps 5
Choice of Output Tap 5
Tube Layout 6
How To Replace the Lamp in the Power Switch 7
Packing up Your Amplifier 8
Warranty Registration 9

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Congratulations on your purchase of the Convergent Audio JL7 A mplifier. Your
decision is an indication that you are a dedicated Audiophile, seeking the state of the
art in music reproduction.
UNPACKING YOUR AMPLIFIER
Open the box from the top. Remove the top piece of foam. You will now see a cardboard
“cradle”. Carefully lift the amplifier out of the box by the handles on the ends of this
cradle. Leave the foam sheets, which are taped to the cradle in place. These will be
needed to protect the amplifier next time you pack up it up.
Before turning on your amplifier remove the bubble packs from inside the metal tube
cages. These bubble packs protect the tubes during shipping
TURNING ON YOUR AMPLIFIER
When you first power up your JL7 you will see that the light labeled “Tube Life” will
come on RED. After a minute or so it will turn GREEN indicating that the tubes are in
good condition.
OPTIBIAS
The JL7 uses a novel new bias circuit we call OptiBias™. With this circuit user bias
adjustment is not necessary. The tubes will bias themselves correctly over a + or -10%
range of line input voltage. This OptiBias™ circuit doesn’t merely hold the current steady,
like the op amp and computer biased circuits of other amplifiers; it actually optimizes the
bias current for the different line voltages in different homes. In fact when the line
voltage goes UP the bias current will go DOWN by the amount which we have
determined here at CAT to produce the best sound. Not only is this a better sounding
method than the “hold it constant” method used by other manufacturers it also
completely eliminates the bad sounding op amps and/or digital processors used to
implement these other schemes.
WHEN WILL YOU KNOW TO REPLACE POWER TUBES JL7
We expect about 6 years of tube life for your output tubes under normal usage. We run
the tubes at a very low power level because this produces the effortless dynamic sound
we prefer at CAT, but this also has the added side benefit of resulting in very long tube
life.
One day you will turn on your JL7 and the “Tube Life” indicator will stay RED not
switching to GREEN. This indicates that your tubes need to be replaced. There is no
urgency to do this immediately, but it should be done soon.

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NEW POWER TUBES
The OptiBias™ circuit works best with tubes in the big middle section of the “bell shaped
curve” and so this is what we provide with your amps. This is also what we will provide
for you when the time finally comes to replace them. Therefore, we recommend that new
power tube sets only be bought from CAT.
DO NOT SUBSTITUTE DIFFERENT POWER TUBES! This will invalidate your warranty.
NOS DRIVER TUBES (SMALL TUBES)
We provide the best driver tubes ever made for your CAT amplifier. These tubes provide
the most natural sound quality, and your amplifiers have been designed around them.
However, feel free to experiment if you wish!
MECHANICAL GROUNDING
Your amplifier is equipped with high loss visco elastic feet which do a very good job of
isolating the amplifier from structure born vibrations. In most situations these will be the
best sounding feet to use.
In cases where the floor is particularly vibration free, especially if the floor is on a
concrete slab, you may get slightly better bass definition by coupling the chassis directly
to the floor. This is best accomplished by using Audio Selection cones. Two are in the
back and one in the front. DO NOT remove the open cell foam on top of the foot, as this
prevents the chassis from chattering against the top of the foot. It is not necessary to
remove the protective layer and actually glue the foot to the bottom of the chassis. There
are other good devices available as well but under no circumstances should you use any
device which places a flat hard surface in contact with the amplifiers chassis. Such devices
always create mechanical resonances which are claimed to enhance “detail”. Your CAT
amplifiers are the most transparent amplifiers in the world. Mechanical noises which
masquerade as “detail” with lesser amplifiers are instantly revealed as false with your
amplifiers. If you must place a foot with a hard surface under your amplifier please put a
piece of felt between the cone and the bottom of the amplifier.
TUBE DAMPERS
Don’t use them

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POWER CONDITIONERS
CAT amplifiers have built in isolation transformers which already provide tremendous
power conditioning. Use of any additional external devices will restrict current delivery
and degrade dynamics and bass response.
SPECIAL POWER CORDS
Your amplifier is provided with a decent standard power cord. Feel free to experiment,
but beware of cords which sound significantly “different”. In our experience, this is a bad.
Subtly better is what you should look for, better bass definition, blacker, tighter etc.
BREAK IN
Your amplifier will sound better after a few hours of use. We play amplifiers here for at
least 72 hours, so they usually sound quite great right out of the box, but they will still
improve a bit after another few hours of playing time. Leaving the amplifier on without
playing music will NOT help break in your CAT amplifier!
WARM UP
Your amplifier will sound best after about 15 minutes of dynamic warm up, playing
music at normal levels. Simply leaving them turned on will do nothing regarding warm
up. We are aware that many other products, especially solid state, do indeed benefit
from static warm up. If you have such a product let it warm up by itself. There is no point
in wasting tube life by leaving the amp on without playing music.
USE OF OUTPUT TAPS
The JL7, like most tube amplifiers, have output taps to maximize power output into either
4 or 8 ohm speakers. The negative, usually black, speaker cable lead should be connected
to the negative terminal on either side of the amplifier and the positive terminal, usually
red, will be connected to either the “4” or the “8” terminal.
CHOICE OF OUTPUT TAP
Do not assume that the best sounding tap will be the one which maximizes power into
your speaker. Many times the other tap will sound best. Generally speaking the 4 ohm
tap will sound tighter and have better control, but the 8 ohm tap will sound bigger and
fuller. (The 8 ohm tap has been specially designed to deal with the high capacitance of
electrostatic speakers, so please be certain to try it if you have such a speaker.)

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HOW TO REPLACE THE LIGHT BULB IN YOUR POWER AMPLIFIER:
Unplug your amp first!
You must remove the red push button from the power switch. Grip the red button with
your fingers on the top and bottom of the side which is out the most. Gently pull it out. It
pops out easily. Inside you will see the top of the bulb. To the side is a flat metal
extraction bar. Pull the extraction bar straight out, the bulb will pop out. Now put the
new bulb in the hole and push it in. Replace the red cover with a gentle push. Now plug
in your amp.

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How To Repackage the CAT JL7 Power Amplifier:
1. Put the box on the ground.
2. Put the large piece of foam inside the bottom.
3. Put the amplifier in the cardboard cradle. Make sure the protective foam sheet is still in place,
particularly in the front where it protects the shiny front plate.
4. Line the box with the 4 smaller pieces of foam. The two smallest in the front and back
5. Gently lift the amplifier up in the cradle and lower it down into the box, between the 4 side
foams.
6. Insert the two folded up cardboard pieces on the left and right sides of the amp. Make certain
that the foam sheets taped to these pieces are touching the amplifier.
7. Fold the cardboard handles over the top of the amplifier. Make certain the protective foam
sheet covers the shiny mirrored finish top plate.
8. Put the other large foam piece on the top
9. Seal up the top of the box with packing tape.

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WARRANTY:
Your JL7 amplifier is warranted for six months from date of purchase. The warranty will be
extended to three years with the return of the completed warranty registration form within 30
days of purchase. Be sure to include a copy of the sales receipt to validate your registration.
Tubes carry a ninety day warranty.
WARRANTY REGISTRATION FORM
Name:__________________________________________________________________
Address:________________________________________________________________
City:___________________________________________State:__________Zip:_____
Phone:_______________________________ E-Mail: ______________________
Serial Number:____________________ Purchase Date:________________________
Dealer:_________________________________________________________________
What Hi Fi Magazines Do You Read?
________________________________________________________________________
Other Components in Your System:
THANK YOU!