CARVER TFM 15 Power Amplifier Owner's Manual

CARVER
TFM-15
High-Current/High-Voitage Power Amplifier
Owner's Manual
RISK OF ELECTRIC SHOCK
DO NOT OPEN
4 CAUTION
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK
DO NOT REMOVE COVER (OR BACK)
NO USER-SERVICEABLE PARTS INSIDE
REFER SERVICING TO QUALIFIED PERSONNEL
Safety Instructions
1. Read Instructions — All the safety and operation
instructions should be read before the Carver
Component is operated.
2. Retain Instructions — The safety and operating
instructions should be kept for future reference.
3. Heed Warnings — All warnings on the Component
and in these operating instructions should be fol-
lowed.
4. Follow Instructions — All operating and other
instructions should be followed.
5. Water and Moisture — The Component should not
be used near water - for example, near a bathtub,
washbowl, kitchen sink, laundry tub, in a wet base-
ment, or near a swimming pool, etc.
6. Ventilation — The Component should be situated
so that its location or position does not interfere with
its proper ventilation. For example, the Component
should not be situated on a bed, sofa, rug, or similar
surface that may block any ventilation openings; or
placed in a built-in installation such as a bookcase or
cabinet that may impede the flow of air through
ventilation openings.
7. Heat — The Component should be situated away
from heat sources such as radiators, or other devices
which produce heat.
8. Power Sources — The Component should be
connected to a power supply only of the type de-
scribed in these operation instructions or as marked
on the Component.
9. Power Cord Protection — Power-supply cords
should be routed so that they are not likely to be
walked upon or pinched by items placed upon or
against them, paying particular attention to cords at
plugs, convenience receptacles, and the point where
they exit the Component.
The lightning flash with arrowhead symbol
within an equilateral triangle is intended to alert
the user to the presence of uninsulated
enclosure, that may be of sufficient magnitude
to constitute a risk of electric shock to persons.
The exclamation point within an equilateral
tnangle is intended to alert the user of the
presence of important operating and main-
tenance (servicing) instructions in the literature
accompanying the appliance.
10. Cleaning — The Component should be cleaned
only as recommended in this manual.
11. Non-use Periods — The power cord of the
Jomponent should be unplugged from the outlet
when unused for a long period of time.
12. Object and Liquid Entry — Care should be taken
so that objects do not fall into and liquids are not
spilled into the inside of the Component.
13. Damage Requiring Service — The Component
should be serviced only by qualified service personnel
when:
A. The power-supply cord or the plug has been
damaged; or
B. Objects have fallen, or liquid has spilled into the
Component; or
C. The Component has been exposed to rain; or
D. The Component does not appear to operate
normally or exhibits a marked change in
performance; or
E. The Component has been dropped, or its
cabinet damaged.
14. Servicing — The user should not attempt to
service the Component beyond those means de-
PORTABLE CART WARNING
Carts and stands - The
Component should be used
only with a cart or stand that
is recommended by the
manufacturer. A Compo-
nent and cart combination
should be moved with care.
Quick stops, excessive force,
and uneven surfaces may
cause the Component and
cart combination to
overtum.
scribed in this operating manual. All other servicing
should be referred to qualified service personnel.
15. To prevent electric shock, do not use this polarized
plug with an extension cord, receptacle or other outlet
unless the blades can be fully inserted to prevent
blade exposure,
Pour préevenir les chocs électriques ne pas utiliser
cette fiche polariseé avec un prolongateur, un prise de
courant ou une autre sortie de courant, sauf si les
lames peuvent être insérées à fond sans laisser aucune
pariie à découvert.
16. Grounding or Polarization - Precautions should be
taken so that the grounding or polarization means of
the Component is not defeated.
17. Internal/External Voltage Selectors — Internal or
external line voltage selector switches, if any, should
only be reset and re-equipped with a proper plug for
alternate voltage by a qualified service technician. See
an Authorized Carver Dealer for more information.
18. Attachment Plugs for Alternate Line Voltage (Dual
voltage models only)— See your Authorized Carver
Dealer for information on the attachment plug for
alternate voltage use. This pertains to dual-voltage
units only.
This apparatus does not exceed the Class A/Class B
(whichever is applicable) limits for radio noise emis-
sions from digital apparatus as set out in the radio
interference regulations of the Canadian Department
of Communications.
ATTENTION - Le présent appareil numérique n'émet
pas de bruits radioélectriques dépassant las limites
applicables aux appareils numériques de class A/de
class B (selon le cas) prescrites dans le règlement sur le
brouillage radioélectrique édicté par les ministere des
communications du Canada.
WARNING - To reduce the risk of fire or electric shock,
do not expose this appliance to rain or moisture.
STOP!
PLEASE READ THIS!
Highlighted
Points Are
in Boxes
Ultra-important information about
hooking up and operating your TFM-15 is
enclosed in boxes like this one.
If you're an experienced hi-fi buff and don't
usually read manuals all the way through
(or are just super-impatient), at least read
all the info in the boxes throughout this
manual.
A MESSAGE FROM BOB CARVER
Thank you for choosing a Carver power ampli-
fier. We at Carver Corporation realize that there is
an abundance of home electronics from which to
choose, and that the differences between the vari-
ous models are not always apparent at first glance.
We strive to produce for you the finest in audio
reproduction equipment. Our intent is to inte-
grate the latest and best technology with the most
competitive price possible.
High current and high voltage
Our TFM-15 is capable of high simultaneous
current and voltage output. Judged against con-
ventional amplifier standards, it is second to
none; its sound quality is smooth, sweet and abso-
lutely dynamically accurate. It can deliver more
than 100 watts RMS per channel into an 8 ohm
loudspeaker with less than 0.1% THD and even
more power into lower impedances. In addition,
the closed-loop frequency response extends from
below 10 Hz to beyond 100,000 Hz.
Transfer Function Calibration
Your new TFM-15 Power Amplifier shares
many of the the sonic charactaristics of my refer-
ence Silver Seven Tube amplifier, including
extended low frequency ce, excellent
power bandwidth, low residual noise, stable per-
formance into complex impedances, flat
frequency response, low distortion and high dy-
namic headroom.
Made where?
Carver is American-owned and based in
Lynnwood, Washington. Of the almost 250
people who work here, most are engaged in build-
ing Carver home, mobile and professional audio
products. Carver's goal is and always will be to
provide audiophile-quality products at affordable
prices. Thus, we strive to take advantage of manu-
facturing economies and methods wherever
possible. As a result, we DO use outside produc-
tion facilities for some products and take great
pains to indicate the country of origin on your
packing box. Suffice it to say that the TFM-15 is
built to our specifications and is the great value it
is because we have chosen the most effective pro-
duction source for the particular model.
I am proud to present to you the best in crafts-
manship and design found in Carver electronics.
Bel Gomer
Robert W. Carver
President, Carver Corporation
HOOK-UP
Don't plug it in yet!
Do not connect the TFM-15 to AC power
until all signal connections have been
made and the installation is complete.
First things first.
Upon opening the box, please check for any
visible sign of damage that does not appear on the
outside of the box. If you do encounter what ap-
pears to be concealed damage, please consult your
Dealer before proceeding to further unpack the
unit.
If no damage is found, gently lift out the unit
by grasping the handles. After lifting the amplifier
out of the box, gently lift first one side, then the
TE E a ts
Please save the box, as well as all of the internal
packing materials! This container is the best way
to store and move your new Amplifier. If your
amplifier should need repair, the original con-
tainer is ideal for shipping to a Carver Service
Center.
Make a note of the serial number which is lo-
cated on the back of your Amplifier. Record it in
the space provided in this manual for convenient
reference. You will need to refer to this number if
you need service or if your unit is (perish the
thought) stolen.
Model: TFM-15
Serial number
Purchased at
Date
Make sure to save your sales receipt. It is ex-
tremely important to establish the duration of
your Limited Warranty and for insurance
purposes.
Finally, take a moment to fill out and return
the Warranty Card that came with the amplifier
and return it to Carver.
Amplifier Placement
The real no-no's are listed on the first page of
this manual. They include common sense stuff
like “don’t use the TFM-15 in your swimming
pool.” Assuming your location is OK, the ampli-
fier can be positioned as part of a “stack” of
components if some care is taken. Because the
TFM-15 is convection-cooled it requires clearance
for air to reach the ventilation slots on the top,
bottom, and sides of the unit.
Do NOT place the amplifier on deep-pile car-
peting or any similarly resilient surface that might
tend to block its ventilation slots from air circula-
tion.
The TFM-15 can be placed in an equipment
rack which has adequate ventilation. If your
shelves do not have open backs, make sure there
are vent holes in them. The situation you want to
avoid is placing your power amplifier in a sealed
cubbyhole such as that created by two shelves
abutting a solid cabinet back panel. That creates a
static air space where temperatures can rise
quickly.
Connection tips
We're about to launch into the actual nitty
gritty patch cord frenzy that results when you get
a new component. First, though, consider the
following tips.
EH Turn all other components OFF before making
any connections.
ME Make sure that “left is hooked to left and right
is hooked to right” at each connection. The
obvious way to assure this is to assign one
hook-up cord plug color to left and the other to
right. Generally RED is used to signify RIGHT.
White, grey or black then represents left.
№ Whenever possible, keep power cords away
from signal cables (inputs from CD player, tape
deck etc.) to prevent hum. This is especially im-
A TS
While hum is less of a problem
eta Mb вони: noise can still find
its way into your system if a component's
power cord becomes too intimately wrapped
up with a hook-up cable. Carver components’
power cords and convenience outlets are on
the right side of the chassis (when viewed from
dn-xXooH
the back). This allows you to bundle all the
power cords and keep them separate from sig-
nal connections.
BB Type of hook-up cords. Also called interconnects,
patch cords or RCA cables. There are lots of dif-
ferent grades of hook-up cables. You can pay as
much as $30 per foot for some of them!
Whether or not you get an incremental in-
crease in sound quality with “audiophile”
interconnects is up to your own ears. However,
really CHEAP connection cables can sometimes
DIS-connect themselves inside, causing a loss of
sound in one channel or hum problems. Be-
fore you send a component in for service, swap
hook-up cables to see if theyre the culprit.
Amp-to-preamp connection
The TFM-15 is designed to be compatible with
virtually any quality preamplifier, preamplifier/
tuner or CD player direct output.
1. Make sure that the TFM-15 is turned off. Better
yet, actually disconnect it from the wall socket
momentarily.
2. Use standard audio cables to connect the
RIGHT and LEFT INPUTS on the rear panel of
the TFM-15 to the appropriate OUTPUTS of the
preamplifier. It might help to refer to your pre-
amplifier (or tuner/preamplifier's Owner's
Manual at this point).
Preamplifier back panel
—J
TFM-15 back panel
Daisy-chaining
You can use the TFM-6C with other TFM-6C
amplifiers in a daisy-chain. Daisy-chaining lets
you run multiple speakers and TFM-6C amplifiers
throughout your house from a single input, such
as a CD player. (Daisy-chaining several amplifiers
together will not affect the quality of the input to
each TFM-6C.) For example, if you want to con-
nect several amplifiers in different rooms to the
same tape deck, you would run the cables from
one set of TFM-6C outputs to the next set of
TFM6C inputs, as shown below.
TFM-15 daisy-chain
Speaker connections
Your Carver TFM-15 has two sets of speaker
outputs on its back panel. You may connect two
sets of speakers and play either or both of them at
the same time using the SPEAKER A/B button on
the front panel. However...
Speaker impedances
While the TFM-15 is capable of high cur-
rent output into low-impedances, we do not
recommend playing two sets of 4-ohm
at high volume at the same time
(see “A further note about impedances”
farther on in this section). If you're not sure
of the Rated Nominal Impedance of your
, consult the owner's manual
which came with the speakers, or call the
manufacturer or your dealer.
Wire. Use thick wire for speaker connections.
Your Carver dealer can recommend a brand of
high quality, oxygen-free speaker cable. Or com-
mon “zip cord” from a hardware store can be
employed if care is taken to use the proper gauge.
Right Speaker A Left Speaker A
(as ibd or back) (as Viewed iron back)
Right Spgaker B
>d Mom back
(as vi
This will depend on the distance from the TFM-15
to your speakers. Use the following chart asa
guide:
WIRE LENGTH. ....... GAUGE OF ZIP CORD
UD ines... 18 gauge
DID ER cig 16 gauge
DO ZUR hir ais sase 14 gauge
ET meo 12 gauge
COI EE enseres 10 gauge
The greater the distance between your TFM-15
and speakers, the larger the diameter the wire
should be (wire thickness specifications or
“gauges” get larger as the wire gets thinner: Thus
16-gauge wire is thicker than 22-gauge wire).
Use the same length of speaker wire for both
speakers, even if one is closer to the amp than the
other. Coil up the excess and make sure it's well
away from your preamplifier's
turntable cables.
must be
connected with consistent polarity
for correct phasing between them.
Incorrect phasing will do no
physical harm, but bass re-
sponse will be diminished.
The key is to make
sure that both speak-
ers connected to the
A or B terminals are
hooked up the same
Way.
1) “nm at the
TFM-15 speaker out-
€ puts to “-" on the
" <A speaker back, and
A “+” at the TFM-15
outputs to “+”
on the back...and
2) Left TFM-15 speaker out-
puts to left speaker inputs, and right
ТЕМ-15 speaker outputs to right speaker
in
puts.
If you're using special speaker interconnects,
“+” and “-” will be identified. If youre using plain
appliance-type zip cord, the two conductors will
be differentiated in one of several ways. They may
be different colors (silver vs. gold). One may have
fine grooves on its outside. Or one may have a
piece of included in one of the conductors
(visible after you strip off the insulation). It
doesn't matter which one you decide to call “+” or
“.”, just do the same for both speakers.
Hook-up. The TFM-15 speaker terminals are
designed to accept bare wire, spade lugs, bananna
plugs.
1. If you're using bare wire, strip 1/2" of insulation
off each wire and make sure to carefully twist all
the fine strands together. If even one is loose
and can touch the opposite terminal, a short
circuit may result.
2. Unscrew each TFM-15 speaker terminal and
insert the wire as shown.
3. Tighten the connection again.
4. Larger-gauge "audiophile" speaker cables may
be too thick to be inserted directly into the
TFM-15 terminals. They may require special
connections such as banana plugs (shown) or
spade lugs. Attach the wires to the plugs and
then attach them to the TFM-speaker terminals
in the appropriate manner.
5. After you've hooked up one or two sets of
speakers, double-check your connections. This
may sound redundant, but we repeat: Be sure
that both speakers are connected in the same
way; positive (+) speaker terminal to positive (+)
amplifier terminal, and negative speaker termi-
nal (-) to negative (-) amplifier terminal.
Amp-to-wall-socket connection
The TFM-15 may be plugged into an extension
cord, splitter or properly rated preamplifier conve-
nience outlet (500 W rating). Avoid using thin,
lightweight cords. Note that one line plug prong
(spade) is slightly wider than the other and will
only insert one way into an outlet. Make sure this
polarity is maintained if an extension cord is used.
If you're using your new TFM-15 with just one
set of speakers, you can skip the next information
and go directly to page 10. If you're using both A
and B speaker connections, read on …
A further note about speaker
impedances
Why do we publish specifications for “2-ohm
and then warn you about not
using two sets of 4-ohm speakers at the same
time? Because impedance has several definitions
and becomes a factor at different times.
Speakers are not simply resistive loads. Instead
they are complex and reactive, drawing dispro-
portionately large “in-rush” currents in reaction to
transient Because music is dy-
namic, with multiple instantaneous peak power
demands, the speaker is constantly bombarded
with short transient voltage drive signals and con-
stantly drawing high “in-rush” currents. The
overall long term voltage and power draws are not
significantly higher than those of a resistive load.
But at any given moment, peak “in-rush” cur
rents must be delivered far in excess of the average
demands. If these cannot be supplied by an am-
plifier, distortion and reduced dynamic range
result. tices EA fhe:
like resistance, inductive reactance and capacitive
reactance. Realistically, it’s a factor of how the
will behave when connected to an ampli-
fier. The lower the impedance, the more amplifier
current will be required.
Modern most often have
NOMINAL im ratings of 4, 6, or 8 ohms.
This rating can be found in your speaker hand-
book, is often printed on the back of the
and can also be found in Audio
's Annual Equipment
The TFM-15 is designed for CONTINUOUS use
with 4-ohm or 8-ohm speaker impedances. If
you're just using one set of speakers, there's no
problem — virtually anything you connect to the
TFM-15 will have a nominal impedance of 4, 6, or
8 ohms. But if you're TWO sets of
the impedance of both sets becomes im-
portant — and interactive.
Impedances for two sets of being -
ated at the same time uses the Bowing Sums
Total ce (Z) of such a system is calcu-
lated with the following formula:
Z.= Z XZ,
Z, +2,
WhereZ and Z, are the individual im
of the two speaker systems. That leads to the
following chart:
Speaker Pair Speaker Pair Combined
B Impedance OK/NO
8 not used ............... O cuina OK
O cin NO USE see Gin OK
SET not used ... 4 „OK
Вс: Cen ina 4 .... OK
6... гене В соооннн 3.4 … No
E [ Lessrensensansnnnences . NO
& ы a an did. sei NO
4... seis ose 2 .... NO
As you can see, two sets of 8-ohm speakers in
parallel represent a 4-ohm total load, which is OK.
However, two sets of 4-ohm speakers is a 2-ohm
load and is not recommended.
Now what about “2-ohm dynamic power”?
First, it's important to understand that NOMINAL
is a fancy way of saying average. While a speaker
is nominally rated at a single impedance, it can
actually vary widely over the entire frequency
range. Shown below is a popular 3-way
$ true im curve. Note that it
varies almost 10 ohms across the 20Hz to 20,000
Hz musical spectrum.
в
2 ohms
E
And yet its published “Nominal Impedance” is
6 ohms! Obviously, 6 ohms is an optimistic aver-
age, NOT a constant.
Note also that this popular, widely-distributed
takes its most serious impedance plunge
in the lowest frequencies where the most power is
required from a amplifier. This design's
perilous 50 Hz and 100 Hz dips d with
many musical instruments including kick drums,
floor tom drums, tympani, plucked double bass
viols and electric bass guitars. You can imagine
how an amplifier is taxed on a well-recorded CD
at realistic listening levels with this speaker.
In addition, because music has wildly varying
frequency distribution (and listeners have wildly
different opinions of what to do with bass and
loudness controls), problems stemming from low
speaker impedances can be frustratingly
intermittent.
Whether anything unpleasant happens when a
speaker's impedance dips into the 2-ohm range
during a song depends on the amplifier design —
particularly its ability to produce large amounts of
current for short of time into low i
ances. We have designed the TFM-15 to satisfy
momentary low im power demands and
that's where the design's “2-ohm dynamic
power” rating comes from. Still, it doesn’t mean
you should operate the amp into a “nominal” 2-
ohm load which may dip under 1 ohm.
Following a short section on the TFM-15's front
panel features, you'll be ready to start enjoying
your new Carver power amplifier.
Front panel features
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1. POWER SWITCH. The TFM-15's POWER
switch should not be switched ON if your pre-
amplifier is turned up loud. Press MUTE on the
preamp, lower the volume control or choose
an input which is not playing, before turning
on the TFM-15.
Switched outlet power rating
The TFM-15's POWER switch can be left
in the ON position if the amplifier has been
plugged into the SWITCHED outlet of a
preamplifier or tuner/preamplifier.
However, the switched outlet's power rating
should not be LESS than 500 watts. Con-
sult your preamplifier manual if necessary.
NOTE: When the TFM-15 is first switched ON,
the inputs will be muted for about four seconds to
allow the amplifier to stabilize. This transient de-
lay circuit helps prevent speaker-damaging
THUMP's when powering up. But because we
cannot vouch for the rest re your signal chain, it is
suggested that you turn on the TFM-15 after your
preamplifier, CD player, tuner, etc. However,
make sure that a loud signal source is not playing
through the preamplifier when you turn on the
power amplifier.
2. SPEAKERS A/B buttons select the pair of
speakers you intend to listen to. If you have
connected two pair of 8-ohm speakers, you can
select both A and B speaker systems and play
them both at the same time. If one or more of
the speaker systems has a lower impedance (see
page 8), you should only select A or B, not both
at the same time.
Speaker switching at high levels
Avoid switching the TFM-15's A-B speaker
selector when playing the power amplifier
at high volumes.
. POWER METERS. The TFM-15 employs bal-
listically-weighted analog power meters which
are calibrated in watts. These “1” and “X 0.1”
scales serve as relative indications of amplifier
output voltage. Meter ballistics include a speci-
fied amount of over-shoot. Therefore, on
much musical material, the meter will often go
past OdB. At this point, the TFM-15's head-
room will be exhausted. Because different
musical material interacts differently with the
ballistics of the meter, the best way to tell if the
amplifier is overloaded is to simply listen. If
you hear distortion at the same time the meter
is “pegging”, vou have probably exhausted the
TFM-15's power reserves.
. INPUT LEVEL controls are used to adjust the
incoming signal level. Normally both left and
right INPUT LEVEL knobs should be set at
MAX (see the next section for more informa-
tion). Wherever they end up being set, both
should be adjusted to the same relative
position.
5. METER RANGE button. When this control is
in its OUT position (not pushed), the TFM-15's
meters will indicate watts of output power via
the upper meter scale. You could think of this
as the “TIMES 1” position.
However, amplifier power output and volume
are not linear. At moderate background music
levels, your speakers may not be drawing much
more than 1 watt, and you won't see much
meter movement. So we've provided a second
level of meter sensitivity, the “X0.1” setting.
When you press the METER RANGE button in,
the meter indicates just 1/10th of the total am-
plifier output on the lower meter scale. In
other words, the meter's display has been
“magnified” ten times. With the button in the
“X0.1” position, a watt of power now moves
the meter as much as 10 watts does when the
METER RANGE button is not pushed in.
If you are playing the TFM-15 at high volumes,
do not leave the METER RANGE button in the
“X0.1” position, to avoid damage to the meter
movement.
Operating
Tips
Make every effort to keep your amplifier away
from high external temperatures, moisture, and
airborne substances that can leave greasy deposits
and dust. When panels and covers become dirty,
they can be cleaned with a soft cloth slightly
moistened with a diluted ammonia solution.
Never use detergents, abrasives, or a wet cloth.
Since the TFM-15 is used in conjunction with a
preamplifier or tuner/preamplifier, there aren't
really any operating instructions except to turn it
on AFTER the preamp and set the INPUT LEVEL
knobs to the MAX position. Still, there are at least
two things which you can check before general
use: L/R connections and speaker polarity.
A short test-drive
1. Turn the TFM-15's INPUT LEVEL controls all
the way down.
2. Turn on your preamplifier, sound source (such
as a CD player) and then the TFM-15.
3. Make sure the volume control on the pream-
plifier is turned all the way DOWN (to MIN on
Carver models).
4. Carefully turn the INPUT LEVEL controls on
the TFM-15 to MAX. Listen for hum or noise.
If you hear any, consult the "Help! Trouble-
shooting Guide" farther on in this manual.
5. Press PLAY on the sound source.
6. S-1-0-0-w-I-y turn up the preamplifier volume
control to your “normal” listening level. If the
volume increases quickly and you can't rotate
the volume knob very far before the sound
level gets deafening, see “Aggressive preamps”
below.
If you don't hear anything, consult “HELP! A
troubleshooting Guide, farther on in this
manual”. Otherwise:
7. Rotate the preamp's BALANCE CONTROL all
the way to the left. Does the sound move to the
left speaker? If it heads the other way, 1) your
LEFT and RIGHT SPEAKER OUTPUTS need to
be switched or; 2) the hook-up cable connec-
sdiy бицелэйо y saanjeay jpued 1UOJJ
tions between preamplifier and the TFM-15
have been interchanged and need to be
switched. Make sure to turn off the TFM-15 be-
fore making either change.
Changing audio connections
The amplifier must be tumed OFF for at
least ONE MINUTE before any AUDIO
cables may be disconnected.
8. If your preamp has a MONO button, have
someone push it while sitting in your normal
listening position between the loudspeakers. If
there is very little perceived change when
MONO is pushed, the “+” and “-” leads of one
speaker are connected differently than the
other. This is called “out of phase” and results
in poor bass response. On the other hand, if
the stereo sound field “collapses” when MONO
is pressed you've made your speaker-to-TFM-15
connections correctly.
If your preamplifier doesn’t have a MONO but-
ton, you can do the same test by listening,
switching the “+” and “-” leads of ONE speaker
and then listening again. Make sure to turn the
TFM-15 off when making the temporary
switch, however.
9. Tum the preamplifier volume down to a back-
ground listening level. Note how little the
TFM-15's meters move. Now press the “X0.1”
button. Big difference.
Aggressive preamps
Normally, you should be able to turn the
preamplifier’s volume control knob up almost all
the way (depending on your speakers and how
loud you consider loud to be). The following
drawing shows how things SHOULD work — and
will with all Carver preamplifiers and preamp/
tuners.
Normal Preamp Volume Range
With “standard” output preamplifier
and TFM-15 controls set to MAX as recommended
However, occasionally a preamplifier design
has a higher output level than the norm. In this
case, setting the TFM-15's INPUT LEVEL controls
to MAX severely restricts the range of control
that's possible with the preamp's volume control.
If the preamp is sufficiently high output, you may
not be able to move the volume control past 11
o'clock before the sound level is deafening.
Loy
ao
- TFM-=15 PNPUT LEVEL - À
Reduced Preamp Volume Range
Due to high output © MAX TFM-15 level
There are two drawbacks to that situation. First,
you run the risk of seriously over-driving the TFM-
15 and hence your speakers (even if YOU never
turn the volume knob very far, someone else
come along and do so). Second, it's hard to make
slight adjustments in volume when you have
such a limited range.
The answer is to reduce the TFM-15's input
sensitivity.
Optimal Hi-Output Preamp Volume Range
With TFM-1 input control
to compensate for high preamp gain
L - VFM-15 INPUT LEVEL - À
1. Tum on your preamplifier, sound source (such 4
as a CD player) and then the TFM-15. e
2. Make sure the volume control on the pream- *
plifier is tumed all the way DOWN (to MIN on
Carver models).
3. Make sure both INPUT LEVEL controls on the = d
TFM-15 are turned to MIN (that’s all the way to g U + e
the LEFT).
4. Press PLAY on the sound source. Before returning your TFM-15 to the dealer or
5. Advance the preamplifier volume control to 3 Service Center for repair, review the “symptoms”
o'clock (see illustration below). and “cures” in this section. In a vast majority of
situations, the problem can be traced to one of the
6. S-l-0-0-w-ly advance the TFM-15's left and right following:
INPUT LEVEL controls until the sound is as . imei
pes 1. Controls or connections incorrect.
loud as you'll EVER play your system. 2. TFM-15 internal protection circuits activated.
7. Reduce the preamplifier volume so that you 3. TFM-15 protection fuse blown
don't get a headache and/or evicted. First, check connections and controls.
8. Double-check that both TFM-15 INPUT LEVEL
controls are set exactly to the same point.
Then, if necessary, make fine adjustments to Handy Troubleshooting Shortcut
the individual LEFT and RIGHT controls to bal-
the soun | The TFM-15's power meters are a valuable
mie EE troubleshooting aid. If the problems in-
volves loss of sound in one or both
channels, try the following:
1. Set the TFM-15 SPEAKER A and
SPEAKER B switches both to OFF.
2. Tum the TFM-15 INPUT LEVEL con-
trols fully down.
3. Set the TFM-15 METER RANGE switch
to "X0.1."
4. Tum on the preamp and music source.
THEN tum on the TFM-15.
92135 Y Bunoousajgno. |
5. Set the preamp volume control to the
"12 o'clock” position (straight up).
6. Slowly tum up the TFM-15 INPUT
LEVEL controls equally and watch the
power meters for an indication of signal.
7. If both TFM-15 power meters indicate
the presence of signal, then the entire signal
chain (sound source/preamp/TFM-15) is
probably OK. In this case, check you
speaker connections.
8. If you have no indication from one or
both power meters, use the troubleshooting
tips that follow:
The meters don't light when POWER
switch is tumed on.
1. Line cord disconnected.
2. Poor fit between plug and wall receptacle.
3. Power off at wall receptacle (check it with a
tester, lamp or VOM meter).
4. If amplifier is plugged into switched preamp
receptacle, the preamplifier is turned off.
5. TFM-15 fuse is blown and needs replacement
with one of the same rating. WARNING:
NEVER replace or check a fuse while the unit is
plugged into an AC outlet.
Amplifier runs initially, then no sound.
1. TFM-15 internal protection circuit has been
activated. See below.
2. TFM-15 fuse has blown. WARNING: NEVER
replace or check a fuse while the unit is plugged
into an AC outlet. The amplifier must be
turned OFF for at least one minute before any
AUDIO cables may be disconnected.
Sound cuts off when
VOLUME control is tumed up.
1. Check speaker wires for a short.
2. Check speakers for damage which may have
caused an internal short.
3. Make sure that the TFM-15 is not driving an
excessively low im due to more than
one set of 4-ohms speakers being connected at
once.
or gr le but no sound from
bo aie
1. Make sure that the TFM-15 INPUT LEVEL
controls are turned up.
2. Check preamplifier-to-power amplifier cables.
3. Make sure that all preamplifier controls, espe-
cially TAPE MONITORS are set correctly (A
TAPE MON button accidently pushed in is the
number one cause of unexpected silence).
4. Make sure that the correct preamplifier input
sound source has been connected.
5. Check speaker fuses.
6. TFM-15 fuse has blown. WARNING: NEVER
replace or check a fuse while the unit is plugged
into an AC outlet. The amplifier must be
turned OFF for at least one minute before any
AUDIO cables may be disconnected.
7. Make sure that the correct speaker output has
been selected with the TFM-15's SPEAKER A/B
buttons.
No sound in ONE channel or ONE channel
has distorted sound.
1. Check preamp BALANCE control. Turn back
to center position.
2. Make sure both TFM-15 INPUT LEVEL controls
are turned up.
3. After turing the TFM-15 off, check speaker
wire connections by momentarily switching
LEFT and RIGHT speaker cables at the
amplifier’s speaker output terminals. If the
dead channel does not switch sides, one of the
wires is to blame. If the dead channel
does switch sides, the problem lies in 1) the pre-
amp-to-TFM-15 hook-up cable, 2) the
amplifier, 3) one of your speakers.
4. Check speaker fuses.
5. Replace preamplifier-to-power amplifier cables.
You can test them by simply switching LEFT
and RIGHT plugs at the TFM-15 end. If the
dead or weak channel switches sides, you have
a bad hook-up cable. (NOTE: Remember to
leave the TFM-15 turned off for one minute be-
fore switching cable connections.)
Hum and constant noise
1. Defective signal cables.
2. Improper fit between signal cable plug and
sockets.
3. Signal cables have been routed too closely to
AC cables, power transformers, motors or TV
sets.
4. Turntable or cassette deck may be oriented in
such a way that it is picking up induced hum
from internal AC wall wiring,
component’s position slightly.
The TFM-15's rear panel fuse
Your new amplifier incorporates a main fuse
along with a specifically designed protection cir-
cuit. The fuse value and type allows the TFM-15
to track the most powerful musical waveforms
without compromising amplifier protection. Do
NOT increase the fuse value under any circum-
stance. Replace with original value and type only.
The TFM-15's internal protection circuits
Overcurrent Protection Circuit. The TFM-15
will mute if the speaker wire at either the amplifier
or the terminals is shorted (in some ex-
a a
inside the speaker itself. Not a pretty sight.). If
such a short or abnormal load occurs, the ampli-
fier will break the connection, protecting both
amplifier and speakers.
Transformer Breaker. The TFM-15's
power supply transformer is internally
with a thermal-cutout switch which operates
when the transformer core reaches 140 degrees
centigrade. This generally occurs only when the
amplifier has been driven flat out at high volumes
for long periods of time, or when proper ventila-
tion cannot occur.
DC Fault Detection. If one of the components
inside the TFM-15 should malfunction and pro-
duce a significant DC voltage (above +2 VDC, the
amplifier will power down to a safe output level.
Thus protecting the loudspeakers.
Service Assistance
We suggest that you read the LIMITED WAR-
RANTY completely to fully understand what your
warranty/service coverage constitutes, and its du-
ration. It will greatly help us provide warranty
service if you have returned the WARRANTY
REGISTRATION CARD.
BE 15 should require service, we sug-
gest you first contact the Dealer from whom you
purchased it. Make sure to bring your sales in-
voice, since it is necessary to establish when you
bought the TFM-15 and hence, the duration of
your Limited Warranty.
Should the Dealer be unable to take care of
your needs, you may contact the CARVER Service
ai by cheri (206) 775-6245, or by
writing CARVER CORPORATION, Service Depart-
ment, P.O. Box 1237, Lynnwood, WA 98046.
We will then direct you to the nearest in our na-
tional network of Authorized Warranty Service
Centers, or give you detailed instructions on how
to return the product to us for prompt action.
We wish you many hours of musical enjoy-
ment. If you should have ons or
comments, please write to us at the above address.
Specifications
Power:
100 watts RMS per channel into 8 ohms both
channels driven 20-20kHz with no more than
0.1% THD.
140 watts RMS per channel into 4 ohms both
channels driven 20-20kHz with no more than
0.1% THD.
200 watts dynamic power into 2 ohms
Frequency Response:
+0,-0.3dB 20-20KHz
Noise:
110dB A-weighted referenced to rated power
Gain:
39 dB
Input impedance:
30K ohms
Power Requirements:
Ao USA & Canada
VAC, S0Hz, Europe
Dimensions:
3-5/8"x19"x 13"
92mm x 482mm x 332mm
Weight:
17.2 Ibs
7.8 kgs
suoge>upads
© 1990 All Rights Reserved, Carver Corporation Pub. No. 900830-B. Part No. 990-20099-00 Rev. B
Written, designed and produced in Lynnwood, Washington, U.S.A.
PRINTED IN TAIWAN
TFM-15cb VOLTAGE CONVERSION
230 Volt Operation
ve
DISCONNECT THE TFM-15cb FROM THE AC POWER
OUTLET.
Locate the AC SELECTOR switch on the back panel.
Set the switch to the 230V position.
Unscrew the fuseholder cap and replace the fuse with
3.15 amp time delay fuse.
Install the 230V adaptor on the TFM-15cb AC plug.
110-120 Volt Operation
DISCONNECT THE TFM-15cb FROM THE AC POWER
OUTLET.
Locate the AC SELECTOR switch on the back panel.
Set the switch to the 115V position.
Unscrew the fuseholder cap and replace the fuse with a
5 amp time delay fuse.
Remove the adaptor from the TFM-15cb AC plug.
P/N 990-10023-01 Rev. A
TFM-15cb
Owner's Manual Addendum
Bridged Mono Operation
To use the TFM-15cb as a 280 watt mono power amplifier:
IMPORTANT: Turn the TFM-15cb power off before changing any connections.
Ч
Connect the speaker (-) wire to the red RIGHT speaker terminal on the
TFM-15cb.
* Connect the speaker (+) wire to the red LEFT speaker terminal on the
TFM-15cb.
For stereo operation (2 TFM-15cb's required):
e Connect the preamplifier LEFT output to the LEFT input jack on the
TFM-15cb.
* Connect the preamplifier RIGHT output to the LEFT input jack on the
second TFM-15cb.
For mono operation (center channel or subwoofer):
* Connect the preamplifier or processor output to the LEFT input jack
on the TFM-15cb.
Set BRIDGE/STEREO switch on the back of the TFM-15cb to the
BRIDGE position.
Use the left input level control on the TFM-15cb to adjust the input
sensitivity (see page 11). The right input level control on the TFM-15cb
is disabled in bridged mono mode.
(AR EH E 990-10022-01
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