Ampete 444 User manual

Owner's Manual 444
Ampete
444
Owner's Manual
Ampete Engineering GbR
Gutenbergstrasse 48
50823 Cologne
Germany
on 49 (0) 221 55 94 118
ax 49 (0) 221 55 94 118
mail [email protected]
web www.ampete.com
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Owner's Manual 444
__________________________
Ampete Engineering GbR, 2014
Ampete is a registered trademark
copyright 2014, all rights reserved
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Owner's Manual 444
We all
... produce electronic waste! It's just a matter of time!
We here at Ampete En ineerin are not only consumers, like you yourselves, but also en ineers of electronic
products that we want to place into a modern world. Here it looks at first lance that everythin has been
invented already. But demands are ettin more refined and specific by the day and as in the economics,
the sports- or even spiritual world, performance, utility and consistency depend on small chan es and
nuances in improvements. In other words we are supposed to et better every day. This is not a one way
street, it's a hu e responsibility in the other hands!
For us it means more than wantin a slice of the pie. It means to review every sin le product we desi n for
its added values, to anticipate the circumstance you put it into in order to ‚simply' be able to maintain it
everywhere it has been sold to.
Today our whole life is determined by electronics, at home, on the road, at work or vacation, in
supermarkets, concert arenas or even in natural resorts.
Today in eneral electronics aren`t built any lon er to last! They`re cheap.
For people from the 70ies like us it is a turnin point. We rew up in a world where an electronic device is
nothin short of a masterpiece. Today 90% of electronic applications are manufactured by usin robots or
exploitation in countries where ` lobal players` celebrate the abolition of workers protection and minimum
salaries. But it doesn’t end there.
After an expected life cycle, more or less short, the cheap electronic waste is onna be ‚disposed‘ of. Dispose
mi ht su est that components like housin , metal and synthetics will be recycled to find their way back
into a product. But of course often this is not how it is done!
If you ever heard of 'toxic city' (and I don't mean the fantastic album of a reat band) you probably know
what we speakin of.
It mi ht surprise you to read this in a manual for an electronic device.
We want to make sure you understand that by purchasin an Ampete En ineerin Product you will et a
device in which we put all our passion, belief and knowled e and that you et a product in the tradition of
many reat people before us, for whom electronics were and still are wonderful masterpieces.
But you also purchased a little piece of responsibility. Maintain your Ampete En ineerin Product – we will
be here to support you, we built this to survive… possibly even us.
In case you should be faced with any issue on any day at any place somewhere in the world, we are here as
you would expect us to be.
This is not a promise, it is our view of life.
Thanks for lettin us be a part in enablin your musical world.
Yours sincerely,
Ampete
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Owner's Manual 444
Table of Contents
Foreword............................................................................... 3
Introduction........................................................................... 5
Features................................................................................ 5
Front panel............................................................................ 6
Rear panel............................................................................. 7
Hook up................................................................................. 9
A typical setup in eneral........................................................ 9
detailed hook up of amps with FX-Loop....................................10
detailed hook up of amps without FX-Loop................................ 11
Controllin the 444 via the front panel..................................... 12
Selectin Amplifiers and Cabinets / Switchin rules & protection....... 12
FX Loops …................................................................... 12
Amps without FX Loops...................................................... 12
Controllin the 444 via MIDI
Checkin and settin the MIDI Channel................................... 13
MIDI Pro ram Chan e....................................................... 13
MIDI Control Chan e........................................................ 13
MIDI Control Chan e modes................................................ 13
Settin the Control Chan e mode.......................................... 13
MIDI Control Chan e messa es table...................................... 14
Troubleshootin ..................................................................... 15
A word on impedances........................................................... 16
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Owner's Manual 444
Introduction
The 444 is desi ned to combine uitar amplifiers, uitar cabinets and uitar effects!
There have been Audio Loopers before, but there hasn't been the possibility to route one out of four
amplifiers into one or two out of four cabinets.
... one out of two, two out of... ??
… furthermore you are not any lon er in need of several delay, reverb, modulation pedals or rack units,
simply route every sin le FX loop of your amplifiers into one common FX loop for drivin one common
FX unit or one common FX ri .
… one common... ???
… nor there has been the option to run a wet/dry/wet system from one system of several uitar
amplifiers without usin line mixers and audio transformers and...
… transformers... ????
Don't et nervous, it sounds complicate, but indeed it's very simple and the 444 truly simplifies your
uitar ri in a way it hasn't been possible before, simply by usin our old and beloved midi pedal.
We will uide you throu h it in this manual.
Features
–4 amplifiers selectable
–4 speaker cabs selectable, up to 2 at a time
–external FX units assi nable to any of the 4 connected amplifiers
–FX-Loops from any of the connected amplifiers assi nable to one common FX Loop
–Line out for drivin external power amplifiers when runnin W/D/W systems
–buffered and unbuffered inputs
–feed thru jacks for easy wirin in the rack
–amplifier and cabinet selection without loss in sound, dynamics or noise
–no switchin noises
–no switchin latency
–protection circuits to prevent amplifiers from dama e
–midi controllable via pro ram chan e or control chan e
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Owner's Manual 444
Front Panel
1. FEED THRU: Jack for an un rounded direct si nal connection from/to the backpanel FEED THRU.
Use it for connectin tuners, wireless systems or any connection you need from back to front
without usin lon cable connections.
2. BUFFER IN: Front Panel instrument input, which routes the instrument si nal to your connected
amplifier inputs via a hi h to low impedance buffer, for keepin si nal clean and noiseless without
colorin it.
3. AMPS 1-4: Select one of four possible connected amplifiers by pushin the correspondin
illuminated switch. The other 3 amplifiers are connected to an internal load to prevent them from
any dama e. Input si nal is only routed to the selected amplifier.
4. CABS 1-4: Select up to two cabinets at the same time by pushin the correspondin illuminated
switch.
5. FX LOOP ON/OFF: Switches the FX Loop Send/Return jacks of the currently chosen amplifier to
the FX In and FX Out jacks to share one FX unit or FX ri with all of the 4 connected amplifiers. That
way spillover effects from reverb or delay effects are possible between the different amplifiers.
Please be aware to set the send and return levels of the connected amplifiers equally to avoid
chan es in volume.
6. MIDI CHANNEL/CC MODE: Displays and selects the Midi Channel when pressed short. To les
the Control Chan e mode when pressed lon . See „Controllin via MIDI“ for more informations
about the MIDI Control Chan e Modes
7. SAVE: Saves the current state of the 444 to the previously selected Pro ram Chan e preset.
8. Display: Gives informations about the selected Pro ram Chan e preset, Midi Channel, or Control
Chan e mode.
9. Power On/Off: I bet you know what this is for...
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Owner's Manual 444
Rear Panel
1. PHANTOM POWER PEDAL Jack: Connect a DC power supply to provide phantom power for your
MIDI pedal. By default the DC jack is connected to pin 1 (center pole) and 3 of the 7-pin MIDI
connector. It can can be internally modified to serve pin 6 and 7.
2. AC JACK / AC VOLTAGE SELECTOR: When chan in AC volta e for usin the 444 in a different
country, make sure fuse values are correct.
3. GROUND LIFT: Controls whether the 444s audio round is connected to earth conductor or not.
The chassis is rounded when the switch is in the 'Out' position. We recommend this position when
usin the 444 as the input device for your uitar. In case you are usin other audio loopers in front
of the 444, you mi ht notice hum noise, which is most often caused by round loops between two
devices. Switchin the round lift to the 'In' position will solve the issue ina lmost any case.
4. MIDI THRU: If you have several MIDI devices in your setup, connect the MIDI Thru with the MIDI
In of the followin device.
5. MIDI IN: Connect a MIDI pedal or any other MIDI device, to control the 444 via Pro ram Chan e
or Control Chan e messa es. If your MIDI device can be powered via the MIDI cable, connect the
correct DC power supply to the PHANTOM POWER PEDAL jack. Make sure supply volta e and pin
assi nment is correct.
6. LINE OUT: Outputs the SPEAKER Outs or FX LOOP Send si nal of the currently selected amp at line
level. It can be internally jumpered to be a speakers or an FX send line out. We recommend the
speaker settin , which also is set by default. Note that when feedin the LINE OUT from the FX
Send Bus, it's only active when the chosen amps FX loop is connected and activated!
7. AMP1 SEND: Connect the FX Loop Send/preamp out/line out of Amplifier 1 to the AMP 1 SEND jack
of the 444. Please be aware that this is not an independent loop but the correspondin FX loop of
the amplifier you drive with the AMP INPUT 1 and AMP OUTPUT 1 jacks of the 444!
8. AMP1 RETURN: Connect the FX Loop Return/power amp in/line in of Amplifier 1 to the AMP 1
RETURN of the 444. Like before mentioned, this is not an independent loop but the correspondin
FX loop of the amplifier you drive with the AMP INPUT 1 and AMP OUTPUT 1 jacks of the 444!
9. AMP2/3/4 SEND and AMP2/3/4 Return: Proceed like described under point 7 and 8.
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Owner's Manual 444
10. FX IN: Connect the FX IN jack of the 444 to the input of your effect, whether it is a sin le unit like
a delay pedal, a chain of pedals or rack units or another audio looper. This is exactly like you would
connect it to your amp's FX Loop Send. When switchin between amps on the 444, it automatically
switches your effects to the currently selected amp.
11. FX OUT: Connect the FX OUT jack of the 444 to the Output of your effect, whether it is a sin le unit
like a delay pedal, a chain of pedals or rack units or another audio looper. This is exactly like you
would connect it to your amp's FX Loop Return. When switchin between amps on the 444, it
automatically switches your effects to the currently selected amp.
12. FX LOOP GND LIFT: The FX LOOP GND LIFT lets you suppress possible pops when switchin
between 2 amps with usin spillover effects like lon delays or reverbs. This is most often caused by
a static volta e rowin to a non rounded electronic si nal path or switchin between from one
audio round to another. In almost any case that switch will solve the issue
13. BUFFER IN: BUFFER IN to drive the AMP INPUTS of the 444. Same as BUFFER IN at the front side,
but disconnected when front panels BUFFER IN is in use.
14. FEED THRU: Direct un rounded si nal connection to the front panel FEED THRU jack only to
simplify the rack wirin .
15. SPEAKER CABINETS 1-4: Connect your speaker cabinets here. No matter which cabinets you
choose, from 1x12“ to 4x12“ with every impedance everythin is possible, but consider not to
exceed the power handlin of the speaker cabinet to avoid any dama e to the speakers and/or the
amplifier. Use speaker cables only!
16. AMP OUTPUTS 1: Connect the loudspeaker/cabinet/amp output outputs of amplifier 1 here. This is
NOT an independent output but it corresponds to the number of the AMP INPUT 1 and the AMP1
SEND and RETURN jacks of the 444. Use speaker cables only!
17. UNBUFFERED IN: Input between the BUFFER IN and AMP INPUTS. This input bypasses the buffer,
when it's used, the BUFFER IN jacks are disconnected. We recommend this input when usin
preceded buffer units or preamps.
18. AMP INPUTS 1-4: Connect the instrument inputs of your amps here. This is the most sensitive
connection settin up the 444, make sure to use hi h quality instrument cables.
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Owner's Manual 444
Controlling the 444 via the front panel
Selecting Amplifiers and Cabinets / Switching rules & protection
At this point you hooked up amplifiers and cabinets to the 444. Let's start switchin !
You should establish a certain operatin process when operatin the 444. Either in the operatin way via the
front panel switches, when pro rammin midi presets or usin control chan es, a cabinet has to be chosen
first by pressin the correspondin front panel CABS switch (or the correspondin control chan e at the midi
send device). It is NOT possible to select an AMP before.
And a ain, a CABS button can only be selected with a speaker cabinet hooked up to the correspondin
SPEAKER CABINETS jack. Thereby the 444 not only controls if a plu is connected to the SPEAKER
CABINETS jack, but also the attached load for its impedance. Hereby a low impedance is interpreted as a
speaker cabinet, a hi h impedance could be a non connected cable, a defective speaker cable or even a
speaker in form of a ruptured speaker coil etc. In that case the 444 would refuse the selection and state an
n.c. in the display for 'no connection'. This way the 444 prevents your amplifier from dama e because of
runnin without a load. The display will state an error status (Er).
A short summary:
–Select CABS button first. Two cabinets can be selected. If two cabinets are selected, one of the
chosen has to be switched off first, before the 444 lets you select another.
–Select AMPS button next. One amp at a time can be selected, which means by selectin another
AMPS button the 444 disables the previously chosen amplifier.
FX Loop
The FX loop option of the 444 allows to assi n one sin le effect unit or even a complex FX ri to any of the
FX loops of your connected amplifiers. That way you are not in need of one effect unit for each amplifier.
Connect your FX or separate looper unit to the FX IN / FX OUT. By pressin the FX LOOP ON/OFF button,
the FX IN / FX OUT are assi ned to the selected amplifiers FX loop. Be aware that it can not be activated
without havin a cabinet and an amplifier selected before. When en a ed, the FX LOOP ON/OFF switch will
li ht up to show its active status.
When switchin between amplifiers, the 444 assi ns the FX IN / FX OUT to the selected amp's FX Loop at
the same time.
Amps without FX loop
There are many especially classis amps like Fender Brown-, Black-, Silverfaces, Vox ACs or Marshall
Plexis, JMPs, JCM800s, but also many newer amps in the tradition of those not featurin any kind of
insert between pre- and poweramp such as an FX loop.
The 444 ives you the option of sharin a sin le FX unit or a complex effect ri not only with any of
your FX loop equipped amp, but also with those classic style amps not featurin an FX loop.
All you need to do is connect the AMP(1-4) SEND and RETURN in front of the amp!!!
This is simply done by patchin a short cable from the AMP INPUTs (1-4) to the correspondin AMP(1-
4) SEND. Next connect the RETURN of that FX loop to the ampflifiers input.
Now you can assi n the 444s FX loop (FX IN and FX OUT) both in front of your amp without FX loop or
in between pre- and poweramp of your amp with FX loop.
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Owner's Manual 444
Controlling the 444 via MIDI
Surely all the control functions of the para raph 'controllin the 444 via front panel' (see pa e 10) pertain if
you control it via Midi. But it offers some options beyond....
Checking and setting the MIDI Channel
By pressin the MIDI CHANNEL button, the display will show the currently active MIDI channel. This is
indicated by an additional decimal point at the lower ri ht corner of the display for only a few seconds
before the display switches back to the MIDI pro ram number.
To set the MIDI channel, consecutively press MIDI CHANNEL for a short period of time. The displayed
number counts up to '16', and starts a ain at '0'. Stop pressin MIDI CHANNEL if the desired MIDI Channel
number is reached. '0' stands for 'all channels' or 'omni mode'.
As soon as the display switches back to the previous state, the MIDI channel is saved to the non-volatile
memory of the 444.
MIDI Program Change
The 444 offers the possibility to save up to 99 presets of different amplifier / cabinets combinations.
You can switch between presets by sendin MIDI Pro ram Chan e messa es from your MIDI foot controler,
or any other MIDI device connected to the 444's „MIDI IN“ connector.
To save a preset, send a MIDI Pro ram Chan e messa e of the desired preset number. The switcher status
saved with the preset number is called, and the preset number is shown in the front panel display.
Note that the 444 starts countin the presets at „1“, even thou ht the MIDI standard internally starts at „0“.
The reason we did this is because almost any MIDI foot controler start countin the foot switches at „1“ as
well.
If the preset is now chan ed by the front panel controls, the SAVE knob starts flashin . Press SAVE to save
the current status to the preset.
To protect your amps, a preset can not be activated if at least one of the cabinets saved with the preset is
not connected to the 444. In that case the display states the messa e (n.c.)!
MIDI Control Change
All front panel controls can additionally be remote controlled by MIDI Control Chan e messa es.
In contrast to recall presets via MIDI Pro ram Chan es, every Control Chan e messa e switches only one
function at a time. You mi ht have heard people sayin „Direct Access“, that's what is meant by it. See
„Control Chan e messa es table“ for a detailed description of the 444 Control Chan e messa es.
MIDI Control Change modes
Even thou h Control Chan e messa es only access one function at a time, some people prefer pro ramin
presets of several Control Chan e messa es inside their MIDI controler, instead of sendin Pro ram Chan e
messa es to access a preset stored in the 444.
Some MIDI controller such as the RJM Mastermind GT offer the possibility to send Control Chan e presets in
an „intelli ent“ way. That means CC messa es are sent to switch the currently selected amp or cabinet off
before switchin on another one. This is important due to the 444s certain rules and orders for the switchin
process to protect your amps from any dama e. (see „switchin rules & protection).
Choose the 444s Control Chan e mode '0' for operatin with such midi controller pedals.
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Owner's Manual 444
If you are usin a MIDI controller pedal with a let's say more simple software structure – meanin the
controller pedal does not „know“ which amp or cabinet is currently in use - or if the number of CC messa es
in a preset is limited, it mi ht work for you better usin the 444s Control Chan e mode '1'. With that mode
the 444 will process Control Chan e messa es with value 127 („switch on“) only after switchin off the
previously selected amp or cabinet.
If you are unsure about which CC Mode works best for you, start with Mode '0'. This is also the 444s factory
default. This is the ri ht mode for almost any cases, especially if you are sendin sin le CC messa es, and
not presets of several CC messa es.
When pro ramin presets of CC messa es to your MIDI controler, always keep in mind that the 444 works
after certain rules for the switchin process mentioned before. I.e. if you pro ram a preset that sends
commands to switch on two amps at a time, the 444 will only show an error status (Er) in the display.
Setting the Control Change mode
To set the Control Chan e mode on the 444, press MIDI CHANNEL for a lon period of time until the display
shows „0“ or „1“ with an additional decimal point in the lower ri ht corner.
Note that in contrast to settin the MIDI Channel this action directly to les the CC Mode, there is no way to
check the current settin first.
MIDI Control Change messages table
CC Controller Number Function Value
80 AMP 1 0=off, 127=on
81 AMP 2 0=off, 127=on
82 AMP 3 0=off, 127=on
83 AMP 4 0=off, 127=on
88 FX LOOP 0=off, 127=on
90 SAVE 127=save
104 CAB 1 0=off, 127=on
105 CAB 2 0=off, 127=on
106 CAB 3 0=off, 127=on
107 CAB 4 0=off, 127=on
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Owner's Manual 444
Troubleshooting
Problem: No signal when an amplifier (AMP1-4) is chosen
Make sure all amp inputs and speaker outputs are properly connected. Never mix amp
in- and outputs to different amplifiers!
Problem: No effect signal when switching FX loop
Make sure the FX Loop of the chosen amplifier is connected correctly to the 444s
matchin FX Loop. For example, if AMP1 is chosen, the AMP1 FX SEND and RETURN
have to be connected to the same amplifier, which is connected to AMP1 INPUT and
AMP1 OUTPUT of the 444!
Problem: No amp can be selected
Check the display for its status while pressin the AMP1-4 button, when showin (n.c.)
a cabinet hasn't been selected. Activate a CAB1-4 button and try a ain.
Problem: No cabinet can be selected
Check if the chosen cabinet and cable is connected properly.
Also check the cable and/or speakers for any defects.
Problem: drastic volume increase or decrease in reverb or delay spillovers when
switching between amplifiers with FX loop option
The send and return levels of the connected amplifiers have to be set equally. Most
often the send level is controled by the channel volumes, sometimes a separate send
level is present
Problem: Cracking noise when switching FX on and off
No proper roundin at the FX loop circuit. Pushin the FX LOOP GND LIFT switch will
solve the issue in almost any case.
Problem: erratic behaviour when switching via MIDI Control Changes
Check if the correct CC Mode is set (see pa e 11)
Problem: No function when switching via MIDI
Check if the correct MIDI channel has been set (see pa e 11)
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Owner's Manual 444
A word on impedances
When it comes to impedances and matchin of valve amplifiers and speaker cabinets, there have been
written a lot of words and there have been told many opinions, myths and beliefs. And as it is so often
in our world, all of them are in between the truth and the untruth. Some more, some less. Don't expect
mine to be the only truth! But I ive you some ar uments on hand, why it is not necessary to match
your amp and cabinet and why your amplifier will not et dama ed when the load does not match the
impedance switch settin .
Let's start with one of the most often heard opinions. Some claim that a mismatch between amplifier
and cabinet causes the valves to wear out quicker or can cause dama e to the output transformer
and/or valves while at the same time advertisin their amplifiers to work with any kind of valves,
doesn't matter if EL34, 6L6, KT66, KT88 etc.
Don't et me wron that this is not possible, but the matchin between amplifier and cabinet isn't
isolated on the secondary windin of the output transformer and the speaker. It's an interaction
between valves, primary windin of the output transformer, secondary windin of the output
transformer and speaker. It starts with a certain impedance each valve type has and which would
require (if we o on with the ar umentation) a specific primary windin and thus a ain an impedance
of the output transformer to be 'matched'. The output transformer itself not only transforms the
volta e, it also transforms the impedance. It continues to the output transformers secondary windin
(with another you know what) and ends with the speaker (sorry, but yes...).
As mentioned above, this is not a one way street, it's an interaction, which means the speaker
influences the power amplifier and the power amplifier influences the speaker. Surely this is not a linear
process, it is dependend on frequency, power or watta e, electric and even mechanic speaker
specifications.
And if this wouldn't be enou h, remember that it's called impedance because it alters with the
frequency... if you have ever seen the impedance curves of a speaker you know what that means.
There are several ways to 'mismatch', usin different speaker impedances is only one possibility.
Different valve types or 2 instead of 4 valves are others. But none of them causes the power amp,
valves or output transformers to fail.
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Owner's Manual 444
The dia ram below shows some simple measurements (in that particular case taken with our Amp
TWO, a 110 Hz, 150mV sine wave, which is similar to the 'A' strin s first harmonic of a Humbucker
uitar). The amp impedance switch has been set to either 4 (blue color), 8 (oran e) and 16 (yellow)
Ohm and in every of these settin s a reactive load of 2, 4, 8 and 16 Ohm has been attached to the
power amp. Let's point out only the two essential characters.
1. When the amp impedance switch and cabinet load are matched, the watta e is nearly identical
in either 4, 8 or 16 Ohm case;
2. The hi her the load the hi her the watta e, or equivalent the lower the load, the lower the
watta e.
Is it as simple as that? Yes and No.
No, as mentioned above this is not as linear as it looks at first lance as it is dependend from several
parameters.
Yes, because - and this is the main fact for all the 444 users – it will never be the other way round. The
Power will not increase when the load impedance is lower than the chosen amp output impedance
(surely as lon as we are talkin about valve driven amplifiers). And not only the watta e will not
increase, also the volta e - primary and secondary – decreases with a lower load.
For those who are interested, the current increases. On the primary side it does not exceed the
maximum current flowin when the amp impedance switch and load are set to its minimum position
(most often 4Ohm). The current flowin on the secondary side increases sli htly about 10-15%.
The 444 is capable of switchin 1 or 2 cabinets to any of the connected amplifiers. That means, the
load to the amplifiers output will chan e when the second cabinet is assi ned to it. Let's assume your
amplifiers impedance switch is set to 16 Ohm, you run a sin le 16 Ohm cabinet with your amplifier and
you add a second 16 Ohm cabinet, then the total load will chan e to 8 Ohm.
Now refer to the dia ram and you see the power of the amplifier drops.
17
0 2 4 6 8 10 12 14 16 18
0
5
10
15
20
25
Wa age dependen from load
Amp Imp swi ch 4 Ohm
Amp Imp swi ch 8 Ohm
Amp Imp swi ch 16 Ohm
Cabine
R Load / Ohm
Power / Wa

Owner's Manual 444
But even if the power decreases by almost one third compared to a matchin load, the subjective
impression will be the volume is nearly the same (as lon as the phases of the speaker cabinets are the
same). This is simply because more speakers are now driven by the amplifier. You will notice a sli htly
different feel, which is caused by a different dampin factor the power amp of your amplifier 'sees'.
Hereby a lower impedance from your cabinet will feel more 'loose', a hi her impedance will ive you a
more 'ti ht' feelin . There is a simple reason for that. As seen before the hi her impedance causes the
amplifier to emit more power, more 'headroom'. Because the bass frequencies require more power than
the hi her frequencies, it can be amplified more accurate, more 'ti ht' as it's often called. The dynamic
does not drop when especially palm muted low strin s are hitted. In contrast there's a natural sa with
the lower impedance because of the lowered power.
But don't expect these chan es to be drastically, we are talkin about nuances in sound. This will be
even more hard to notice because the number of speakers has chan ed.
Havin said that, we recommend to undermatch the cabinet load when usin 2 cabinets at the same
time.
–one or two 16 Ohm Cabinets (=8 Ohm) → Impedance switch 16 Ohm
–one or two 8 Ohm Cabinets (=4 Ohm) → Impedance switch 8 Ohm
–one or two 4 Ohm Cabinets (=2 Ohm) → Impedance switch 4 Ohm
It is also possible to mix cabinets with different impedances, you only have to be aware that the power
to the cabinets will be different as well, to be precise it will be twice as hi h at the cabinet with half the
impedance.
–one 16 and one 8 Ohm Cabinet (=5,33 Ohm) → Impedance switch 16 Ohm
–one 8 and one 4 Ohm Cabinet (= 2,66 Ohm) → Impedance switch 8 Ohm
In any case do not exceed the power handlin of the speaker cabinet! Be aware of, that the settin of
your volume control is not an indicator for the power your amplifier emits.
This is just a rou h overview on the interaction between a valve driven power amplifier and a
loudspeaker. Believe me, that process is far too complex to put it in such a manual, and to be honest in
it's entirity it would exceed my knowled e. And even if the era of valves is lon one, this is why some
very few people - includin me - are still researchin on it.
… and we keep you informed!
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Owner's Manual 444
_______________________________________________________________
Dimensions Front Panel: W 17,2“ (438mm), H 3,5“ (88mm), D 8,8“ (223mm)
Front Panel: W 19“ (482mm)
Wei ht 10 lbs (4,5k )
Power consumption 10W max.
_______________________________________________________________
Ampete En ineerin reserves the ri ht to chan e specifications, wether it's technical, dimensional or in the owner's manual.
Fender, Marshall, Vox, RJM or other brands or models are re istered trademarks to their respective holders. Ampete En ineerin isn't affiliated with them in any way.
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Owner's Manual 444
__________________________
Ampete Engineering GbR, 2014
Ampete is a registered trademark
copyright 2014, all rights reserved
20