Comparison Marshall DSL40CR vs Marshall JVM410C

Rated power of the device.

Let us recall that in acoustics the rated power is the highest average (root mean square) power of a sound or signal that a device can produce for an indefinitely long time. Individual volume jumps can be several times higher than this indicator, but the key characteristic is the average value. But the specific meaning of this parameter depends on the type of equipment (see above). So, for combo amplifiers, this paragraph usually gives the power of the built-in speakers; The capabilities of your own amplifier, by definition, correspond to this figure, so for such equipment the rated power determines solely the overall sound volume. The power of the acoustics is also indicated for cabinets, but here another point becomes relevant - compatibility with an external amplifier (primarily the “head”). The output power of this amplifier should not be higher than the rated power of the cabinet to avoid overloads; and ideally, these characteristics should match - this will allow you to use the speaker at full power without sound distortion.

For the head, accordingly, this paragraph provides the rated output power, which determines the ability of the amplifier to operate with a specific cabinet or other speakers. However, it is worth noting that the maximum possible power value is indicated as the nominal value for heads, which is not always achieved. Thus, many models provide several sound outputs - for passive acoustics with different...impedances (remember, standard impedance values are 2, 4, 8 and 16 Ohms); and the higher the impedance of the connected speaker, the lower the actual power will be. Other heads have the ability to limit the maximum power - for example, so that at the maximum level the device produces not 100 W, but 50 W or even 25 W. Sometimes these features are combined in one device.

In any case, when choosing according to this indicator, it is worth taking into account the features of the planned use of the equipment. For example, it hardly makes sense to purchase even a 40-watt “combination” for practicing at home - for these purposes 15 watts, or even less, will be quite enough. And if we are talking about a tube device, then in our example the maximum recommended power will be only 5 W - the specificity of tube circuits is such that with the same rated power they are more effective than transistor ones in terms of audibility. For rehearsals in a group without a drum kit (for example, two guitars plus a bass), a higher power is desirable, about 40 “transistor” watts, and if there are drums, at least 60 watts. Transistor devices with a power of up to 150 W and tube devices with a power of up to 40 - 50 W are suitable for specialized rep bases and concerts in relatively small rooms, and higher figures are found mainly in equipment for large-scale events. Detailed recommendations regarding optimal power for certain conditions can be found in special sources.

It is worth mentioning bass amplifiers separately: it is believed that for normal coordination with each other, the power of a bass “combination” should be twice as high as the power of a guitar one.

The impedance of the speaker(s) installed in the amplifier.

Impedance is the resistance to alternating current — that is, the current flowing when an audio signal is applied. This impedance affects the compatibility of the speaker with the power amplifier: if the impedance is too low, sound distortion occurs, if the impedance is too high, the volume is reduced. However, in combo amplifiers, this parameter is most often given as a purely reference: such devices have their own power amplifier, which, by definition, is designed for the impedance of the “native” speaker, and separately, with extraneous components, the speaker and amplifier are not used.

The number of speakers provided in the design of the device.

This parameter is indicated in cases where there is more than one speaker. Its meaning may vary. Thus, in some models several speakers are provided to be divided into frequency bands (see “Number of bands”); in this case, a small high-frequency emitter can be installed directly in front of the low-frequency one (the so-called coaxial circuit). In other devices, several speakers of the same type are used to provide the necessary sound power - for a number of reasons this is preferable to installing a single powerful speaker.

The presence of a phase regulator in the design of the amplifier.

When using the device simultaneously with other sound sources (for example, when a guitar and bass “amps” are working side by side), a situation may arise when the sound from these devices is out of phase. This can lead to a noticeable deterioration in sound and a decrease in its volume. You can correct the situation by adjusting the phase on one of the devices; This is what this adjustment is for.

Built-in effects provided in the combo amplifier. You can also achieve various effects with the help of external “gadgets”, however, such gadgets need to be searched for and connected separately, while built-in effects are available immediately and without unnecessary settings.

— Overdrive. Distortion in the form of a characteristic electric guitar "buzz" at low frequencies and "howl" at high frequencies, a little softer than distortion. Popular, in particular, in hard rock.

— Distortion. Sufficiently hard and sharp distortion, similar in sound to overdrive, but more intense and brighter. It is widely used in various styles of metal, and is also found in rock.

— Reverb. An effect based on simulating multiple decaying echoes from each sound. Depending on the duration and intensity of repetitions, it can give the sound a different colour. Used as an artistic device; among other things, it can create the effect that the guitar sounds in a certain room (concert hall, room with stone walls, an open area in the mountains, etc.). Note that the reverberation can be adjusted both by individual parameters (intensity, echo duration, etc.), and by selecting a preset set of parameters (for example, “sharp sound in the room” or “soft sound in the hall”).

— Tremolo. Tremolo is basically a trembling effect that res...ults from small and quick fluctuations in the volume of each note. Sometimes this term means vibrato (see below) — to the point that the manufacturers of guitar amplifiers themselves mean the effect of vibrato by the tremolo effect, and vice versa. So the specifics of this effect in each case should be clarified separately. Anyway, the tremolo can be "fixed" or adjustable in depth (range of volume change) and speed (jitter frequency).

— Vibrato. Another effect of "jerking" sound, which is often confused with tremolo (see above) — to the point that both these terms are used as identical. However, this is not true; the difference lies in the fact that vibrato is carried out due to the rapid fluctuations of the note not in volume, but in frequency. A similar effect can be achieved on the guitar itself by "pulsating" the strings, but using the amplifier's built-in instrument is much more convenient in most cases.

— Chorus. An effect designed to simulate the choral sound of an instrument. To do this, the amplifier copies the sound of the guitar and plays several copies simultaneously with the original signal, slightly shifting them in time (about 20 – 30 ms with a constant change) and frequency. However it is impossible to achieve a full-fledged choral sound in this way, but the effect is quite original in itself.

— Delay. A specific type of reverb (see "Reverb") that has become widespread as a separate effect. Delay simulates a clear single echo from the sound being played; for this, the original signal is copied and reproduced with a certain time delay (at least 50 ms).

In addition to those described above, other effects can be found in modern guitar combo amplifiers, in particular:

— Flanger. The effect is reminiscent of the whistle of a jet engine; it is often compared to a plane taking off. It is created similarly to the Chorus described above, differs from it in a shorter delay time and the presence of feedback.

— echo. Another kind of reverb, similar to delay (see “Delay”). It differs in that in this case the echo is reproduced repeatedly.

— Octaver. An effect in which a copy of it is added to the signal, shifted by an octave or two.

— Wah wah. An effect that produces a characteristic "croak" sound.

The type of line output provided in the design of the combo amplifier.

This output, as the name suggests, provides a line-level analogue audio signal. In this case, unlike the preamplifier output (see above), the signal level at the line output is not adjustable. This interface is mainly used to connect recording devices, although it can also be used to output a signal to an external amplifier (in fact, in the absence of a Pre-Amp output, the only option for such a connection is a line input). And the types of connectors used for the line output can be as follows:

— Mini-Jack (3.5 mm). The classic "minijack" is small in size, but inferior to larger connectors in terms of reliability and connection quality; compactness in the case of combo amplifiers most often does not play a decisive role. That is why such exits are extremely rare, mainly in the most compact “amps”.

— Jack (6.35 mm). Connector, quite popular in stationary audio equipment, including pretty advanced. Theoretically, it can even provide a balanced connection (see below), but this feature is far from mandatory, its presence should be specified separately. Also note that a 3.5 mm mini-Jack plug can also be connected to such a jack using a simple adapter.

— Balanced XLR. The XLR output is a characteristic round three-pin connector with a balanced connection type. With this connection, the signal is transmitted over thre...e wires instead of two, and in a special way, due to which the interference induced on the wire is extinguished. This allows even fairly long cables to be used without sacrificing signal purity, making this type of connection suitable even for professional audio equipment. Actually, XLR is also considered a professional interface — both because of the ability to work with a balanced signal, and because of the rather large dimensions and increased reliability (connectors are often equipped with locks for fixing plugs).

— Jack/XLR. Usually, in this case, a combined connector is meant, combining a 6.35 mm Jack and XLR. On the features of both, see above; and the combo jack looks like an XLR jack, complete with a hole for a Jack plug in the centre.

Jack/RCA. The presence in the device of two linear outputs at once, with different types of connectors. See above for more details on the Jack interface. And RCA is a connector for a coaxial cable with a “tulip” plug; this is one of the most popular interfaces in entry-level and mid-range stationary audio equipment, but it is relatively rare in guitar amplifiers.

— Corporate. A proprietary connector that does not belong to any generally accepted standard. It is mainly used to connect equipment of the same brand as the combo.

The presence of a pedal (footswitch) in the scope of delivery of the combo amplifier.

The pedal is the most convenient way to quickly change amp settings and can be used while playing the guitar. At the same time, the specific functions of such a switch may be different, depending on the functionality of the “amp” itself: the pedal can turn certain effects on and off, switch the channel used, etc. These points should be clarified separately. Anyway, the presence of a footswitch in the kit eliminates the need to purchase such a switch separately, while the "native" pedal, by definition, will be optimally compatible with the amplifier.