If I have to decide what personally appeals to me most in a guitarist's entire signal chain, I'd have to say it's the amplifier. Guitars are extremely important, and pedals help us get a little closer to the sound we want, but the foundation everything rests on is the sound of the amplifier, both the sound it gives us on its own and the sound it can deliver when we add pedals or use this or that guitar. Going into a bit more detail, we can say there are countless types of amplifiers, but if we think of high-end tube amps, we can't go without talking about KOCH.

Within the KOCH family, we have quite a few amps to choose from, depending on the sound needed. For heavier sounds, the Powertone II; for cleaner, smoother sounds and, above all, for home use, the Classic SE; for a more versatile sound with a great crunch tone, the Multitone is the most advisable; and finally, for a completely all-purpose and very versatile sound, there's the Supernova, which has all kinds of MIDI options, channels, etc.

Today we have two amplifiers from the family with us: the Studiotone and the Twintone. They're the last two siblings in the brand that we hadn't yet mentioned, and they're truly useful in their respective fields: the Twintone as a rock amp, the Studiotone as a versatile, all-terrain amp. So let's wait no longer and analyze every detail of these amplifiers, cable by cable, tube by tube, solder joint by solder joint.

Construction
KOCH amplifiers are characterized by a very serious, classic look. Most of the amp is built by hand, so the quality they offer is quite carefully crafted.

Let's analyze each of them, knob by knob.

Twintone
Let's start with the Twintone, a 50 W amplifier with two EL34s that can drive the speakers whatever cabinet we connect it to. On the front panel we find two inputs for connecting the guitar: a normal one and one with extra brightness, according to the label below them. The idea is to accommodate every option: humbuckers, single coils, etc., so the amp can deliver the best sound in each case. In my opinion, if you need a bright sound with a humbucker, it's advisable to use the bright clean input.

The next control we find is the switch for selecting the channel. This is rather unusual since it's generally located on the back. Personally, I prefer it on the front, because if at a critical moment in the middle of a concert you have a problem with channel switching, you can easily reach it to change channels manually. The first channel is the clean channel, where we can control the volume as well as the bass, mids and treble. The other is the saturated channel, where we can control the volume and gain, as well as the power amp control, Presence, which lets you choose how much the guitar cuts through in the final sound. Of course, there are also the three EQ controls, that is, bass, mids and treble. And finally, the On/Off and standby switches.

We should point out that, although only two channels appear, there's a third channel, so to speak, since a kind of booster can be added to the second channel. So the channel selector switch consists of Clean, OD and OD+: clean, crunch and distortion.

Moving on to the rear, the first connection we find is the power input next to the fuse. That's also where the footswitch input is located, which consists of a seven-pin connector, along with a rhythm volume control. When you connect the footswitch, you can choose between the rhythm or lead volume. If channel switching isn't connected, keep in mind that the active volume is the rhythm one. The next knob we find is the reverb control. We can therefore conclude that the reverb is shared by all channels.

Continuing along the rear panel, we next find the inputs and outputs belonging to the loop. We can choose which format to use: series or parallel. So we have one send, with which we route the signal to the effect, and two return connections. These last two are associated separately with the series loop and the parallel loop.

Next come the outputs for connecting the cabinets, that is, the speakers in the enclosure. There's a main output with an impedance selector (4 ohms or 8 ohms), and an auxiliary one you can connect to a second cabinet. Now comes the surprise: they offer a crucial protection, the power soak. A fantastic tool for protecting our cabinets or working with headphones.

Besides other applications of the feature mentioned above, keep in mind that we can use it to halve the amp's power (from 50 W to 25 W), leaving the main output free and connecting a cabinet to the extra output.

Rounding out the arsenal of connections, we find the recording output, which comes straight from the amp without going through the cabinet and has speaker simulation. This lets us use it directly with the input of our recording interface, getting real amp quality (and not line quality). The headphone output also has speaker simulation, so we'll hear the sound closest to the original sound through speakers.

Getting right into the inside of the amp, the most important thing to mention is the tubes it uses: 12AX7s in the preamp and EL34s in the power amp. So we can already start to guess the kind of sound it will give us: a fairly British one.

Studiotone
Let's analyze the Studiotone, one of the brand's most versatile and successful amplifiers. There are two versions: the Studiotone, 20 W Class A, and the Studiotone XL, 40 W Class A.

Let's break down every detail of the amplifier.

The first element we find is the guitar input itself. Here there's no distinction depending on whether the pickups are single coils, humbuckers, etc. As in the previous case, there's a channel selector that works if the channel-switching footswitch isn't connected.

Like the other one, there are three channels: clean, crunch (OD) and distortion (OD+). In addition, there's a bass, mid and treble boost control that only works on the OD+ channel.

The first knob we find is the clean channel volume, used exclusively by that channel. The next one is the gain, for both the OD and OD+ channels. Be careful not to set it too high, since excessive gain can lead to an overly noisy sound.

Next we come to the EQ controls, made up of treble, bass and mids. From this we can conclude that the EQ is shared by all three channels, which I personally don't mind, since you can see the thinking behind the amplifier. On the other hand, there are two controls for boosting mids and treble. For the mids there are two positions: a natural position and one that gives a small boost in the midrange.
Another control has three options: first, a treble-cut position; then a small boost for the highest frequencies; and finally, a third option that bypasses the control. Lastly, we find the reverb, which is a spring type, and the On/Off and standby switches.

On the rear panel we can see how many inputs and outputs there are, some of them particularly interesting. The first one, as in the previous case, is the power input and the fuse. A jack input lets us connect the channel-switching footswitch, and it's very welcome that the connection is a simple stereo jack. The effects loop send and return are also there.

One of the most important sections is the recording outputs, which have speaker simulation, meaning the output includes both external effects and the reverb itself. First we find a selector for the mic angle we want to simulate, on the center of the speaker or angled, which has less brightness but is better for more saturated sounds. The next control simulates a 1x12 or a 4x12, the larger cabinet giving us more bass. And, of course, the recording output, which is unbalanced. The Direct Out is used to send an unfiltered signal, generally if we want to feed it into the return of another amplifier.

The "to guitar amp clean input" output is a very particular one, designed for when we want to send the Koch's output to another amplifier without a loop. It should be plugged into the clean channel input.

The next output block is for sending to the cabinets, which can be 4, 8 or 16 ohms, but we can only use one speaker at a time. There's a setting that doesn't go to any speaker and lets you use the amp through the recording or phones outputs without needing to connect a cabinet. There's also a headphone output.

Inside, the amplifier uses 12AX7 tubes in the preamp and EL84s in the power section, giving us 20 W of Class A, which is more than enough.

Sound
Now let's describe the sound of these amplifiers. Before explaining each amp's sonic characteristics, I should say that I ran the tests with quite a few guitars: The Heritage Les Pauls, one with humbuckers and another with P-90s; a Strat with three single coils and a Telecaster; I also used a 335 and even an SG. In every case, I have to say that both amps behaved sublimely. I also used a couple of pedals to see how they reacted to a bit more saturation: a Fulltone Full Drive, a Xotic AC and the Retrosonic Boost.

Twintone
The moment you plug in, the Twintone breathes rock, specifically the very British sound we mentioned earlier, for which the EL34s are largely responsible. The clean channel sounds quite crisp, with the particularity that, with the Strat, it quickly brings out those "little bells," although, as you might guess, as soon as you turn up the volume a bit it starts to break up and therefore saturate, easily reaching a crunch. If we add a boost or overdrive like the ones above, we get a completely AC/DC sound. With the SG, there's no doubt it will deliver a pretty rock sound. On the OD and OD+ channels, we get the crunch sound we've been talking about but with even more bass and, if possible, "fatter." As for the Les Pauls, adding a delay gives a perfect lead sound to dazzle anyone and blow their hair back.

Studiotone
The Studiotone is a very versatile amplifier that covers a great many registers, so whatever guitar you plug into it, you'll find a sound that suits the amp. The clean channel is completely crystal clear, even reminding me a little of a more Fender-like sound; with Telecasters and Strats it sounds simply brutal. The crunch channel sounds very rock, and the OD+ sounds aggressive without becoming thunderous, perfect for a lead sound. The recording output is highly recommended and, of course, can save us in a tight spot at a concert or recording session.

Conclusion
The Twintone and the Studiotone are truly two top options: the former for a rock sound, the latter for very versatile tones. As we've said, their quality is spectacular in both cases, and their size and weight help, since they're easy to carry. If we add a more than competitive price, we're talking, in my view, about some of the best options available to us.