After 18 years, Dutch manufacturer Koch has revised its Classictone combo, which was then equipped with four 10″ speakers. However, the cabinet of the Classictone-II Twenty is no less spacious despite the single 12-inch speaker. With otherwise identical features, Koch offers the amp with either 20- or 40-watt power amplifiers. As a special feature, the amps offer a recording output section, each with a jack and balanced XLR connector with frequency correction. In addition, an integrated load resistor (dummy load) allows the on-board speaker to be switched off even under full amplifier load, but should definitely remain connected. IMPOSANT The mighty cabinet and the 22 kg live weight of the Classictone-II Twenty lead us to expect anything but a 20-watt combo. But we know that the cabinet and its volume influence the amp sound not insignificantly. 15 mm thick birch plywood forms the frame, in the corners of which four 4×4 cm square timbers provide increased stability. The tightly fitted, screwed rear panel and front were made of 13 mm birch plywood, each with trapezoidal openings. Behind the front sits the actual baffle with the textile covering and the custom KochVG12-60 speaker, which is screwed four times from the rear and whose feed line is connected via plug-in shoes and amp-side via jack plug. The large spring reverb system was mounted in a tolex pocket on the bottom of the cabinet, the high-quality send and return cables meticulously laid with cable clamps and connected to the amp via RCA plugs with gold contacts. The cabinet, front and rear panel have been carefully covered with dark brown Tolex and visual accents have been set using black and gold piping. Eight screwed corner protectors made of sheet steel, four large rubber feet and a solid leatherette handle complete the case equipment. Velcro straps are available on the inner side panel to secure the footswitch and power cord during transport. Shielded by aluminum foil, the amplifier chassis, which is bent from 1.6 mm sheet steel, hangs vertically from the rear panel on four threaded screws. Thus, tubes and transformers are aligned to the front, which requires dismantling the rear panel along with the chassis to change the glass bulbs, since the speaker magnet also obstructs access. The cabinet, front and rear panel have been carefully covered with dark brown Tolex and visual accents have been set using black and gold piping. Eight screwed corner protectors made of sheet steel, four large rubber feet and a solid leatherette handle complete the case equipment. Velcro straps are available on the inner side panel to secure the footswitch and power cord during transport. Shielded by aluminum foil, the amplifier chassis, which is bent from 1.6 mm sheet steel, hangs vertically from the rear panel on four threaded screws. Thus, tubes and transformers are aligned to the front, which requires dismantling the rear panel along with the chassis to change the glass bulbs, since the speaker magnet also obstructs access. All pots and connectors, standby switches and fuse holders are screwed to the chassis, four mini toggle switches are reliably soldered to circuit boards. The exemplary workmanship underlines the high manufacturing standards of the manufacturer. Briefly, I am confused, because Koch speaks of a three-channel amplifier, but the layout of the controls suggests a two-channel. Between the Clean and Gain controls I discover the small Gain/Boost switch, which allows the selection of crunch or high-gain sounds in the OD channel. Gain/boost and channel change can also be accessed with the included dual footswitch, suspending the function of the Clean/OD and Gain/boost switches. Two sturdy footswitches and bright red (Clean/OD) and green (OD/OD+) status LEDs are used in the robust sheet steel housing. The permanently connected supply cable with TRS jack plug is generously dimensioned at 5 meters. The amp chassis offers three control surfaces, namely top, rear and bottom. On top we find input, channel select switch, clean volume, the OD channel with gain/boost switch, gain and volume pots, a classic passive 3-band tone control with bass, mid and treble for both channels (post-distortion) as well as reverb control, level and standby switch and a red pilot lamp as operation indicator. Level switch? This three-way rotary switch, located directly in front of the power amp, replaces the familiar master volume pot with the positions Home, Studio and Stage. The rear panel provides a connection for an external speaker (8 ohms), a speaker on/off switch (dummy load), a balanced XLR DI out with ground lift switch and a jack line out (both with speaker simulation) as well as FX send and return (serial). You have to bend down very deep - or put the amp on your face - for the lower connection panel, where Koch placed the sockets for on-board speakers, double footswitch and power cable, the holder for the HT fuse and the power switch. I would have liked to see the latter on the top, or at least on the back. NOT A BIT QUIET For the first listening I turn the (master) level switch to the home position as a precaution. The Clean Channel shows plenty of headroom, because with PAF pickup types and powerful string attack, the first tightening (break-up) can be detected on the scale of 0-10 at about 6, and that at an impressive volume. What does Koch mean by "home level"? If you turn up Clean Volume further, the distortion ends with a very subtle crunch, characterized by powerful but tight, never boomy basses, warm mids, crystal clear, airy highs and pleasant brilliance. In general, the Clean control works extremely precisely and increases the input level completely continuously over the entire control range. The amp's impulsive response and outstanding dynamics allow you to turn Clean up full and leave any further tone shaping to guitar volume and/or attack. More effectively than initially expected, the passive tone control intervenes in the action, the individual sections even interact a little. Thus, the most diverse guitar types can be balanced without any problems. In terms of distortion, the overdrive channel starts where Clean ends, namely in gain position 1 with a subtle crunch. From here, the distortion intensity increases with almost astonishing continuity over the entire gain range up to heavy rock rhythm or singing blues rock lead. As expected, the amp shows increasing compression, but even at the highest settings it still reacts extremely dynamically and conveys a pleasantly sensitive feel. But it gets even better: I turn OD Volume to 1 - yes, to ONE - and the Classictone-II delivers almost the same characteristics and dynamics at bedroom level! Okay, not with the pressure of higher volume settings, but voluminous, fat and yet lively and transparent. Gradually the concept of the master level switch makes sense to me. Amps with conventional gain/master control sound at room volume - i.e. gain fully up and master down to emission compatibility - mostly characterless and expressionless, floppy and meaningless. Here, however, the power amp is always included in the sound by the master switch, since the master level cannot be lowered lower than "home". The boost switch of the OD channel activates the third channel of the Twenty and at the same time adds a clearly audible boost of gain, even when the pointer of the gain control points to higher realms. Result: Creamy, homogeneous lead distortion, healthy compression, precise, detailed resolution, high assertiveness, sustain until the day after tomorrow, all this with manageably limited dynamics and, last but not least, surprisingly low ambient noise. In view of the home level, I hardly dare to select Studio and Stage. But this is absolutely recommended when testing this combo - preferably with band level - because then the amp shows its qualities to the fullest. The reverb pot mixes the effect signal of the large spring reverb with the direct signal, i.e. it is connected in parallel. Thanks to the even control characteristic, the effect component can be finely dosed until it produces an intense, natural, homogeneous, warm and spatial sound with a healthy portion of brilliance and clean signal at full output. The long decay time of the large system may not suit everyone's taste, but can be compensated by lower reverb settings. With its nominal level of -10 dBV, the non-switchable serial FX loop is compatible with both pedals and 19″ processors and is exceptionally faithful to the signal. Both recording outs, the balanced XLR as well as the jack output, deliver appealing speaker-emulated DI sound that requires at most slight (taste-related) corrections at the mixer. The DI sound deviates somewhat from that of the on-board speaker, as it doesn't sound quite as lively and airy. I can always live with it, and the recording and FOH personnel certainly can as well. The Verdict
With the Classictone-II Twenty, the Dutch amp manufacturer Koch once again makes a successful contribution to the popularity of small tube amps, which has been increasing for years. Although, in view of the housing dimensions, there can be no talk of small here, here the adjective "power-reduced" would certainly be more appropriate. And so it happens that the 20-watt combo not only looks like a big one, but also sounds like one. With voluminous yet differentiated, transparent and lively clean to high-gain sounds, the Twenty is tonally very variable and displays impressive dynamics and sensitivity at no less impressive volume. On the other hand, the amp also masters the discipline of bedroom levels without losing its vital characteristics. Practical line/recording outputs, serial FX loop, very good sounding spring reverb and master level switch complete the equipment of the impeccably manufactured three-channel amp, which is also offered at a fair price. PLUS ● Sounds & tonal flexibility ● Precision, response & dynamics ● Harmonic distortion character ● Master level switch concept ● low side noise ● Quality of components & workmanship ● price/performance MINUS ● Access power switch ● Inconvenient tube change For the first time in 30 years, the Dutch amp manufacturer Koch presents an amplifier with 6V6 power tubes. With this, they want to tie in with the classic small US combos of the 50s and early 60s, but without sacrificing any contemporary upgrades. With its carefully applied red, cream and extra-thick Koch Custom vinyl cover, delineated by black piping, the Ventura V20 looks visually stunning. The two-channel amp delivers 20 watts and is equipped with a 12″ speaker, serial FX loop and speaker simulating jack output, which is also influenced by the sound characteristics of the power amp. Thanks to the integrated load resistor, the speaker can even be switched off completely. BALTIC BIRCH ... is used for the solid plywood cabinet, namely 15 mm for the frame and baffle, and 12 mm for the screwed rear panel, on which the amp chassis is mounted vertically. A tight front covering, eight screwed steel corners, four large rubber feet and a comfortable handle complete the exterior. A large opening in the rear panel not only provides storage space, but also reveals the large spring reverb system mounted in a leatherette bag on the bottom, the Koch Custom VG12-60 12″ speaker bolted from the rear, and the Velcro straps on the side panel that hold the foot switch and power cord during transport. Everything was processed very meticulously, which can be seen, among other things, the send and return cables of the spring reverb carefully laid and fixed in the corners. The Ventura is operated from the top, everything else can be found on the underside of the amp chassis. To change the tubes, you have to reach around the chassis or - more recommendable - disassemble the rear panel. While I'm at it: Inside the amp chassis, bent from 1.6 mm steel sheet, I'm presented with solid careful circuit board construction, lots of insulated lugs and connections grouped into harnesses. The thick speaker cable is routed directly into the amplifier housing and is plugged in on the speaker side. The control panel is clearly laid out, and thanks to cream-colored chickenhead buttons, settings are instantly recognizable: Input, channel switch Clean/Overdrive, the pots Clean Volume, OD Gain, OD Volume, the passive tone control with Bass, Mid and Treble, Reverb Volume, FX Send and Return connections, standby switch and large red power indicator (Pilot Lamp). Accessible on the bottom are the connection for the foot switch (channel/reverb), the recording/PA output with speaker on/off switch, holder for the HT fuse, the power cord socket with drawer for fuse and spare fuse, and the main power switch. SMALL?LOUD! Power On ... Standby On ... Clean Channel. First, I set the passive tone controls, which are rather nuanced due to the circuitry, to the center position and reverb to zero. My Les Paul with vintage-style 58 PAFs is the first guitar I use. I carefully turn up Clean Volume from zero to 1, where I hear the first tones. At 2, I almost fall off my chair, because the 12-incher literally roars at me. Goodness, what a volume! Even an old tweed amp couldn't get this clean sound any better. Crystal clear, warm and wide, wonderfully transparent, tight, defined, full-bodied bass, silky brilliance around the top and in between concise, percussive mids, everything perfectly balanced. It goes on continuously up to 5, where I notice the first tightening with an intensive attack. Level-wise, I could easily go on stage with it. I turn up the volume further, the volume increases completely evenly, to end - I hardly dare - at 10 with a fat crunch. Ouch, that's not really possible without ear protection! Now it sounds really fat but still defined and even with full chords with fine resolution. The subtle compression supports the sustain of the guitar, and the impulsive response gives the Koch Ventura the finest dynamics. It gets even better. My Les Paula has a conventional 50s Wiring, normal CTS pots, current Bumblebee capacitors and no-Treble bleeds. Nothing special, then. Turning down the guitar volume, I get down to 1, and the level decreases steadily without any significant treble loss. I am amazed. Basically, I'm fine with the previous EQ setting, but I still correct Bass to 4, Mid to 6 and leave High at 5. Mind you, the controls interact, and if I turn them all to zero, nothing more is heard. Traditional passive tone control. At about Gain 2, the distortion intensity of the Overdrive channel is equal to that of the fully turned up Clean channel. With identical EQ settings, the OD sounds a bit leaner overall and leaves more room for upper mids. If you turn up the gain further, not only does the distortion increase evenly, but the sound becomes fatter, punchier and richer in sustain with hardly any reduced transparency, yet always retains assertiveness and dynamics, all this with surprisingly low ambient noise. Even with the gain fully turned up, whose tonal event I would like to call a hard rock or mid-gain lead, OD Volume regulates completely continuously over its entire range. A Strat with vintage single-coils delivers no less pleasing sound results on the Ventura if you always set the Volume and Gain controls one or two strokes higher. In any case, however, the individual sound character of the guitar is always preserved. The little chef also masters the notorious high-gain living room level with flying colors. So I turn OD Volume to 1 and Gain to 10. Sound characteristics and dynamics are almost preserved, and even the tone formation still finds support. The whole thing is not with the pressure of higher volume settings, but fat, lively, transparent and with a high fun factor. The recording/PA output delivers a well-tuned speaker simulation that lacks a bit of the vitality, freshness and transparency of the on-board speaker, but after slight corrections via mixer EQ is perfectly suitable for direct recording, for recordings or for practicing at home. A clear advantage of the Ventura is that you can simply switch off the speaker, but in this case you need a headphone amplifying device. The reverb pot mixes the reverb to the direct signal, which can be precisely dosed and, when set to full, delivers natural, dense and warm-sounding spring reverb with a dash of brilliance, freshness and transparency. Thanks to its nominal -10 dBV level, the signal-true serial FX loop is compatible with both pedals and 19″ processors. The Verdict
Sonically located more in tweed territory, the VenturaV20 combo not only delivers excellent, lively clean and break-up sounds - for a 20-watter even with considerable headroom and overwhelming level - but also convinces with homogeneously distorting, extremely dynamic rhythm and lead sounds that can be shaped with expressive variable playing. Even in home use, the combo hardly loses any of its dynamics and sound characteristics, even at living room level. If it should be even quieter, you can also use the speaker-simulating output with dummy load, where even the speaker can be switched off. Spring reverb and FX loop sound and work just fine. The Ventura V20 C112 was processed in an exemplary manner and also has eye-catching qualities. I am happy to give it a very good price-performance ratio. PLUS Sounds & tonal flexibility response & dynamics harmonic distortion character speaker simulation with dummy load low side noise quality of components & workmanship price/performance MINUS Access to power switch Uncomfortable Tube swapping |
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