Koch Guitar Electronics 2023.
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.
... 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.
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.
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.
Sounds & tonal flexibility
response & dynamics
harmonic distortion character
speaker simulation with dummy load
low side noise
quality of components & workmanship
Access to power switch
Uncomfortable Tube swapping