This time last year I had just purchased a Blackstar HT-1RH and put a review up on Gearslutz for it, in which I praised the features and overall sound. However since then the tubes died and in search of more clean headroom and pedal-friendly use I ended up coming across the VHT Special 12/20 on offer at Thomann. Please note this is not the newer model with reverb and tremelo built in.
The 12/20 moniker represents the fact that this amp is capable of putting out upto 20w in high-power mode and 12w in low-power mode, with a switch inside the rear panel allowing you to change the power output. The mod-friendly layout and self-biasing means you can swap tubes out very easily - it comes shipped with stock Chinese 6V6 tubes but can take 6L6 and EL34 for 20w operation and also EL84 for 12w although this requires a special adapter. I am currently running it in 12w mode and have ordered some new tubes for it (Tung-Sol 6V6.)
*EDIT* I changed all the pre-amp and power amp tubes - Tung-Sol 6v6GT for the power tubes and 2 x Tung-Sol 12ax7 and 1 x JAN Phillips 12ax7 for the pre-amp tubes and they have made a large improvement - less hum and a sweeter drive sound! I paid about £75 to upgrade all five tubes and it is certainly worth it!
Going across the top panel, you have a on/off switch, a pentode/triode switch, a Watts control, a six-position Depth control, a three-position Texture switch, Effect Send/Return controls, Tone control and Volume control.
The pentode/triode switch allows you to cut the output power by approximately half which gives a wide variety of tones on its own - the triode setting offers smoother compression and early break-up while pentode setting gives lots of clean headroom and that classic Fender sparkle.
Then you have the Watts control, which controls the power output of the amp but works differently to a Gain control, in that fully counter-clockwise gets the amp down to 1w output for crunching the power tubes at bedroom levels and fully clockwise gives the cleanest tone possible at 12/20w.
The Depth control has six settings, with the first three designed for humbuckers and the second three for single-coils which add various amounts of bass to the tone and it makes a nice change to the usual bass control on most amps.
The Texture Switch is a high-frequency roll-off with three positions - middle is none, to the left is subtle and to the right is more pronounced. To me moving to the left or right produces a 'woodier' midrange like a Marshall amp but it is not as harmonically rich as the middle position to my ears.
The Effect Send/Return controls are the levels for the inputs on the back, but they also control the volume of the amp itself - I tend to have both controls turned all the way up and use the Watts and Volume controls to set levels.
The Tone control is the same as most amps - counter-clockwise rolls off mid and high frequencies.
The Volume control appears normal, but pull out the knob and you get a 20dB boost which also partly by-passes the tone stack, making the amp sound less 'scooped.' Using this in conjunction with the Watts control, you can get various levels of overdrive/distortion.
Round on the back panel, there is the power cable output, which has three settings for US/Euro/UK voltages so make sure you choose the right one for your country. Next is two speaker outputs followed by an impedance switch for going between 4-16 ohms (I have mine at 8 ohms running a Celestion Greenback speaker,) then then is a tube-buffered Line Out jack for going to a PA or studio pre-amp, the Effects Send/Return jacks, a 9v DC out for powering your guitar pedals and a socket for a footswitch to turn the boost on/off (the footswitch comes provided with the amp.)
So how does it sound? I've never played through many amps but many observers say it sounds like a Fender Princeton or Deluxe Reverb and the VHT is more on the Fender tone than a Marshall tone (although putting in a set of EL84 tubes may change this.) This amp is designed to bring the best out of your pedals and I have a range of overdrive and distortion pedals - Big Muff (USA and Russian), Proco Rat, Boss SD-1 (modded), Joyo Vintage OD and I also run a EHX Small Clone in the Effects loop and the difference between each pedal is night and day compared to other amps I have used - you can really hear the subtle drive of the SD-1, the low/medium gain of the Rat and the all-out fuzz attack of the Big Muff and stacking pedals can bring a whole new palette of tones.
Add in the Depth and Texture controls and you can basically have any sound you want out of this amp, from sparkling Fender cleans to high-gain Mesa sounds to warm Marshall crunch all with the flick of a button. For cleans my favourite is the Triode setting, Watts all the way up and Volume at around 75% and for overdrive I like the Pentode setting, Watts at around 25% and Volume at 100% with the Boost engaged.
For the price I paid, this is a whole lot of amp! Although it is made in China, it is all hand-wired onto a turret board rather than PCB mounted and you can swap out the tubes very easily making it easy to modify to your own tastes. The Depth and Texture controls add a host of new options that your regular Bass/Treble control can't quite do and the whole thing feels very user-friendly. If you're a pedal tweaker like me, this is a perfect platform to build your own palette of sounds without too much of the amps characteristics getting in the way. Overall, I would recommend this amp to anyone who is in the market for a low-wattage amp for the studio or for small gigs.