FrugalGuitarist.com sits down with Terry Buddingh, the Designer of the VHT Special 6

Hello Terry, Thanks for taking a moment to sit down with FrugalGuitarist.com

I’d like to begin by saying thanks to Will and the all the FrugalGuitarist.com team for providing the opportunity to share some insights and information about the VHT Special 6 — FrugalGuitarist.com revives and redefines the art of guitar journalism with a fresh approach and focused perspective that’s perfectly suited to our times — and with the same timely and focused perspective, the VHT Special 6 revives and redefines the art of boutique guitar amplification with unprecedented value. FrugalGuitarist.com and VHT clearly share a similar vision; it’s a pleasure to be here, thanks again for the opportunity.

I'm flattered, especially considering your background! You've had a long career in the music instrument industry...

Music and electronics have always been key elements of my life. I’ve had many great teachers, beginning with intense piano and music theory lessons at a very young age; and at the same time, my father taught me the fundamentals of electronics. In college, I majored in music, but continued to study electronics as well.

I worked for Bartolini Pickups in the ‘70s and early ‘80s. (By this time I was seriously into guitar and bass.) I learned a lot about testing, evaluating and listening from Bill Bartolini. Bill is among the best scientific minds in the MI industry, and he’s one my greatest influences and teachers.

I started gigging a lot during my Bartolini years, and eventually left Bartolini’s to play music full time. Since then I’ve played more than 3,000 gigs worldwide.

In my lifelong quest for tone, I was always experimenting, modding and maintaining my gear at home and on the road, and over the years I’ve learned what sounds good and what works on the gig, and what doesn’t. By the early ‘90s, between road gigs, I was doing enough amp work to set up a little amp shop. During that time I played just about every amp ever made, and I tried to understand what made the great ones sound great.

My relationship with Guitar Player magazine goes back to the late ‘80s. Guitar Player was pioneering a new approach to in-depth and comparative gear reviewing, and I contributed my testing and gig experience to many reviews. I also discovered I have a knack for describing tones. Tom Wheeler, Guitar Player’s Editor in Chief and supreme guru at that time and until 1991, set the highest standards for selfless style and unbiased fairness. To read more about the godfather of modern guitar journalism, the golden days of print guitar magazines, and where this all came from, everyone should check out this link.

I'm also a fan of Wheeler's work. Loved American Guitars: An Illustrated History as well as his more recent books covering the history of Fender.

Always inspired by Tom Wheeler’s vision, I wrote and contributed to many gear reviews for Guitar Player, and I wrote for Guitar Player’s sister publication, Bass Player, as well. During this time I began writing for some other publications, including Vacuum Tube Valley (the bible for tube history and lore).

I became Technical Editor for Guitar World’s Bass Guitar magazine in 2005. I could see how the Internet was changing the world and I could see the untapped potential these new tools offered, and how they could take the art of gear reviewing to next level.

During its brief existence, Guitar World’s Bass Guitar was on the leading edge of the print/Internet revolution/evolution. We started with audio clips and led the industry with Ed Friedland’s YouTube gear reviews. The magazine is gone now, and Ed and I moved on to write for Guitar World, but Ed still maintains the old Bass Guitar channel, check it out here.

Continuing the quest for a print-plus-Internet magazine, I joined the startup Bass Gear magazine, founded by former Bass Guitar gear reviewer Tom Bowlus. Boldly going where no magazine has gone before, Bass Gear really raised the bar to new heights with super technical amp measurements and graphs. Check it out: http://www.bassgearmag.com/web/

I’ve been following the migration of consumer electronics manufacturing for more than a decade, and it became clear to me that the MI industry would soon follow the consumer electronics industry’s lead. Years ago, researching information about China’s MI factories was difficult, I knew many of the major brands were having gear made in China, but most of the people working for these companies were reluctant to share any details. Eventually, with a journalist’s persistence, I was able to penetrate these artificial barriers, and in 2006 I made my first trip to China. I’ve visited many factories since then, and have been to every Music China show since 2006 (held in Shanghai, Music China is Asia’s largest MI trade show, it’s the NAMM of Asia).

I made many new friends in China, and this led to my current position as Senior Manager of AXL’s electronics division (AXL is VHT’s parent company). This also gave the opportunity to do what I’ve been wanting to do for more than a decade – make handwired tube amps in China.

Can you speak a little about the motivation and inspiration behind the VHT Special 6?

The VHT Special 6 was intended to introduce and showcase our handwired capability, and with the help of savvy design and manufacturing techniques, we made a cost-cutting breakthrough that created a new category of extremely affordable boutique-style amplifiers.

My goal was to design a handwired tube combo with a target MAP price of $200. At that price point, it had to be as simple as possible, so it had to be a single-ended design, so it had to have one output tube. And it had to have minimal preamp controls, so it needed only one preamp tube.

While it had to be as minimal as possible, it also had to have some unique features to set it apart from the pack. So I designed a unique preamp circuit using a classic tone stack, but with resistors in place of pots, and combined this circuit with a single-pot tone circuit that’s essentially in parallel with the Volume control, and thusly isolated from the tone stack. The trick is the fixed tone stack can be defeated/bypassed with a footswitch (or the push/pot switch on the Volume pot), while the separate Tone control remains functional.

The rest of the circuit had to be minimalized (aka “Muntzed”) as much as possible. See this amusing link for more about Earl “Madman” Muntz’ method of cost-cutting electronics design: http://en.wikipedia.org/wiki/Madman_Muntz

With an unlimited budget, making a great amp is easy. It’s much more challenging to make a good amp with a limited budget. I was fortunate to have enough budget left to include a Pentode/Triode switch with middle Standby position (renamed High Power/Low Power) and a beefy output transformer with three output taps (4/8/16 ohms). We make our own transformers in our beautiful handwired amp factory in Ninghai China (south of Shanghai). Making our own transformers also helps to keep costs down. Steel is a commodity, and it’s not cheap these days, so the clever chassis design uses as little metal as possible, this is one of the ways we were able to afford to put more layers of transformer iron in the output transformer — it makes sense to put the money (and steel) where it improves the sounds the most.

We make our own speakers too, so we can afford to use larger magnets than similar lunchbox and small tube combo designs. We can also voice the speakers to suit the associated amp design.

Of course it’s the mod friendly handwired eyelet board that really sets the Special 6 apart from the pack, especially at this price point. Also, all of the wiring is on top of the board, so it’s really easy to see where everything is going. It might look neater if the wiring was under the board, but it would be much more difficult to service and mod.

Following the mad scientist inspiration behind the Classic 6, making it as simple as possible to experiment with mods, what would you suggest as a simple first mod for tube amp mod virgins?

It’s usually best to try the easiest mods first, and it’s usually best to start at the beginning. This isn’t what you’d really call a “mod,” but I’d start with different preamp tubes. Every 12AX7 brand has its unique gain and sound characteristics; the old Mullards from the ‘60s are a favorite of mine, they have an incomparably robust and rich tone. A 5751 will provide a clearer and more open tone; try to find an old GE 5-Star. Different output tubes can make a noticeable difference. The good news here is I recently visited the Shuguang tube factory in Changsha China, and they showed me three new 6V6 tubes that they’ve developed. I’ve tested these new 6V6s, and they all sound great, I’m sure they’re going to be a big hit as soon as they become available. Look for more new great tubes from the Shuguang factory in the future.

I’ve been asked about substituting different output tubes in the Special 6. We’ve tested it with all of the usual guitar amp output tube types, and it works fine with all of them, thanks to its cathode-biased output stage. Beware that larger tubes can stress the power transformer’s heater winding current capability, so if you really like the sound with a EL34, 6550 or KT88, turn it off and let it cool down every hour or two.

You can also experiment with different output transformer taps. The Special 6 has a sturdy oversize output transformer; it’s wound for a 9k ohm plate impedance. If you prefer the more aggressive sound of a lower plate impedance, you might prefer running an 8-ohm speaker off the 16 ohm output jack.

Of course the fun really begins when you pop the hood, and just about every component inside is fair game. Want to trim the low-end and brighten the top so humbuckers have more punch and bite? To trim the low-end, decrease the preamp cathode cap values (C8 and/or C13), try 1 uF each to start. (You might also try reducing C15; 5 uF would be a good place to start. (C15 needs to be rated for at least 25 volts, preferably more.) To add more bite, replace R16 with a 470k ohm resistor with a 470 pF capacitor soldered across it (capacitor in parallel with R16), and perhaps a 470k resistor soldered from the grid side of R16 to the preamp ground bus wire. Experiment with different values to season to taste.

If you want to re-voice the clean mode’s sound (non-boost mode), resistors R10 and R12 form the clean mode’s “Treble pot;” decrease R10 for more treble, increase R12 for less treble. R13 is the “Bass pot;” increase R13 for more bass, decrease it for less bass. R15 is the “Middle control;” increase R15 for more mids, decrease it for less mids. R22 controls the amount of boost you get in boost mode; increase it for more boost, decrease in for less boost. For a cleaner tone, change R3 and R4 to 100k ohms.

I’m sure some experimenters will want to try a negative feedback loop on the output stage for more clean headroom, and perhaps an elevated DC heater supply for less hum. A Variable Voltage Regulator (aka Power Scaling) might be fun. Of course someone is bound to try different tubes, like an EF86 in place of the 12AX7 or something like a 6DZ7 in place of the 6V6. It’s a simple circuit with a lot mod potential. It’s all good, and I’m really looking forward to seeing and hearing all of these mutations in the future.

I understand you have a rather large collection of vintage tubes, what are some of the most unique pieces of your collection? Favorite sounding?

Yes, over the years I’ve assembled an extensive reference collection of all the classic audio tube types and brands. Favorites? There is no universally “best” anything, but there’s always something that best suits a certain application and your own personal tastes.

Having said that, I have to admit I often favor British tubes from the ‘50’s and ‘60s, like Mullard ECC83/12AX7 preamp tubes and Mullard EL34 output tubes. They’re tough to beat; they really make an old Marshall sound “proper.” Can’t forget the Mullard EL84 for the definitive AC30 tone.

In the right circuit, a good Genalex KT66 can deliver an incomparably beautiful, elegant and refined presentation, with exquisite detail and musical dynamic response. And of course for high-power applications, the Genalex KT88 reigns supreme with it assertive punch and still-nuanced texture.

And the Mullard GZ34 rectifier tube is always tough to beat (unless you want something with more sag).

Amperex made some great sounding tubes, like their ECC83, EL84 and EL34. Can’t forget the Tung Sol 5881, good ones sound amazing in old Fenders. I have to mention the GE 6550A too, definitely one of the most awesome tubes ever made.

What do you see as the future trend regarding tube amp design?

More value. And more affordable handwired tube amps. VHT intends to lead the way with more affordable handwired amps, and frankly, we’re going to be difficult to beat. We have our own factory, we make our own transformers and speakers, and we’ve already honed and mastered the art and processes of low-cost handwired manufacturing. And our factory only makes guitar amps; no mobile phones, computers or TVs. (Most Chinese-made amps are made in “contract factories,” factories that aren’t owned by the brand-name company, and are instead contracted to do the work, and they work for many brands. Transformers and speakers are usually acquired from other contract factories, thus increasing costs and reducing quality control.)

I expect small low-powered amps will remain popular, but I see a trend away from the current crop of EL84-powered lunch boxes. It’s the normal cycle of trends to swing from one extreme to the other, and those craving a more robust tone will surely rediscover the 6V6. The great sounding new tubes from the Shuguang factory should help fuel the 6V6 resurgence as well.

Beyond traditional tube amp designs, there could be some interesting hybrid technologies down the road, such as a new breed of onboard digital processing that works synergistically with the tube circuitry. Combining technologies can produce great things if you let each technology do what it does best.

Any hints at some future offerings from VHT?

We have more handwired amp designs in store, as well as many new speaker cabinets and configurations, and we’ll be selling our raw-frame speakers separately too. Be sure to catch us at Winter NAMM, we’ll be debuting a boatload of frugal-centric surprises. And keep an eye on vhtamp.com for fresh updates as well.

Download the official VHT Special 6 schematic here.