New "Vintage" guitar amplifiers
Engineer
http://kn.theiet.org/magazine/issues/0918/hand-built-cooler-0918.cfm
I can't imagine using old or even new carbon resistors and
"bumblebees" in a new production unit but there's no accounting for
taste. Of course, this is not Hi-Fi, rather "serendipitous
distortion"... never .liked that stuff!
Note the bit about old amps catching fire... :-(
Cheers,
Roger
Bret L
CE Sucks! RoHS Sucks! They are not appropriate for MI gear!
Hopefully when the BNP takes 10 Downing Britons will be suitably
exempted from it...
When hand-built is cooler
Published on 19 October 2009
You are here: Knowledge Network home > Magazine > Issues > 0918
By Jonathan Wilson
>>"In a production-line world, what room is left for hand-wired audio amplifiers? Plenty, given guitarists’ fondness for ‘authenticity’, reports E&T.
In an age when the majority of music released has been recorded,
mixed, processed, distributed and consumed almost entirely in the
digital domain, why is it that, when it comes to amplifiers, so many
guitarists are obsessed with the primitive - some engineers would say
obsolete - technology of the 1950s and 60s?
Tag boards, point-to-point hand-wired circuits, valves of all shapes
and sizes, mustard capacitors, retro cloth and tolex coverings: these
are the key elements of design that quicken the pulse of the vintage-
amp enthusiast.
For the discerning guitarist, a hand-wired valve-powered low-wattage
amp represents the pinnacle of sound, offering an almost zen-like
simplicity and purity in its circuitry design and signal flow. Like
retro-winged moths to a valve-powered flame, guitarist of every stripe
continue to be drawn to the old ways.
How is it that this desire persists today? Why, in the 21st century,
are major manufacturers still laboriously hand-wiring valve amps,
using 50-year-old circuit designs?
Shane Nicholas, senior marketing manager for Fender Guitar Amplifiers,
has the simplest answer: “Some folks want amps that are built the Leo
Fender way, the 1950s way. Most guitarists have returned to the
basics: a great-sounding tube amp and a couple of stomp boxes.”
Fender, Vox and Marshall
Companies like Fender, Vox (makers of the venerable AC30, the Beatles’
touring amp of choice) and Marshall (enjoyed by everyone from
Aerosmith to ZZ Top) all currently have a hand-wired element to their
product catalogues, often for very different reasons.
Vox had a straightforward reason for resurrecting historic designs to
create its hand-wired Heritage range: the company’s 50th anniversary
in 2007.
Meanwhile over at Marshall, Peter O’Neill, assistant head of R&D, says
the company sensed the winds of change as players began looking back
to what was perceived as a golden age: “To some of the guitarists who
were buying amps in the 1960s and early 1970s, hand-wired amps are
just amps, but to a newer generation they are a rare and desirable
object. As the quantity of amps on the second-hand market was drying
up, people were buying imitations of early Marshall amplifiers and
sometimes paying well over the odds for them. It made sense that we
should start making these amps again. Why have a copy when you can
have the real deal for a better price?”
Fender’s Nicholas echoes this sentiment: “Back in the early 1990s, a
few new ‘boutique’ companies introduced amps that were direct copies
of Fender, Vox and Marshall. This helped to alert us that there was a
market out there for high-end, hand-made amps. We knew it was time to
do the ’57 Twin, for example, when they became extremely collectable
and pricey.”
The spiralling cost of the vintage originals in keeping with their
sustained popularity is the reason Mark Baier - owner of the Victoria
Amp Company, which has made its name producing latter-day hand-wired
replicas of Fender’s 1950s Tweed classics - gives for the burgeoning
reissue and boutique amp market.
“Fender’s biggest competitor used to be itself - its second-hand used
gear on the market,” he says. “Then Fender reissuing the Bassman begat
this little industry. People noticed the difference in tone and
started looking deeper underneath the hood. It had the effect of
arming the public with information and they consequently went looking
beyond the norm.”
With a ready market now beating a path to the manufacturers’ doors,
reviving the hand-wired tradition made good business sense on a number
of levels.
Vox R&D’s Ian Doggett has a twin theory as to why companies like to
produce hand-wired products: “I think hand-wiring shows an ability of
the company, the technical level of the staff,” he says. “I also think
there’s a lot of marketing magic as well, because you can create an
additional premium on the price for hand-wired because it has this
aura of ‘hand-wired is better’”.
Doggett’s colleague Dave Clarke (one of the designers behind Vox’s
Heritage AC15) gathers up the nebulous issue of end-user perception,
stating: “Tone is subjective. An amp could indeed be considered more
authentic because it’s using original components, but that doesn’t
necessarily mean it’s going to sound better. It might actually sound
worse.”
Clarke puts forward the argument that vintage amps may have their
signature sound for the ‘wrong’ reasons: “Back in the 1960s, the
components were by and large very poorly made. So you’re listening to
an amp that’s 40 years old and all the caps are just on the cusp of
drying out and the smoothing caps have gone and the mustard caps are
going and everything needs replacing. You’re going to have to replace
it all if you want your amp working any more - you can’t not have
smoothing caps - and then it’s going to sound completely different.”
The issue of component supply is one familiar to all the
manufacturers. Historically, component shortages dictated that
necessity be the mother of invention, such that what might now be
considered a classic amp came about purely by chance. Doggett
describes how a company might “buy in a couple of hundred of this and
a couple of hundred of that and put something together”, going on to
explain how “because of the compliance issues, you can’t buy original
components new anymore.”
Equally, Nicholas’s concern for Fender is about being able to maintain
production levels: “The tricky part can be finding the right
components in an age where nobody else in the electronics world cares
about guitar amps. Mobile phones and laptops aren’t hand-wired, you
know,” he says.
Marshall, on the other hand, has been luckier, as O’Neill points out:
“Many of the component manufacturers from the early days are still
producing and willing to supply components to us. This includes Drake,
who made transformers and chokes for Marshall in the early days. This
is a major boon for us as it really helps us say to people, ‘Yes, this
is as close to the original as you can get’.”
Retro amp safety
One major headache common to all R&D departments is the clutch of
safety regulations that impose a heavy burden on manufacturers,
particularly EU-based companies.
“From a safety point of view, we have to follow CE approval,” explains
Doggett, “which is extremely stringent. Now we have to go through EMC
testing for Europe as well, which is emissions and immunity. When you
consider that you’re paying up to $50,000 per product to achieve these
certifications, that’s a problem.”
Mulling over the hypothetical possibility of Vox reissuing a period-
correct AC30, Clarke lays out the hurdles facing the company: “We
wouldn’t be able to use completely original components, because we’re
simply not able to. The lead content would be too high. People say all
the time, ‘Oh, why can’t Vox put in this type of resistor or that sort
of cap?’ Because we’re not allowed. You know, the AC30s of old had a
habit of bursting into flames! And they’d have done that for a reason,
so we’d have to change that. Critical components for your AC30s, like
the output transformers: to make them vintage correct, we’d have to
have them wound the old way, and then they probably wouldn’t pass
insulation tests, so from a safety stand point it’s just not viable to
do it.”
Marshall’s O’Neill elaborates: “If a safety engineer looked in an
original amp from 1967, he’d probably faint. We’ve had to make a few
changes to things like mains transformer construction, mains
connectivity (the old three-pin Bulgin connectors are no longer
acceptable), mains voltage markings and selectors, earth bonding and
the use of flame-proof (metal film) resistors in some circuit
locations. Although these changes have no effect on the tone of the
amplifier, they can still have an effect on the way it is perceived.”
Clearly, building a reissue valve amp is far from a straightforward
case of pulling a sheaf of old blueprints out of a drawer marked
‘historic hand-wired’. There’s also the issue of production: where and
by whom.
“We have to fit in with how our manufacturer can efficiently run its
production line,” explains Doggett. “We use OEM manufacturing, so we
have to design within the capabilities within that factory. Everything
is standardised. There are key components that have to come from a
certain supplier.”
“We chose a certain type of handwiring for [Vox’s Heritage series] for
a number of reasons,” explains Clarke. “We chose to use a turret board
with tracks underneath, purely for power and grounding. Everything
else was mounted on turrets. They look like PCBs, but they’re not
PCBs. The way we designed them was to make them easier to produce.”
Vox uses Chinese company IAG to build its Heritage hand-wired amps and
it’s worth noting that they are built on the same production line as
the PCB/valve AC30 Custom Classic amps, the bread and butter wedge of
Vox’s revenue stream.
Fender also manufactures in the Asia-Pacific region, as well as in
Mexico, but the hand-wired jewels are predominantly US-made as part of
the Custom Shop range.
“The assembly crew has to be specially trained, because they are
soldering components one at a time. It’s precise, painstaking work,”
says Nicholas. “Our Custom series models cost more to build than PCB
amps because time is money. The circuit board in a Vibro-King takes
about eight times as long to build as, say, a Super Reverb. Is it
better? That’s up to you. Is it different? Yes.”
Handbuilt in Milton Keynes
Marshall, meanwhile, continues to build many of its amps in its UK
factory in Milton Keynes. There are workers taking their time
carefully handwiring flagship amp reissues like the 1974X, while
colleagues sitting alongside them churn out high-volume, lower-cost
PCB-based valve amps.
As O’Neill explains, “I think a lot of the success of [Marshall] is
down to having all the design, manufacturing, assembly and test in one
location. If there’s a problem in production a member of the design
team can be witnessing it first hand and working on it within a minute
of hearing about it - we can react fast.
“We have a good training system and strict technique guidelines in
place for the people who are wiring the amplifiers. It also helps that
there are people working here in our factory that have been building
amps since the 1970s, so they have been able to revive their
techniques as needed.”
Thus even after decades of technological advancement in other areas,
the same simple hand-wiring techniques are still being practised in
the name of rock ’n’ roll on the production lines of the companies
that first blazed the valve amp trail.
There’s magic in those simple circuits, the allure of the hand-wired
valve guitar amp eloquently summarised by Victoria’s Baier: “The
connection between the electron movement and the string movement is
more intimate, more readily understandable, and that affects your
playing. There is a sense of optimism that the mind can comprehend the
physics of it all - passive components, simple analogue tube circuits.
You can really follow the electrons through the circuit,
metaphysically anyway. Yes, as electronics go, it’s romantic. An op
amp or transistor chip are hardly as tender and warm as a Tung Sol
5881, now, are they?”<<
http://kn.theiet.org/magazine/issues/0918/hand-built-cooler-0918.cfm
Eeyore
> This is excellent, thanks for bringing it to our attention....
>
> CE Sucks! RoHS Sucks! They are not appropriate for MI gear!
> Hopefully when the BNP takes 10 Downing Britons will be suitably
> exempted from it...
CE is very good for MI gear. It has forced designers to redesign their
gear to be hardened against unwanted RF susceptibility for example. The
techniques can be quite simple actually and rarely involve radical
circuitry changes. Some of those changes also improve audio quality and
are likely to reduce the problem of 'hum loops' too.
RoHS is another matter. Lead-free solder DOES suck in a high vibration
and potentially very cold temperature environment. Pure tin starts to
turn to dust below 13C ( tin pest ). Small amounts of copper or maybe
silver in the alloy only slow down the process. And don't even mention
'tin whiskers' !
Graham ( approvals expert )