august 2010

The Dynamic 2040 HG DynaLead is backed with versatile tones that are easy to use

Every once in a while, a product breaks away from the norm and dares to be different than the rest of the pack. In the current golden age of gear, there are many, many great amps available—more than I’ll ever play in a lifetime—so it takes something extra special to stand out. In the case of the Dynamic 2040 HG DynaLead, I feel they’ve discovered a way to bring something unique to the table while still making it dead simple to operate and get great tones. Like any good design, you wonder why it hasn’t been done this way before. To be honest, I’d never even heard of the Dynamic brand until the amp arrived for review, but I’m sure that will change very soon. Again, I haven’t played every amp in the world, but the 2040 HG opened my eyes to a new design concept that works for me. Let’s take a look.


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A history of Guild''s early amps

Although the electric guitar era officially began in the late 1920s, it wasn’t until the early 1950s that the electric guitar fully established itself as an instrument of major popularity. Manufacturers and retailers realized the electric guitar represented a sales bonanza—not just as far as selling the guitars themselves, but also in selling the accompanying amplifiers. As retailers began to ask for amps, many companies that built guitars were happy to comply. (Some companies, like Fender, came from the opposite direction, too.) Guild was no exception.

Guild Guitars Inc. was formed by guitar and accordion retailer Alfred Dronge and ex-Epiphone manager George Mann in New York City in late 1952. The first guitars to bear the Guild brand were made at Guild’s lower Manhattan factory by a group of workers that consisted in part of ex-Epiphone employees, with some Gretsch expatriates sprinkled in. Epiphone had recently de-camped from New York in favor of Philadelphia because of labor issues, something that would affect Guild as well. The first Guild guitars reached the market in early 1953. In the spring of 1954, Guild printed its first catalog, which featured a new line of acoustic archtops to go along with the acoustic flattops and electric archtops already available. Business was brisk, and approximately one year later Guild released its second catalog. The 1955 catalog featured jazz great Jimmy Smith on the cover and was packed with stellar guitars—including the sublime new Aristocrat M-75, a low-production Les Paul killer with mahogany back and sides, a spruce top, and P-90-style pickups. The new Guild catalog also presented the company’s maiden foray into the wild and woolly world of guitar amplification with the Masteramp line.


A 1955 Guild Model 200 Double-Twin combo with “TV-front” cosmetics.

Shooting for the Moon
The amp business in 1955 was still a fairly open field. Fender was the leader, but not yet the all-ruling juggernaut it would become. Gibson ran a distant second, although it was introducing new models at a rapid pace. Smaller brands such as Premier, Epiphone, Multivox, and Magnatone were either looking for their niche or rapidly falling behind. While the majority of amps available on the market were still relatively small and low-volume, with minimal features and weak output, Guild made an attempt to take a place in the higher end of the market. But while the new Guilds were built a bit more sturdily than most amps and offered good controls and speaker options, they lacked a truly robust circuit design.

The initial line of Masteramps dripped ’50s style, with chunky “TV” front plywood cabinets and a two-tone vinyl covering of fabric-textured tan on top and dark faux wood grain on the bottom. Staying to the industry-standard price-point formula of low, medium, and high, Guild offered three models. The smallest of the ’55 Masteramps was called the 66. Standing a foot-and-a-half tall, the relatively compact 20-pounder offered 15 watts through a single 12" RCA hi-fi speaker. Next up in size, price, and power was the 99, a 25-watt amp with a 12" Jensen and two Jensen tweeters.

Guild shot for the moon with its top-of-theline amp, the Double-Twin. It was stocked with two 12" Jensen P12P Concert-series drivers and two switchable Jensen 4" tweeters. By adding the tweeters, Guild aimed squarely for the high-end market. An amplifier with two 12" speakers was big stuff for any company in 1955, much less a startup. The few other 2x12 amps of the time came from major manufacturers like Fender and Gibson. The 1955 catalog billed the Double- Twin as “perfect for small combos.” That pronouncement may seem odd or obvious unless you know that, at that time, all the players in a group usually shared one amp. Guitarist, singer, and even a string bass player would plug into the same multi-input amp.

Each of the three ’55 Masteramp models had top-mounted controls on a chrome panel with screened white lettering. They all had two channels, with a single input for the Accordion/Mike channel and three inputs for the Instrument channel. One of the instrument inputs was labeled “Recording,” and according to the catalog, this input was modified with a “Filtertone” buffer for use specifically in recording situations. The Recording input ran through a separate filter network and, unlike the two other instrument inputs, was not wired at the jack with 68k resistors. Each Masteramp had the same set of controls: Volume for each channel, plus master Bass and Treble controls. Also on the panel were controls for the tremolo feature, including an on-off slider, knobs for Strength and Speed levels, and a jack for the optional trem-control footswitch.

From 50L6s (and No Transformers) to 6L6s Tube selection is where the Masteramp story gets weird. The catalog mentions that the 66 has a six-tube chassis—RCA tubes at that. The 99 had a seven-tube chassis, and the Double-Twin had nine. What the catalog doesn’t say is that the power tubes on all three amps are of the 50L6 variety. Mention the 50L6 to any amp old-timer and they’ll guffaw and roll their eyes. In the 1950s, the 50L6 was not used as a high-fidelity tube. Rather, it was used when the goal was to push volume through a speaker. The benefit of the 50L6, at least in 1954 and 1955, was that it had enough voltage to eliminate the need for a power transformer and allow the use of a weak (read “cheap”) output transformer. This type of construction would, at least in theory, lower the price of the amp. Using the 50L6 involved wiring the filaments of three tubes in series, creating a trio. The Masteramp 66 had a single trio of 50L6 tubes. The Double-Twin and 99 had two sets that ran push-pull. The Double-Twin also used dual selenium rectifier units that are similar to today’s diode rectifier. Preamp tubes on all three were 12AX7 and 6SN7.

In addition to the aforementioned problems with 50L6 tubes, heat issues were a real concern. Today, many amps that came equipped with 50L6 tubes show signs of heat damage to the chassis. Guild certainly became aware of the issue, because at a certain point during the run of the first Masteramp series, 50L6s were ditched in favor of the more stable, more powerful, and—above all—more musical 6L6. While the transformerless 50L6 circuit was a money-saver early on, glass-tube 6L6 and 6V6 tubes were rapidly coming down in price enough to make up for the expense of a power transformer. It was an added bonus that these tubes also offered a much more toneful solution. Consequently, Guild amps from that point on used a more standard circuit design and tube complement.


Early Double-Twins featured a nine-tube complement powered by 50L6s, as well as two 12” Jensen P12P Concert-series drivers and two switchable Jensen 4” tweeters.

The ultra-clean Model 200 Double-Twin shown in this article dates from late 1955 and belongs to collector and historian Lynn Wheelwright. It’s on display at the Museum of Making Music in Carlsbad, California, through 2010. The amp seems to be all original, which gives us a neat look at the type of components Guild used in their Masteramps. The speakers are Jensen P12P C5 775s, which feature an alnico 5 permanent magnet and were cutting edge hi-fi technology at the time. Guild, like Gibson, used home hi-fi as the benchmark for sound and quality, which explains the use of two Jensen P3VH C5 628 tweeters. In addition to the standard controls noted above, the Double-Twin has a Standby/On/Tweeter rotary knob. Connected to a ganged pair of potentiometers, this control allows for operation with or without the tweeters. Also in the tweeter circuit are two 1.0 μf capacitors that serve as a crossover, in effect allowing high-end signals to be sent only to the tweeters.

Riding out the 1958 Recession
These first-series Masteramps were made at Guild’s factory on New York’s Lower East Side. Rumors persist that Multivox, which was located nearby, made Guild amps, but this is most likely untrue. Hans Moust, author of the excellent Guild Guitar Book (Hal Leonard, 1999), states that former Guild employees remembered amplifiers being built at both the original New York City factory as well as at the subsequent facility in Hoboken, New Jersey, using components supplied in part by Ampeg. This does not completely eliminate Multivox from the picture, however. If Guild used Ampeg components in New Jersey, it is entirely possible that they used Multivox components while based in Manhattan.

From 1955 to 1958, Guild’s guitar and amp lines remained almost identical from year to year. The 1958 Guild catalog shows the same line of amplifiers as the previous three years, all still with the same covering and the small Masteramp logo just under the company logo. Masteramps hadn’t set the industry on fire (no 50L6 pun intended), but they remained a valuable part of the Guild business. As mentioned previously, the one-two sale of an electric guitar and amplifier was new for the ’50s and something that dealers demanded.

Going into 1958, the US guitar industry felt the effects of a severe economic downturn. The Recession of 1958 would prove to be the worst such event between World War II and 1970. Auto sales fell 31% from their 1957 levels, and unemployment in Detroit reached 20%. Consumer prices rose 2.7% and continued to rise through the end of 1959. Regardless, American industry forged on with bigger, bolder, and wilder designs in everything from household appliances to automobiles and electric guitars.

As such, the dichotomy of 1950s exuberance and the stark economic conditions of the day were reflected in the 1959 Guild catalog. The number of electric guitars being offered nearly doubled, and new additions were made to the archtop and flattop acoustic lines. A new amplifier— the new 100-J—was added to the original three. The 100-J was similar to the 99-J (model names began incorporating “J” over the intervening years), with the exception of having an extra tube, five additional watts, and a 15" Jensen speaker. The Masteramp brand was gone, and all amps were simply referred to by the Guild brand name. The catalog describes the look as a “Light Brown ‘tweed’ with a Dark Brown fabric covering on a ¾" hard plywood lock joint cabinet.” Grille cloth was a white swirl pattern on dark cloth, similar to Ampeg amps of the time. The speaker opening was trapezoidal, a design theme that would appear again in future Guild amps. By and large, the guts of the amps were the same as they had been since 50L6 circuits had been abandoned.

The real shocker in the ’59 catalog was the price. The ’58 recession had clearly made its impression on the Guild business. The 66-J, the smallest amp of the Guild line—which had held steady at $145—was listed at an eyebrow-raising $210. That’s an increase of more than 40%! The other amps in the Guild line also jumped in price, with the 200-D Double-Twin (note the name morphing) topping out at $395—that’s a $3000 amp in today’s dollars. Considering the competition, a Guild amp at a premium price had little chance on the market.

The Double-Twin Goes Stereo

In late 1959, the 200-D Double-Twin became the 200-S. This new variation was a dual-amplifier stereo model similar in theory to the Gibson GA-79. Each amp had a separate control stack with Volume, Bass, and Treble controls. Channel 1 also featured tremolo. The amps could be run separately, with signals coming out of each speaker, or the guitarist could use the stereo jack that drove signals to both amps. The 200-S did not appear in the 1959 Guild catalog, although there are 1959 versions of the 200-S. These units are covered completely in tweed, with a tweed-covered vertical bar bisecting the rectangular speaker opening. In 1960, Guild revamped its amp line yet again. The catalog describes “scuff-proof Blue-Grey vinyl,” but the 200-S cabinet was the same as 1959 versions except for the new covering. Interestingly, the 200-S carried a list price of $350—$45 less than the previous year’s model. This may have reflected an improvement in economic conditions or, more likely, may have signaled an attempt to attract more dealers and buyers with a more affordable offering.

Throughout the 1960s, Guild would struggle with low amp sales. As the company attempted to capitalize on the massive boom in demand for electric guitars and amps, it moved further and further from its roots in acoustic guitar making and invested more in the largely unrelated market of low-priced electric instruments. Ultimately, the company would be sold to a much larger—and equally unrelated—corporate parent, which would eventually culminate in the complete dissolution of Guild’s electric lines.

For more information on Guild and its amplifiers, read Guild Guitars by Hans Moust and Guitar Stories Vol. 2 by Michael Wright.

Early Double-Twins featured a nine-tube complement powered by 50L6s, as well as two 12” Jensen P12P Concert-series drivers and two switchable Jensen 4” tweeters.

The ultra-clean Model 200 Double-Twin shown in this article dates from late 1955 and belongs to collector and historian Lynn Wheelwright. It’s on display at the Museum of Making Music in Carlsbad, California, through 2010. The amp seems to be all original, which gives us a neat look at the type of components Guild used in their Masteramps. The speakers are Jensen P12P C5 775s, which feature an alnico 5 permanent magnet and were cutting edge hi-fi technology at the time. Guild, like Gibson, used home hi-fi as the benchmark for sound and quality, which explains the use of two Jensen P3VH C5 628 tweeters. In addition to the standard controls noted above, the Double-Twin has a Standby/On/Tweeter rotary knob. Connected to a ganged pair of potentiometers, this control allows for operation with or without the tweeters. Also in the tweeter circuit are two 1.0 μf capacitors that serve as a crossover, in effect allowing high-end signals to be sent only to the tweeters.

Riding out the 1958 Recession
These first-series Masteramps were made at Guild’s factory on New York’s Lower East Side. Rumors persist that Multivox, which was located nearby, made Guild amps, but this is most likely untrue. Hans Moust, author of the excellent Guild Guitar Book (Hal Leonard, 1999), states that former Guild employees remembered amplifiers being built at both the original New York City factory as well as at the subsequent facility in Hoboken, New Jersey, using components supplied in part by Ampeg. This does not completely eliminate Multivox from the picture, however. If Guild used Ampeg components in New Jersey, it is entirely possible that they used Multivox components while based in Manhattan.

From 1955 to 1958, Guild’s guitar and amp lines remained almost identical from year to year. The 1958 Guild catalog shows the same line of amplifiers as the previous three years, all still with the same covering and the small Masteramp logo just under the company logo. Masteramps hadn’t set the industry on fire (no 50L6 pun intended), but they remained a valuable part of the Guild business. As mentioned previously, the one-two sale of an electric guitar and amplifier was new for the ’50s and something that dealers demanded.

Going into 1958, the US guitar industry felt the effects of a severe economic downturn. The Recession of 1958 would prove to be the worst such event between World War II and 1970. Auto sales fell 31% from their 1957 levels, and unemployment in Detroit reached 20%. Consumer prices rose 2.7% and continued to rise through the end of 1959. Regardless, American industry forged on with bigger, bolder, and wilder designs in everything from household appliances to automobiles and electric guitars.

As such, the dichotomy of 1950s exuberance and the stark economic conditions of the day were reflected in the 1959 Guild catalog. The number of electric guitars being offered nearly doubled, and new additions were made to the archtop and flattop acoustic lines. A new amplifier— the new 100-J—was added to the original three. The 100-J was similar to the 99-J (model names began incorporating “J” over the intervening years), with the exception of having an extra tube, five additional watts, and a 15" Jensen speaker. The Masteramp brand was gone, and all amps were simply referred to by the Guild brand name. The catalog describes the look as a “Light Brown ‘tweed’ with a Dark Brown fabric covering on a ¾" hard plywood lock joint cabinet.” Grille cloth was a white swirl pattern on dark cloth, similar to Ampeg amps of the time. The speaker opening was trapezoidal, a design theme that would appear again in future Guild amps. By and large, the guts of the amps were the same as they had been since 50L6 circuits had been abandoned.

The real shocker in the ’59 catalog was the price. The ’58 recession had clearly made its impression on the Guild business. The 66-J, the smallest amp of the Guild line—which had held steady at $145—was listed at an eyebrow-raising $210. That’s an increase of more than 40%! The other amps in the Guild line also jumped in price, with the 200-D Double-Twin (note the name morphing) topping out at $395—that’s a $3000 amp in today’s dollars. Considering the competition, a Guild amp at a premium price had little chance on the market.

The Double-Twin Goes Stereo

In late 1959, the 200-D Double-Twin became the 200-S. This new variation was a dual-amplifier stereo model similar in theory to the Gibson GA-79. Each amp had a separate control stack with Volume, Bass, and Treble controls. Channel 1 also featured tremolo. The amps could be run separately, with signals coming out of each speaker, or the guitarist could use the stereo jack that drove signals to both amps. The 200-S did not appear in the 1959 Guild catalog, although there are 1959 versions of the 200-S. These units are covered completely in tweed, with a tweed-covered vertical bar bisecting the rectangular speaker opening. In 1960, Guild revamped its amp line yet again. The catalog describes “scuff-proof Blue-Grey vinyl,” but the 200-S cabinet was the same as 1959 versions except for the new covering. Interestingly, the 200-S carried a list price of $350—$45 less than the previous year’s model. This may have reflected an improvement in economic conditions or, more likely, may have signaled an attempt to attract more dealers and buyers with a more affordable offering.

Throughout the 1960s, Guild would struggle with low amp sales. As the company attempted to capitalize on the massive boom in demand for electric guitars and amps, it moved further and further from its roots in acoustic guitar making and invested more in the largely unrelated market of low-priced electric instruments. Ultimately, the company would be sold to a much larger—and equally unrelated—corporate parent, which would eventually culminate in the complete dissolution of Guild’s electric lines.

For more information on Guild and its amplifiers, read Guild Guitars by Hans Moust and Guitar Stories Vol. 2 by Michael Wright.

The ''74 Gibson J-50 Deluxe with tortoise binding rot is finished

We’ve come a long way in restoring the decayed binding on this ’74 Gibson J-50 Deluxe. In part 1 (May 2010), I discussed "binding rot," which is when tortoise binding begins to deteriorate as the plastic binders— the substances that cause the material’s components to cohere—start to age. We lightly scored the top and side edge of the decayed binding using the Sloane purfling cutter, then simultaneously softened the glue joint and binding using medium heat from a hair dryer, and finally removed the decayed binding with a channel spatula. Part 2 of this restoration (June 2010) was one of my favorites, as I used the new MacRostie binding trimmer to properly size the replacement tortoise binding down to .100" in height. The MacRostie, with its adjustable fence and large-dimensioning gauge, precisely duplicated the dimensions of the original binding.

Seating and Gluing the Purfling
We were ready to glue the .060" white/black/ white purfling in place after using a flat luthier’s file to finalize and remove any leftover slivers of old purfling and tortoise binding. Weld-On 16 is a fantastic and widely used glue for adhering wood and plastic laminates, but due to the specifications of the repair— the original finish on this Gibson body was to stay intact with no alterations, other than some lacquer overspray on the replacement binding—it would not be the glue of choice for this factory-finished body. Weld-On sets very quickly, can have a webbed taffy texture, and requires acetone as a clean-up solvent. So I chose Super Glue because it’s easier to control and offered me a much cleaner end result.


The Whip Tip attached to a bottle of medium Super Glue.


A scarf joint is used to hide the seam where

the two pieces of purfling meet end-to-end at

the tailblock, centered with the top’s center

seam. A scarf joint is the angled mating surface and can be angled across either the top

or the side of the binding strip. I attached

the Whip Tip to a bottle of medium-textured

Super Glue. The Whip Tip, a 1-3/4" precision

nozzle extension for glue bottles, makes my

job so much easier, helping me control the

glue and minimizing cleanup. I started at the

tailblock end of the guitar working my way

up towards the dovetail joint, gluing about

3" to 6" sections at a time, using binding

tape and whispering amounts of Accelerator.

Note: Always pre-check if the finish is too

delicate before using binding tape, as the

adhesion strength of this tape may cause a

major tear-out in the final removal.



Flexing Tortoise

After gluing in the purfling, I went around the

channel to make sure there was no excess

glue buildup anywhere, which helps to guarantee tight seam lines in the final stages. We

were almost ready to shape this single strip

of tortoise binding to the top, but first we

needed to scuff up the bottom and inside

surfaces of the binding with 320-grit sandpaper, which was double-stuck to a flat work-

table. This gives the glue something to bite

into for a secure fit.




Using a hair dryer to flex the new binding into place.



Using a hair dryer for heat—mounted on our

ShopStand and Guitar Repair Vise set for controlling the heat’s direction—I was able to flex

the binding into place. I placed 1-1/2" strips

of tape—alternating top to side, and side to

top—spaced ½" to ¾" apart to secure the

binding in place and create a new memory for

where the material needed to be positioned.



The next day, I removed the tortoise binding

and then glued it permanently into place,

using the same procedure as in the previous

gluing and taping process. Using the medium

Super Glue allowed extra time for fitting and

getting the plastic to gently melt and bite in

before permanently setting up. After all of

the binding was glued into place, I used Stew

Mac’s thin Super Glue for final touchups.




Performing the final level trimming with a razor blade.



A razor blade with masking tape on one end of

the cutting surface, used as a spacer, works very

well for protecting the top and sides when doing

the final level trimming before light sanding and

airbrushing on a thin nitrocellulose top coat.



I used the following supplies for this restoration (all are available at stew-mac.com):

  • Luthier’s file set (0842)
  • Binding tape (0677)
  • Thin Super Glue (0010)
  • Medium Super Glue (0020)
  • Whip Tip (1161)
  • Accelerator (5984)
  • Drop-fill toothpicks (3110)
  • ShopStand and Guitar Repair Vise set (5391)


You can buy the hair dryer, razor blades, and

masking tape at your local hardware or convenience store.



I hope this series has given you some valuable

insights on rebinding a vintage instrument.

This is truly a major job and requires many,

many hours if you’re looking to rebind while

keeping a treasured original finish intact. Until

next time, keep those chisels sharp!



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