Build your own tube preamp pedal built around a 12AX7 tube. Go from clean, warm tone to smooth, real tube overdrive. This kit includes pre-drilled die-cast aluminum enclosure and all parts with easy to follow instructions. All you need to provide is solder and soldering iron. Operates on a 9V battery or AC adapter, which is not included.
SPRING REVERB TANKS EXPLAINED & COMPARED
by Kurt Prange
The Reverberation Effect3
A listener standing some distance from a sound source will perceive sound that is actually a combination of direct sound and indirect sound that has been reflected from the boundaries of the listening area. The reflections are referred to as reverberation. Reverb can enhance the perceived sound from a source by adding depth, color and liveliness.
Reverb can be thought of as being composed of two parts:
1) Early reflections – shape the listener’s conception of room size
2) Cluttered reflections – convey the liveliness of a room
The Significance of Multiple Transmission Springs3
Imagine you are inside a large hall and you clap your hands once. The length of time required for the arrival of the very first reflections is called the delay time (usually on the order of tens of milliseconds, e.g. 33 ms) and is related to the volume of the room (or distance of the reflective surfaces from the listener). The number and density of reflections increases rapidly with time and they become cluttered while simultaneously decreasing in level until they are no longer audible. The length of time required for a sound to decrease in level by 60 dB is called the decay time(usually on the order of a few seconds, e.g. 3 s) and is related to the acoustical properties of the reflective surfaces in the listening area. For example, poured concrete walls will reflect more (absorb less) acoustic energy than drywall.
Electro-Mechanical Reverberation Devices: The Reverb Tank
Historical use in Musical Instruments
Laurens Hammond of Illinois popularized the use of artificial reverberation devices through his church organs in the 1940’s and 1950’s. “The early (pre-B-3®) Hammond®organs were sold to churches on the principle that organ music is greatly enhanced by reverberation, but the minister’s speech in the church is hampered by reverberation. Therefore, churches were designed to be acoustically dead, and the Hammond®organ had to have its own artificial
reverberation. “[Reverberation] made its debut in the Fender®line as a separate item, using a spring [unit] bought from Hammond®, [in] 1961. It was first incorporated in a Fender®amplifier with the Vibroverb®of 1963 and then spread widely throughout the amp line, just as vibrato/tremolo had before it.
DESIGN AND BUILD YOUR OWN TUBE GUITAR AMP
by Kurt Prange
Why Tubes?
If you’re not an electric guitar player or if you’re just starting out, you might ask why anyone would build anything with tubes. Aren’t vacuum tubes an obsolete technology? Well, yes and no. While tubes are no longer the technology of choice in the computer industry, they are very much alive and well when it comes to modern high-end guitar amplification. It is because of the electric guitar amp that vacuum tubes are still being manufactured today. Visit your local guitar store and take a peek at the rear side of the amps, you’ll most likely see a variety of glass tubes projecting from the amp chassis.
Guitar amps with tubes are currently front and center in the high-end market because many guitar players find their sound characteristics to be superior to solid-state amps (i.e. amps with transistors as the main active electronic devices). Modern mass produced tube amps use printed circuit boards to connect components, but at the extreme high-end there are “boutique” amp builders who hand wire connections from point-to-point and select high quality components. Point-to-point wiring is how vintage guitar amps from the 1950’s and 60’s were wired and it’s a technique that allows for easy maintenance and circuit modification.
DIY and the Boutique Amp Builder
Boutique amp builders are individuals or small companies who build a relatively small number of amps each year with an emphasis on quality and attention to detail. Boutique amps are usually priced in the thousands of dollars, because they require a lot more time and skill to produce. The builders will often customize circuit designs to satisfy the different tastes and styles of individual guitarists. Most boutique amp builders at one time started out as electronics hobbyists who thought it would be fun to modify or build their own tube amp. The internet continues to make it easier to find books and parts to help you build your own boutique quality guitar amp.
Suggestions for a First Build
The quickest way to get acquainted with the parts and standard layout techniques used in tube amp building is to build an amp kit. Most kits come with a pre-punched chassis, parts and instructions to assist you in building it.
If you’re interested in more of a challenge than building a kit, classic tube amp schematics are easy to find on-line and their patents are likely to be long since expired. Find a Fender schematic and its related layout drawing and start making a parts list. Most of the boutique amps being made today are cloned vintage Fender and Marshall amps or at least heavily influenced by their circuits. There are also many books on the subject of tube amp circuit theory, design and building that you can read to help make your first build of boutique quality.
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Kurt Prange (BSEE) is the Sales Engineer for Amplified Parts in Tempe, AZ (amplifiedparts.com). Kurt began playing guitar at the age of nine in Kalamazoo, MI. He is a guitar DIY’er and tube amp designer who enjoys helping other musicians along in the endless pursuit of tone.
HURW38G5KQAG
http://www.amplifiedparts.com/products/tubes/T-12AX7-SET
12AX7 Tube Set, Assortment of 10 different types.
There are so many different opinions about the sounds of different tubes, that we decided to offer a package with some of the most popular 12AX7’s, so that way people can just buy the set and experiment themselves. Decide which ones that you like best. Comes with one of each of the following. We reserve the right to substitute any of these tubes with one of equal value based on availability:
# 12AX7-S-JJ
# ECC803-S-JJ
# 12AX7 China
# 12AX7B China
# 12AX7-PS-TAD
# 12AX7-C-GT
# 12AX7A-C5 Ruby
# 12AX7-EH
# 12AX7WA Sovtek
# 12AX7 Fender
For our own test results and a comparison of how each of these sound, refer to our 12AX7 comparison chart:
http://www.amplifiedparts.com/tech-corner?art_id=262
P-RMOD-4AB3C1B
P-RMOD-8EB2C1B
P-RMOD-9AB2C1B
These new MOD reverb tanks are voiced to sound like the original tanks from the 60’s. What’s the difference between these and other currently made tanks?
The Transducers are wired directly to the RCA jacks as opposed to the other current production tanks where Transducers are connected by a detachable plug to RCA jacks. This make them less receptive to any outside interference. The original Hammond Accutronics tanks from the 1960’s were also wired directly to the RCA jacks. Also in these MOD tanks, the spacing and size of the laminations of the Transducers results in a more vintage like tone.
Here’s what people are saying about the new MOD reverb tanks:
” These tanks are really great. A lot more “drip” than most new production tanks. The sound is also smoother and warmer with a bit more decay. Highly recommended!”
-Danny Medrano
Excellent alternative to some of the, ahem…other tanks out there. Pop this in your amp for a warm, authentic sounding reverb. Highly recommended!
-Jeff
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