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RICK-TONE AMPS: DESIGN AND CONSTRUCTION NOTES

This page contains a brief collection of notes about the design and construction of Rick-Tone amps that may be useful to repair technicians or DIY builers.

General Design (Why These Amps Are the Way They Are)

The earliest amps I built for anyone other than myself were an outgrowth of some amp mod and repair work I started doing while I was a part-time intern/slave/repairman/gofer at a small recording studio in the 1980's. So, those earliest amps were built to be studio amps, and that meant they didn't need onboard effects like reverb or tremolo. They didn't need channel switches or even multiple channels. And they didn't need to be very powerful, usually just a few Watts. But they did need to have tones that appealed to the players that came into the studio, or they wouldn't get played. The studio intern gig only lasted a few months, but the same needs that shaped the earliest amps continued to shape the amps that were to follow.

Some of the characteristics that I valued in the design of each Rick-Tone amp were:

  • Minimal number of stages between the guitar and the speaker.
  • Use of easily obtainable tubes and other parts.
  • Overall simplicity of the circuit.
  • A compelling character to the sound that appealed to guitar players. Some might call this 'flavor' or 'mojo' or 'that tone'. This is the part of an amp that's hard to describe to someone using just words, but easy to understand after hearing the amp play.

BELOW: Interior of a typical point-to-point wired amp    

Wiring

The style of wiring used in these amps was usually simple point-to-point, where all wires connect to components or terminal strips without the use of circuit boards. Tag boards or turret boards were used sparingly, usually only in custom amps with more complex circuitry. The style of wiring doesn't really have any effect on the sound of the amp, so someone could conceivably use a board when reconstructing or cloning a point-to-point wired amp and still get the same sound as the point-to-point wired amp.

Shielded wire was used sparingly. Usually only if there was a run of more than a couple of inches from an input jack to a tube grid, or from a potentiometer to the circuit it controlled.

Solid vs. Stranded: I tended to prefer solid core hookup wire over stranded wire. Most of the wiring in most of the amps used solid core unless stranded happened to be more readily available at the time.

Output Transformers

Output transformers play an important role in the sound of Rick-Tone amps. Generally speaking, these amps used output transformers that would be considered vastly undersized for 'high fidelity' applications. This causes a couple of things to change in an amp's sound: (1) The mid and high-mid portions of the frequency response curve are enhanced, which is a desirable characteristic in certain classic rock and blues guitar sounds. (2) The smaller transformer core is more easily saturated, and that increases the 'grind' of the amp's overdrive sound, giving it a more 'organic' flavor. It's easier to hear than describe.

The original makes and models of output transformers that were used in these amps are no longer being manufactured, but I do have a few original spares left in my parts supply for replacement use or for individuals that want to build totally authentic sounding Rick-Tone clones. See the parts page for info. It is possible to use a similar off the shelf transformer, but the sound of the amp may not be exactly like the original.

Power Transformers

Rick-Tone amps usually used surplus power transformers that were readily available at the time of production. It was not unusual for several different makes/models of power transformer to be used in the same models of amp, depending on which suppliers had suitable transformers available at the best prices at the time. The precise specs of the power transformers are not critical to circuit operation, so it's possible for the B+ supply voltages to vary by as much as +/-25% from the published voltages without significantly changing the tone of the amp.

Tone Stacks

The most common types of tone controls in Rick-Tone amps were the following:

1. Simple treble-cut tone control. This is just a potentiometer that sends some of the audio signal to ground through a small capacitor.

2. Baxandall tone stack. This has bass and treble controls that work in a manner similar to the tone controls on a home stereo.

    Notes on tone stack variations in Type 11 and related amps

Instead of the tone controls described above, some of the amps (particularly custom units) had three-way (bass, mid, treble) style tone stacks or single-knob tone contour controls that provided more variation than a single-knob treble cut control. Some units were also equipped with a ''presence'' control that tapped a variable amount of negative feedback from the output stage back into the preamp or phase splitter.

Resistors

Rick-Tone amps generally used either 1/4 Watt or 1/2 Watt resistors anywhere the required dissipation was 1/8 Watt or less. Some experts say that 1 Watt resistors are less noisy than 1/2 or 1/4 Watt resistors, but my personal experience was that it didn't seem to matter much what Wattage of resistors were used as long as they were decent quality resistors. I tended to favor metal or carbon film resistors over carbon composition, even though they were slightly more expensive than carbon comps back then. Some boutique amp builders now seem to prefer building amps with carbon composition resistors for ''vintage authenticity'', even though the prices for carbon comps have gone sky high in recent years. In my opinion the carbon comps have always been noisier, more prone to deteriorating around heat sources (tube amps generate heat), and much more prone to drifting in resistance over time.

Tubes

Most Rick-Tone amps were originally equipped with 1960s or 1970s production USA-made tubes. These 'NOS' or new-old-stock tubes were still plentiful and cheap back in the 1980's when the amps were built. The exact tubes supplied with each amp often depended on what the customer wanted at the time, or what was available to me at the time, but I personally tended to like Sylvania or General Electric tubes in most amps. Different makes of tubes can make a very noticeable difference in the sound of an amp, especially in amps like these that are trying to squeeze the most tonality out of the fewest number of tube stages between the guitar and the speaker.

Most new tubes are now manufactured in ex-Soviet countries and China. These import tubes will usually work just fine in Rick-Tone amps, though they may sound different from the original USA-made tubes. Early generations of Russian and Chinese tubes had some quality control problems (lots of bad tubes out there on the surplus market), but the import tubes have been steadily getting better over time as their production techniques have been refined. Some of the most recent import tubes are excellent.


Schematics: To go to the schematics page, click here.

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