Steve's Gear

4 input/ 2 Channel (Bright and Normal), Non-Master Volume, 2 x El34 Output, Reverb, Footswitchable tube driven series EFX loop, "Variac" Control, THD "Longhorn" 10" speakers (mono/stereo wiring), THD solid state Rectifier,

Currently THD has combined the "Plexi" amp features with their previous "Blues" and "Rock" variations into the "Type-O" Model.

HI-MU INFORMATION FROM BARRY BREISCH (Hi-Mu designer)

"The HI-MU Model 5.5 is a pro-quality tube amp which is designed specifically to provide full power tube performance at a moderate loudness. Using a single 6v6 power tube, the amps put out up to 7-8watts of pure Class A Power. Mated with an efficient 12" speaker, these amps deliver the full bodied tone that you just cannot get from a 30, 50, or 100 watt amp with its volume set low. The sound is surprisingly big, and because no negative feedback is used, the amps can get louder than you might expect from 7 watts.

HI-MU amps are available as either single 12" combos or as head-only units. The basic models are single channel with 3 band EQ (treble, mid, bass), switchable high/low input sensitivity, and a preamp level output as standard features. Optional features include: 3-channel preamp, tube driven efx loop. tone control bypass switch, twin rectifier (switchable tube or solid state), and various speaker upgrades.

SINGLE CHANNEL models perform like a vintage, non-master-volume amp. Below about 6 or 7 on the volume knob the amp stays clean. The sound is lush, bell-like, and richly harmonic. Pushing the volume up towards 10 yields increasing amounts of pure power tube distortion, with little or no preamp distortion present. This type of distortion is smooth, somewhat compressed, and very responsive to playing dynamics. Varying how hard you play directly affects the amount of distortion. This touch sensitive type of distortion is a large part of the classic blues guitar sound, and you can really only get it by driving the power tube section of an amp into distortion. For blues, vintage rock, country, and jazz sounds, many players find that the single channel version has all the variet;y of tone and gain levels necessary. This is especially true when used with the effect loop, which can act as an additional gain stage (see below).

To provide an even wider range of sounds, a 3-Channel switchable preamp is available. The clean channel is identical to the single channel described above. The Gain 1 (crunch) and Gain 2 (lead) have a master volume style setup with preamp level controls in addition to the volume control. Higher wattage master volume amps often sound thin and buzzy at low volumes because all the distortion is generated in the preamp. With the model 5.5, because the total power of the amp is right to begin with, you will be able to make use of both preamp and power amp distortion together. The result is a strong, full sounds that is still at reasonable loudness.

The Gain 1 channel provides a wide variety of crunch rhythm or moderate distortion lead sounds and still maintains a degree of touch sensitive response. You can also get a clean sound that is slightly different from the single channel clean. It is a tighter, harder-edged sound with more punch and drive.

Gain 2 is the classic, saturated tube preamp sound with lots of natural tube compression and smooth, singing sustain. This channel is capable of fairly massive amounts of gain and cover a lot more of the contemporary guitar sounds. Picking dynamics are largely sacrificed but sustain becomes virtually unlimited at higher settings.

TUBE DRIVEN EFFECTS LOOP. The loop is a tube driven (no transistors) circuit which is placed at the end of the preamp section. This allows you to generate preamp level distortion before applying effects. The output impedance of the loop is exceptionally low (920 ohms) which assures the proper impedance matching with all outboard devices, including vintage reverb units. The loop is provided with an on/off switch and level controls on both the send and return sides. The return level control is an active circuit which is capable of a fair amount of gain. This allows for exact matching of the amp's loudness with the loop either on or off. Additionally, if the loop is turned on with nothing plugged into the loop jacks, the loop can be used as an extra gain stage. When the loop is switched off, the effect loop circuitry is completely removed from the audio signal path. The frequency response of the loop is identical to that of the amp itself so there is no loss of high or low frequencies due to the loop circuitry. All signal wiring in the loop is shielded cable, ensuring the quietest possible operation.

TONE DEFEAT SWITCH. Many of the early single power tube amps had no tone controls and this switch allows you to recreate that type of sound by completely removing the tone controls from the audio signal path. The effect is dramatically different from simply turning the tones all the way up. The sound is very wide open, pure, and expresses the individual 'voice' of your guitar in great detail. Also because the tone controls are passive devices which consume some of the signal voltage, removing those tones from the circuit allows a larger signal to appear at the power tube. In essence, the amp can be driven harder at lower settings on the volume knob.

TWIN RECTIFIER. This option allows for operation of the amp with either a solid state (diode) or tube (5y3) rectifier in the high voltage supply. The solid state rectifier produces a higher voltage lefel at the tubes and has a somewhat tighter feel than the tube rectifier. Using the tube rectifier give a slightly softer note attack and somewhat more compressed sound. Overall, the effect of switching between the two is subtle but definitely noticeable.

Although we use well-proven, traditional tube circuitry, HI-MU amps are more than merely vintage replicas. Because of our superior circuit design, custom transformers, 12' speaker, and very substantial cabinets, even the basic model HI-MU will give you a wider range of sounds and a fuller tone than you would be able to get from a low wattage vintage amp. Add on the available options and you have got an amp that is exceptionally versatile, from vintage to modern.

Low wattage amps are all we do. The Model 5.5 is our top of the line piece and every amp we build reflects that fact. Each amp is meticulously hand-wired; there are no printed circuit boards. Tube sockets are ceramic and are bolted directly to the chassis. All hardware is either stainless steel or nickel finish; and because we use shielded wiring and a DC tube heater circuit, these amps have the lowest possible level of background noise and hum.

The HI-MU amps are the honest approach to overcoming the Tone vs. Volume dilemma. By providing the right amount of power, they simply allow you to turn up the volume to the point where really great tone begins to happen.

Lennon Audio STR6v6 Power Amplifier

HERE'S SOME WRITTEN INFO TO GO WITH IT:

* * * * * * Description from Lennon Audio:

MODEL STR6V6 DESIGN FEATURES

The Lennon Audio STR6V6 is a stereo, two space, rack mount power amplifier specifically designed for the guitarist. The audio path is completely vacuum tube based with one 12AX7WA and two 6V6GT's* tubes for each channel. The only solid state devices are silicon diodes in the power supply and protection circuits. This is a rugged amplifier designed for the professional with flexibility and reliability in mind. The STR6V6 is designed to have appropriate power for playing clubs and for studio recording. The output signal is in phase with the input signal for hassle-free recording. ( * The driver and output tubes can be replaced with several different types for even more tonal flexibility.)

The STR6V6 has features not found in any other amplifier, yet its design heritage can be traced back to the legendary Fender* Princeton* and Deluxe* amplifiers which utilize 6V6 tubes in the output section. This tube is best know for its rich, smooth, warm sound. The STR6V6 is designed so you can get that "classic" 6V6 tone plus several other tones that range from "smooth and sweet" clean tones to "thick and crunchy" overdrive and distortion tones.

The STR6V6 can also be operated with EL84 tubes in the output section by simply using our special adapters and adjusting the bias voltage. This option produces a meaty, slightly edgy sound compared to the 6V6 tubes. The EL84 has more gain than the 6V6 and its tone has been described as more "in your face" by some who play harder rock yet its greater dynamics is also preferred by some Jazz guitarists. The channels can be changed independently so you can run one channel with 6V6's and the other one with EL84's for a bigger, thicker, more complex tone. Many of the top guitarists run their guitar through two or more different sounding amplifiers to achieve a unique sound. With the STR6V6 you can have this tone in one compact package.

The front panel controls include: an Attack switch, two Input Level controls, two Output Mode switches, a Run/Standby switch, and a Power switch. The Attack switch changes the response or "touch" of both channels. The Output Mode switch selects between Pentode and Triode operation of the output tubes. The Output Mode is selectable for each channel independently. The green Run/Standby switch is illuminated in the RUN position indicating the tubes have high voltage on them. The red Power Switch is illuminated in the ON position indicating that AC power is connected.

The Attack switch changes the way the amplifier responds to your playing. In the PUNCH mode, notes and chords have a fast "punchy" attack. In the SUSTAIN mode the attack is slightly compressed and notes "hold" longer. The difference in the two modes is subtle and difficult to describe but once you plug-in and listen you will hear and "feel" the difference.

The Output Mode switch changes the way the output tubes operate. Without getting overly technical, the output tubes in 95% of all tube guitar amps operate in the PENTODE mode. This familiar tone is very recognizable and is one of the main reasons tube amplifiers are so highly desired. The output power is also the highest in the PENTODE mode. In the TRIODE mode the output tubes operate differently, producing a noticeable difference in tone. In the TRIODE mode, tubes are more linear, that is they have less distortion, when they are not overdriven. When you dial up a "clean" tone, the tone is warmer than in the PENTODE mode. Does this mean you can't get a good overdrive tone in this mode? NO WAY! Since the output power is reduced by about 50% in the TRIODE mode, you can push the output tubes into distortion earlier. This means you can get a thick rich overdrive tone at a lower volume, which is perfect for small clubs and recording. Different players with different styles describe the tone differently - your ear is the final judge. In general, the TRIODE mode is warmer and thicker for Jazz and Blues styles and darker and more compressed when overdriven.

The Level controls allow you to drive each channel at different levels. When the STR6V6 is used with most stereo preamps we recommend setting the level controls to maximum and using the output level control(s) on the preamp. The level controls are most useful to balance the output volume when running one channel with 6V6's and the other channel with EL84's.

The rear panel features: an IEC power cord receptacle which includes a voltage selector switch and fuse jack, a ground lift switch, a 1/4" input jack for each channel, two 1/4" output jacks for each channel, a 1/4" uncompensated D.I. output jack for each channel, and an impedance selector switch (4, 8, or 16 Ohms) for each channel. All the tubes are accessible from the rear panel without removing a cover. A quiet DC fan cools the tubes.

The Input jacks are designed for maximum flexibility. When only the Left input jack is connected, the signal is routed to both Left and Right channels. When only the Right input jack is connected, the Left channel has no output.

The STR6V6 has two built-in speaker loads. These help protect the amplifier, and aid in recording and when biasing tubes. When a tube amplifier is operated without a speaker (or load), the output tubes and output transformer can be destroyed. Forgetting to hook up the speakers or someone tripping over the speaker cables spells bad news and big bucks for most tube power amps. With the STR6V6, when no cables are plug into the speaker jacks, the signal goes to the built-in loads. This means if you go "brain dead" and forget to hook up your speakers, or someone rips the plugs out of the back of the amp when your playing, you're covered!

Another advantage to having internal speaker loads is when you need to record but the sound of a real speaker cabinet will get you evicted. Sound familiar - home recording freaks ? With the internal speaker loads, just disconnect the speakers (on the amp side), take your signal from the D.I. outputs into an EQ and you can turn up to 11! Of course nothing sounds exactly like miking a speaker, but with a little EQ tweaking, you can capture much of that tube power amp tone. Your Tech will love the internal loads when quick tube changes are required on the road.

The signals for the D.I. outputs come from the secondary of the output transformers for maximum tube tone. These outputs are in phase with the inputs and the speakers which is a must for recording. You can run the output of the preamp, the D.I. outputs and a signal from a mike in front of the speaker cabinet into your board without any phase canceling problems The D.I. outputs can also drive an external power amp or the house PA when larger venues call for more volume.

The STR6V6 can be operated almost anywhere in the world. The IEC connector lets you change the power cord to match the country you are in. The voltage selector (which is accessible without opening the chassis) can be switched for 100V, 120V, 220V, or 240V operation. The power transformer is designed to operate in 50 or 60 Hz systems. This gives our power amp flexibility not found in others. The STR6V6 is also designed to comply with world wide safety regulations.

The STR6V6 features a heavy duty steel chassis with an aluminum front panel and handles. The chassis and front panel are powder coated for a tough durable finish which can take the abuse of touring. Powder coating is superior to standard paints and the process is better for the environment than solvent based paints. Machine screws and threaded inserts are used throughout - no sheet metal screws! This means you will never have a stripped screw or a flimsy chassis.

Quality components such as 1% metal film resistors, Bourns* potentiometers and multi-turn trimmers, Switchcraft* connectors, and 0.093" thick glass epoxy circuit boards, are used throughout the design. Most of the major components are made in the USA. The vacuum tubes are top quality Russian made components. The Sovtek 6V6GT is a very rugged, excellent sounding 6V6.

Lennon Audio products are hand-crafted in small quantities by people who care about tone, quality, reliability, and customer satisfaction. Each amp is thoroughly checked out and tested before shipping. A copy of the final test data, signed and dated by me, Bryan Lennon, is shipped with each unit. Before packaging the amplifier, the tubes are carefully removed and placed into individual boxes for safe shipping. The boxes are numbered so you can re-install the tubes in the same sockets they were in at the factory. This attention to detail reflects our commitment to producing the highest quality products available.

The STR6V6 is warranted for two years. This warranty is extendible to five full years for a modest charge when you return your registration card within the first 30 days. The vacuum tubes are warranted for 90 days. A coupon for 50% off the purchase of replacement tubes is shipped with each amplifier.

Bryan Lennon * * * * * * * * * * * * * * *

Copyright 1995 - 1997, Digital Video, Inc.