This amp is available in built form only!
DESIGN The Trinity Amps ODS is modelled after the 100W Dumbl3 #124 with just a few less frills. It boasts a nominal 24W output in a compact format of only 15-1/2 in W X 7-1/2” in H X 9-1/2 in D and 25 lbs., two channels - Clean and Overdrive. The amp uses using 6V6 output tubes in fixed bias mode. The Overdrive channel provides a very smooth, sweet sustaining distorted tone. Activating the Overdrive circuit adds two additional gain stages and the result is an Overdrive that ranges from clean and harmonically rich to smooth and thick with ample saturation.
ODS FEATURES The amp has one input going straight to the first tube stage. The first tube triode is followed by a passive tone stack with controls for Treble, Middle, Bass and Volume. There are two mini toggle switches on the front panel for Mid Boost and Rock/Jazz and the Volume control can be pulled out for a brighter sound. There is a presence control for sparkle and a Master Volume. VOLUME / PULL BRIGHT: Volume adjusts the signal strength coming out of the tone stack, and going into the second tube stage. Think of this as a gain control primarily for your clean channel, but it will impact the Overdrive mode as well. The Bright switch is a push-pull located on the Volume control and bypasses the volume potentiometer with a capacitor to boost the high frequencies. This is a high-frequency boost that can be used to add sparkle to your tone in both clean and Overdrive modes. This high frequency boost is more prominent as Volume is turned down. MID: toggle switch increases the value of the treble capacitor in the tone stack to boost the midrange frequencies. ROCK/JAZZ: toggle switches between a Fender-esque voicing (Rock) and a more hi-fi-type of voicing (Jazz) with less bass and gain. Rock has a fatter midrange and a deeper, spongier bottom end. Jazz tightens up the bottom end and adjusts the contour of the midrange, giving the amplifier more of a hi-fi response. The TREBLE, MID, BASS tone stack is followed by another triode stage. The resulting signal is either fed straight into the power amplifier (Clean channel) or into the Overdrive channel circuitry. The output section uses a standard long tail pair phase inverter utilizing negative feedback. Since there is negative feedback, the phase inverter section of the amp also features a PRESENCE control. This will add sparkle and clarity to your tone. Prior to the phase inverter there is a MASTER VOLUME control which is very effective at setting the overall volume of the amp. The power supply uses a diode full wave rectifier to convert the power transformer high voltage AC to high voltage DC. The ODS is somewhat unique in that they use a lot of filtering in the power supply. The large filter capacitors help keep the tone tight and focused because you don’t want loose sounding bass especially in Overdrive mode! On the back of the amp, there are also two speaker output jacks, a 4-8-16 ohms speaker impedance selector and fuses for Mains and High Voltage.
OVERDRIVE CHANNEL For the Overdrive channel to attain its very smooth, sweet sustaining distorted tone, it is carefully tuned in terms of gain and frequency response. The Overdrive channel and Pre-Amp Boost (PAB) are activated with a two-button, illuminated footswitch. Both the channel switching and PAB switching is done by two relays inside the amp. PAB: provides a boost function by disconnecting the treble potentiometer from the bass potentiometer in the tone stack. The PAB accentuates midrange frequencies and attenuates low frequencies, making it great for cutting through during a solo. Engaged, you will also notice an increase in gain and distortion characteristics. This is useful for pushing the power section, lead boost and getting a bit of extra dirt from the amp. The Overdrive channel is two cascaded triodes being fed from the clean channel signal. Gain is attenuated before and after each of the two triode stages in the Overdrive channel. This limiting of gain keeps the amp smooth and prevents over the top harsh distortion tones. The Overdrive channel features two front panel controls - Ratio and Level. RATIO: serves a sort of volume control for the overdrive channel. However, just like the original amplifier, there are no individual master volume controls for the clean and overdrive channels. Instead, the Ratio control serves to balance out the volume of the overdrive channel with the clean channel. LEVEL: adjusts the amount of gain, and in turn distortion in the overdrive mode. TRIM: On the back of the amp there is a Trim control that controls the amount of signal sent into the first stage of the Overdrive circuit. Lower settings yield more touch-sensitive, lower gain sounds. Higher settings are more compressed, higher gain, and more harmonically complex. Different settings on the Trim control can yield dramatically different results to the tone, amount of gain, and feel of the Overdrive channel. Increasing Trim will increase the gain and compression the Overdrive channel yields, and will also impact its frequency response.
Due to the ODS compact size, a heavy duty printed circuit board (PCB) is used rather than the traditional eyelet board. However, the board holds only the resistors, capacitors and relays and not controls, switches or vacuum tubes which are wired in the traditional point-to-point. This hybrid design provides a compact and noise free design with excellent reliability. Tubes: 3 -12AX7 and 2 - 6V6 power tubes fixed bias. Solid State Rectifier
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