Yamaha E1010 E1010 Owners Manual Image - Page 11

How the E1010 works 10 A SIMPLIFIED FUNCTIONALDESCRIPTION You don't have to know how the E1010 works in various control settings before you even turn the unit order to use it. However, a careful reading of this section ON, and duplicate effects without having to document will enable you to get the most out of the unit. Instead the settings. The following paragraphs are numbered of guessing, you can truly understand how the E1010 to correspond with the blocks in Figure 9, which depicts processes the sound, predict the sound obtained at basic signal flow through the unit. INPUT LEVEL DISPLAY (FRONT) N 1 PREAMP STAGE LINE 2 AMP STAGE (REAR) LEVEL FOOT -3.0 TONE CONTROL STAGE SWITCH 4 gcBASS TREBLE PRE DELAY CONDITIONING STAGE FEEDBACK Fig. 9 - E1010Simplified Block Diagram DIRECT ONLY OUTPUT 6A DELAY TIME PUSHBUTTONS 75 150 1 225 1 300 MIXING ANALOG DELAY LINE (BOO'S) 6B POST- 7 DELAY CONDITIONING STAGE (REAR) 9 OUTPUT (FRONT' OUTPUT • (REAR) 6C CLOCKRATE CIRCUITRY 6D MODULATION CIRCUITRY DELAY SPEED DEPTH Preamplifier Stage (1) The input signal from either the front or rear panel INPUT jack goes through two preamplifiers, one on either side of the INPUT volume control. Because the INPUT control is buffered (comes after a stage of amplification), volume adjustments do not change the input impedance; hence the tone from a high impedance guitar pickup would not shift with volume adjustments. After the preamp stages, the signal is split, part of it going to the DIRECT OUTPUT, and part going to the E1010's tone control and delay circuitry. Direct Output Path (2) The signal goes through a Line Amplifier before it reaches the DIRECT OUTPUT. The INPUT LEVEL display circuits sense the voltage at this point and cause more LED's to turn ON as the level increases. Thus, only the VOLUME control affects the INPUT LEVEL display. Tone Control Stage (3) The Tone Control Stage is an equalizer which has BASS and TREBLE controls. Any tone adjustments only affect the delayed portion of the signal. Foot Switch Jack (4) The FOOT SWITCH JACK comes between the Tone Control Stage and the Delay circuits. It permits the input to the delay circuits to be shorted (turned off) if an external foot switch is plugged in. It is thus possible to turn the delay effect ON and OFF without affecting the E1010's direct output signal. When no switch is used, the signal goes straight through the jack so the delay is ON. Pre-Delay Conditioning (5) This circuitry prepares the audio for delay by cutting out very high frequencies (via a low pass filter), boosting mid to high frequencies (pre-emphasis), and preventing the signal from getting too loud or soft (compression). The pre delay processing helps to avoid noise, distortion, or overload of the actual Delay circuitry (6). NOTE: Up to this point we have described circuitry that, while necessary, is not directly involved with delaying the audio. The actual "delay line" itself (6A, 6B, 6C and 6D) comprises only a portion of the E1010's overall circuitry. Analog Delay Circuitry (6) The Delay Circuitry consists of several integrated circuits (IC "chips") of the variety known as BBD's (Bucket Brigade Devices). Each BBD provides a variable amount of delay, up to a certain maximum; more BBD's can be connected together to increase the maximum available delay. A. The Delay Time pushbuttons determine how many of the BBD's are connected in the signal path; a 300 millisecond delay utilizes all the BBD's. B. The BBD's slow down the audio signal by dividing it into small segments, and then passing those segments through a very long series of storage registers. Each signal segment stays in a storage register for a brief period before moving on and making room for the next signal segment to take its place. The length of time a signal resides in a storage register is determined by the Delay Time Adjustment circuitry, which is why engaging any