Hifi Stereo pre amp & Bass treble Board price list

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• High Bass Treble Boost / Cut -   up to 15dB symmetrical curve Boost / Cut. 1khz cutoff  frequency. 
• Very high signal GAIN -  17dB signal GAIN. Output  of 9 volt peak to Peak can be achieved.
• Universal amplifier usability - can be used with any amplifier made of IC or transistors.
• On-board regulated power supply - power supply rectifier with 3 voltage regulators. 
• USB / Bluetooth connectivity - Easy to use with USB / Bluetooth audio modules,+5 Volt regulated supply.
• Standard Components - this high gain bass treble board is made of standard components which are available online or at your local electronics store.
•  No SMD components used - only through hole components are used in the pcb, this makes soldering and replacement of components hassle free. 

                                                                                             Click Here to download high gain stereo bass treble circuit diagram.

if you have used our Bluejay bass treble board then you will find this easy understand, for those who are new it is not that hard anyway.

This circuit has Four main sections namely - Regulated power supply, Input Buffer, Bass treble section and Gain section.

Regulated power supply section -

AC input supply at J3 is converted to DC by diode D1,D2,D3,D4 and filtered by C3,C4,C5,C6. voltage regulators U1 and U2 give fixed output of +15 & -15 volts respectively. 

U3 is used to provide +5 volts to USB, Bluetooth or any other type of audio modules. 

in simple words, regulated supply section converts AC to DC and provides +15v & -15 volts supply to other sections. +5 volt for other applications.

Pre amp Section - 

Ic U7 is used in the input section to amplify the week input signal.

Bass treble section - 

This classic bass treble circuit designed by respected Peter J Baxandall was First published in Wireless World in 1952. You can see, nothing significant has changed since then. the following description is for one channel. other channel works the same just different part numbers so no use repeating.

Input signal is received through C14. At high frequencies the impedance of C12 is small and the bass control RV2 is effectively shorted out and R7, R8 give unity GAIN. At low frequencies RV2 is active with maximum boost / cut is set by end-stop resistors R7, R8.

At high frequencies again, C10 has a low impedance and treble control RV1 is active, with maximum boost / cut is set by end-stop resistors R3, R4. at low frequencies C10 has a high impedance, so RV1 has no effect.

U4 works as negative feedback amplifier. the amplified signal is sent to next stage. 

in simple words RV1 is active at high frequencies and RV2 is active at low frequencies thus we get boost / cut in treble and bass respectively.

GAIN Section-

Another great circuit of respected Peter J Baxandall. this GAIN circuit amplifies the input signal to drive power amplifiers with minimum noise and distortion.

U5B U6B works as buffer and gain of U5A U6A is determined by R20 R22 & R21 R23 respectively. C20 & C21 ensures high frequency stability. this shunt feedback amplifier has gain of 17dB regulated by preset RV3 &RV4.

in simple words, signal received from bass treble section is amplified by ic U5 & U6. output at J5 can be connected to any power amplifier input.

• Full wave Diode Bridge Rectifier
• Triple Voltage regulators
• 12v to 15v  Positive and Negative voltage regulators can be used
• +5v dedicated supply for USB / Bluetooth Audio module adapters.
• 12 0 12 or 15 0 15 VAC 1A Transformer Recommended.

• Baxandall type Symmetric Tone Control 
• Maximum Bass Boost - 15 dB
• Maximum Treble Boost - 15 dB
• Phase -Inverted  Phase output
• Cutoff  Frequency - 1 Khz

• Shunt Feedback gain circuit
• Maximum Gain - 17 dB
•  Phase - Inverted Phase output 

          IC 

• U1 - L7812, L7815

• U2 - L7912, L7915

• U3 - L7805

• U4, U5, U6 - NE5532, TL072, JRC4558, LM833, OPA2134

   * - Please read datasheet carefully before use.