Description: Details：On the basis of the popular B2, the B21 preamplifier has made significant changes to the sound, making it closer to the reference level. In addition to atmospheric balance, high dynamics, and no change in listening endurance, it also strives to accurately reproduce the sound and soundstage, allowing the various textures, positioning, and soundstages of vocals and instruments to be reproduced as much as possible.This preamp adopts a 4-layer PCB design to minimize interference and noise as much as possible to achieve a dark background quietness.PCB size：155x145mmWork voltage：AC14V-0-AC14V To AC18V-0-AC18V above 20WOp-amp model：Use 4pcs single operational amplifier （opa1611，OPA627AU，JRC5534DD，MUSES03 etc）Debugging instructions:Before testing, ensure that all components are installed correctly and there are no virtual soldering or short circuits.1. Do not install all operational amplifiers before powering on2. Connect dual 14V-18V AC, adjust VR1 ，set +V to+15V, adjust VR2 ,set -V to-15V3. Install operational amplifiers U1 and U2, adjust VR3, and measure TP1 to be close to 0V (+/-10mV),Adjust VR4 and measure TP2 to be close to 0V (+/-10mV), all measured to ground4. Install operational amplifiers U3 and U4, You can test the soundNote：This is diy pcb ，not included any parts ！have no circuit diagram，can provide parts list ！Assembled board ，just for reference：
Price: 13 USD
Location: Guang Zhou
End Time: 2024-12-16T09:06:21.000Z
Shipping Cost: 5 USD
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Item Specifics
Return shipping will be paid by: Buyer
All returns accepted: Returns Accepted
Item must be returned within: 30 Days
Refund will be given as: Money Back
Compatible Brand: Universal
Brand: SENGTERBELLE
Type: Preamp Board
Unit Type: Unit
Color: Green
Compatible Model: Universal
Features: Universal
MPN: does not apply
Unit Quantity: 1
Amplifier Class: A
