User manual TRENDS AUDIO TA 10.1 TECHNICAL NOTES VERSION 1.0

[. . . ] Trends PA-10 Tube Headphone/Pre Amplifier Version 1. 0 Technical Note Trends PA-10 Technical Notes (2008/12/31) Copyright Notice Copyright © 2006 ITOK Media Limited, All rights reserved. All rights in this publication are reserved and no part may be reproduced without the prior written permission of the publisher. [. . . ] Trends PA-10 supports two major tube series: (1) 6DJ8, 6922, 6N11, 6H23n, ECC88, E88CC, etc. . . , and (2) 12AU7, 5963, 5814, ECC82, etc. . . If you change the tube within the same series, it needs to re-tune the DC bias voltages ONLY. If you change the tube from another series, it needs both to re-tune the DC bias voltages and re-set the jumpers. Otherwise, the tube may be burnt out. 1. Jumper Setting for Different Tube Series You can simply configure the amplifier to support the two different tube series by resetting the jumpers in J3, J4, J5 in the PCB as follows. (Remember to power OFF the machine before setting) J3 J4 J5 6DJ8 series OOO OOO OOO OOO 12AU7 series OOO OOO OOO OOO Trends PA-10 Technical Notes (2008/12/31) 2. DC Bias Voltage Tuning Since each tube may derivate a bit in parameters, especially from different series, it needs to re-tune the DC bias voltages to guarantee the machine is working in the best point and performing the best sound quality. There are two blue precise adjustable potentiometers (R3, R13) for tuning the DC bias voltage of each channel. But after run-in for a period or changed another tube, it would be deviated that the fine-tuning is needed. Before you tune these, you need a screwdriver (take off the case), a small screwdriver (turn the screw of the potentiometer) and a (digital) multi-meter to detect the DC bias voltage. Use screwdriver to take out the two upper level screws in the front panel & another two screws in the back panel. [. . . ] Then, repeat step 4 and 5 for the RIGHT channel by changing the test point to A(R) [red] and turning the screw on the top of the R13 potentiometer. Contact Us ITOK Media Limited (Trends Audio) Address: Unit E, 13/F. , World Tech Centre, 95 How Ming Street, Kwun Tong, Kowloon, Hong Kong Phone: +852 2304 0730 (9am-6pm, HKG Time) Fax: +852 2566-5740 Email: sales@TrendsAudio. com (Sales) support@TrendAudio. com (Support) Web: http://www. TrendsAudio. com Trends PA-10 Technical Notes (2008/12/31) [. . . ]