Elektronics World Hybrid Amplifier Query in Solid State Thread

[patrahul]

Hi All,
I have some questions regarding the Hybrid Audio Amplifier I am building from March 2004 issue of Electronics World magazine and I have posted it under Solid State amplifiers forum, as there is no dedicated Hybrid Amplifier forum.
Could you please have a look at it and answer my query if possible. Just don't want to create duplicate post.

P

Thread 'Electronics World Hybrid Audio Amplifier'

Tuesday at 5:14 PM

Hi All,
I am currently building the hybrid audio amplifier published in March 2004 issue of Electronics world/ Wireless world. It uses ECC88 Valve , BD139 transistor for thermal feedback/compensation and IRF640/IRF9640 as output MOSFETs. The author has mentioned that potentiometer PR1 is used for output stage quiescent current adjustment. he has also instructed to start the amplifier by tuning the PR1 fully clockwise and then input a low level audio signal, which should be distorted. The PR1 should be then turned counter clockwise slowely until the distortions stop. it should not be turned...

• patrahul
• Replies: 27
• Forum: Solid State

Thanks in advance,
Pat