Pro Audio Design Forum

I lowered the pullup resistor to the bias diode to 1K. With a 68 ohm load I now see 1 KHz open loop distortion figures of -100 dB at 2nd and 3rd at 10V P-P. The Iq is roughly 80 mA.

I'm thinking that 68 ohms is a realistic load for 32 ohm headphones with a 27R buildout.

Thanks Roger. No I didn't see much offset which is surprising. Maybe I got lucky "matching" random transistors. For a line driver you can't beat the bare 1646 or a 1646/transformer configuration as you've shown us. The open loop distortion performance driving 30 ohms is not spectacular: I ...

As many of you know I've explored unconventional ways to use the THAT1646. See: https://www.proaudiodesignforum.com/forum/php/viewtopic.php?f=6&t=140 We've discussed driving the THAT1646 in common mode so that both outputs swing together rather than anti-polarity. In the common mode configurati...

Yes and a lot of room service too!

And Gridley's...

Thanks Greg for dropping in here.

We're looking forward to more projects too!

I'm dying to try a quick project with the THAT1646 to add external current boost transistors.

Wayne

I lived at the Peabody for months while working at both Ardent and the Fire Station. Gary picked up most of the tab: I think SSL's net cost was about $30/night. I didn't really like living in hotels for long periods: The Peabody (and Memphis) were an exception.

Thanks for joining us here BTW!

I've been looking for this SSL blue line drawing and just found it. It shows how the 82E26 cards and the 82E27 in the original SSL are connected together. Note that pins 16, 33 and 42 of the 82E26 are bussed from one board to the other and common at the 82E27 sidechain card. https://www.ka-electron...

ghengis: Thank you for the reply. I agree that balanced I/O would probably be better. One of the reasons I might be reluctant to do it is that the circuit, for full stereo encode/decode, has 8! I/O ports. So the balancing stuff takes a really simple circuit and doubles the part count. But as a pract...

Thanks Roger. DIPS and bypass so not a hard one to route. It pays to eliminate all the resistors. What do you think we should do about I/O. Balance it?

I didn't have to think about that one too long.

My Dad, only about ten years before I was born. I'd like to know the things that shaped his life before I knew him as a child.