or Connect
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › THAT 1646 unbalanced to balanced line driver
New Posts  All Forums:Forum Nav:

THAT 1646 unbalanced to balanced line driver - Page 2

post #16 of 20

did your design work? is it truly noise-less? i am trying to add this IC THAT 1646 to an equalizer that has a unbalanced output coming from a NE5532 Opamp, that's why I ma so interesed to know about the performance of your application. thanks a lot!

 

Cheers.

post #17 of 20

Why not use a transformer? 

Ground loop proofing and lower noise contribution may be worth more than slightly lower measured THD. 

post #18 of 20

 

Quote:
Originally Posted by nikongod View Post

Why not use a transformer? 

Ground loop proofing and lower noise contribution may be worth more than slightly lower measured THD. 

 

You sure love your transformers... wink_face.gif

 

Totally right though, I use them in distributed audio systems all the time, as in to send a balanced signal hundreds of feet, and currently use these in my home system to go between my preamp and my altec lansing power amp:  http://www.rdlnet.com/product.php?page=164  granted these are $55 a piece, you can always go to a local electronics shop (or order online) and get audio unbal to bal transformers.  You can probably get a naked pair of transformers for around $20.  Nice thing about transformers is that they don't require a power source...

post #19 of 20

Hi,

I am looking for a PCB for the THAT 1646 with the gain OPA op amp all on board, your PCB looks ideal. Can you tell me if it is possible to purchase 20 unpopulated PCBs from you and ship them to me in the UK?

 

Many thanks,

 

Kind regards,

 

Colin.

post #20 of 20

OPA227 datasheet states your R3 should always be used (so the trace cut on your PCB) when in unity gain follower mode if the source is able to drive 20mA or more into its load.

Assumed page 6 Absolute Maximum Ratings |Vin|<|Vs-0.7|, for a +/-15V supply R3 would be 14.3/0.02=715Ω to be sure any allowed input voltage won't break noise and drift specifications (see bottom of page 17). IIUC, as long as we don't use your R2, gain remains 1.

So whatever the gain we set, 1 or higher, we always should use R3. When in gain>1, I don't know if R3 still has to play this input protection role, and if yes, how do we calculate it.

Thank you for your job. I forked it to add the RF extra protections and a THAT1206 receiver here: http://www.diyaudio.com/forums/analog-line-level/220892-1646-balanced-line-driver-pcb-3.html#post3268215

New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › THAT 1646 unbalanced to balanced line driver