News:

Hi!

Welcome to my DIY audio forum.

Cheers
Per-Anders Sjöström

Main Menu

input bias servo with OP177FPZ

Started by fantast, December 27, 2011, 07:42:04 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

fantast

heaveno,

I have some OP 177FPZ in spare. Was it possible to use them for the input bias servo OPs without any changes?

Kind regards
Claus

peranders

/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

fantast

Thanks Anders,

I assume I shall remove C61/62 and G61/62 if I am going to use them in the input bias servo?

(And possibly I will also do not need the Zeners DZ9 and DZ10).

Many regards
Claus

peranders

Correct and the zeners will go also.
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

fantast

What about the tendency to put DC back into the MC System in your design?

peranders

/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

fantast

Maybe a silly question, but how was it necessary to have a 8slot wago for power supply, as only 5 channels seem to be sufficient (R+/R-/L+/L-/Ground)?
Kind regards
Claus

PS: Finsished with the soldering now and putting the power supply to it...

peranders

You can have one or two power supplies.
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

fantast

Thanks,

now the hard stuff. It is running, however I am missing the left preamp part (no diode, no output). Any good idea where to start to find the failure?

Best regards
Claus

peranders

What is your problem? I'm not sure what you mean.
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

fantast

I have checked all connections and parts and everything seams to be OK so far. However, I have a big unbalance at the crossing going to R16 and to R17. Via R8 and T2 the the voltage in around 6V wheras it is just 0.6V the way across R9 and T1. I am not sure where this is from.
Also the DC adjust (after R29) is constantly increasing, starting 5.2V going up to 8V within in few minutes.

Kind regards
Claus

fantast

OK.
It was the Zener DZ1 :roll:
Regards
Claus

fantast

It is running. First impression is quite good  :wink:
Thanks Anders

peranders

/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

fantast

Next time I am at Chalmers or VTI I will give you a call.
Cheers,
Claus