ANN: LF01 Discrete/Hybrid Opamp Module

[atupi]

If the Y termination of Q1,2,3 is referring to the package layout i don't see any problem.
I'm preparing an order to Mouser for several small project that i have in plan and i want to include also the parts for LF-01.

[atupi]

I've solved the Y-termination mistery, is related to Hfe:
hFE classification O: 70~140,
Y: 120~240,
GR: 200~400

What would be the influence over sound of different Hfe ?

[jayadev]

What all apparatus is required to test this circuit for linearity consistency and whatever possible.

I am on look out to set up a Test bench.

Breaking news:- I don't even have an oscilloscope yet !!

I am not a pro but an enthusiast who like to see his hands are buzy.

[AndrewT]

learn to use the instruments you have.
Learn to build accurate instruments that can be relied on for the accuracy you have proved you can build into them.
eg,
precision stepped dB attenuator.
precision stepped decade resistance bank.
precision Hamon divider. http://conradhoffman.com/HamonResistor.html
precision (simple resistive) Wheatstone bridge.
using a resistor to monitor current flow.
etc.
etc.

BTW,
combining a Wheatstone Bridge, with a Hamon divider on one side and a stepped precision resistance on the other side allows very accurate resistance measurement over a vast range that a bench DMM cannot approach for accuracy. eg 0r01 to 100M to <0.01%

[jayadev]

Thanks AndrewT

This has been a somewhat abbreviated write-up, as I've omitted discussing resistor stability, lead compensation and best wiring wiring practices to avoid voltage drops in the divider.

Learn to build accurate instruments that can be relied on for the accuracy you have proved you can build into them.
eg,
precision stepped dB attenuator.

"Precision" what is this this word pointing to ?
I have only known metal film resistor precision-ed to 1% tolerance ,
is there anything better accessible to Diy'ers like me ?

[jayadev]

Ever wondered What an electronics enthusiast would do in weekends when rest of his friends are hanging out in pubs and parties..

I did simulation in Ltspice..(newbie here)
Used basic components here to be quick.

first is 200khz and second in 2mhz.I hope pictures are self explanatory .

what all reasons are attributed for decrease in amplitude..

[linuxguru]

Originally Posted by jayadev

what all reasons are attributed for decrease in amplitude..

Q4, the output-stage PNP, is incorrectly connected - the collector and emitter are reversed. LTSpice doesn't know or care about this - it will apply whatever model it has for the transistor (Gummel-Poon or Ebers-Moll), regardless. You'll probably get a very low-gain (hFE ~=1) transistor in inverted operation, and that's probably why it shows attenuated output.

[jayadev]

My Bad , I Did not notice the emitter of pnp in negative. when I saw it worked in first run I assumed circuit is alright. (shockingly) it showed me working perfect in 200khz range.I will try again correcting it.

BTW does that implies Lt spice is flawed? I was thinking of designing some filters.
Any other better software ?

[linuxguru]

Originally Posted by jayadev

BTW does that implies Lt spice is flawed? I was thinking of designing some filters.
Any other better software ?

LTSpice (or any other simulation program) has no way of knowing if a particular circuit configuration was deliberately intended or an unintentional error. They're all going to simulate it the way it is drawn, but may throw up errors or warnings in some cases. As simulation SW goes, LTSpice is actually very convenient and probably the easiest to use. TI's TINA is another popular alternative.

[jayadev]

I am Planning to buy 10 pcs of LM318N (Price 1 : INR 78 ) from Kits n spares; very good VFM proposition for a performance Opamp.

I think it is same as LM318m but the package as mentioned for Lf01.