Discrete I-V conv.

[alex0]

This schematic of discrete I-V converter was published in “Current-steering transimpedance amplifiers for high-resolution digital-to-analogue converters” by M.O.J. Hawksford
http://esewww.essex.ac.uk/research/audio
Opinions?

 

[Elso Kwak]

Link

Hi,
You mean this link?:
http://www.essex.ac.uk/ese/research/audio_lab/index.htm;)

 

[ojg]

Y'all probably meant this link! 😉

Very interesting paper, thanks!

 

[Nixie]

Why did discussion die here?

I find this paper very interesting. Anyone implement any of the circuits in there? Or why not?

 

[Bricolo]

Nice paper and very smart design, strange that we don't see anyone building it here

 

[X.G.]

I guess the basic topology is inspired from the Super Linear C ircuit of Japanese Pioneer.

I have recently re-designed/modifed the SLC circuit for my pre-amp,and got excellent sound which more like tube.

I will build the I/V circuit based on it next step.

 

[Nixie]

That makes no sense. Error correction is a Hawksford invention, superficial similarities to other topologies notwithstanding.

 

[Bricolo]

I have one question;

In page 19 the author claims that the return path for the filter and I/V resistor (going to T1's emittor) is a current feedback path.

I don't really see the feedback here, I see this path as a return pth for the currents, making them go back in T1's path and so T1 operates in a constant current operation (nice!)

Where is the current feedback in here?

 

[Bricolo]

Did anyone build or even simulate the circuit?

On my simulations, it's drawing 60mA o both supplies (15V), that seems to be a bit on the high side...

 

[aparatusonitus]

Hi Bricolo,

I've simulated it in LTSwCad and have almost the same results: 62mA88 on +15 and 67mA19 on -15 rail, but I've place a 2mA J-fet current source for TDA1541A current offset nulling at the input.

 

[Bricolo]

is the nulling really required?

 

[aparatusonitus]

I belive so, otherwise DC servo won't be able to correct DC offset at output.

 

[Guido Tent]

I belive so, otherwise DC servo won't be able to correct DC offset at output.

the servo is a true integrator so within its' linear range it will regulate output to 0V, no input offset nulling is required.

best

 

[Bricolo]

Guido got the point.


But I think there could also be a way to use it servo-free and to adjust some bias currents in order to get 0V output while the input is 2mA

 

[Guido Tent]

Guido got the point.


But I think there could also be a way to use it servo-free and to adjust some bias currents in order to get 0V output while the input is 2mA

Yes, that should be possible, the trimming hand acts a s a servo 🙂

 

[jan.didden]

Guido got the point.


But I think there could also be a way to use it servo-free and to adjust some bias currents in order to get 0V output while the input is 2mA

Yes, but after you adjusted it, you would see that it would drift over time and with temperature.

Jan Didden

 

[peufeu]

Ha ! This discrete IV schematic looks quite like what I've been listening to in the last few years.

Try it, it's worth it.

 

[Bricolo]

Yes Guido, except from the fact that I didn't really think about the trimming hand as a servo but more as a one time setting 😉 Of course that's only possible if the DC doesn't drift that much with time/temperature/age...


Hey Peufeu, nice to see you here. Do you still live in Lyon? I'm there for a few months!