ruffrecords

Re: Neve Output transformers - Distance and Position ?
« Reply #20 on: January 10, 2017, 02:45:16 AM »
Nice, neat experiment that perfectly illustrates the the problem. Useful to know.

Cheers

Ian


Re: Neve Output transformers - Distance and Position ?
« Reply #21 on: January 10, 2017, 03:52:23 AM »
Hi, the youtube videos do not work for me.  ???

Whoops

Re: Neve Output transformers - Distance and Position ?
« Reply #22 on: January 10, 2017, 09:05:56 AM »
Hi, the youtube videos do not work for me.  ???
I tried them now and they'e working.
Could you please try again and let me know?


Nice, neat experiment that perfectly illustrates the the problem. Useful to know.
Cheers
Ian

Thanks Ian.
It was fun to do and gave me some useful info.

One thing I noticed it was that you can improve the crosstalk with transformer distance, but after the initial distance improvment then the crosstalk seems to stay the same independently of the output transformer distance.
So I guess in this scenario we are talking about crosstalk that is not related to Output transformers coupling, it has to do with other parts of the circuit. Am I right to assume this?

Probably Grounding would be the next crosstalk contributor.
Also wiring, input transformer positions, distance between BA cards.
What do you think?

I'm using this experiment and the work in this unit to learn a bit more

Thanks

ruffrecords

Re: Neve Output transformers - Distance and Position ?
« Reply #23 on: January 10, 2017, 12:20:15 PM »
One thing I noticed it was that you can improve the crosstalk with transformer distance, but after the initial distance improvment then the crosstalk seems to stay the same independently of the output transformer distance.
So I guess in this scenario we are talking about crosstalk that is not related to Output transformers coupling, it has to do with other parts of the circuit. Am I right to assume this?

Probably Grounding would be the next crosstalk contributor.
Also wiring, input transformer positions, distance between BA cards.
What do you think?

There will always be some crosstalk. It can occur in a number of ways. Most Neve modules had a 1000uF capacitor right across the 24V supply where it entered the module. Apart from minimising noise, this also helps prevent crosstake between channels via the supply  (the BA238 output stage has a very poor power supply rejection ratio).

You can tell a lot by listening to the crosstalk on headphones. If it has no bass the it is probably capacitive coupling. This is often cause by unscreened signal wires.  If it has the full frequency range then it is more likely a resistive common connection like poor grounding. Neve consoles typically achieved -90dB crosstalk figures so now you know why they used copper bus bars for the supplies and signal 0V.

Cheers

Ian

Whoops

Re: Neve Output transformers - Distance and Position ?
« Reply #24 on: January 10, 2017, 01:14:34 PM »
You can tell a lot by listening to the crosstalk on headphones. If it has no bass the it is probably capacitive coupling. This is often cause by unscreened signal wires.  If it has the full frequency range then it is more likely a resistive common connection like poor grounding. Neve consoles typically achieved -90dB crosstalk figures so now you know why they used copper bus bars for the supplies and signal 0V.

Nice to know.

The wiring from the input transformer until the BA283 is shielded.
The Output wiring is not.

I will change to shielded wire from the BA boards to the Out transformers, and from the transformers to the Out XLR's

Re: Neve Output transformers - Distance and Position ?
« Reply #25 on: January 10, 2017, 01:35:56 PM »
Sorry, the videos are still "not available".

Whoops

Re: Neve Output transformers - Distance and Position ?
« Reply #26 on: January 10, 2017, 02:09:08 PM »
I'm able to watch them , Ian also was able.
My friend also watched it.

I really don't know why is not being available to you.

Try a different browser (Safari, Firefox, Chrome)
Update Flash plugin




Re: Neve Output transformers - Distance and Position ?
« Reply #27 on: January 10, 2017, 02:29:35 PM »
No worries! I am surfing on a ipad.  I will try it on my PC when I am back home. Thanks for the trouble, 8)