ruffrecords

Re: Direct output from Neve channel switching unit
« Reply #80 on: July 23, 2019, 05:15:31 PM »
I downloaded and tried that app. Do you use a stylus? I have great trouble seeing where the trace is going when I use my finger.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


Re: Direct output from Neve channel switching unit
« Reply #81 on: July 23, 2019, 05:35:09 PM »
I downloaded and tried that app. Do you use a stylus? I have great trouble seeing where the trace is going when I use my finger.

Cheers

Ian

Haha, yep if takes a bit of getting used to.  No I don't use a stylus, just my fat podgy index digit!  😀

I was on a smallish Lenovo tablet and just really zoomed in to get the traces where I wanted.  I set the raster size to 25 thou which got the components on grid and it snapped the traces to where I wanted for the most part.

I don't think it'll be my new primary layout app but it was nice to just sit on the sofa painting away with my finger.

Cheers Ian

ruffrecords

Re: Direct output from Neve channel switching unit
« Reply #82 on: July 24, 2019, 05:23:05 PM »
Haha, yep if takes a bit of getting used to.  No I don't use a stylus, just my fat podgy index digit!  😀

I was on a smallish Lenovo tablet and just really zoomed in to get the traces where I wanted.  I set the raster size to 25 thou which got the components on grid and it snapped the traces to where I wanted for the most part.

I don't think it'll be my new primary layout app but it was nice to just sit on the sofa painting away with my finger.

Cheers Ian

OK, I will give it another go once it gets a little cooler!!

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: Direct output from Neve channel switching unit
« Reply #83 on: July 25, 2019, 01:45:35 PM »
OK, I will give it another go once it gets a little cooler!!

Cheers

Ian

Looks to be cooling down across the country as of tonight.

ruffrecords

Re: Direct output from Neve channel switching unit
« Reply #84 on: July 25, 2019, 04:52:09 PM »
Looks to be cooling down across the country as of tonight.

We spent much of today in the air conditioned car and at Sainsbury's which is also air conditioned. We even went out for tea this evening to Morrisons for the same reason. It was till over 30 degrees C when we got home around 7pm. For fun we switched the car temperature gauge from Centigrade to Fahrenheit 'cause us old folks don't understand these new fangled units. According to the car, the outside temperature reached 100 degrees which by anbody's standards is bloody hot.

In the last half hour we have had some rain with some pleasant thunder and lightening which has definitely cooled things down about here in North Norfolk. After last year's summer we toyed with the idea of having A/C fitted. This year we have decided we definitely will.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: Direct output from Neve channel switching unit New
« Reply #85 on: August 06, 2019, 01:52:25 PM »
Following up on this:
I looked at the BA512 output amplifier which was a BBC desk upgrade to the BA340/BA440 amplifier (pdf posted somewhere above).  In several ways it is indeed an upgrade. However,  I first put the circuit in LTspice to check phase margin, gbw, slew/transient response etc.  and -
The two-pole miller used in the amp does help THD at high frequencies as expected, but, as is, caused some peaking and overshoot with lower clg's.   This was fairly easy to ameliorate with the addition of another small cap though.  The slew also wasn't the best and this too can be improved.  Lastly,  although the bias point for the output pair is in the right ballpark for lowest crossover distortion, the amp mostly operates in a class A/B mode as used with typical Neve loads. 
I decided I could improve on the circuit in all the above  as well as in noise performance so, using spice and a lashed up breadboard, I came up with a circuit which ended up looking more like a small power amp by the end, but seems to perform very well as far as the above points and all in class A mode down to loads of 150 ohms.
I still need to try a possibly better output pair and I'll post the circuit if there's interest when I've done more tests.
Thus endeth this post, cheers,
Hinson.
« Last Edit: August 06, 2019, 03:39:46 PM by Winston O'Boogie »


 

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