The devil and idle hands eh
Location: KY - Scotland
Posts: 5,470
I'm Mike.
The devil and idle hands eh
Location: London
Posts: 741
I'm Colin.
Well now forced to stay indoors and my pit I can do some R&D work so first project is a volume control using optics.
It will allow us to have any value and multi channel pots at any pre-fixed value i.e. 10R-1000MR and either Log/Anti Log or Linear well any curve you want basically.
The track sliding noise will go away and matching can be between 20% to 0.01%.
It can also be driven with a voltage reference or a R2 Ladder. The ref/control voltage will be set to 1.00V to 5.00V but with a simple attenuation network this could also be changed.
Pre-set lower and upper limit can also be set i.e. 158R Min to 1099R Max
The pot will have upper and lower BW limits 1Hz - 400KHz but special can be made.
PCB for this unit will be available from me or ABCaudio.
The unit can also be master slave configuration. For mixer and motor control references.
So watch out for it.
Location: Beds
Posts: 349
I'm Kulwinder.
Probably the wrong thread (mods: please move if inappropriate) but just thought I'd ask a quick question of you, Colin. I own a sample of the prototype Class A amp I think you designed (for Arcam?). Just changing out the 4.7uf/63v axials (all, unsurprisingly, out of spec now).
Usual hassle with lifting traces but all done now but for one remaining axial (shown in last pic). Appears it's either in the wrong way around or the PCB is incorrectly marked for positive. Looks original. I know it was a squillion years ago but you wouldn't happen to recall which is the more likely?
DSC05999 by Brer Rabbit, on Flick
DSC06012 by Brer Rabbit, on Flickr
DSC06012 (1) by Brer Rabbit, on Flickr
Last edited by tankertop; 30-03-2020 at 14:19.
Location: London
Posts: 741
I'm Colin.
Location: Beds
Posts: 349
I'm Kulwinder.
Measure the voltage across the cap, could be next to nothing, then fit the new one to suit the polarity.
Location: Beds
Posts: 349
I'm Kulwinder.
Location: Huddersfield
Posts: 90
I'm Ian.
Location: London
Posts: 741
I'm Colin.
A experiment, NOT TO BE DONE AT HOME BOYS AND GIRLS
I got some of the EWA IC cable which has four conductors and a shield,
Tested the break down voltage at 2500VAC between all.
OK the wire could handle about 3Amps max.
Made a simple cheap and nasty MK plug and Bulgin IEC lead 2 M long.
And tried it on the New Oberon I have, based on the M50 and M50P mixed (only 3 ever made cost to high)
We have one my sons Sam and Scott have one each.
It was fantastic the cheapo Woolworth IEC was crap in conclusion.
Just a fun and dangerous things to do under lockdown.
Still waiting for Solar Panel from space Mike, phew
Keep well all.
Location: London
Posts: 741
I'm Colin.
Well so far the retirement has gone well, ha ha, not a chance I have been more busy doing more designs than ever before. This include new cable idea and construction, so I decide to retire at 99yrs 364 day, just to keep busy.
I love walking and the last year that was not possible, that is due to my health state and has not been a good idea so into my pit I go now 7 day a week .
I have had few interest bangs I managed to blow up a 1600V 300A IGBT, the beast was 4 x 3 x1.5 inches approx and the smoke escaped blowing it lid off and the 5mm connector bolts.
Thank good I have few more, I was building a 400V 100A charger. Clocking at 50KHz I only had to find lots of mobile phone bats to make it work. I need 80 of 5V 2500mA per Cell block and I need 50 blocks. So has any body got 4000 mobile phone batteries?