Build This MoFo!

I am planning to use a couple of Dell laptop 65 watt adapters. 19.5 v 3.34 amps. They come with 7.4 x 5.0 mm connectors. Is there a socket I could buy that fits such a plug. I've looked at Mouser and other places but have not found anything.

Otherwise of course I could simply cut off the plug and determine which of the two wires is positive but I thought I would try to be neat and tidy.

ray
 
Founder of XSA-Labs
Joined 2012
Paid Member
Founder of XSA-Labs
Joined 2012
Paid Member
Beautiful boards have arrived! Super quick from US to UK

Is a preamp with 15db gain (I figure that’s about 5.5v) enough to move these MoFo’s to action?

I was able to get 26.8vpp out of MoFo (red trace) with The Aksa Lender pre with 22dB gain. This is with 19v PSU and 68mH choke.
649235d1512320583-build-mofo-max-output-unclipped-oscope-jpg
 
Nice! I have a pair of LL2733’s lying around. At least 100mH @ 3A with 0.85 ohms DCR (coils in parallel).

http://www.lundahl.se/wp-content/uploads/datasheets/2733.pdf

A CCS as the current sink may provide even better performance with advantages in PSRR & CMRR.

Still, should try it with a choke as the current sink as designed.

Best,
Anand.
 
Thanks for the sonic insight regarding chokes vs. CCS. I guess one should investigate both these possibilities further with measurements as well.

Regarding MOT, it would be nice if you could order a pair that measured the same! At least with Lundahl, I know that a pair will measure close but they cost $100 each iirc.

Best,
Anand.
 
Hi X,

The differences may be in the core laminations, the gap, and the turns and the winding gauge. More inductance will not affect midrange and top end; but it will make more bass, which because it is not directional may not make perceived differences in balance.

The 'dead loss' on these inductors is the DCR. 0.98R means that with 1.7A you will throw away 1.67V from your supply; so if you have 27V supply, you are effectively working only with 25.33V, which reduces your headroom but is not too much of an issue if you can deal with the heat from the active device.

Ciao,

HD