Millett "Starving Student" hybrid amp - Page 74

Apparently. As Fitz described up there, it's the voltage difference that's limited to ~40V. That still means you could regulate from 300V down to 260V, for instance - as long as you floated the ground.

This note probably ? http://www.national.com/ms/LB/LB-47.pdf

It becomes quite clear why you can do such thing once you look at the internals of the lm317, as shown here: http://www.national.com/an/AN/AN-178.pdf

First Timer questions...

I am yet another first timer. I have been reading and researching and re-reading for a few weeks.

I am looking at all the Nichicon 470uF caps on Mouser, and looking at this Nichicon diagram of audio caps...


(diagram is interactive, click on it for data sheets)

which raises questions...

FG and KZ are labeled "High Grade" and KW is labeled "High Sound Quality" (KW). What's the difference? KZ vs KW?

Mouser has these..
647-UKW1J471MHD (KW, 470uF 63V)
647-UKZ1H471MHB (KZ, 470uF, 50V)

Is the KZ part's 50V rating too low for this project?

What gauge of hook up wire (stranded I assume) is best suited for this type of project? I'm thinking of the physical ease of working with the wire, as well as sufficient gauge for the current. It would be nice to find a kit of a few meters of several colors.

Thanks,
Brian

Notice that KW uses the word "standard" while KZ uses the word "Premium?" Also, the KW path is not labeled "High Sound Quality" but "Improved of the Sound Quality". Sometimes things are lost in translation, but it should be easy to see that the KZ path is superior.

Strictly speaking, yes. There are some who are willing to take the risk, but you won't see it as an "official" recommendation. The UPW's from Mouser are just fine, but it might be interesting to try the KW. I didn't realize Mouser had started carrying some of those Nichicon caps. Anyway, I've used Panasonic FC's which are comparable to the UPW's and it sounds great. If you want to tweak it later with some boutiques you can get them from Handmade Electronics, PartsConnexion, Michael Percy, etc.

22ga silver-plated copper with teflon insulation is what I use, but you may get many opinions on this. John Silver Teflon Wire Shop on e-bay (navships) is a good place to look to get different colors in small lengths.

FWIW, it does say "High Sound Quality" on the KW data sheet itself (the graphic showing an improvement as compared to the FW)... but also says "standard"

I had concluded pretty much the same, but I thought it possible the KW was a new product or something, so worth asking.

Thanks for the reply and advice!

Yep, that's the one.

One more thing I noticed - that Cisco PSU is actually regulated, put out exactly 48.1V. That won't leave any room for the LM317 so I'll just have to go insane on the PSU caps, likely will add a coupld of 1000uF at the beginning of the circuit.

Does anyone else "Cisco" PSU say completely different values on teh label than what is on the output?

Too much capacitance can cause the PSU trouble. Instead, make it pi filter instead. Or, if you really want to regulate this, dropping a few volts is fine -- there is nothing magical about 48V here.

Finally mine is all done Now I hope I'll find a PSU to give it a try.

^^

Neat wiring!! wow!! very neat..

Are your mosfets isolated from the case?? you could very well run into problems if they aren't...

Congrats jericoh that looks great!

No, and I've seen multiple.

Ok... so I'm in trouble ...
I totally forgot the mica insulator. One more thing on my shopping list

KT also says standard and it is above the KZ in that chart. Perhaps this logic is flawed?