[tomb]

Quote:

Originally Posted by Zigis /img/forum/go_quote.gif Is it possible to use LM317 for "real" high voltage tube amp, like MJ ?

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.

 

[00940]

Quote:

Originally Posted by Fitz /img/forum/go_quote.gif I've read an article on natsemi's site about that specifically mentioned the LM317 being suitable even up to several hundred volts, as long as the voltage drop is kept below 40V. Since it has no ground reference, all it cares about is the voltage differential between the input and output.

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

 

[OldKing]

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

 

[tomb]

Quote:

Originally Posted by OldKing /img/forum/go_quote.gif 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... <IMG]http://www.nichicon.co.jp/english/products/images/mini3-m.gif[/IMG> (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?

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.

Quote:

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?

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.

Quote:

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.

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.
Quote:

Thanks, Brian

 

[OldKing]

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!

 

[Fitz]

Quote:

Originally Posted by 00940 /img/forum/go_quote.gif 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

Yep, that's the one.

 

[FallenAngel]

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.

 

[-=Germania=-]

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

 

[dsavitsk]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif 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.

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.

 

[jERiCOh]

Finally mine is all done

Now I hope I'll find a PSU to give it a try.

 

[bperboy]

^^

Neat wiring!! wow!! very neat..

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

 

[gurusan]

Congrats jericoh that looks great!

 

[n_maher]

Quote:

Originally Posted by -=Germania=- /img/forum/go_quote.gif Does anyone else "Cisco" PSU say completely different values on teh label than what is on the output?

No, and I've seen multiple.

 

[jERiCOh]

Quote:

Originally Posted by bperboy /img/forum/go_quote.gif ^^ Neat wiring!! wow!! very neat.. Are your mosfets isolated from the case?? you could very well run into problems if they aren't...

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

 

[Hayduke]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif 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.

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