Millett "Starving Student" hybrid amp
May 15, 2008 at 11:20 PM Post #196 of 7,277
Quote:

Originally Posted by Zigis /img/forum/go_quote.gif
Very interesting design !

Just one thing, I reed all treed and no one ask this - 150 mf otput cap, are this enough for 32 ohm? Maybe something like 470 mf, usually used in OTLs, is better.
Maybe this is reason why Gross reported about not enough bass ?

Anyway, I want to try it one day!
Zigis.



Well, to tell the truth - for resistors, I went for some Stackpoles from Handmade - very cheap and they sure do sound good. That made an easy excuse to get some 470uf 100V Nichicon Muse FG's for the output couplers. That's probably not in the spirit of the Starving Student, but I couldn't resist - still only a couple of dollars each.

I figure my Goodwill-purchased Spiderman lunch box and/or my Crayola crayons tin will make up for it. Or, maybe I'll mount the caps on the top with some clamps and pretend it's Nate's Menace.
tongue.gif
 
May 16, 2008 at 12:24 AM Post #198 of 7,277
Zigis, I am assuming it is a capacitor thing with my amp. I haven't been able to do any changes or give any updates since I have been out of town this week. I will report in this weekend.
 
May 16, 2008 at 12:46 AM Post #199 of 7,277
Quote:

Originally Posted by Snicewicz /img/forum/go_quote.gif
THe only thing I am having trouble with now is obtaining a PSU. I need to have this build by next thursday for a school project .

Also does anyone have any extra 7-pin miniature tube socket, top chassis mounts?



Yikes man, didn't leave yourself much wiggle room there did ya? I'll have a look in the parts bin and see what I can find. I'm not itching to sell my spare PS but in the name of you not failing a project I might be coaxed out of it.
 
May 16, 2008 at 12:55 AM Post #200 of 7,277
Quote:

Originally Posted by n_maher /img/forum/go_quote.gif
Yikes man, didn't leave yourself much wiggle room there did ya? I'll have a look in the parts bin and see what I can find. I'm not itching to sell my spare PS but in the name of you not failing a project I might be coaxed out of it.


That would be nice but no need to do that. I would not fail. The project is just an alternative to taking a final in that class.

Its my AP Physics course so I would obviously like to do something I like and not have to take a final. Now that I think about it. If i order tonight 3-5 days shipping it will be here before next thursday.

That was very generous of you to offer thank you
 
May 16, 2008 at 1:32 AM Post #201 of 7,277
Quote:

Originally Posted by Snicewicz /img/forum/go_quote.gif
That would be nice but no need to do that. I would not fail. The project is just an alternative to taking a final in that class.

Its my AP Physics course so I would obviously like to do something I like and not have to take a final. Now that I think about it. If i order tonight 3-5 days shipping it will be here before next thursday.

That was very generous of you to offer thank you



Well, if you get stuck let me know.
 
May 16, 2008 at 2:14 AM Post #202 of 7,277
Quote:

Originally Posted by n_maher /img/forum/go_quote.gif
Well, if you get stuck let me know.


Thanks I appreciate it, but there is no worry. Worst comes to worst I explain and show it with out the power supply.

Does anyone else know where I can get the 7 pin tube mounts so I dont have to buy 10?
 
May 16, 2008 at 2:30 AM Post #203 of 7,277
May 16, 2008 at 2:38 AM Post #204 of 7,277
Thanks tomb but the quantity is 0 and I cant wait 2 days for auctions to end.

Thanks for the help though
smily_headphones1.gif
i bought the gold plated ones however
 
May 16, 2008 at 6:21 AM Post #205 of 7,277
Quote:

Originally Posted by Snicewicz /img/forum/go_quote.gif
Thanks tomb but the quantity is 0 and I cant wait 2 days for auctions to end.

Thanks for the help though
smily_headphones1.gif
i bought the gold plated ones however



You waited too long. It was 2 when I posted it.
wink.gif
Besides, there are many more listings under that seller. He even runs a separate store where you can buy them directly - cascadesurplus.com:

Cascade Surplus Electronics: 7-pin Ceramic Mini Tube Socket

He has other ones, too - plastic, phenolic, and gold - take your pick.
smily_headphones1.gif
 
May 16, 2008 at 6:52 AM Post #206 of 7,277
Is it possible to put an LED in somewhere?
 
May 16, 2008 at 7:24 AM Post #207 of 7,277
Quote:

Originally Posted by J.D.N /img/forum/go_quote.gif
Is it possible to put an LED in somewhere?


This amp uses 48V DC PS, so you can tap this 48V PS and add a 15KΩ - 20KΩ resistor in the path, then connect a LED on this path (+48V -> (15KΩ - 20KΩ) resistor -> LED -> Ground).
This is a P-P build, so it's not too difficult to find an appropriate point to connect 2 additional components. Good luck !
smily_headphones1.gif
 
May 16, 2008 at 12:11 PM Post #208 of 7,277
Quote:

Originally Posted by Ferrari /img/forum/go_quote.gif
This amp uses 48V DC PS, so you can tap this 48V PS and add a 15KΩ - 20KΩ resistor in the path, then connect a LED on this path (+48V -> (15KΩ - 20KΩ) resistor -> LED -> Ground).
This is a P-P build, so it's not too difficult to find an appropriate point to connect 2 additional components. Good luck !
smily_headphones1.gif



Sweet. Im thinking of getting a little creative with this. I know its supposed to be the 'Starving Student' but id quite like it to look the part too. Its going to be my post exams project, so going to tincker with it as well.

How difficult would it be to put 6-8 LED's in there? I have an idea... might be rubbish, might not. Will just have to wait and see!
 
May 16, 2008 at 12:15 PM Post #209 of 7,277
Careful adding that many LED's. You'll need to account for their current draw (which you can vary via the resistor) and the existing PS may not be up to the task, or at least struggle even more at startup.
 
May 16, 2008 at 12:20 PM Post #210 of 7,277
You should be able to use ferrari's method for n leds.
Just put resistor (R) between the ps and and the LEDs (which will be in parallel). Then for n LEDs calculate R as 20k/n (for bright LEDs) and 15k/n for dimmer LEDs.
Each LED will take about 2.4 mA and the PS is rated for 380mA. It probably will be fine unless you're going for like 50 LEDs.
 

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