Millett "Starving Student" hybrid amp
Jul 10, 2010 at 1:10 PM Post #5,372 of 7,258

Ikarios

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Quote:
I don't know where you do your shopping but those prices are very high. A simple DPDT switch at my supplier is only €0.75 (~USD 0.95).


Mouser's cheapest DPDT switches are ~$2.50, from what I can find. Switches from tubesandmore were ~$8, too. I was also looking at metal film resistors, which are like $2 for the 2W versions. I did find power resistors which are maybe 20 cents. It actually doesn't matter, because I discovered that we have lots and lots of switches at work, so I borrowed a few. Regardless, I really like the idea of being able to fade the tube LEDs. Now that I think about it, though, I may not have enough room on the panels of the case; it's a lot smaller than I thought. I'll have to rethink this whole thing...
 
Also, it appears that the DC jack sourced at mouser is OOS until August (http://www.mouser.com/Search/ProductDetail.aspx?R=163-4025virtualkey11180000virtualkey163-4025). I looked for a replacement but couldn't find one with the right jack sizing. Does anyone have a spare lying around that they would sell/donate to me?
smile_phones.gif

 
Jul 10, 2010 at 5:54 PM Post #5,374 of 7,258

Beftus

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Quote:
Are these boards available anywhere?
checked out beezar and seems like they are sold out 
would love to build this as my first amp

No more boards. The Starving Student became victim of its own success. The supply of cheap 19J6 tubes has dried up. They're now very difficult to find and if you do prepare to pay a premium price. So far the bad news.
 
The good news is that you can still make a Starving Student with other tube types. There's the 12SR7, the 12AU7 and the 17EW8 modifications. There's no PCB for these mods though. You'll have to do a point-to-point or make your own PCB. I have made the 12AU7 mod and it sounds awesome. Schematic is here. Good luck!
 
Jul 19, 2010 at 11:34 AM Post #5,375 of 7,258

Ikarios

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Anyone know if I can use a 1A/250VDC rated DC power jack as opposed to the spec'ed 2A/100VDC jack?
 
http://www.mouser.com/ProductDetail/Kobiconn/163-2325-E/?qs=sGAEpiMZZMu2f9RNbWupYlhRViv1JeBB6A17xm18uDs%3d
 
The one in the BOM is backordered until August 6th and I plan on buying all my crap Friday this week. The PSU is only rated for 0.38A, I just have to not use a different PSU, right?
 
Jul 19, 2010 at 11:59 AM Post #5,376 of 7,258

nullstring

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lol, I am sure the original part was chosen pretty arbitrarily. (or for cheapest price)
 
If it's rated for more than 48V and .38 amps.. I think you're good.
 
Jul 19, 2010 at 12:24 PM Post #5,377 of 7,258

the_equalizer

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As nullstring mentioned, I'd say you're safe using that part. You could even use the 1A PSU if you so wish it, since the amp's current draw won't go near 1A during operation.
 
cheers!
 
Jul 20, 2010 at 2:05 PM Post #5,378 of 7,258

Beftus

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A question about the 12AU7 mod. The optional caps C7 and C8 are listed as 220uF 16V. I measured the voltage across those caps in my build and there's only 1.12 and 1.14 volt across them. Why are they specified as 16V? Do they get to handle more than what I measure? Or was their voltage rating chosen arbitrarily?
 
Edit: Please ignore question. Found the answer here. Gotta learn to use the forum search...
redface.gif

 
Jul 23, 2010 at 2:23 AM Post #5,379 of 7,258

swedishhatfaction

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Quote:
Just finished my first DIY amplifier, wanted to show it off here :)
 


 
I never realized how small 4" x 4" really was, until I started to solder everything together. Also, I really should think about buying another colour for wire, staring into a blue mess doesn't help in debugging, though luckily everything worked the first time I turned it on.
 
-Dark



 
[size=medium]
 
Wow darkraver -- that's a pretty snazzy exterior you got going on there. It kinda reminds me of the crazy abstract art my sister paints. Also, congratulations on having it work the first time. I was not nearly as lucky/skilled and ended up rebuilding mine from scratch.
 
Edit: Whoops. Didn't realize that post was 10 pages back.
[/size]

 
Jul 27, 2010 at 4:03 PM Post #5,382 of 7,258

WC Annihilus

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Curious, does anyone know how this would pair with the DT990/600?  I'm considering trying to build one as a relatively cheap summer project to burn time and get an intro to amps as well.  Other option I've been looking into is the CK2III.
 
Jul 27, 2010 at 4:36 PM Post #5,383 of 7,258

nullstring

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I just got a PM about that today.
 
This was my response.
Quote:
I think it sounds good.
It certainly has enough volume for the vintage DT880/600.
I don't, however, think it sounds as good as it could.
 
I am planning on building a much better amp to replace it soon.

 
Jul 28, 2010 at 8:00 AM Post #5,384 of 7,258

the_equalizer

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Quote:
Hi,

Will the SSHT properly drive low impedance headphones like the 25 ohm and 8 ohm Beyer DT48?

Thanks,

Ross


The output stage has enough muscle, so I think it'd do perfectly with the 8 ohms cans. Though the lowest impedance I've tried with the amp has been some 16 ohm earbuds; it had no problems with them.
 
cheers!
 
Jul 29, 2010 at 6:04 AM Post #5,385 of 7,258

hellomoto

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Hello!
 
I'm now finished with my build, the tubes are glowing, but I still haven't put my heaphones on it: I found a really nice post from the_equalizer about testing your amp, so It doesn't destroy your whole setup
dt880smile.png

 
Here it is: http://www.head-fi.org/forum/thread/319231/millett-starving-student-hybrid-amp/3870#post_6032606
 
I've got some questions about it, more precisely about the different voltage test:
- How do you measure the voltage at the tube filaments
- How do you measure the voltage in the Output Jack? Do you plug in a Mini to Mini, and measure at the other side?
- How do you measure the voltage in the Jack Plug?
 
Thank you very much, I'll post some pics!
 
Antoine
 

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