Millett "Starving Student" hybrid amp
Jan 30, 2010 at 10:53 PM Post #4,576 of 7,277
Quote:

Originally Posted by UKToecutter /img/forum/go_quote.gif
Hmmm

So maybe I'll do a P2P balanced SSHA then.

:)



Ditto, would make a great present for my bro, along with the decent headphones I am planning on getting him for his birthday.

smily_headphones1.gif
 
Jan 31, 2010 at 10:01 PM Post #4,577 of 7,277
Hey everyone, just finished building my 12AU7 SSMH.
It's not entirely finished as I still need to finish the case, but at least it works.
tongue.gif

I had a rough time getting it to work, (you can see my frustrations documented earlier in this thread) but with the help of the_equalizer, I managed to find my problem and now all is good! Right now, I'm using this with my K702's and they sound great!
I'll post more details later since I'm busy building second 12AU7 SSMH for my bro at the moment.

EDIT: forgot to add pictures of it turned on
k701smile.gif


Here are some pictures:

21nqn8m.jpg


zleslz.jpg


ml6t85.jpg


20apfgi.jpg
 
Jan 31, 2010 at 11:25 PM Post #4,578 of 7,277
Quote:

Originally Posted by getllamasfast /img/forum/go_quote.gif
Hey everyone, just finished building my 12AU7 SSMH.
It's not entirely finished as I still need to finish the case, but at least it works.
tongue.gif

I had a rough time getting it to work, (you can see my frustrations documented earlier in this thread) but with the help of the_equalizer, I managed to find my problem and now all is good! Right now, I'm using this with my K702's and they sound great!
I'll post more details later since I'm busy building second 12AU7 SSMH for my bro at the moment.

EDIT: forgot to add pictures of it turned on
k701smile.gif


Here are some pictures:
<snip>




Great news! Another 12AU7 build
smily_headphones1.gif
I'm really glad that it worked! I also used JJ tubes to build mine.
k701smile.gif


I particularly like the turned-on pic, the illuminated volume control you used for your build looks really great! I'm sure your brother will like his a lot.

cheers!
 
Feb 1, 2010 at 12:51 PM Post #4,579 of 7,277
Just an FYI to ask for a little patience of those who've ordered kits so far. I'm running about a day behind and hope to get the first kits shipped out tomorrow. Doing those tube sockets took a little longer than I'd hoped. Gluing and testing 70 of them was a little daunting. I think I lost some brain cells that will never come back from all of the epoxy fumes.
confused_face.gif
 
Feb 1, 2010 at 8:38 PM Post #4,581 of 7,277
hey tom, i didnt specify a led color when i was ordering, i ordered from my phone at a bar. i don't know if its too late or not but is there any way i can get sea green leds? my order is #1013.

Thanks,
Kevin
 
Feb 3, 2010 at 11:16 PM Post #4,583 of 7,277
Starting to wire mine up now with the tube sockets am I right in thinking that they're numbered in order clockwork with the first one being the first from the gap?

Also any tips for soldering the earth to the enclosure, other than keying it beforehand?
 
Feb 3, 2010 at 11:20 PM Post #4,584 of 7,277
Quote:

Originally Posted by simwells /img/forum/go_quote.gif
Starting to wire mine up now with the tube sockets am I right in thinking that they're numbered in order clockwork with the first one being the first from the gap?

Also any tips for soldering the earth to the enclosure, other than keying it beforehand?



Yes, as you look from the bottom. When I flip mine over, I see (clockwise): gap, 48V, 48V, output cap, ground, pot, pot. EDIT: and lastly the 2k resistor to ground, of course.
 
Feb 4, 2010 at 12:47 AM Post #4,585 of 7,277
Hey everyone, halfway done with my P2P amp, when I noticed a problem.

C1, C2, and C7 all have their correct capacitor in, however, I noticed I don't have the right capacitor (as marked) for C3a, C5a, C8, C7.

Capacitors I have: (2) Muse 470uF 35V, (2) 470uF 63V, (3) 0.22uF 35V.

Can I still use these, or is it back to Mouser I go?
wink.gif
.

Edit-

On a different note, I forgot to cut the holes for the mosfet to attach directly to the heatsink, so instead I've used Arctic Silver 5 and a little bit of glue to attach the mosfet to the steel chassis wall, and then mounted the heatsink, also with AC5, directly above where the mosfet is, just on the other side of the wall. Would this still work? (I used the same 'sink as in the original BOM)
 
Feb 4, 2010 at 1:32 PM Post #4,586 of 7,277
Quote:

Originally Posted by Dunceiam /img/forum/go_quote.gif
Hey everyone, halfway done with my P2P amp, when I noticed a problem.

C1, C2, and C7 all have their correct capacitor in, however, I noticed I don't have the right capacitor (as marked) for C3a, C5a, C8, C7.

Capacitors I have: (2) Muse 470uF 35V, (2) 470uF 63V, (3) 0.22uF 35V.

Can I still use these, or is it back to Mouser I go?
wink.gif
.

Edit-

On a different note, I forgot to cut the holes for the mosfet to attach directly to the heatsink, so instead I've used Arctic Silver 5 and a little bit of glue to attach the mosfet to the steel chassis wall, and then mounted the heatsink, also with AC5, directly above where the mosfet is, just on the other side of the wall. Would this still work? (I used the same 'sink as in the original BOM)



Unfortunately, the Muse 470uf 35V has a voltage rating that will only work at C7 and C8. The 470uf 63V caps can be used at C1, C3, C5 or C6. The 0.22uf can't be used at all if it's a truly a 35V rating, but I suspect you're wrong about that - 35V is pretty low for a film cap, which is what I assume a 0.22uf is. If so, those are used at C2, C4, and C3a, C5a.

As for the MOSFET - the Artic Silver is not the key - the fact that you have no insulator is the problem. I'm afraid you'll have a direct short when you power it up unless you have an insulator in there between the MOSFET and the chassis wall.
wink.gif
 
Feb 4, 2010 at 8:20 PM Post #4,588 of 7,277
Quote:

Originally Posted by simwells /img/forum/go_quote.gif
Last question I should probably already know the answer to!

The mosfet pins are from left to right when the pins are pointing down right?



Yes, looking straight at the MOSFET, pins pointing down, black side toward you, heatsink behind the mosfet, 1 2 3 left to right. So the rightmost pins connect to the output caps.
 
Feb 4, 2010 at 8:40 PM Post #4,589 of 7,277
Ah, you're right. I mistook '358' on the 0.22uF caps for 35V.

However, I've taken a second look and I think I actually have everything I need. The capacitors I still need are C7, C8, C3, C3a, C5, C5a, C4.

Would this work?

C7: Muse 470uF 35V
C8: Muse 470uF 35V
C3: Nichicon 470uF 63V
C3a: 0.22uF 250V
C5: Nichicon 470uF 63V
C5a: 0.22uF 250V
C4: 0.22uF 250V

And regarding the insulating material, what would you suggest? I was a little rash and put Gorilla glue on the back of the mosfet in the plastic area, and AC5 in the metal area's, then stuck it to the chassis. Doubtful I could get the mosfets off unharmed, but hey, they were cheap anyway.

Quote:

Originally Posted by tomb /img/forum/go_quote.gif
Unfortunately, the Muse 470uf 35V has a voltage rating that will only work at C7 and C8. The 470uf 63V caps can be used at C1, C3, C5 or C6. The 0.22uf can't be used at all if it's a truly a 35V rating, but I suspect you're wrong about that - 35V is pretty low for a film cap, which is what I assume a 0.22uf is. If so, those are used at C2, C4, and C3a, C5a.

As for the MOSFET - the Artic Silver is not the key - the fact that you have no insulator is the problem. I'm afraid you'll have a direct short when you power it up unless you have an insulator in there between the MOSFET and the chassis wall.
wink.gif



 
Feb 5, 2010 at 1:43 PM Post #4,590 of 7,277
Quote:

Originally Posted by Dunceiam /img/forum/go_quote.gif
Ah, you're right. I mistook '358' on the 0.22uF caps for 35V.

However, I've taken a second look and I think I actually have everything I need. The capacitors I still need are C7, C8, C3, C3a, C5, C5a, C4.

Would this work?

C7: Muse 470uF 35V
C8: Muse 470uF 35V
C3: Nichicon 470uF 63V
C3a: 0.22uF 250V
C5: Nichicon 470uF 63V
C5a: 0.22uF 250V
C4: 0.22uF 250V

And regarding the insulating material, what would you suggest? I was a little rash and put Gorilla glue on the back of the mosfet in the plastic area, and AC5 in the metal area's, then stuck it to the chassis. Doubtful I could get the mosfets off unharmed, but hey, they were cheap anyway.



If the Gorilla glue is not conductive, then maybe you'll be OK. Use your DMM to measure the resistance between the metal tab of the MOSFET and the case - see if you get near infinite resistance or near zero (very bad).

The caps look OK as you have them arranged in that list.
 

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