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Millett "Starving Student" hybrid amp - Page 429

post #6421 of 6815
Thanks equalizer. I figured that was the case. And thanks for your updated schematic! Without it this wouldn't have happened for me. Can read schematics fine, but designing/modifying is out of my league. Haha
post #6422 of 6815
Quote:
Originally Posted by tdubl07 View Post

Thanks equalizer. I figured that was the case. And thanks for your updated schematic! Without it this wouldn't have happened for me. Can read schematics fine, but designing/modifying is out of my league. Haha

bought a Millet Max Hybrid in the FS forum [the Heat Sink on it is HUGE] it comes in today I'm super excited

 

http://www.head-fi.org/t/650018/fs-12au7-starving-student-sold

 

it came with 3 pairs of tubes

 

rca clear tops n 5963 rca 12ua7s


Edited by Mshenay - 2/25/13 at 9:00am
post #6423 of 6815

Very nice looking amp tdubl07! I am going for a similar design my self. Yes I will add a low and high gain switch as this thread suggests hissbuster and make it a high/off/low and use it for turning on and off while plugged in aswell

post #6424 of 6815
Quote:
Originally Posted by Grumus View Post

Very nice looking amp tdubl07! I am going for a similar design my self. Yes I will add a low and high gain switch as this thread suggests hissbuster and make it a high/off/low and use it for turning on and off while plugged in aswell

Thanks man, You will have a good time building this thing. My wiring is a mess, I'm actually embarassed it's so bad but it works perfect and you can't see it, so oh well. Maybe I'll redo it someday. It took me the entire day Saturday to build it, but that included drilling all the holes in my case as well which took some time. Also remember that the mosfets have to be insulated from ground. You can't ground the back of the mosfet out or it will blow, or so I've read. Thankfully I read that comment before I mounted mine. Good luck and have fun!

post #6425 of 6815
I went searching the local shops for 19J6 tubes and picked up enough to share. I thought I post them in the sale/trade forum. Is there a minimum number of posts required to post there? I'm not seeing a reply box when I visit that forum.
post #6426 of 6815

You aren't really allowed to make any money over there. But, Tomb may be interested, if you got enough, he was talking about starting selling a full kit with boards and the old enclosure, if he found enough tubes.

post #6427 of 6815
I see. Tom mentioned 50. I thought he was joking!
post #6428 of 6815
Scootsit,

Thanks. I read the rules. There was a mention of knuckleheads. That's me. Thanks for the heads up.
post #6429 of 6815
Quote:
Originally Posted by Captn Dave View Post

Scootsit,

Thanks. I read the rules. There was a mention of knuckleheads. That's me. Thanks for the heads up.


I mean, it's okay to make a few dollars on a deal here and there, I think - the real point is to prevent people turning head-fi into a business. I will admit, that there are some deals I've made where I made a couple of dollars and probably even more deals where I've lost a few. I've come pretty close to breaking even. I think if you were to make those tubes available at or near to what you paid for them, many would be appreciative, and few would balk. But, I could be mistaken.

post #6430 of 6815

I got my Millext Hybrid in and it sounds nice! Although I'm sure EVERYONES sounds different since they are hand built and customized by each of u e.e still. I'm glad I bought one 

post #6431 of 6815
Scootsit,

I think the point is they don't want members competing with paid advertisers. That's understandable.
post #6432 of 6815
Quote:
Originally Posted by Captn Dave View Post

I see. Tom mentioned 50. I thought he was joking!

Actually, I was going to say 100, but I thought I might be just able to support another run if we had 50.  The original kits were based on lots of 30 kits.  However, that means you need 60 PERFECT tubes.  You can't sell someone a kit and then say, "too bad you got a bad one - there are no more tubes."  The bad thing is with the 19J6 and its rarity now - about 1 in 5 tubes are bad right out of the box.  So, you really need 72.  Then there's the odd microphonic tube that doesn't show up in testing - you're up to 80-85, now, so with matching - you might as well make it 100.

 

Keep in mind that a PCB run of only 30 PCB's will be fairly expensive.  The other parts are best bought at 100, too.  So if we only get 30, that's going to drive the cost up even more.  The original SSMH PCB kits sold for $120 with the machined case from Hammond, but we had at least 3 rounds  of 30 kits if memory serves - maybe 4.  Then again, the number of tubes I had to support that when we started was 400.  There's the proof, unfortunately: a single run of 30 kits means about 100 tubes.

 

I still have about 2 dozen tubes - for the reason stated above.  I had to be certain that everyone who bought a kit had a pair of good, working tubes.  In my mind, that meant holding the extras for at least a year.  It's been longer than that now, but that's why I still have them and haven't sold them.

 

Anyway, I thought we might think seriously about it if we found another 50 and I could add the ones I already had.  That's the practicality of the situation. wink.gif

post #6433 of 6815
Tom,

I am finding about the same reject ratio. I have discarded two shorted tubes and set aside another two with low readings on one section and i have more to go. i intend to test in circuit and listen to those with low readings in one side to see if they are usable. Given the circuit design, it wouldnt surprise me.

The Emerson branded seem to be the best for matching but in this application, with paralleled sections, I don't think that mismatching is a particular liability. Do you have an opinion on that?

Have you used MYRA for boards? I have some Maida boards that they did. They were very nice and crazy cheap.

I'm always looking for good SE and PP output transformers. I have quite a few of these and I'd trade with you if you have something interesting.
post #6434 of 6815

Hi again. I've almost finished my amp. I have one question. This is schematic that I'm using:

 

 

 

I noticed that pins 4 and 5 are unused. Is it ok to leave them like this or I should connect these pins to the ground? 

Thanks.

post #6435 of 6815
Quote:
Originally Posted by ProTofik View Post

Hi again. I've almost finished my amp. I have one question. This is schematic that I'm using:

 

 

 

I noticed that pins 4 and 5 are unused. Is it ok to leave them like this or I should connect these pins to the ground? 

Thanks.

Those are pins for the diodes features in the 12SR7 tubes.  The Millett Hybrid amp family (MAX, MiniMAX, MOSFET-MAX) uses tubes that have diode connections.  We tie them to ground.

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