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Another Millett Starving Student Build

post #1 of 16
Thread Starter 

The parts are in and the soldering iron is heating up...

 

I decided to build on a 100mm x 160mm stripboard since this is my first foray into DIY circuitry.  P2P just looked like it would be too easy to make a mess.  I felt that a stripboard would allow me to trace the circuitry more easily.

 

So, here are links to a couple of drawings I did in DIYLC.  I've been over them several times and they seem to reproduce the 12au7 version of the amp.  If any of you see a problem, please let me know.

 

 

ssmh.jpg

 

 

ssmhline.jpg

 

More to come...


Edited by bengoshi2000 - 3/9/12 at 12:05pm
post #2 of 16
Thread Starter 

Well the build is done and pics will follow later today.  I ended up building on a perfboard as opposed to the stripboard layout above.  The stripboard was too large for my selected enclosure (and I didn't have the guts to cut it). 

 

Working with diylc and working the layout helped me (a rank newbie) learn the schematic and how to "see" the circuit in another form... so I found the time well spent. 

 

Two things I learned along the way:

 

1) triple and quadruple check your BOM and your purchase list... I left off the 390k resistors by accident and had to do a work around.

2) TUBE PINS ARE NUMBERED LOOKING AT THE BOTTOM OF THE TUBE!!  I thought they were numbered as if looking down from the top.  I wasted 3 days in frustration until I realized this bonehead error...

post #3 of 16
Thread Starter 

My workspace (aka - The Kitchen Table):

P2267174.JPG

 

 

First components... I labeled all of the junctions with  a marker as went.

P2267175.JPG

 

 

Used electrical tape flags to mark the tube pin leads.

IMG_0301.JPG

 

 

End day one...

IMG_0300.JPG

 

 

Without a set of helping hands, I had to get creative on ways to hold the resistor to the gate so I could solder it.

P2267176.JPG

 

 

Finally taking shape...

IMG_0304.JPG

 

 

Sweet test run victory!

IMG_0311.JPG

 

Final assembly...

P3177222.JPG

 

P3177223.jpg


Edited by bengoshi2000 - 3/18/12 at 11:38am
post #4 of 16
Thread Starter 

The Case...

 

I really wanted something different than what I'd seen on the SSMH thread so I hit a few antique stores, got an idea, then found this on eBay:

 

%2524%2528KGrHqN%252C%2521n8E8VDqiT6kBPNI6%2521tcMw%257E%257E60_57.JPG

 

%2524%2528KGrHqJ%252C%2521k4E74%252Bn2DmdBPNI6Js9DQ%257E%257E60_57.JPG

 

%2524%2528KGrHqZ%252C%2521hQE8ki%2529e%2529ghBPNI6T5oy%2521%257E%257E60_57.JPG

 

%2524%2528KGrHqV%252C%2521g0E8hpQKBirBPNI69jfY%2521%257E%257E60_57.JPG

 

 

It's an old antenna rotor control box.  It had that nice old, art deco feel to it.  I was really excited about the prospect... I would have been even happier if the seller had packaged it properly for shipping... GRRRRR!!

photo.JPG

 

 

I repaired it the best I could with JB Weld and then worked the entire case over with 800 then 2000 and finally 3000 grain sandpaper.  I finished it off by waxing it with Maguiar's car wax...


Edited by bengoshi2000 - 3/16/12 at 8:10am
post #5 of 16
Thread Starter 

So here's the final result.  I used a piece of aluminum angle bar for mounting the RCA jacks, switch and power jack.  The ivory chicken head knob for the volume seemed somehow appropriate.

 

P3137217.JPG

 

P3137218.JPG

 

 

Still irked about the crack repair I had to do.  In retrospect, I should have probably super-glued it, but the plastic was old and brittle and I knew JB Weld would hold.  Did I mention I'm still pi$$ed?

P3137220.JPG

 

 

 


Edited by bengoshi2000 - 3/13/12 at 4:13pm
post #6 of 16
Thread Starter 

My Impressions...

 

I don't think you can beat the SSMH in the "bang for the buck" category.  I ended up spending less than $100 USD and I have a headphone amp that drives my 20-year-old AKG240 Monitors very well.  So far, my tubes of choice are a pair of Baldwin (probably RCA made) 12AU7A tubes.  The mids are present but not harsh.  The bottom end is tight.  The highs are transparent and clear (though it reveals some of the flaws of the .mp3 compression format).  I also have some 12AT7WA's (GE mil-spec) that are a little crunchy/sparkly on the high end, but have enough bottom end to chip a molar.  I also have a pair of GE mil-spec 12AU7's that sound nice, but lack the definition and expansive soundstage of the Baldwin's.  I did pick up a pair of new Tung Sol 12AX7's but one of the tubes has a short... one makes my volume knob crackle and it causes one channel to sound out of phase.  I'm disappointed because the one "good" channel sounds superior to any other tube I've rolled so far.

 

I must say that the tubes do a good job of masking the artifacts of .mp3 compression.  The amp itself is whisper quiet.  With no source and the volume maxed out, I can barely hear any hiss.

 

Simply put, I couldn't be happier with the result (and I can't wait to build another one)!


Edited by bengoshi2000 - 3/13/12 at 4:31pm
post #7 of 16

That looks very nice; original.

I like bakelite and refurbish All American 5 radios.

When I buy a radio on Ebay I ask them to double box it and I will pay extra. The antique radio lovers usually do that automatically.

 

Check out Radio Daze, Antique Radio.come, et. al. for various original and reproduced knobs if you tire of that one.

 

F

post #8 of 16
Thread Starter 

Thank you, I've really enjoyed this build.

 

I've sold stuff on eBay and I tend to go overboard on packaging... it's easy to assume everyone else does the same.  The next time I buy anything of this nature, I'm going to ask for the extra packing.  I don't think this Seller was much more than a junk picker who was selling odds and ends (clearly not one who appreciates vintage appliances/antiques).

 

Thanks for pointing out those websites...

post #9 of 16
Thread Starter 

Added two pics of the finished perfboard.

post #10 of 16

Nice work with the circuit layout, I am on an almost identical journey. I even ordered the same incorrect resistor but I just reordered from mouser and desoldered the 220k one. I wish I had ordered a little bit larger enclosure, but i just ordered the one on the BOM and was having a hard time finding the right size perfboard and ended up using these tiny little break apart boards that I posted pictures of on the ssmh main thread. In hind sight it would have been way easier to have more room to lay the circuit out. I still need to order my power supply and tubes, I was looking at the tung sol tubes on tube depot. Sounds like these would be a good choice. Where did you get your power supply?
 

post #11 of 16

Hey guys. So I just ordered parts for my Cmoy and I'd like to already on top of the Cmoy start building a Starving Student amp. I'm very new to the scene so I have a few questions I'd like for you guys to answer for me. Oh just before I ask, beautiful rig bengoshi!

1. Is it possible to have the parts excluding the enclosure and tubes to be under $50 without getting parts that really degrade sound quality? And how much would a pair of tubes sound, a relatively cheap pair that has the same pit layout as a lot of other tubes so that I can start tube rolling with better tunes in the near future?

2. Is there a website somewhere that has a parts list and instructions available? I can't seem to find suck a source

3. (To anybody who built the Starving Student amp) On a scale of 1 to 10, 1 being not at all and 10 being you can't do without it, how useful would a pair of helping hands be when building the amp?

post #12 of 16
Thread Starter 
Quote:
Originally Posted by RanDiesel View Post

I still need to order my power supply and tubes, I was looking at the tung sol tubes on tube depot. Sounds like these would be a good choice. Where did you get your power supply?
 

 

I got my 12AU7A tubes off ebay... keep your eyes open and you can score a pair for less than tube depot.

 

I found the Cisco PS on ebay as well.  They are readily available for about $20-25 shipped.

post #13 of 16
Thread Starter 
Quote:
Originally Posted by GeneralSmirnoff View Post

Hey guys. So I just ordered parts for my Cmoy and I'd like to already on top of the Cmoy start building a Starving Student amp. I'm very new to the scene so I have a few questions I'd like for you guys to answer for me. Oh just before I ask, beautiful rig bengoshi!

1. Is it possible to have the parts excluding the enclosure and tubes to be under $50 without getting parts that really degrade sound quality? And how much would a pair of tubes sound, a relatively cheap pair that has the same pit layout as a lot of other tubes so that I can start tube rolling with better tunes in the near future?

2. Is there a website somewhere that has a parts list and instructions available? I can't seem to find suck a source

3. (To anybody who built the Starving Student amp) On a scale of 1 to 10, 1 being not at all and 10 being you can't do without it, how useful would a pair of helping hands be when building the amp?

 

1)  I ordered all my stuff from mouser (except for the tubes, tube sockets and enclosure) for $46 before shipping.  I did pick up some standoffs and terminal blocks from RadioShack. Probably spent another $8 bucks there.  I ordered 20ft of teflon coated 22 awg wire from ebay for $8 bucks shipped.  $50-$60 bucks is do-able without downgrading parts.  Caveat:  That doesn't include the Cisco power supply... that's another $20-25.  My feeling is that the component brands selected by Millett were already picked with a small budget in mind.  I don't know that cheaper components would save you more than a couple bucks.

2)  Check the first post in this looooong thread.

3)  I didn't use a set of helping hands.  There were a couple of places where they would have helped, but I was able to work around it (see the pic showing how I held the resistor to the mosfet for soldering).  If I had to choose between getting quality components for this build OR spending the $$ on helping hands, I'd rather spend the money on the components.  To answer your question directly, 2.


Edited by bengoshi2000 - 5/27/12 at 5:00pm
post #14 of 16
Quote:
Originally Posted by bengoshi2000 View Post

 

I got my 12AU7A tubes off ebay... keep your eyes open and you can score a pair for less than tube depot.

 

I found the Cisco PS on ebay as well.  They are readily available for about $20-25 shipped.

I found better spec'ed ones for half this price.

 

examples:

http://www.ebay.ca/itm/390277887505

http://www.ebay.ca/itm/180692659213

http://www.ebay.ca/itm/320891016671

http://www.ebay.ca/itm/140423679845

 

And if you can find a transformer with between 73 and 80 volts on the secondary winding, you might as well buy this linear voltage regulator and build your own power supply.

post #15 of 16
Thread Starter 

I'll be honest, I'm not comfortable ordering stuff from China/Taiwan/Etc.  Plenty of opportunity to get ripped off with a piece of junk and no recourse against a seller on the other side of the planet.  That's not to say high quality stuff can't be had from there, but I'm not one who's willing to take the risk (or wait for the long shipping time).

 

As for the $9.95 PS that was in Canada, it would cost $22 USD to ship it to me here in the USA.  :/

 

For beginners like myself (and I assume most of the folks that build the MSSH) building a power supply is well beyond our skill set.  Building a PS may be simple, building one that doesn't make noise (like pimpin') ain't easy.

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