[zhtham]

**Dedicated to Eleanor**
It's her birthday today, i used to make her DIY birthday cards every year

But I have been slackin' off recently... so here's what I'm gonna do, I'm gonna call this particular amp I assembled "Ellen". There you go Eleanor, here's an Great lookin (IMHO), and Solid Amplifier name after ya'. How's that for a Birthday Card?

Happy Birthday! -Z


After months of part searching, assembling, configuring and debuging. I finally got this amplifier the way i want it to be.

I want to thank everyone that hangout in Head-Fi, I've learned so much from you guys. It feels GREAT to know that create sometin' out of a bunch of parts isn't a Mission Impossible anymore!

This is my second DIY amp, first one was a CHA47 in a Penguin mint box. Things i learned from building the penguin amp really helped a lot. I have some pictures of it in the link attached.

My advice to those who are thinking of making a DIY amp, look no further! Head-Fi & Headwize DIY forum is where you'll wanna be.

PART LISTS:

Power Supply
Board: META42 V1.0 PCB - Tangent
Buffers: Elantec EL2001CN * (3) - Tangent
V. Gnd: TI Rail Splitter TO-92 - digikey.com (296-1994)
D1: STM Diodes 3A/40V - mouser.com (511-1N5822)
LED: T-1 3/4 Red Diffused super-bright - mouser.com (604-L53SRDG)
RL: 15k 1% resistors - RadioShack
C2,C3: Panasonic FC Electolytic 470ìF/16V * (4) - digikey.com (P10275-ND)
C4: Wima MKS2 10uF/16V * (2) - Tangent


Amplifier
Vol: Alps Stepped Attenuator - Read this
OpAmp: Analog Devices AD8620AR - analogdevices.com
Adapter: Browndog SO8 to DIP8 adapter w/ pins - brndog.com (970601S)
C1: Wima MKS2 1uF/64V * (2) - erix
R1: 1k 1% resistors * (2) - RadioShack
R2: 200k 1% Metal Film D-Vishay * (2) - Mouser.com (71-RN60D-F-200K)
R3,R7,R9: 47.5 1% Metal Film D-Vishay * (6) - Mouser.com (71-RN60D-F-47.5)
R4,R5: 475 1% Metal Film D-Vishay * (4) - Mouser.com (71-RN60D-F-475)
R6: 47.5k 1% Metal Film D-Vishay * (2) - Mouser.com (71-RN60D-F-47.5K)
R8: Jumpered

Enclosure, I/O, & Etc.
PS jack: 2.1mm/5.5mm Panel Mount DC Jack - digikey.com (CP-5-ND)
Switch: Panel Mount SPST Rocker Switch - alliedelec.com (908-0100)
In Jack: 3.5mm Stereo Jack - digikey.com (CP-3535-ND)
RCA Jack: Panel Mount Insulated RCA Jack - partsexpress.com (091-1120)
Encl.: Hammond Aluminum Extruded Enclosure - alliedelec.com (806-3628)
Ph. Jack: Neutrik Locking 1/4" Phone Jack - markertek.com (NJ3FP6C-B)
Vol Knob: 0.925" Matte Black Volume Knob - alliedelec.com (664-1654)
IC Sockets: Mill-Max Gold DIP8 Sockets * (4) - digikey.com (MV8305-ND)
Screws: #4-40 x 1/2" machine screw * (2) - Home Depot (for the Neutrik Locking Jack, bcoz it doesn't come with matching screws)

BRIEF REVIEW
First thing that came into my mind when i fired up the amp was "Wow! Kick A**!" The bass is punchy, it really shook my brain I tell ya! I was using Cowboy Junkies - Miles From Our Home - Track 6: "Hollow As A Bone" as my test track

Drum beat was very controlled. I don't know how else to describe it.... You know when you hit a drum --- "boom...chzzz", the trailing sound "chzzz" is so realistic! I feel like i could touch the drum that's right in front of me

Next thing i noticed was imaging improved compared to my CHA47, i could tell the position of the instrument easier. I didn't have to try too hard to find out what's playin' where. High frequency is not shrilling when i turn up the volume. Now i can enjoy the music while trying to listen to the details in mid-high volume (i'm listening with the knob at 12~1 o'clock position now). Yeah, the vocal is just SWEET! You can hear how the voice of the singer trembles. Plus, the guitar strums is so realistic, just like the drum beat, i can almost reach out an touch it!

Well, overall, I've listened to different amps, and I think it's a great step ahead of CHA47, OBH11, or X-Can V2. BUT of course that's just my humble opinion

I will consider doing a more detail review if it's necessary.

BTW, i listen to the amp with my SONY CD3000 Headphone (a Low Impedence Headphone), and powered by 2 9V batteries in series (i tried 15v walwart, but it gives this soft but still audible hums, thinkin' of building a highly regulated Linear PS someday!).

THANKS & CREDIT
Big thank yous to Morsel, Eric343, Tangent, Apheared & Antness for making this whole amp possible! I used PRR suggested values for R3~R6 and it works like a charm. JMT sold me his extra Alps Attenuator so that i don't have to order em' from Hong Kong. Erix sold me some caps with a reasonalbe price and fast shipping.
And hats off to all the people out there that contribute to the META42 project.


Cheers,
Z.

p.s. Pictures of Amps are here.

Following is picture of miscellaneous parts:

 

[puppyslugg]

Hi zhtham,

Congrats! Nice amp!

Who makes the box? Are those ad8610's? How does it sound?

 

[CRESCENDOPOWER]

Could you tell us where you got the enclosure, knob, headphone jack etc. I would like to have one like that. The dimensions of the amp would be nice also. Thanks!

 

[aos]

Nice! I have the same Hammond box but a bit longer and in silver, and thought of arranging Alps Blue and Neutrik jacks on front, just the way you did it. You actually pulled it off - cool!

 

[RVD]

Awesome amp, can not wait until mine arrives. aos could you by chance post a pic of the silver Hammond as the picture on the Hammond site is not very good. Thanks

 

[lextek]

Very, nice.

 

[evilcthul]

Great work dude that's some top class craftsmanship.

Manage giving us a bit of a run down about the construction process? The wiring you use seems to be some type of silver wiring. What's the deal with the cable braid to the RCA jacks on the back?

 

[erix]

I love those new Hammond boxes! Excellent build.

One thing, however. The caps you have in the C1 position (MKS2?) are not the greatest for signal quality. You should find a good polypropelene (Wima MKP4 or MKP10 or Panasonic's from Digi-Key or Solen or other exotics from Welborne or somewhere) for that position.

Or leave it out.

ok,
erix

 

[HD-5000]

zhtham, thats an awesome looking amp! BTW, I am planning to build a META42 with a Hammond 1455 Case. What size Hammond case did you use and does the amp open from the sides too or does just the top come off?

 

[JMT]

Beautiful work.

 

[legoman]

great looking amp
if it sounds like it looks ...

 

[morsel]

You did a fabulous job, congrats! I second Erix's comment. Whatever you are using for C1 looks to be too small and/or low quality. If you know your sources are DC free, you can just bypass C1. If you don't feel safe doing that, go for some nice polypropylene or polycarbonate films.

 

[ringtheorist]

Is that a Brown Dog adapter I see there? Was it very difficult and/or time consuming to solder the SMT part onto it?

-b

 

[fiddler]

Wow, good job! I'm thinking of making a META42 my second DIY project as well. Your craftsmanship will be hard to top, though!

Congrats!

 

[zhtham]

Thanks for all your comments, i really appreciate em'. I've edited original post with a parts lists and a brief review of the amp with my Sony CD3000 Headphone.


Quote:

evilcthul: Manage giving us a bit of a run down about the construction process? The wiring you use seems to be some type of silver wiring. What's the deal with the cable braid to the RCA jacks on the back?

No Problem, i'll try to share some of the tricks that i used to get around/solve the problems I had during the construction:

EFI Noise:
I used 24 Guage white hookup wires from RadioShack, the silver braid you see is a heavy duty shielding braid i got from allelectronics.com (GS-12). I was troubled by the EFI when i turn the volume way up without any input/have the box opened, so i shielded it with this braid and ground the braid. BAM! works like a charm! Total silence when there's no input signal. Actually i tried to wrap all the signal cable with this shielding braid, but after the input was wrapped, the noise went away.

PS Noise:
The PS Jack gave me tons of problem because it wasn't insulated. When hook it up and mount it to the box, the amp gave me this noisy hum! I tried to insulted the drilled hole with super glue, didn't work. Tried to find some isulated washer like the one on the RCA Jack i got from Partsexpress.com, too much trouble. Finally i figure out this great plan

I "Heat-Shrunk" the jack at the thread with a big enough heat shrink tube! and i "Super-Glued" some anti static wrapper i got from the chip package to the nut. Wholla! No more hum!

Drilling holes:
It was really a pain in the A** to drill so many holes on the Hammond enclosure's 3mm thick panels! And i have limited budget, can't go buying all these industrial strenght drill! So,
I got my self a Cordless Dremel Tools Set, Walmart sells it for less than $40.
Before I started drilling, i plot the circles/box on the inner side (remember to mirror the position of the holes) of the panels using pencil and compass. make the outline of the plots a little bigger than the components Outer diameter so that you'll have a guide after you started drilling. Scotch tape another side of the panels to protact em' from accidental scratch.
Find a stable rack that you can used to hold the panel you'll be drilling (I used a small shoe rack). Tape the the panel horizontally with some masking/Scotch tape (they are good because easily removable).
**Warning: always use a safety goggle while drilling**
Make a tiny mark in the center of every circle/box using a nail. This will guide the drill bit so that it won't swing around when you start drilling.
Hold the cordless Dremel vertically above the panel with both hands. Start making a small indent using 7,500 RPM, when you are sure that the drill bit will not run, use 15,000 RPM. After you make a through hole, start grinding the edge with a counter-clockwise motion using the mid lenght of the drill bit (not the tip, or base it's not stable).
Slowdown the griding process when the hole is expanding close to the pencil mark. Try to fit component through the hole and repeat the grinding process if necessary, until it fits. if it's the DC jack you're fitting, remember to take the heat-shrink tube thickness into consideration. For some bigger holes like the Neutrik Locking Jack and the rocker switch, you can use sanding bands & cut-off wheels to speed up the grinding process.

Fitting Knobs to Alps Stepped Attenuator:
I cut off about 5mm of the shaft using Dremels cut-off wheels. And I tape some Aluminum Foil Tape (picture attached) i got from allelectronics.com (ALT-2) to the shaft to increase its diameter. Now the volume knob fit snugly. BTW, this Kilo knob (664-1654) i got from alliedelec.com needs Hex wrench to secure itself on the shaft.

Fitting Neutrik Locking Phone Jack:
Do not drill/plot the 2 holes for the screws until you fit the Jack through the panel. When the jack fits snugly on the panel, rotate it to the angle you want. Then, use a pencil to mark the holes' position. Start drilling, i believe the default diameter make by the drill bit is suffecient for the screws (picture attached).

Fitting LED:
Needs a little bit of grinding on the panel to let the LED fit. Check frequently when diameter of hole is close to the pencil mark. You don't want to hole to be too loose. I painted the edge of the hole black using a marker, originally its silver color. I don't want the LED to stick out from the panel, so i cut a piece of foam from a packaging filling, cut a slit and glue the LED to it. Off course it's easier to use a glue guy and skip the foam thingy. But i don't have a glue gun

Soldering AD8620 to BrownDog Adapter:
Use a double-sided tape to secure the adapters' pin to a plier (you can use anything heavy and stable). I apply a thin layer of solder to the adapters PCB contact points (8 of em'). Use a desoldering braid if it gets too messy. Position the AD8620 on the contact points (remember 1st pin position). Hold the chip down with a scotch tape, do not cover one side of the pins. Use a soldering iron with a fine point to depress one of the corner pins (pin 1,4,5,or 8). When you feel the solder is melting, lift the soldering iron immediately, you don't want to fry the chip with too much heat. Now you can take the scotch tape off, the chip should be holding on the adapter. Match the pin to the contact point on adapter, and continue soldering with another diagonal pin (do pin 1 & 5, or pin 4 & 8 in pairs).

Well, that's about it, I'll update this when it's necessary.

Happy DIYing,
Z.