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The Christiansen "DG" 300B Amplifier Build Thread - Page 2

post #16 of 631
Thread Starter 

Western Electric 300B 

The one. and only, $1,000 a pair.

Grail extra.

Thanks Fearless1

 

I have most of the 1/4 watt resisters populated.  I found an ordering error.  I ordered a 200R instead of a 220R.

At least I caught it.  This is not a cheap project, I hope it sounds like A Damn Good AMP when it's done.

 

 

post #17 of 631
Quote:
Originally Posted by sceleratus View Post

Western Electric 300B 

The one. and only, $1,000 a pair.

Grail extra.

Thanks Fearless1

 

 

I would guess that the Full Music 300B is a decent tube as well, I like the tone of the their tubes and they are about 800 dollars cheaper then the Western Electric. (sorry to disrupt this thread, I find it fascinating!)

post #18 of 631
Thread Starter 
Quote:
Originally Posted by Fearless1 View Post

 

I would guess that the Full Music 300B is a decent tube as well, I like the tone of the their tubes and they are about 800 dollars cheaper then the Western Electric. (sorry to disrupt this thread, I find it fascinating!)

No disruption at all.

 

I want to get all the 300B and 6N6P input I can get before I start ordering.

 

Any other input or suggestions are welcome.

post #19 of 631
Thread Starter 

The driver board assembly progressed nicely.  I had to stop soldering until the correct R23 and R3 resistors arrive.  If I go further, I won’t be able to get to them.

 

I also ordered the heat sink assembly kit for the MOSFETS.  You can see below that the heat sinks are attached but the MOSFETS are not soldered in.  When the kit arrives, I will attach the MOSFET to the heat sink and solder it to the board at the correct height.

 

The mounting kit contains a shoulder washer, screw, nut, and a Mica insulating pad.

 

I had a couple challenges today.  I put the 100K trimmer pots on the wrong side of the board.  I discovered this while searching for the U1 and U2 pads. I discovered both components go on the bottom of the board.  Tom neglected to put that detail in the instructions.

 

The reason is simple.  The back side of the board faces up.  This is the side with the valve sockets.  One will want access to the trimmers for biasing.

 

The problem was easily corrected by my solder sucker.

 

 

 

post #20 of 631
Thread Starter 

Worked on a rough panel layout.  I do not have the dimensions for the output transformers because, according to Jack at Electra-Print, all the housings are custom built to the transformer specs. Wow. Thus I used the ClassicTone specifications for the output transformers.  FYI: Jack said he could wind them with silver wire but it would be about $900 for each transformer.  Wow2

 

When I have all the correct specifications / dimensions, I will update the layout and print an actual size print with hole centers. I will glue it to the sheet metal and take it to the drill press and see how accurate I can get it.  I am going to experiment with nickel-plating for the final finish.  I'll try a few small items first.

 

 

 

 

 

 


Edited by sceleratus - 5/26/13 at 5:53pm
post #21 of 631

This thread will be the rebirth of DIY on head fi!

post #22 of 631
Thread Starter 
Quote:
Originally Posted by PinkLed View Post

This thread will be the rebirth of DIY on head fi!

gosh.

 

Just added the DYI Nickel Plating video.

post #23 of 631
Thread Starter 

This is Jack from Electra-Fidelity.

Besides making transformers, he also make $150,000 amps.

He has  Littler ones too.

 

 

EDIT:

 

Here's a handy tip from Jack emailed me:

 

..... Also, do you know about keeping the power trans and outputs out of coupling?

Keep both outputs as far as you can from the power trans and the power trans
should be 90 degrees, exactly in core mass centers of all transformers. Like
a "T", top is one core, vertical line is other core.  If you do not do this,
there will be an induced hum from the power to both output primaries, you
will never get rid of it.

 

I did not know that.


Edited by sceleratus - 5/26/13 at 7:52pm
post #24 of 631
Thread Starter 

I'm working on the Power Board today and I thought I take a couple of annotated photos to show diode and capacitor placement on the PCB.

 

If you've built boards before ignore this post....

However, if you do have any suggestions, (other than give up, it's going to be a moulton mound of smoldering rubble),  Please post them.

 

Capacitors and Diodes:

 

 

 

post #25 of 631
Thread Starter 

Well they arrived.

 

Power Transformer: 14 pounds

Output Transformers: 9 pounds each

 

Lyr: 7 pounds

 

I hope sound is by the pound smile.gif

 

 

post #26 of 631

So much for the "portable" option! biggrin.gif

 

Cheers!beerchug.gif

-HK sends

post #27 of 631
Thread Starter 
Quote:
Originally Posted by HK_sends View Post

So much for the "portable" option! biggrin.gif

 

Cheers!beerchug.gif

-HK sends

It'll be a manly-man headphone amp.

Not of that dainty IEM cr..

post #28 of 631
Thread Starter 

All components have been soldered to the boards with the exception of 3 bridge rectifiers on the PSU Board.  I need to fabricate a heat sink before they can be soldered on.  I have to drill and tap the heat sink for the Maida regulator too.

 

I have all the other components with the exception of the Volume POT (ordered) and the 300B and 6N6P valves (not ordered).  I’ve been holding off ordering them, but I guess it’s time.

 

The next step is to lay everything out on a piece of plywood, wire it up and listen for pleasant music.  If it passes that test I will work on fabricating the panel and enclosure.

 

I would estimate a week until Alpha Testing.

 

Driver Board:

 

 

Driver Board Valve BIAS pots

Holes for 300B sockets

9 pin cluster each side of trim pots for 6N6P sockets.

 

 

 

 

 

PSU Board:

 

 

 

Maida High Voltage Regulator:

 

 

 

5V and 6.3V Filament Regulator:

 

 

post #29 of 631
Thread Starter 

This is the new panel layout with the in-line transformer configuration.  Panel dimensions are 19” wide 15.75” deep.  The boards are suspended below the panel by stand-off’s.

 

 

post #30 of 631

It looks to be shaping up nicely!

 

popcorn.gif

 

Cheers!beerchug.gif

-HK sends

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