DIY JE Labs Darling 1626 Build

Do It Yourself
Went to the lumber store yesterday and picked up a board for the base.

I went in intent on getting a piece of Goncalo Alves but they didn’t have anything in anywhere near the size (thickness)I wanted.

Thought about Padauk as it was on sale, but again nothing in the right size.

Then, near the cutoff pile was a stack of Sapele 6/4 on deep discount. Most of it looked ok but not very exciting grain patterns...till I found this one!


E4B503EB-3898-4F5C-BADC-731525615C6D.jpeg250A49F1-379D-4426-A892-4C4EF1F88262.jpeg
 
Looking really nice! Good find on the aluminum plate. I'll have to check that out.
 
One of my favorites! I'm fortunate enough to own a very rare, and unique antique talking machine which was constructed using a beautiful Sapele veneer. The cabinet was manufactured for the Edison Phonograph Works in the mid teens of the last century, but sold off when the contracted co. (likely the Jamestown Mantel Co. of Jamestown, NY) was faced with economic troubles when the Edison co. canceled their massive order for their Sheraton "Inlaid" Phonograph model. Someone apparently purchased some of the excess cabinet stock, and outfitted some very few with generic late-teens motors, tonearms and wooden horns.

Only 2 or 3 have been documented.

Sorry for pirating your post, I look forward to seeing your finished amp. 😊
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Probably a silly question, but I’ll ask it anyhow.
I’m going to add a headphone jack, so will need volume control. However, when run as a speaker amplifier, it will be behind a preamp and i’d rather not have the volume control in circuit.

So:

1.Can anyone recommend a good quality headphone jack.

2. Is it possible to put a volume control just ahead of the headphone out, rather than at the input of the circuit? I can’t imagine why not, but figured its worth asking.

3.What is the best value for a the volume control if used only for headphones; 100k, 50k,etc? Recommendations welcome here as well.
 
MikeyFresh said:
For chassis mount Neutrik has a few nice options (black or silver chassis mount, gold or silver plated contacts) assuming you'd want 1/4":

NJ3FP6C-B 1/4in TRS Chassis Mount

View attachment 18310

Switchcraft and maybe Canare among others also make something similar, including non-locking versions.
Click to expand...

Ordered in one of these Neutrik locking 1/4” jacks. Thanks @MikeyFresh for the tip!

I am thinking about a 10k pot for volume control...any problem with putting it right in front of the headphone out rather than at line in?
 
marantzfan said:
Ordered in one of these Neutrik locking 1/4” jacks. Thanks @MikeyFresh for the tip!

I am thinking about a 10k pot for volume control...any problem with putting it right in front of the headphone out rather than at line in?
Click to expand...

Fwiw i wouldnt use the locking one, once i pulled a whole amp off its shelf when answering tbe phone when i was a bit hungover, the lock is quite secure!

I now use a 4pin xlr connector and have my headphones terminated that way, i think it sounds better too.
 
marantzfan said:
2. Is it possible to put a volume control just ahead of the headphone out, rather than at the input of the circuit? I can’t imagine why not, but figured its worth asking.
Click to expand...
This will create a ton of problems. You'll either have variable output impedance because the pot value is too high, or you could go really low and end up loading down the amp a bunch. A pot is not what you want, you'll want a proper L-pad to avoid all these issues.
marantzfan said:
3.What is the best value for a the volume control if used only for headphones; 100k, 50k,etc? Recommendations welcome here as well.
Click to expand...
An 8 ohm L-pad!
 
Anthony, I suppose you could put your volume control on the input end and add a switch to bypass the thing when you wanted to.
 
paulbottlehead said:
This will create a ton of problems. You'll either have variable output impedance because the pot value is too high, or you could go really low and end up loading down the amp a bunch. A pot is not what you want, you'll want a proper L-pad to avoid all these issues.

An 8 ohm L-pad!
Click to expand...

Any old 8 ohm L-Pad will do or is there one you'd recommend?
 
Those are autoformers, which can replace an L-pad, but is functionally a bit different. I wouldn't recommend them in this particular application, as extra measures will have to be taken to switch them out when they aren't in use.
 
I'm also starting a 1626 Darling build (using the ubiquitous Sony iron), although I'm going to use a 6SF5 instead of 6F5 as I'm not a big fan of the top grid connection. I've got some motor-run caps for the PSU, and some K40Y-9 (or K75 - haven't decided yet) for coupling caps. I'll fire up a build thread once I get started in earnest.
 
Got the iron (actually ended up with a complete second set thanks to a generous donation from @electrovice) - now to figure out the chassis layout.

This is the layout I'm tentatively going with (still need to CAD - e.g. Cardboard Aided Design - the layout to ensure there's sufficient spacing between components) - dimensions are 12.25" x 9" on a 2mm thick aluminum plate:

1582910482066.png

Upper left corner is 6CA4 and 20uF oil cap. PT in the center. 40uF and 20uF oil caps in the upper right corner. 156R choke in front (below deck) of the PT. Output transformers underneath the deck and rotated 90 degrees (and offset) from the choke. RCAs are placed next to the 6SF5 driver tubes in the interests of low noise.

The top plate will be dadoed into the wooden base via a 0.25" deep slot (so once it is in, it's in). Power inlet and binding posts will be on a sub-panel rabbeted and screwed into the back of the base. Bottom panel will be rabbeted and screwed into the bottom of the base.

Also, I'll finally be able to use some of those nifty EF Johnson octal tubes that @Redboy turned me on to (thanks, Nate!).

(if anyone wants the .FPD files once I've verified the layout, send me your email address in PM and I'll fire 'em off to you)
 
paulbottlehead said:
IMO, you're a little on the big side for 2mm AL. I would step up to 3mm/0.125".
Click to expand...
Good point. Plus that'll make it easier to cut the dado as 3mm (0.118") is much closer to 1/8" (0.125") so there will be less slop.

Thanks, Paul!
 
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I guess I join in ..... I almost finish with the darling amp but the B+ Don’t match ...Waiting on some resistor
 

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