DIY JE Labs Darling 1626 Build

Do It Yourself
I have parts for but not sure if its worth it as my speakers are 16 ohm and the sony output transformers are 8 ohm

I did think about using the 600 ohm tap for headphones but my headphones are 32 ohm so not sure that woukd work out that well either.
IMG_20200229_113529.jpg
 
I have parts for but not sure if its worth it as my speakers are 16 ohm and the sony output transformers are 8 ohm
If your speakers are 16 ohms and sensitive, then it could work. I would estimate that you'd need 16 ohm 98+dB sensitive speakers for it to make much sense.
I did think about using the 600 ohm tap for headphones but my headphones are 32 ohm so not sure that woukd work out that well either.
If the output transformer has a 600 ohm tap and an 8 ohm tap, then I might go looking for a different transformer for a Darling project. If you use the 8 ohm tap, there will be tons of copper on the secondary that's unused, and in my experience this will seriously degrade the performance of the transformer. The 8 ohm tap on 32 ohm headphones will have plenty of power for most headphones. 750mW into 8 ohms is about 2.5V RMS, and 2.5V RMS into 32 ohms is 180mW. That's a lot of power for what is likely a very sensitive headphone.
 
You can also try shrinking the first power supply cap to tune the voltage a bit lower. You may need to add some capacitance to the second power supply cap to keep the noise floor low.
 
Are you using the 110V or 121V primary tap?

Sorry all

my B+ Is 182 vdc not 380 vdc

using blue wire 121V primar tap

I think my B+ is low Because of the choke I used

My B+ to 1626 plate was 182 vdc if i use 1.5k resistor before the choke, I try with Couple different resistor and 400 ohm will give me 250 vdc
(waiting for a 400 ohm resistor)
 
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 3mm thick aluminum plate:

View attachment 20455

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)

Cardboard Aided Design checked out (choke and outputs will be below decks) , so now to order the panels. Given we're ground zero in the COVID-19 outbreak in the USA, I figure I'll have lots of 'at home' time in the next few weeks.

20200302_001220195_iOS.jpg

-D
 
Cardboard Aided Design checked out (choke and outputs will be below decks) , so now to order the panels. Given we're ground zero in the COVID-19 outbreak in the USA, I figure I'll have lots of 'at home' time in the next few weeks.

View attachment 20544

-D

Very nice and compact layout, thankfully there aren't many components in the circuit. You're in for a treat, I love my Darling's.

Cheers,
Gable
 
Panels came back - a few minor hiccups as I was a bit too tight in the tolerances for the capacitors and forgot to account for the 0.1mm variance in the hole sizing. Thankfully a bit of judicious sanding using small cylinders and I got the holes sized correctly. I was also a tad too tight in the sizes for the octal holes as I didn't realize that the 6SF5 tubes have a wafer bottom and therefore a flange. In this case, I decided to sand the wafers flush with the metal on the tubes.

Here's the top with the sockets, caps, RCAs, and iron laid out:

20200306_024130878_iOS.jpg

Waiting on a Mouser order before I can start mucking about with wiring up the circuit. I'll also need to do the base so I have a way of mounting the back plate and wiring up the AC inlet module and binding posts.

BTW - to mount the oil caps, I tried something different. I have some Q-GLUE which is used as a high strength metal adhesive for railing systems. The instructions indicated it *should* work on aluminum, so I'm giving it a shot. If it doesn't work, I'll have a bit of a mess to clean up before I try something more traditional. If it *does* work, then that's less drilling / bracketing I'll have to do when everything is said and done.

-D
 
I've got to travel this weekend, so I may not get around to wiring up until next week. Hopefully no surprises in store...
 
Some additional progress:

49653025918_0d81149a94_b.jpg
 
Looks like progress to me.
Very nice.
Thank you - I'm waiting for some 270k KOA-Speer resistors which are coming from Canada (Mouser was out), so I'm stuck. Also, I need to build a chassis, but we're sorta in a quarantine lockdown in the state of Washington right now, so I'm not sure I'll be getting over to my brother-in-law's house (he's the finish carpenter / cabinetmaker in the family) any time soon. :(
 
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