diytube.com

After over a month it's finally done and the sound is very impressive! I can't belive it's only .75 watt.

Most time was spent stripping the plating off the chassis, it was then shot with a coat of etching primer, then black Hammertone paint.

The build is mostly stock except the tube rectifier, a 6X5W. All tubes are military surplus, 1626's are dated Nov 1942, the 12SL7 is a NU dated June 1944. Transformers are Edcor XPWR 177-0/120/220 and GSXE10-8-5K.

Actually the 12SL7 box says:
US ARMY--US NAVY
TUBE JAN CNU 12SL7GT
VT-289
CONTRACT NXSA 40001
WESTERN ELECTRIC COMPANY
ACCEPTED JUNE, 1944

I paid $5.50 each from AES and someone on e-pay has a pair listed for $199.99!

That looks great Terry. Looks like the perfect size for a Darling.

... tom

It's been playing for around 25hrs now and sounds really great! I've tried all types of music through it, from Classic rock to Jazz, Classical, pipe organ, etc and handles it all really well!

I guess my biggest question is how long will the 6X5 last? It doesn't get very hot and neither of the other tubes.

Hmmm ... 10 years? Hit me up if you need one, I have a lot of
NOS 6X5's ...

You can't beat the simplicity of the Darling and the sound amazes
you when you think about the low power.

... tom

In a 1626 Darling, the 6X5 will probably outlast the other three tubes

I just snagged eight NOS, NISMB (New in Slightly Moldy Boxes) Sylvania JAN-12SL7s off the e-place, as well as two groups of five 12V6GTs. Time for a "slightly plump" Clementine, not too chubby, and not so slim, either I'll run it with 12VDC on the filaments. I'll try it triode-strapped , UL, and pentode modes, and decide which sounds best for me Appx 325VDC B+, TBD

Something like this:



A little jump in time:


viewtopic.php?f=19&t=5496&p=45509#p45509



/ed B

Anyone notice Terry painted his car Edcor blue?

Cheers!

and did you notice he's feeding a car radio into the new Darling
(subject of another thread)

I have a slight problem, there's a hum in the speakers. Haven't noticed the hum before because it is mainly hooked to my computer an a set of Bose subwoofer / satellite speakers. Going through normal troubleshooting I ended up pulling all tubes and the hum is still there, so it must be a magnetically coupled somehow.

The power transformer has a 220-120-0 primary so the 220v tap is not connected to anything, should it be referenced to the "0" tap somehow? Could it be the source of the hum? The PT barely gets warm and all voltages are spot on.

While fiddling with the hum problem I decided to try 6V6's. What I did was remove the remove the R26 jumper (very handy!) to isolate the filament doubler, moved the filament leads to the other connector, added the 1k ref resistors and changed the bias resistor to 430 ohms. For feedback I threw in a 470k plate to plate resistor between the 6V6 and 6SL7. 6V6's are UL connected. Still sounds really good just noticeably more power!

TerrySmith wrote:Going through normal troubleshooting I ended up pulling all tubes and the hum is still there, so it must be a magnetically coupled somehow.

Interesting, Terry. I'd go ahead and connect the OPT secondary grounds back to the PCB GND eyelet with a couple wires. I can't tell from your drawing, but also run a wire from the PCB GND eyelet to the chassis where the safety ground connects.

Shannon

I just looked at the pictures of the amps I've built, and except for the ST-35's ... all of the transformers are oriented the opposite of yours ... end bells of the output transformers pointing forward and PT side to side. Too much hassle to flip them now of course.

How loud is the hummmm ?

my stuff at http://tmamps.com

I ran the gnd wires and no change. The hum is not loud but audible across the room.

The reason the transformers are mounted this way is because they would not fit the chassis the other way.

Well I ended up replacing the power transformer and the hum is gone! The replacement is a Hammond 270DX. This was chosen because it would drop right in without butchering up the chassis.

I've been rolling several tubes such as various 6V6's, NOS CRC 6L6 metal, 6P3S, and a pair of Mazda 6P25 tubes I got from a junked British radio. I'm getting around 310v B+ with the 5V4G pictured.

What chassis do you have there, Terry? That's actually a small footprint.

Looks great - glad you fixed the hum.

Shannon

That is a blank MK-3 chassis from Soundtastick, found it on ebay several years ago. It measured 9" x 9" x 1.75" and fits the Clementine perfectly. The reason it's painted is the chrome plating peeled, so I stripped and painted it with Hammertone.

This is my daily setup for my computer, A Clementine driven by a 12 volt Aikido.