"Darling"
and "DC Darling" SE 1626 Triode Amplifiers
Latest Update – 2/6/07
Brief History of the SE 1626 “Darling”
Amplifier
When I built my first 1626 amplifier in 1997 it was started as a humble
experiment. I had no idea it was going to sound so good!!!
Because it was small and cute and looked like a miniature version of a 300B amp
- one listener described it as just a “darling” little amp.
The name stuck...
10 years later I am still amazed by the sound, and by this amplifiers
popularity with tube-experimenters around the world .
For some folks their first introduction to this amp was via an article I
wrote for Sound Practices magazine.
This article is available here: Hello Darling
Later, I took some of my “Darling” variants to nyNoise 1999 show.
A brief review of the "Darling" amplifiers, was published in the June
1999 issue of Stereophile Magazine as
part
of their coverage of the New York
noise, Audio Design Exhibition.
This led to another meeting at the NJ Audio Society where a whole slew of
“Darling” Variants were auditioned.
My pal Jeremy Epstein (a.k.a. TUBEGEEK) was one of the stars of that show. He
wrote this article on the “Darling-fest”.
Over the years, I’ve built a whole bunch of amplifiers. But I keep
coming back to the 1626 for it’s sheer charm and “fun-factor”.
Below is a sampling of the Darling variant that I have built.
The Original Darling: (updated
9/2/99)
When I built the original "Darling" amplifier in September of
1997 I was so suprised and intrigued by the results,
that I eventually wrote an article on it
which appeared in Sound
Practices Magazine , issue #15.
here's a photo of the original amp:
Here is the complete schematic for this amp:
This amp now resides in my living room system. My wife and kids listen to
it every day.
The nyNoise Darlings: (updated
9/2/99)
Since then, I've built quite a few "Darling" amplifiers for
family, friends, and even a few "real-paying-type-customers" !!!
Just recently I had the opportunity to show off some of these amps at the nyNoise audio design
exhibition.
It was a fun time. See the write-up in Stereophile magazine, June 1999.
Here are pictures of the amps I took to NY noise:
Cap
Coupled Darling Twins Original
DC Darling
> 
Photo by Steve
Rochlin
Here's the schematic for the latest version of the Darling amp (cap
coupled):
Here's the power supply schematic the cap coupled Darling amp, above:
The DC Darling: (updated 9/2/99)
Also at the nyNoise show
I tried out a new variation on the "Darling" theme.
This one was an all DC coupled version which I cleverly called the "DC
Darling" (no reference to Monica L., here).
Here's the schematic for the DC Darling amp:
Here's the power supply schematic for the DC Darling amp, above:
I recently updated the schematic for the DC Darling, above, due to a
problem caught by my friend L.D. Moore (see his DC Darling here.)
I included a voltage divider hanging off the common 1626 cathode resistor. This
is used to bias the 1626 and 8532 heater supply to approximately +75V.
This is done to keep within the heater-cathode voltage ratings of both tubes.
Note: This would not be necessary if a separate heater supply was used for the
8532 ans 1626 tubes.
In this case, the 1626 heater supply should be connected to the 1626 cathodes.
(Thanks again, L.D.!!!)
Other Darling 1626 Designs (9/2/99)
I have been pretty busy with other things this past summer. But I did
manage to throw together a couple new variants of the Darling amp.
See Below:
This one I call the
"Sakuma Darling". Schematic Below:
This amp follows the philosophy of it's namesake: like-drive-like. (e.g.,
Sakuma-san would drive a 211 with another 211).
In my case, I'm using a 1626 to drive a 1626 through an Interstage Transformer
(IT). This unit is a 10K:10K
interstage from Allied Electronics.
I'm also using a 10K:90K (1:3 step-up)transformer as an input transformer. This
transformer is available from Antique Electronics Supply.
Read more about it in the “Darling-fest”
article by Jeremy Epstein.
The next one I call the "Darling
3.5". Schematic Below:
The 3.5 designation represents the fact that it uses (3) 8532 driver tubes
and (5) 1626 output tubes in parallel - per channel.
Cleverly enough, the power output is just about 3.5W...
This was simply an excercise in Brute Force and excess. I am perfectly
happy with single 1626 output stages.
But at nyNoise, it was clear that just a little more power was needed to fill
the large hall.
Both Jeremy Epstein and I have done Double Darlings . But I decided to try for 2A3 power
levels.
Here is the power supply for the Darling 3.5
As you can see, I simply paralleled 3 power transformers to get the
required juice.
These are the same transformers I used in early versions of the Darling.
At 35VA, two would have been adequate. But that would have blown the 3.5 motif.
I Also used 3 of the “nyNoise” Darling caps in parallel. If all goes as expected, I should get
the same "Darling" sound, but at a higher power level.
The filament transformer is actually a 25.2VCT / 2A unit. I had to perform
minor surgery to disconnect the center-tap connections. I then wired the coils
in parallel (observing polarity) to create a 12.6VAC / 4A tranny...
Read more about the D3.5, including listening impresions, in the “Darling-fest” article by Jeremy
Epstein.
The “James” DC Darling: (updated
11/22/06)
I have had such good luck with “James” brand Output transformers
on some of my bigger projects, I decided to try them in a Darling 1626 amp.
I also used their “matching” power transformer. All potted style
transformers give the amp a very distinguished look!
Best of all, the prices are very reasonable. I buy mine from Euphonia Audio.
Here's the schematic for the James DC Darling amp:
Here's the schematic for the Power supply for the James DC Darling amp:
Here are some pictures of a similar James DC DOUBLE Darling amp:
10/14/05
Here's the schematic for the James DC DOUBLE Darling amp:
This Amp was originally built using the same power supply as the DC
(Single) Darling, above.
Unfortunately, this appeared to be just a little too much current draw for this
power supply, as the voltage began to drop a little more
than I would have liked.
In retrospect, the James 930 power transformer data
sheet was very clear on this voltage performance.
The Dueling Darling 2 Channel SE 1626 Guitar amp: (updated 01/03/07)
Well… It was just a matter of time before I came around to building a
GUITAR amp with 1626s. ;)
Actually, it was my (twin) brother Rich’s idea to make a two-channel amp
– so we can practice/jam together.
I carried over all of the typical “Darling” themes, including
common supply for all stages, sharing the cathode resistors, etc.
As much as I would have loved to use 8532s in the input stage, I would have
needed to use two per channel to get the required gain.
I chose another old-stand-by tube, the 5695, since it has been employed in
other “Darling” variants out on the web.
Plus, I can then experiment with the more guitar-friendly 12AX7, 12AY7, etc.,
since they all share the same pin-out with the 5695.
The power supply is identical to the “Original” Darling, at the top
of this page.
Output transformers are 5k:8ohm units, originally designed for SE 6V6 guitar
amps like a Fender Champ.
(To that end, I have it wired with a B+ supply to pin 4 of each output tube
socket so I can retrofit 12V6 beam power tubes for more power.)
Note that the Left input is referred to as the “Stingy”
input.
It is wired so that when the Right input is not used the Left input is routed
to both channels.
Pictures below of the prototype. Note that I like to put the chassis on the
bottom of the cabinet.
Here's the schematic for the Dueling Darling SE 1626 Guitar amp:
Other Fans of the 1626: (updated 9/2/99)
Just to prove that I'm not the only fan of this tube, my friend Jeremy Epstein also built a few different versions of
the "Darling" amplifier.
Read all about them, here. Includes schematics.
L.D. Moore is now a member of the
"Darling" amp club.
L.D. recently finished a DC Coupled Darling. Click here.
A couple of photos, included.
New 8/31/99: L.D. sent me a photo of his latest "Darlings". See
bottom of his page...
Gary Kaufman is now a member
of the "Darling" amp club.
Gary built a DC
Darling out of an old Heath amp. Click here to
visit Gary's
web-site.
Here are a couple photos:
photo 1
photo 2
Tim Reese is the latest
member of the club.
Click here
to visit Tim's web-site.
There is also another “Darling” FAN CLUB here: click here.
Thanks to Yeo in Malaysia
for setting this up!!!
If you wish to have your "Darling" or variant displayed on this
site, drop me an e-mail: robert.m.danielak@lmco.com
This page, and all contents, are Copyright (C) 2007 by Bob.
D.