Welcome to my 5th Darling amp. This series of amps have all been a great pleasure to build and listen to. Something about a Darling just sounds right. I've built others using more high-end output trannys, and they sounded great, but there is something charming about what this humble configuration can do with a pair of old console trannys that keeps me coming back to the basics (and avoiding spending $100's on new output trannys). The trannys in this case pulls I bought on eBay. They were not the prettiest looking trannys around, so I encased them with a cover. I'll be using the encasement style to rescue some other very good trannys that deserve to be built, and I would appreciate feedback on this style.

This particular amp premiered at the GPAF this May, 2006. It didn't get a lot of use since I had my Loftin-White version there as well as my 1625SE amp, but was well received when playing. We ran this specifically on the FB-16's from Bob and it was a good matchup.

See here for the original Darling concept and more than you ever want to know about these amps.
Be sure to check out the Darling Club.

This particular Darling uses the 5965 as the input/driver tube. Also, I have learned through my experience with these amps, that separating the bias on the input tube cathodes sounds better than using a shared bias resistor. However, the output section retains the classic shared bias resistor. This Darling uses a 5Y3 rectifer. The power tranny is a pull from a Roberts tube reel to reel. This worked perfectly, since the tranny had two 6.3V windings to combine to net the 12.6V for the 1626 heaters. However, I did add a 5V tranny for the rectifier.

The choke based power supply is very low noise, and the power for the 5965 is further CRC filtered for additional reduced noise. The result is a very low noise amplifier.

The actual circuit is classic Darling, with a cap-coupling to the grid of the 1626. The picture shows oil caps in this position, but I changed these to a film cap as these particular oils sounded a bit dull.

I used my standard ground-bus type layout following the traditional RCA style of grounding as seen in their amps. The main ground starts at a tranny lug where the CT of the power tranny and first filter cap are all connected. The ground is then run through the amp in such a way that all higher currents are nearest the power supply, with gradually lesser current all the way back to the input jacks which are also grounded to the chassis. The 1626 heaters are biased referencing their cathode, which puts the 5965 heater about 25V above ground. This seemed to work the best in this amp, although I've had some that worked better with the CT on the heater supply simply grounded. The summation of everything makes a clean, quiet amplifier suitable for the efficient speakers it will be used with.

As for all my amps, we (Deborah & I) listen to a huge variety of music to make sure we got it right. All adjustments are made before cutting any metal. Our tastes run from hits of the 50's and 60's right on up thru rap (that's me on the rap). We're both into 70's and 80's rock and we have a mutual interest in Native American and World music as well. I'm into some Jazz and claissical so the amp receives a wide range of music to evaluate. Here's what I say about this Darling, and about all the Darlings of this series: The typical slightly warm and very detailed Darling sound comes through. The output trannys on this one sound very detailed in the mid and upper registers and a bit less warm than most of this type. So bass detail is perhaps a bit cleaner, especially the upper bass area. Male vocals sound natural, and female vocals are clean and without s-s-s-sibilance. The amp is very sweet, non-fatiging and toe-tapping listenable.

I keep telling myself I will build one of these for us to keep, but the only place I can use it is in my shop where I have 94db speakers. In the shop I would prefer an enclosed case to protect the amp from flying bits of wire ends from my busy amp building! In the livingroom system, we need more power to drive our 12" full-range single driver system than a 1W amp can provide (sigh).