I recently received some pics from W of a Bad Hombre Mk2 build (12AU7 + ECC99). This one uses Lundahl LL1676 input transformers and LL2765 output transformers, and features a regulated B+ and a loaded front panel of controls. Very nice!
The LL2765 is a fine transformer with ECC99 output tubes in this circuit. It has a 5k primary and multiple output taps for 32, 150, 600 ohm headphones. The 5k primary will result in more power than the 8k in the original design, but it can also be used to reflect a higher impedance depending on what taps and headphone load one chooses (e.g. 300 ohm headphones on the 150 ohm tap for 10k load).
On a side note, I see Lundahl also now has a LL2774 3k primary headphone output transformer (16, 64, 300 ohm secondary taps). This is a very similar turns ratio but it looks like the LL2774 is available with a bigger gap in single-ended configuration for higher current output tubes. Great to see new options for headphone output transformers!
This was a busy week, so all I have to post is a couple of quick pics of people I chatted with at the NAMM show in Anaheim (which I attend for my day job).
Kevin from K&K Audio was hanging out in the Lundahl booth on Saturday morning before the show. We chatted about the state of DIY, local building groups, and the NAMM show. I had never met Kevin before but we had an immediate connection over the DIY hobby. K&K is the USA distributor for Sweden-based Lundahl Transformers. Their C-core construction, multiple winding configurations, and super-detailed datasheets are unique in the tube building hobby. Lundahl products are also sought after for studio and pro line-level applications and microphones (hence the NAMM booth).
I also found a booth for Triad Magnetics at the show this year! This was the first time I’ve seen Triad at NAMM and I had to say hello and thank them for manufacturing such affordable and easy to source power supply chokes (which I use in almost everything I build). The Triad team said the show was going well and that they’d probably be back next year.
I had a whirlwind NAMM schedule this year and didn’t get to spend any real time at tube booths like JJ Electronics or Electro Harmonix. I did take some time to get scanned for CIEMs at Ultimate Ears, though. There may be a portable amp project somewhere in the future…