Audio Note Amplifier Kits

@charles1dad - Thanks Charles. I used the AN non-magnetic Silver Tantalums for all the parts in the audio path. These are the white-colored ones in the photo above.  

I built a pair of 300B monoblocks starting with the ANK kit but I made a lot of "upgrades" to the design. I am very pleased with the results. I like them better than my Pass XA60.8s. I built my own enclosures to allow more room for the changes I wanted to make and to move all the connections to the rear. You can see them on my virtual system page.  

@charles1dad - When I first finished the ANK amps, I was using GR-Research NX-Oticas. These cross over to powered subs at around 70Hz. The 300B amps provided a bit more depth and width to the sound stage, a more natural decay, and a smoother midrange. Since I'm not using the amps for the lowest couple octaves, I can't really comment on the deep bass performance differences.

My new speakers (based on the GR-Research Line Force) cross over an octave or so higher (around 170Hz) and are more efficient (98db/w vs 93). With these speakers, the 300B amps are an even better match. The midrange, particularly vocals, sound exquisite. 

I started with ANK's top amplifier model - C-Core Interstage parallel 300B SET monoblocks. As I mentioned, I made a lot of upgrades including high-impedance current-mode heater supplies for the 300Bs, regulated DC heater supply for the driver tube, Maida regulator on the driver stage, Audio Note silver tantalums for all resistors, upgraded wiring and connectors, and a couple minor circuit changes. And a much beefier, aluminum chassis. Also upgraded to Western Electric (new issue) 300B tubes. 

@johnah5 - I've heard some Audio Note amps at audio shows, but not in my system. I think the kits deliver similar performance to the lower-end AN commercial units, but none of the kits (that I'm aware of) have the silver wire transformers and the highest quality resistors and caps that AN's top models have. Still, they are a good bargain and are amenable to upgrades to deliver even higher performance. 

@vinylvalet ​​@charles1dad - Thanks for the compliments. 

If anyone is interested, I created a build thread on the SH forums. 

https://forums.stevehoffman.tv/threads/ank-300b-interstage-monoblocks.1112018/#post-27958720

@changeout - I bought the upgraded resistors/caps and the TentLabs DHT filament supplies from HiFiCollective.com.

The Jensen line input transformers came from PartsExpress.com.

I built the heater supply for the input tube using a pmillet PCB I bought on ebay with parts from Mouser.

The Maida regulator for the input stage, as well as the soft-start controller came from Neurochrome. Parts for the Maida regulator came from Mouser, although Neurochrome now sells assembled boards.

The delayed start output relay PCB was purchased from the DIYAudioStore.com site, with parts from Mouser.

I used hookup wire from DHLabs.com (solid silver for audio signals, silver plated copper for power signals, all using PTFE insulation).

The connectors were purchased from various places including PartsConnexion and Amazon.

The enclosure panels were purchased from FrontPanelExpress.com, and were all designed using their free software.

Here's a photo of the inside of one of the two amps. 

@larryi - thanks for the compliments. I imagine those AN silver transformers are pretty amazing. One of these days, I'd like to try to build an amp with silver OPTs. There are a few companies that will make them with silver wire, although they get pretty pricey. 

@johnah5 - I own a lot of bikes (I own an e-commerce cycling business), but the one in the photo is one of my oldest - a Serotta ti with S&S couplers, SRAM red etap. This is the one I usually take to Europe since it fits in a small 24"x24"x10" case so it's easy to travel with. 

Audigon seems to have a lot of bugs with their website. Here's a direct link to my system page - jaytor's system. You can try in incognito mode if a direct click doesn't work. It works fine for me, but I've run into lots of quirky problems on this site.

I don't have any experience with the Bottlehead kits, but they look pretty nice and I've heard a lot of good feedback on them. 

I'm in Portland, OR, so a long way from Indy. But if you ever get out to Portland, I'm always happy to show off my system 😁

Nice bikes. IF makes an excellent steel frame. I don't own any steel frame bikes at the moment - mostly high-end carbon road race bikes and a couple gravel bikes. I've got to pare down my stable at some point. 

Here's a decent book to start with. It introduces basic electronics concepts before going into vacuum tube amp info. 

Vacuum Tube Amplifier Basics by EJ Jurich

A more advanced book that covers vacuum tube amps in much greater detail is

Valve Amplifiers by Morgan Jones

This one requires a bit more basic electronics understanding though, and has a lot more detail than you will probably ever need. It's also several times the price of the first one I listed.