CanJam SoCal 2015 Member Table Frank Cooter

When Warren Chi said there would be a curated member display at CanJam SoCal 2015, my instant response was, "Will Frank Cooter be there?" Yes, he's that amazing.

This year Frank's creation is a rare re-creation of an amp he created last year. Commissioned by Jude Mansilla, founder of, this amp is designed to mate the current top-of-the-line Stax SR-009 with the classic sound of direct heated triode (DHT) tubes to produce a somewhat meatier sound than usual from these fine headphones.


The power supply chassis incorporates five regulated power supplies: 700 Volt; 400 Volt; -125 Volt bias supply; and two separate filament supplies, one for the main 845 tube and one for the remaining tubes.


The main amp chassis holds a three-stage, single-ended, DHT tube amp. Input stage uses a type 76 triode tube with a constant current load on the plate directly connected to 6V6 tubes prior to the interstage transformers. The main power output tubes are DHT 845 tubes that drive the custom Electraprint output transformers, which split the signal into the high voltage balanced signals needed to driver the stators of the Stax SR-009.

I had a nice listen and, boy, this amp does provide a tasty grunt for the SR-009. Jude has a little slice of heaven coming his way!

Now, I said above that this amp is rare because Frank has a practice of only building one version of each amps he creates, usually timed to be ready for a big California meet. He always has a theme or particular goal in mind as he makes his amps, and his interaction with folks at the meet is a measure of how well he has succeeded in meeting his goals. The amps are always stunningly beautiful. Frank says the woodworking and electrical design aspects of his hobby share equal importance and satisfaction for him.


Some of Franks previous creations. (Apologies for not getting permissions for photo use. Very constrained on time with these posts, and thought it important for folks to be able to see a few previous amps.)

And then, when the meet is over and Frank has received his feedback and had a good time with folks, he disassembles the amp, re-stocks the parts, and starts all over again. It reminds me of the Buddhist monks that make the sand mandalas and then destroy them when the ritual is over.


Frank is not a prolific poster on Head-Fi, but he does maintain ongoing relationships with members that share his interests and says a lot of his on-line activity is by PM as he gives and gets advice in his area of interest.

He's an absolute treat to have in the community and a pleasure to chat with as you'll see in the video.

Click here if you can't see the video.

sfoclt's picture

Truly works of art. Those are gorgeous.

Jazz Casual's picture

Very nice work Frank. I make card tables from matchsticks so I appreciate the craftsmanship involved. I trust that you cleared the choice of shirt with Tyll before the interview. ;)

Mrip541's picture

I've always wondered about those shirts...

DC2Light's picture

He does look a little like Capt. Kangaroo in the opening headshot. You don't even need to squint your eyes because the Focal Pro's I'm wearing are doing it for me. So, maybe he doesn't look like him?

Three Toes of Fury's picture

Photo's from Franks table have been a highlight of the head-fi updates on the show. Thanks Tyll for providing more information and that great interview video.

Im flabbergasted at the thought that Frank disassembles his stuff after showing it off!?! It makes me appreciate his artwork (which these are...they are works of art) even more.

Thanks Frank for sharing your creations with the audio community..great great stuff!

Peace .n. Living in Stereo


n_maher's picture
I've had the great pleasure of both meeting Frank face to face and enjoying some of his creations. They are, as others have said, true works of art. His attention to detail couple with amazing craftsmanship is something that is rare to come across in any walk of left, let alone our little DIY hobby. He's an inspiration to many of us. Thanks for taking the time to interview and write about him, Tyll.
dsound's picture

I'd just like to add to the chorus here that Frank is a fantastic member of the HF community. He is generous (and patient) in explaining the design of his amps. He also (unsolicited) offered assistance to me should I ever want to scratch-build an amp of my own.

eggil's picture

He is not only the best in DIY, but also the nicest guy.
I have had the pleasure of listening to his creations dating back several meets. True works of art and sound.
Thank You Frank!