P Millet Jonokuchi

So for the last couple of months I've slowly been gathering parts to build Jonokuchi (link to website). From the site: "I wanted this amp to be as easy to build as possible, so a beginner could make it. The name - "Jonokuchi" - refers to the lowest rank of sumo wrestlers in Japan. It can be roughly translated as "just beginning" in English." I planned on paring this with my turntable and phono pre to give the option to listen to speakers.

Jonokuchi is a single ended headphone / flea powered speaker amp based on 13EM7 tubes. Not sure of the amps underlying architecture, maybe SET (single ended triode)? Amp can be built point to point using schematics on Pete's site, or buy buying a PCB from his ebay store with everything all laid out. 2 inputs selections (RCA or 1/8" mini jack), 3 outputs selections (1/4" headphone, 1/8" headphone, speaker) . I also opted for the Front Panel Express case that Pete has already worked out.

I am roughly 80% of the way finished. I have the amp up and running (sounds great), but I need to work on the case a bit. The tube sockets (on back side of PCB) and 1/4" headphone jack didn't quite fit through the holes in the case, so some filing / drilling bigger holes is needed. I currently have super long standoffs which don't allow the front or bottom panels to be attached. This is my first Front Panel Express case, and I ordered the exact same case using same file Pete had. I am probably using slightly different sized parts.

Very quick listening impressions last night / this morning left me pleasantly surprised. I don't know if its the RCA tubes or inherent design, but this is a fun warm sounding amp while still being pretty resolving. Bass wasn't sloppy, mids didn't seem to be recessed, just enough sizzle and top end. Certainly doesn't sound like a beginner amp. I think it may sound better than the BH Crack + SB, but this could be in the eye of the beholder - time will tell. Would be interested in a side by side with BH S.E.X.

As always this project taught me that I have a ways to go in my DIY skills. This project is more complicated than a Bottlehead project as you have to source all the parts from the BOM provided, but as the BOM was created in 2011, many parts are discontinued and substitutions have to be made. Not being able to just copy and paste part numbers into Mouser was actually a learning experience as I had to compare part specs to what was recommended vs. what was available. Edcor transformers took roughly a month to come in, but these made for this amp, not something off the shelf, so lead time is reasonable. They appear to be high quality.

Total cost of the PCB and stock mouser parts is about $100, $30 for RCA tubes, $120 for the transformers shipped, and my big splurge was the case at $230 bringing the total cost to $250 w/o case and just under $500 with FPE case. I really liked the FPE case even though some of the stock holes were a bit small as it lays everything out perfectly. I could see someone being perfectly happy with a $50 hammond case.

Will take more pictures this evening of the PCB mounted to the top panel, all the transformers hooked up, etc.

 

Looking good. The FPE case is nice. Very cleanly milled.

 

I built one of these back when it was released, still use it in my near field speaker setup everyday. Good job on the build.

 

Updated pics. Mostly all together. Still having slight height issues with standoffs and tube sockets - but not a major concern, just need to fuss with it. Probably just need an even bigger hole for the sockets in the top. Also thought I had a volume knob for the pot, but its MIA.

Listening with HD580. The soundstage is great - deep, but not super wide, with good separation. I think this may attribute to the fun feeling I was getting before. Still getting awesome clarity, and I am noticing a punchy low end response. Maybe this is due to good power as it drives (small) speakers as well. Overall I think this will make a great desktop setup.

 

I have built the Millet Butte and that is a really nice sounding solid state amp. I would be interested if you feel this amp is on the same level as the BH Crack. I have been looking for a amp to use with my HD650 which I can DIY for reasonable money's.
I was looking at this one too as it is also a amp/headphone amp: http://audiovideo.fi/opas/putkivahvistinrakennusohje-se84-brachyera-osa-2
until I noticed your post. I have been very impressed with the Butte and Pete has been very patient and answer all my questions. A true scholar and a gentleman.

 

I like this amp alot. From memory, it's more resolving and neutral sounding that the BH crack + SB. Still has a bit of warmth just not as much. Unfortunately didn't do a true side by side, probably 2 months between selling the crack and finishing up this built, but I think jonokuchi could be a hair less tubey sounding. Works very well with HD650.

 

No problem. The nice thing about this compared to the BH Crack is that I can build this here in Europe without having to pay import tax. Have you tried it with speakers yet?

 

Does it have the same kind of punchy, "rock and roll" presentation of the Crack? IoW, nice macrodynamics?

 

Not yet - my B&W bookshelf speakers are too inefficient. I have some Fostex full range speakers on the way from OJ though. The plan always was to use this as my analog rig where I could listen to speakers or headphones.

I need to do more listening here, but presentation is quite different. I need a bit more time to listen and nail down what I hear (been distracted by BW). Punchy would be accurate, but tighter bass - not quite as smooth and laid back as crack. Lyr 2 is another amp I owned for a while and it seems to sway back to the better macrodynamic, more fun side of things any maybe better dynamics and detail (looking back wasnt a huge fan of Lyr 2). Comparing OTL's to a SET probably isn't recommended, but, I find put it in the middle of the crack and a valhalla 2 between the wet to dry scale. Looks like I have some homework to go do and report back on.

 

Looks like you have good/wide spacing and orientation between the OPTs and the mains transformer. How much space did you use there?