Bijou All Tube Futterman Headphone Amplifier - Page 143

We wait . . .

If you need to saw more, I'll bring my super sawz-all over...I can't believe you did 56mm by hand (x2)!!!

Scott

I don't know where you live, but if it is within driving distance of San Jose I could turn a knob on a lathe for you.

Thanks for the offer Srserl! And thanks for the lathe access Boilerbots! I may take you up on some short runs, if my local access(Sacramento area) falls through. A friend that I see once in awhile works in a high-tech medical instrumentation machine shop. Don't know if he would get into trouble if we went in after hours. ;-)

Runeight, esteemed peers, here it is...........

Amphead, how did you bond the rod inside the pipe?

Hi everybody. I just ordered a Bijou kit from Jeff at GlassJar. I’ve already read this thread more than once through in deciding what amp to build next. Now that I’ve decided, I’ll go back through to glean as much as I can to help finalize the details of my build (and the Cavalli Audio website too). I would be happy if anyone wants to jump in with any preemptive advice. I’m particularly going to be looking for:

1) Should I do Regal’s mod from the start?

2) Capacitors: especially, what reasonably priced solutions will tame the large output caps. I listen to classical and jazz, with some bluegrass, newgrass, blues, and rock through K701s (low Z).

- Should I buy shielded hookup wire? If so, does the shielding need to be grounded? Use it for everything or just certain things?

3) Should I use a beefier transformer than the 270 DAX (370 DAX?) in case I want to go balanced or will I need two transformers for balanced? What was that R-core transformer?

4) I gather that ample room is needed inside the case for keeping the high voltage leads (and transformer obviously) away from the amp boards to eliminate hum.

5) I’ll have to decide what to do for a case. I am fond of the BottleHead style with the wood frame around the sides and the metal plates top and bottom (who made a Bijou like that, TimmyMac? and runeight’s PTP prototype) but I decided not to do PTP and I’m not that excited about the tubes half out by bottom mounting components and raising the boards just under the top (especially the power supply tube just peaking out). Can all the tubes be air-wired without detriment to the sound? How? Ferrari must know how.

6) What else???


Thanks in advance.

The inner rod has been epoxied to the outer pipe. I roughed up the surfaces with sandpaper first though. Those building a knob, would have the option of drilling a side hole and threading for 4/40 to have a traditional knob. My knobs are epoxied to the 1/4" stainless rod. The rod will ride in a bronze bearing through the front panel, lubricated with machine oil.

No reason not to do Regals mod first, and yes the case needs ample room for heat and to help route wiring properly to avoid hum. Shielded wire on the input wiring with grounds directly to star ground. You might also shield output wiring depending on your noise floor.

Ron, get some meat on that sandwich... and make up a couple extra badges...

As far as recommendations, Obbligato has some new caps, where serevral have used rather exotics on c6.

There is also the issue of socketing R2 which lets you roll through different tubes, which is also a choice you have to make. Oh, and make sure you start looking at tubes you might want to try - that is half the fun, though the Russian tubes can take a while to settle in (ime).

Do not scrimp on your attenuator - TKD, or (gulp) eBay stepper, at some point - the R27, while serviceable, really holds this amp back.

Finally, take your time, ask questions, and we all have pictures - no one on this thread is shy about sharing images, and offering advice, expecially Alex, the creator.

Others will have to contribute, but you will always get feedback - usually good, sound feedback, all from experience, not just 'from what I've read' stuff.

1. yes
2. I'm interested to know this too
3. 270DAX is lots for an unbalanced build. You need something bigger for balanced, or two if you want to go dual-mono. R-core is available here: Audio Catalog the R0080-036 *might* be sufficient for a balanced build, but I wouldn't recommend Regal's mods or hotter tubes like 6n6p's on it with 4 amp boards.
5. Yes, I did a wood-cased one. There's pictures around somewhere - I posted one 2-3 pages back - but I think it turned out pretty well. My recommendation is definitely to mount the boards on the top panel and all the components on the underside of the board. My setup with air-wired tubes is fine and gives you a smoother top panel and allowed me to put the tubes where I wanted, but it's a pain in the ass to unscrew the sockets with only the length of the air-wires to reach under the top panel with!

Impressive work amphead. I can't wait to see it finished. I don't remember if you mentioned this yet...will you be going the pcb or air wire route with this one?

As for output caps, I am very pleased with my mundorf 330uf poly caps... but you could probably get by with 150uf or 220uf with k701's, giving -3dB points of ~17hz and ~12hz respectively.

Amphead,
looks great!!! yes, we wait....

i finally bought a router, DeWalt DW621. i have a pretty hunk of maple for the side panels. i've found a local aluminum supplier that i'm hitting tomorrow, Discount Steel - The widest selection of steel, aluminum and other metals at discount prices.. pabbi1, these guys are "local" for you as well. also bought a nice non-ferrous blade for the chop box, Freud. i could have built a nice Bijou for the cost of what i've spent on tools to slap together a homebrewed chassis.

the Bijou, M3, and Mini3 are all getting chassis make-overs and parts upgrades.


(my beard is not quite as long. this guy's could be a hazard around a router, or a spagehtti fork for that matter.)

V-Div,
welcome to Club Bijou - i hope you enjoy your stay.

SIP sockets for resistor pad/leads are your friends. consider using these in the NFB circuit as well - R2 is a no brainer. i think pabbi1 played with the NFB circuit a bit. read this thread again.

pabbi1,
you've converted me into an "attenuator nerd". the R27 is a real let down. i've ordered a PEC for my M3. i will also try some nude Vishays in shunt configuration as well.

that is quite simply an amazing beard.

Yes, though Ft Worth is still about 50 miles from me, though they do have copper (wink) and titanium also, in addition to a lot of tasty aluminum. But, I just bought $1000 in aluminum, and will look at a couple hundred more this weekend... MULTIPLE casing projects... <sigh>

Hearing really is believing, though sometimes, the RK27 is 'good enough', but, just not here. I looked at the PEC, but just had to go with the TKD P-2500, but still think the Bijou is worth the TKD P-65... not quite RK50 territory, though.

Discount Steel is a 10 min drive. they have "drop" cuts in various sizes at $3/lb. i bought a 2'x2', 1/4", 5052 plate, and a 2'x4', 1/8", 5052 sheet: 15# total, and with tax came to $48. if you custom order these sizes on the web, the total comes to $114. it may be worth your time and gas to pick up some drop cuts. also, they are very friendly and helpful. i highly recommend them to anyone looking for metal, and they also have a very user friendly website.

wood and aluminum chips are gonna fly tonight.

Completely agree, they have a range of great stuff, but someone is tempting me with six (6) 144" x 36" sheets of .25 6061, for $100 a sheet (~$3 sf)... too tasty. Just gotta figure out how to get it home... after I get my 376 lbs in from Colorado.

I am SERIOUSLY looking at copper plate in .125", if they'd ever have a piece big enough.

Might well have to recase the Bijou, but not for a bit.