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Bijou All Tube Futterman Headphone Amplifier - Page 170

post #2536 of 3981
5/4/09 at 6:34pm

New Bijou to come

Hi all,

I received the Bijou kit from Jeff a couple of days ago, and I'll start soldering next weekend
First of all, I want to thank all of you (Amphead, Adamus, Ferrari and others) for the incredibly useful information you shared in this forum. This was very useful to prepare, and also very inspiring.
I had a hard time deciding about the case. I finally chose a 230mmx230mm Hifi200 Galaxy. It might be a challenge to fit everything in it, but I wanted something as small as possible.

I'm experienced in tube DIY (I built one of these), but not in audiophile stuff, so I have a couple of questions.

I'll replace C2 with SILMIC II ELNA cap and C6 with Mundorf MCAP.
C5 will remain Jeff's part, since I haven't found the right value/money compromise yet. Any suggestion here?

I have a last concern with cable. I'm about to take silver plated single strand wire, PTFE coated - 18 awg for heaters, 22 for the rest. See here
What do you think? Is that an acceptable choice?

I'll keep you posted

Thanks again, guys!
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post #2537 of 3981
5/4/09 at 7:06pm
Quote:
Originally Posted by pabbi1 View Post

I'll replace C2 with SILMIC II ELNA cap and C6 with Mundorf MCAP.
C5 will remain Jeff's part, since I haven't found the right value/money compromise yet. Any suggestion here?

I have a last concern with cable. I'm about to take silver plated single strand wire, PTFE coated - 18 awg for heaters, 22 for the rest. See here
What do you think? Is that an acceptable choice?
A lot of people have had good luck with photo caps for C5. And they don't break the bank.

That wire should work fine but seems a bit pricey to be using for hook-up wire. IMHO.
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post #2538 of 3981
5/4/09 at 11:16pm
Quote:
Originally Posted by Proutch View Post
Hi all,

I'll replace C2 with SILMIC II ELNA cap and C6 with Mundorf MCAP.
C5 will remain Jeff's part, since I haven't found the right value/money compromise yet. Any suggestion here?

I have a last concern with cable. I'm about to take silver plated single strand wire, PTFE coated - 18 awg for heaters, 22 for the rest. See here
What do you think? Is that an acceptable choice?
Send me a PM, and I'll send you some of the photoflash caps.

The wire looks fine, and those are the values I use for heater and signal - just didn't see a temp value. 600v minimum, 105c is good and 200c is better - overkill, but best in case of archy-sparky.

Naaman, thoughts on the sound?
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post #2539 of 3981
5/4/09 at 11:41pm
Quote:
Originally Posted by pabbi1 View Post
Send me a PM, and I'll send you some of the photoflash caps.


Naaman, thoughts on the sound?
Al's good on caps

I claim to be a member of team lead ears, but hmm.....the words I would use are alive, punchy, and vibrant. My reviews fit in three catagories. I like it, it's okay, and meh. It's in "I like it" territory.
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post #2540 of 3981
5/5/09 at 4:53am
Quote:
Originally Posted by Proutch View Post
Hi all,

I received the Bijou kit from Jeff a couple of days ago, and I'll start soldering next weekend
First of all, I want to thank all of you (Amphead, Adamus, Ferrari and others) for the incredibly useful information you shared in this forum. This was very useful to prepare, and also very inspiring.
I had a hard time deciding about the case. I finally chose a 230mmx230mm Hifi200 Galaxy. It might be a challenge to fit everything in it, but I wanted something as small as possible.

I'm experienced in tube DIY (I built one of these), but not in audiophile stuff, so I have a couple of questions.

I'll replace C2 with SILMIC II ELNA cap and C6 with Mundorf MCAP.
C5 will remain Jeff's part, since I haven't found the right value/money compromise yet. Any suggestion here?

I have a last concern with cable. I'm about to take silver plated single strand wire, PTFE coated - 18 awg for heaters, 22 for the rest. See here
What do you think? Is that an acceptable choice?

I'll keep you posted

Thanks again, guys!
My 5 cents worth...........

The kit C2 (Panasonic) is a reasonable cap but the SILMIC should be better. Whether you'd hear the difference is a moot point. I have some Blackgate FK & NX as well as Cerafine's to replace C2, but haven't done anything as yet. Its on the to do list.

C6 - I initially tried a Jupiter 1uF 600V paper/beeswax (solid Ag leads) & this was a huge improvement, but I found the bass still a bit too prominent for my taste. If you intend to keep C6 as an electro, my suggestion is to get the best cap for C6 you can afford. It seems to matter. IMO, Jupiter is a very underrated cap, but a search of this thread will show others have been used successfully as well.

C5 - I'm now running a Mundorf Tubecap 200uF 600V, no bypass. This has tightened up the sound significantly, but bass is still deep & sustained. WTG, IMO.

C1 is also a very important cap & may benefit from an upgrade. I'm using an MCap (15uf) with good results. See previous posts as well as feedback from Alex re this.

Hookup - I used Welborne silver plated stranded PTFE in the gauges you specify for heaters & HV. Its one of the best wires I've used. All signal wiring is Jupiter 23 & 28G solid 4N Ag cotton covered. This is also beautiful stuff to work with & won't get in the way of the music.
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post #2541 of 3981
5/5/09 at 8:53am
Thanks a lot for your (super fast) replies

I was uncertain whether C2 would really matter, but I'll definitely take a look at previous posts for C1 options
Thanks also for your advice about wires - I guess the one I found are a decent option, so I'll take those (even if it's not deal of the century)

And last but not least, photoflash caps look like a great option - and not to pricey...
Pabby, you're offer is much appreciated. Youv'e got a PM


Thanks again guys, your help is awesome
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post #2542 of 3981
5/6/09 at 5:14am
Quote:
Originally Posted by rolotube View Post
fishki
Just finished a rebuild of my heavily modded Bijou, including a full complement of Mundorf Tubecaps, which take up lots of room. Not having the time or resources to construct a fully custom chassis/case from scratch, I went for a couple of Hammond chassis #1441-22BK3 & perforated covers #1451-22BK3. These aren't flash but provide functional & durable housings for the amp & power supply. Being steel, they also provide a measure of shielding, so long as sound earthing procedures are followed. Which brings me to the other issue you discuss - noise. I'm running a 370 DAX, EZ81 (6CA4), amphead's heater mods, & no shielded cable anywhere. The amp is dead silent - black as night - at least as quiet as any mains, or even battery powered, SS amp I've built. I would not have believed this was possible using AC heaters & one of my first reactions when I decided to build the Bijou was how could I convert the heaters to DC. But the level of silence is such that I could not possibly HEAR anything quieter, let alone imagine it, so any advantage DC heaters may provide would be perceived rather than actual. I'm not entirely sure why this should be so, but the separate amp & PS chassis together with careful attention to proper star grounding probably has much to do with it.

As for the sound - I haven't heard anything that comes close. Its only after a few weeks of listening to other amps, then coming back to the Bijou, that I realise just how good it is.

I'll post some photos of the new build shortly.

cool. thanks...good to know!!! i think the decision for DC heaters will primarily depend on the P2P wiring lay-out i finally decide on. if it ends up too much bigger than the PCBs, i'll stick with the PCB - besides, they're already done, silent, and operational.

a bridge rectifier with some caps doesn't take up a whole lot of room and is maybe $10 in parts: see pic for the guitar amp i built with homebrewed aluminum plate at 1.25" x 2.75.

since i'm DIYing the chassis, i have some flexibility. but jeeez, DIYing your own chassis can be a lot of work.
LL
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post #2543 of 3981
5/6/09 at 5:20am
wow is that your star ground ? The one with all the hex nuts?..damn!
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post #2544 of 3981
5/6/09 at 5:50am
Quote:
Originally Posted by sachu View Post
wow is that your star ground ? The one with all the hex nuts?..damn!
yup, multiple gain stages without "intermediate", isolated ground-stars.
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post #2545 of 3981
5/6/09 at 8:21am
Quote:
Originally Posted by fishski13 View Post
cool. thanks...good to know!!! i think the decision for DC heaters will primarily depend on the P2P wiring lay-out i finally decide on. if it ends up too much bigger than the PCBs, i'll stick with the PCB - besides, they're already done, silent, and operational.

a bridge rectifier with some caps doesn't take up a whole lot of room and is maybe $10 in parts: see pic for the guitar amp i built with homebrewed aluminum plate at 1.25" x 2.75.

since i'm DIYing the chassis, i have some flexibility. but jeeez, DIYing your own chassis can be a lot of work.
I didn't realise you were doing P2P. My comments above were in the broad context of the "kit" Bijou plus or minus some mods, but still using the PCB's & same basic layout. If you've got the space in a P2P build, I'd definitely recommend try DC. Theoretically, it should be significantly quieter with no high current AC fields floating around.

A DIY chassis is the ideal & can really show off a great build (consider what's been posted here just lately). I'll be interested to see the results of your labors.
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post #2546 of 3981
5/6/09 at 10:23pm
NVM.
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post #2547 of 3981
5/7/09 at 7:55pm
Yeah the Bijou can be built quiet with AC heaters. Happy to see others having success. Still working on and off to get volume assemblies finished.
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post #2548 of 3981
5/7/09 at 10:09pm
Thread Starter 
so u ever going to finish building this thing or is the mill too much fun in its own right ..dB
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post #2549 of 3981
5/9/09 at 4:13am
I'm jumping through hoops to have 2 finished by CanJam. Here is a recent distraction however........ Eye candy to support more ear candy.

Laser Pointer Forums - Discuss Lasers & Laser Pointers
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post #2550 of 3981
5/10/09 at 2:38pm
It's been a long time in the making. Sadly to report it's been sitting on a shelf for a year, incomplete. Anyhow, it's mostly done now. I need to drill the NABU cover.

My B+ is sagging to 245V with the regulator at max output.

I'm running the Regal mod (6DJ8, 6N6Pi, EZ81) with PP caps and the feedback version with feedback at minimum. It's a PITA to remove the resistors, so I may remove the pot and put in a 1M feedback resistor. No noise so far. Volume knob has very good movement with the feedback at minimum.

My heater voltage is a bit high @ 6.9V, I need to increase the resistor.

I know I need to vacuum, but I just finished all the wiring.

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