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Bijou All Tube Futterman Headphone Amplifier - Page 148

post #2206 of 3981
1/25/09 at 4:05pm
I too like obbligatos on c6 - good value caps.
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post #2207 of 3981
1/25/09 at 9:25pm
Quote:
Originally Posted by pabbi1 View Post
Yeah, down to my last 100 or so...

I really like the Obbligatos on c6. There are fancier options if you are so inclined.
Thanks Pabbi and Adamus. I'm not that fancy, so Obbligatos will probably be just fine. Pabbi, I sent you a PM.

I just realized that I can procrastinate some more on making decisions on the casing: I still need to find, well I don't really have to at the moment, but I will anyway - I still need to put in a bit more into looking for an attenuator of some sort. In the little looking that I have done I haven't seen anything that struck me as an easy choice, good bang for the buck.
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post #2208 of 3981
1/26/09 at 12:32pm
So I've been able to do most of the board stuffing over the weekend, but I'm trying to decide my next move. I'd like to keep as close to the stock schematic as possible. Tubes will be PCC88, 6n6pi, EZ80 at least for now. I'm a bit stuck with the big 470uF capacitors. I was hoping to use TIP50's with 47uF caps, but for the sake of simplicity I don't think I'll go down that road yet. So I'm wondering. Why 470uF? That's pretty darn big. Any reason I can't use 120uF's instead? I've already got em and it would save me some $$. I've also got a 600uF 500vdc metallized polypropylene that I could perhaps use at C1, but I'm concerned the big value may cause issues. That and it's huge!

Photos to come.
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post #2209 of 3981
1/26/09 at 12:45pm
Quote:
Originally Posted by whitelabrat View Post
...I'm a bit stuck with the big 470uF capacitors. I was hoping to use TIP50's with 47uF caps, but for the sake of simplicity I don't think I'll go down that road yet. So I'm wondering. Why 470uF? That's pretty darn big. Any reason I can't use 120uF's instead? I've already got em and it would save me some $$. I've also got a 600uF 500vdc metallized polypropylene that I could perhaps use at C1, but I'm concerned the big value may cause issues. That and it's huge!

Photos to come.
HINT.
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post #2210 of 3981
1/26/09 at 12:58pm
My fault. I should be more precise. I'd like to use 120uF capacitors for the power supply caps at C1, C4, and C5. I could potentially use a 600uF 500v metallized polypropylene for power supply cap C1. I'm also thinking that attaching a 1uF metallized polypropylene in parallel with the 120uF should help smooth any ripple. What benefit is there from the 470uF's in the power supply aside from bigger is better?

I do intend to use at least 100uF metallized polypropylene output coupling capacitors at C5 and to do without C6 altogether.. I'll be using at least 100ohm headphones.
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post #2211 of 3981
1/26/09 at 2:07pm
Quote:
Originally Posted by whitelabrat View Post
My fault. I should be more precise. I'd like to use 120uF capacitors for the power supply caps at C1, C4, and C5. I could potentially use a 600uF 500v metallized polypropylene for power supply cap C1. I'm also thinking that attaching a 1uF metallized polypropylene in parallel with the 120uF should help smooth any ripple. What benefit is there from the 470uF's in the power supply aside from bigger is better?

I do intend to use at least 100uF metallized polypropylene output coupling capacitors at C5 and to do without C6 altogether.. I'll be using at least 100ohm headphones.
The 470u caps are sized to reduce the ripple to a neglibile amount. You may have a fair amount of ripple from the PS if you only use 120u.

In addition the 470u at the output flattens the frequency response of the regulator so that it responds equally well over a wide frequency range.

You may get away with 120u but the 470u are there for a reason.

Otherwise, good luck on the build. It's good to have a few more folks trying this amp out.
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post #2212 of 3981
1/26/09 at 2:34pm
Quote:
Originally Posted by V-DiV View Post
Thanks Pabbi and Adamus. I'm not that fancy, so Obbligatos will probably be just fine. Pabbi, I sent you a PM.

I just realized that I can procrastinate some more on making decisions on the casing: I still need to find, well I don't really have to at the moment, but I will anyway - I still need to put in a bit more into looking for an attenuator of some sort. In the little looking that I have done I haven't seen anything that struck me as an easy choice, good bang for the buck.
Missed the PM, might resend... many other builders like the TKD2511 (regular taper, not the tkd2508 that I have), but the ebay guys are hit and miss, especially on the smd flavors. The surest shot is Goldpoint or DACT, both of which I am a fan, and prefer on the pricier builds.
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post #2213 of 3981
1/26/09 at 8:29pm
Nice to see so many busy builders. Well I have mounted both L/R volume knobs on the front panel, through the precision bearings. They turn extremely smoothly, with a nice weight. I have polished the front panel to a near mirror shine, going from 2000 carbide paper, to Dico WR1 compound, and finally to Dico jeweler's rouge JR1. I wasn't sure that I wanted the super lustre, but now I like it. Pics of the progress coming soon.
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post #2214 of 3981
1/27/09 at 12:48am
I ran some simulations using PSU Designer II and dang it! I learned something new today. I think I'll go with some variation that will include the 470uF caps in the power supply. Allied Electronics had some very nice pricing on some caps so I ordered a few, along with a 10H 270ohm choke. Perhaps overkill, but that's the spirit right! Don't laugh at my photos. I know the 1w 300ohm resistors are ridiculous. Its the only ones I could get along with all the other bits I wanted from a single source.

I need to think enclosure now.
LL
LL
LL
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post #2215 of 3981
1/27/09 at 2:23am
Quote:
Originally Posted by amphead View Post
Nice to see so many busy builders. Well I have mounted both L/R volume knobs on the front panel, through the precision bearings. They turn extremely smoothly, with a nice weight. I have polished the front panel to a near mirror shine, going from 2000 carbide paper, to Dico WR1 compound, and finally to Dico jeweler's rouge JR1. I wasn't sure that I wanted the super lustre, but now I like it. Pics of the progress coming soon.
ooolala. can't wait to see some pics. i'm taking notes on your polishing protocol.

i have to finish the chassis for a Mini3 + passive line stage for a friend before i can tackle the Bijou re-chassis. drawings/layout are finalized. i've spent hours honing my routering skills and cutting aluminum with reasonable accuracy. clamps are your friends, hot kerf aluminum shavings are not.
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post #2216 of 3981
1/27/09 at 3:19am
Quote:
Originally Posted by pabbi1 View Post
BTW, I still have PLENTY of those caps for Bijou builders... do not pay the ebay price. Search the thread for details. Basically, I will send you a cap for every $1 donated to Head-fi, and I pay shipping.
It wouldn't hurt to give the Rubycon's a listen when that time comes. I have sent you a PM.
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post #2217 of 3981
1/27/09 at 9:44pm
Here's a pic with polishing at about 80% on the front panel, and 90% on the volume knobs. The precision bearing is visible on the right hand side mounted into the front panel. More polishing tonight............

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post #2218 of 3981
1/27/09 at 11:58pm
Amphead, your Bijou (gem) is going to be very lustrous!
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post #2219 of 3981
1/28/09 at 1:23am
Quote:
Originally Posted by amphead View Post
Here's a pic with polishing at about 80% on the front panel, and 90% on the volume knobs. The precision bearing is visible on the right hand side mounted into the front panel. More polishing tonight............
Your missing a valuable accessory for your chassis. I did not see any holders for the white gloves needed as protection for greasy fingerprints! Very nice work amphead!
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post #2220 of 3981
1/28/09 at 10:33pm
Quote:
Originally Posted by balderon View Post
Your missing a valuable accessory for your chassis. I did not see any holders for the white gloves needed as protection for greasy fingerprints! Very nice work amphead!
I was thinking the same thing. Won't he be afraid to touch it?
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