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Bijou All Tube Futterman Headphone Amplifier - Page 154

post #2296 of 3981
2/14/09 at 2:22pm

Smoke test and bad things

I have to hang my head low. Apparently I wasn't entirely lucid when I bought the parts for the power supply. I left the 'K' off of R2, R9, and R6. The EZ80 was not at all happy. I could imaging having 250+ vdc on the heaters doesn't go over well. The EZ80 got bright red, but didn't fail. R7 and R8 started smoking, as well as R6 and R7 which have charr marks on them.

Ugh. I need new glasses. Thank goodness for my variac.

I had a super overkill 30k metal oxide resistor that I put into R2, but I'll need to put in an order for the 348k's.

I'll need to double check the amp boards to be sure I didn't do anything silly there too.

I've attached some poor quality photos courtesy of my blackberry.
LL
LL
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post #2297 of 3981
2/14/09 at 4:36pm
Quote:
Originally Posted by whitelabrat View Post
I have to hang my head low. Apparently I wasn't entirely lucid when I bought the parts for the power supply. I left the 'K' off of R2, R9, and R6. The EZ80 was not at all happy. I could imaging having 250+ vdc on the heaters doesn't go over well. The EZ80 got bright red, but didn't fail. R7 and R8 started smoking, as well as R6 and R7 which have charr marks on them.

Ugh. I need new glasses. Thank goodness for my variac.

I had a super overkill 30k metal oxide resistor that I put into R2, but I'll need to put in an order for the 348k's.

I'll need to double check the amp boards to be sure I didn't do anything silly there too.

I've attached some poor quality photos courtesy of my blackberry.
Big bummer. I won't sneer, at least not until I start mine up without smoking something.
I hope you didn't do too much damage. Good luck sorting it out.
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post #2298 of 3981
2/14/09 at 5:33pm
Today i received a pair of ecc99 to replace the 6n6p-i.
I put them in my bijou and... the PS output drop at 234V without an head-phone plug into the amp.

In fact, the output of the PS board varies between 245 and 234V wit my beyer pluged-in and the trimpot do nothing.

I have tested again my PS board with a 100K resistor and it works fine, including the trimpot.

I have done regal mod and have a 250-0-250 transformer.


Some measure on the PS with all wired:
R7:240V
R8:288V
pin 5 of the EZ81: 38V
6,7V-AC on the heater.


The amp works fine however but with a lake of bass but a mush clearer sound.


EDIT: After reading again some messages, i think, my mosfets are dead... crap -_-
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post #2299 of 3981
2/14/09 at 8:14pm
If you can't get a stable reading of 250vdc from the power supply, that would be very likely. Sorry to hear about your misfortune guys.
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post #2300 of 3981
2/15/09 at 1:41am
received my M-caps today, but unfortunately my Bijou re-chassis is on the back burner. i'm building a SOHA II, gamma-1, Gainclone, and some full-range Fonken speakers for a friend - plus....

amphead,
i have parts for the High Octane guitar amp i'm building for another friend arriving tomorrow. thanks for the recommendation - i can't wait to hear how it sounds. he's pretty stoked.
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post #2301 of 3981
2/15/09 at 2:02am
That's awesome man! I wish I had the time to put a guitar amp on the front burner, but for now at least it's my slooowww.... bijou build. I decided to spend time doing each step, to try and get it right the first time. ;-)
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post #2302 of 3981
2/15/09 at 3:17am
Quote:
Originally Posted by whitelabrat View Post
.... I left the 'K' off of R2, R9, and R6. The EZ80 was not at all happy. ....
Blowing things up is a powerful means of learning! I should know... It's handy to meter every resistor, even if you order the right ones, there can always be a mix up... Good luck!
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post #2303 of 3981
2/15/09 at 1:52pm
Quote:
Originally Posted by wiatrob View Post
Blowing things up is a powerful means of learning!
That's right. Just as long as I don't blow me up.

I finished checking the amp board again, and sure enough a lot of resistors have a decimal in the wrong place. Man, I hate replacing bits. Geez.

An interesting side note, there's a thread on another forum that goes into 6N6P-i vs 6N6P. It seems that the 6N6P-i may be the lesser of the two, but I'm not 100% convinced yet. The impulse version is designed to take more of a beating which may explain a rated life of 500hrs vs the 6N6P's 2000hrs.
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post #2304 of 3981
2/17/09 at 5:22am
Has anyone bought anything from this site? I like their cases.
Audio Catalog
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post #2305 of 3981
2/17/09 at 6:20am
A member by the Head-fi name Mazuki bought an R-core transformer from them. You could PM him, but I believe he had a positive experience. Good Luck!
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post #2306 of 3981
2/17/09 at 11:05am
Thread Starter 
Quote:
Originally Posted by Fast3d View Post
Has anyone bought anything from this site? I like their cases.
Audio Catalog
Yes - I have used them a fair amount recently and they are very reliable. Great selection of quality DIY parts too ..dB
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post #2307 of 3981
2/17/09 at 9:17pm

Thanks

Thanks for replying I'll start ordering here soon for a case for my Bijou. Any other site with good cases?
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post #2308 of 3981
2/18/09 at 4:22am
agreeing with others - vt4c is a superb seller.
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post #2309 of 3981
2/18/09 at 5:48am
I was looking at some polished carbon fiber, for control plate material. Black, shiny, beautiful, and the 1/4" is astronomical in price. Very lightweight and strong. Would be nice to consider for a future project though. 2 week lead time however for custom W x L.
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post #2310 of 3981
2/18/09 at 6:08am
You could always buy the cloth and lay it up yourself. It's fun, but a lot of work. And you'll need access to a decent router if you want anything like straight edges.

I'm assuming it's just for cosmetic purposes? 1/4" plate is a bit beyond what carbon is normally used at unless it's cored
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