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Bijou All Tube Futterman Headphone Amplifier - Page 267

post #3991 of 4179

I thought I'd ask to clarify; on the PSU, C2 does not have a polarity so I can just solder it in place?

 

I today got all the resistors, diodes and some capacitors in place. Still missing the biggest caps and accidentally bought tube sockets that don't fit the PCBs so have to replace those. ;[

Finally taking shape, though. I had so much fun today, this is my first DIY project so I propably have to be super careful before introducing it to a power socket.

post #3992 of 4179

That is correct, C2 orientation doesn't matter.

post #3993 of 4179

Bought wrong kind of the biggest capacitors ;[ What do you suggest I do if I wanted to still try to mount them on the board? Cut or bend the excess legs and find something to lenghten the + and - to reach the holes? Mosfets are meant to be tightened to the heatsink with a bolt, amiright?

700

post #3994 of 4179

Yes, mosfets are tightened with a bolt and a nut, but don't forget insulating pad and a plastic washer for bolt (like these). As for the caps - I'd cut out excess legs, insulate the pads, and use some 22 awg cable to connect to the board. And also insulate the connections between caps legs, wire and board with some heatshrink tubing.

post #3995 of 4179

Finally got the last remaining parts and connectors. Got everything running today with all tubes glowing nice. The voltage is very low after connecting the amp boards (210VDC) and doesn't get any higher. I'm using EZ80 on the PS and 6n6p-i & 6n11 on amps. Also have a massive hum while trying it with headphones. I suppose the low voltage is to blame and atm messy wiring within the pizza box.redface.gif

 

I have no additional mods. Pretty much just gathered everything according to the list. Should I try the EZ81 for additional juice?

 

PS; when are the leds supposed to glow? They don't.

post #3996 of 4179

Sorry for the late reply. 

Let's try to troubleshoot a little: 

1. Did you try to load PS with 100K 1W resistor prior to connecting amp boards?

2. What trafo are you using? Are the ratings correct?

3. Check mosfet legs for shorts, if there's any, they have to be replaced.

4. Pictures of fully populated PS and amp boards would help to further investigate the issue :)

 

As for the leds - I myself omitted them (was too lazy to calculate led resistor), so can't help you on this one, maybe double-check the orientation.

post #3997 of 4179
You can not just ignore the other 2 poles of a 4 pole capacitor. 4 pole capacitor has separate input and output leads, 2 inputs and 2 outputs. Do read about them, you most likely won't be able to use them without modification to the PCB.
post #3998 of 4179
Quote:
Originally Posted by Navyblue View Post

You can not just ignore the other 2 poles of a 4 pole capacitor. 4 pole capacitor has separate input and output leads, 2 inputs and 2 outputs. Do read about them, you most likely won't be able to use them without modification to the PCB.

It says "do not connect" on the two other poles. I humbly obeyed. (at work atm, will check and make sure after.)

 

@Fred_com,

1. I did. Got a solid 250V.

2. R-core  R0080-036B-EU from www.vt4c.com:

 

100W power transformer Recommend for Single Ended tube power AMP or Mono power AMP.

Primary 0-220-230-240V
260-230-0-230-260V 100mA
0-6.3 3A with CT (I have 6,6V for some reason, measured yesterday. Maybe should try the alternative windings for more accurate V?)
 
3. Not really sure how to do that if there's some trickery involved.
4. Will take pictures! After work or tomorrow.
 
Thanks for the help guys, it was quite a let-down when it didn't function properly. The whole pile is in shambles atm (parts intact on the PCBs ofc, took off the wires). I have to get some more wire to do the wiring properly and neatly to minimize it's effects on the hum.

Edited by Kirnupiima - 8/21/12 at 11:39am
post #3999 of 4179

Yes, it seems that those additional poles are just for mechanical stability ( panasonic ce tha capacitor datasheet )

post #4000 of 4179
I see, those aren't 4 poles electrolytic.
post #4001 of 4179

Well, transformer is fine then. Did you measure 6.6V with or without the load (i.e. with PS connected)?

 

As for measuring mosfets for shorts: make sure that capacitors on PS boards are fully discharged (wait 5 minutes after disconnecting power, or check PS output voltage with your multimeter so its 0 volts), then check each of three mosfet legs for continuity between them (if there's any continuity - mosfet is dead).

 

On the other hand, you've said that PS gave 250V with resistor, so mosfets are probably fine, but check them anyway just to be sure.

post #4002 of 4179

Got the EZ81 today and it works! Sorry for not taking the time to take and upload the pictures for troubleshooting. The heater voltage is only 6V (not 6,6V anymore) for some reason and B+ doesn't get higher than 246VDC but it works! No hums of any sort. Leds don't work either but that's not a big deal.

 

The sound is a bit soft after few hours of uptime and a bit dark compared to what I've used to. This is an experiment with tubes of course so everything is new/old to me. Does is get brighter or more open with time and are there positive effects if the voltages reached the optimals? Any tips achieving those?

 

 

 

edit: B+ went up to 250 by itself<3


Edited by Kirnupiima - 8/30/12 at 2:31pm
post #4003 of 4179

After looking at the wiring diagram again I noticed that I had soldered the volume pot right before the headphone jack and NOT right after the line inputs. Can this cause damage and does it make how big of a difference? I inted to fix it asap but just to learn something for the future I'd like to know. triportsad.gif

 

edit: I changed the volume pot to it's rightful place and got a huge hum as a reward. It seems to come from the NFB pot and disappears if I connect all the pins from the same channel. Need to investigate and propably get rid of the pot anyway.


Edited by Kirnupiima - 9/14/12 at 4:09pm
post #4004 of 4179

I removed the NFB pot and tidied up the star grounds into one shared point as in the wiring diagrams. I also located the source of the hum. It's the transformer and the hum can be heard from half a meter away. I noticed this because of the wooden chess board on which I've kept the pizza box but now the transmormer slipped off the cardboard and began to sing the song of it's people aloud. Is there something I could do about it or is it a lost cause and time for a new one? Please help, I'm so close to finishing the whole project and this pains me so much.triportsad.gif

post #4005 of 4179

Hello all,

 

I'm new to this headphone enthousiasts forum. This is also  my first post here, however i have read this entire thread before and during my own build of the Bijou amp.

SInce i am new to the DIY scene, i did my homework first. I had already build a phone preamp (from boozehound lab). But a tube amp is something else for sure.

 

The build wasnt to difficult though, most of my time went into the casing (all wood). And the wiring, since i by mistake ordered and installed the wrong pot for volume. 

It worked the first time i fired it up, however with to much noise. So when i ordered the new pot i also decided to upgrade the C6 of the amps and do the amphead mod, and upgrade the signal wiring. What a difference!!!

 

I am now listening to the amp, what a joy!

 

I am using a Grado 325I headphone (32ohm), i am looking for something that might match better with this amp, maybe the Beyer dt990 (600 ohm).

My source is a media pc via an arcam Rdac. 

 

I am using rather standard tubes now, so maybe ill see if i can find some nicer models to upgrade this amp further.

 

Thanks everyone on this thread to share their knowledge and experience with this amp.

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