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Bijou All Tube Futterman Headphone Amplifier - Page 262

post #3916 of 4234

So been reading the thread and judging from the symptoms of the non adjustable voltage I should change the mosfets.

Does that seem right?


Checked the BOM on Runeight's site and the mosfets are not available on mouser.  Can anyone recommend mosfets to buy?  What are the important specs for future reference?


Thank you much!

post #3917 of 4234

I've been thinking about building this amp for a while, and was wondering how would it pair with the HD600s? I haven't found too many people who talk about how they compare. To be fair, I didn't go through all the pages of this thread, but I did use the search function with minimal results. 

post #3918 of 4234
post #3919 of 4234

Im about to order parts from mouser to upgrade my bijou but Im having trouble finding a good 250k 2 channel pot for NFB, any suggestions?


Im Also looking for a soloution to remote control the volume, but I have very limited space inside the casing.


Krtzer, Bijou is great with my hd650 and they arent so different from hd600.

Edited by vlb - 6/18/11 at 5:16am
post #3920 of 4234

Balderon used this one: http://cgi.ebay.com/ALPS-250K-DUAL-LINEAR-CONTROL-POT-/150510750996?pt=LH_DefaultDomain_0&hash=item230b23cd14 


Make sure that whichever one you choose is linear, not logarithmic. 

post #3921 of 4234



Ive been thinking about ebay, but how do I tell a real alps from a copy?


post #3922 of 4234
Always a legitimate concern with eBay. Pay close attention to the feedback.

Mouser has them, but, with a 14 week lead time and minimum 100 quantity order, that is somewhat impractical.

Seller familygate has them as well. They are recommended by a few folks around here:

post #3923 of 4234

Ill think I have to take a shot at the first one, familygate only  have 250k log. The 250 lin seems to be rare.


Can you recommend a good source for nobs? I think I want big metal nobs.



post #3924 of 4234
post #3925 of 4234


  Thank you so much for the MOSFET parts!  Both PSUs are alive @250Vs and the amp lives!  Thank god for that Hakko Desoldering gun!  Incredible investment.  beyersmile.png  Friday night...
  There is a ticking sound with a computer source plugged in. Also there is a buzz that changes with volume, not as noticeable.  Let's tackle the tick first.  The tick disappears when the input is unplugged. The tick increases with the Bijou volume, but does not change with the source/computer volume.  The noise was interfering with listening enjoyment, so I switched back to the FiiO E9.  Interestingly enough, I heard it on the E9 for the first time. mad.gif    What could this be?  I noticed one of the input shield grounds was broken and fixed that.  So, After re-soldering all the input shield grounds and trying again on the Bijou, the tick was still there.  It didn't change with volume... ARGH!  Well after many trips to the 10k resistor I decided to put this down and sleep on it.  Wake up refreshed and continue today.
  Went to bed, 5 AM.
  Woke up 10 AM to... Why wasn't this here before, when the amp was received and had bad MOSFETs?  More importantly why was there a tick on the E9?
  I asked myself, what changed?  Why didn't I notice this with the E9 before?  It was VERY noticeable.  The first guess was my motherboard.  The motherboard southbridge fried (meh on that one) after the Bijou was taken offline because of the bad MOSFETs. Changed from a 5850 to a 6950 and then CF the 6950s  However, I have been using the E9 every day since then.
The source...?  So I started unplugging all peripherals.  Video, mouse, keyboard, other USB pl.... wait.  It's gone on the E9.  Where did this USB go to.....?   Ahh it's the DAC connect for when the E7 is plugged in.  I plugged it in to make using the E7 easier (so much for streamlining)!  Plugged in some low resistance D2000s and tested with Line in.  Turned the volume way up and there is static and the tick at max volume, with gain on, nothing noticeable at all, given that I would never put the E9 with that volume.
  So I decided to plug in the E7 to test a digital signal for interference.  I put it in and it didn't mount.  confused.gif  Jeez what could it be now.  Took the E7 out and I noticed the dock connector on the E7 is now broken.....  Now poor Micca is involved in this saga.
  So the movie continues.  It's funny because I always try and be careful with devices that could be fragile.  The E7 dock connector is not the highest quality.  This isn't a knock on FiiO.  Either you can't think of everything, or there is only so much awesomeness you can squeeze out of a sub $100 portable DAC/AMP.  As you can see, from the video I treat my audio components well.....  What can I say I like resting with solder beads and wire wrappings. wink.gif
So, I then plugged in the USB connector on the E7 and 1/8th it to the E9.  No tick just normal hiss at ultra high volumes.  This must be an issue with the common factor of two plugs!  The PCI-e bridge is common to the USB and the sound card.  How to test?  Hmm.  Let's try USB E7 -> 1/8th E9 and leave the USB connector in the E9.   The hiss is increased, but no tick.  The USB for the E7 is a top connection.  Let's move the E9 USB to the top connection with it.  Hiss the same.  OK, So the tick isn't passing through the PCI-e bridge.   Now let's plug the 1/8th from the soundcard into the E9.  We will leave the USB connector to the E9 @  the top connector of the PC Case.  The tick is back!
  So this isn't a PCI-e interference.  Don't think its location issue (USB wise). The USB  front panel connector is on the bottom; however, it's shielded and runs through the back of the case.  The case is aluminum.
 It wasn't present on the old MB with the Auzentech/Bijou before it was taken down.  However, I don't remember if I added the second 6950 after the Bijou was taken down.
Auzentech 1/8th (amp out or front out makes no different) -> Bijou - tick increases with amp volume / no change with source volume. *note* Computer activity also provides interference.
Auzentech 1/8th -> E9 - unnoticeable tick
Auzentech 1/8th -> E9 w/ USB plugged in any location - tick
Docked E7 -> E9 w/ USB Plugged in -> frown.gif
USB any location E7 1/8th -> E9 - biggrin.gif
USB any location E7 1/8th -> E9 w/ USB plugged in any location -> Amplifies hiss
USB any location E7 1/8th -> Bijou - Hiss, no tick *note* Computer activity also provides interference.  Even w/ E7 turned off, but USB plugged in/charging.
What would you guys suggest as the next steps, for either the tick or the buzz? 
post #3926 of 4234

After a long time i completed my first tests,


One of the caps was smoking like the case in the previous 3 pages and also i got a rather high heaters v, ~7 to be exact, any way to lower it? shall i add a resistor?

post #3927 of 4234
Originally Posted by yiancar View Post

After a long time i completed my first tests,


One of the caps was smoking like the case in the previous 3 pages and also i got a rather high heaters v, ~7 to be exact, any way to lower it? shall i add a resistor?


I been running my amp with 7.4vac heaters for 2 months, tubes are ok but decided to lower it to safe level. here is advice I followed :





my latest upgrade was to add 250v switch, choke, change power supply to film caps and add 2 transformers for l and r channel heathers so I decided to build transformer box that doubles as rolling tube holderwink_face.gif

after removing feedback pot I decided to get switch for cathode resistors. now tube rolling takes 2 minutes at the most.



Edited by MrClean - 7/2/11 at 9:14pm
post #3928 of 4234

nice casing :), also tnx for the link ill do some current measurements ;)

Btw if i measure correctly , i see 7 tubes on ur amp , what are those extra 2 used for?:)

post #3929 of 4234

Here are some pics :)

Its a balanced setup , with a separate housing for the psu.



A closer shot



Closeup of the tubes



The back



And the inside of the psu



Its rather difficult for me to open the amp case now but i think I've posted some pics in earlier posts :)


Comments are welcome :)


Edited by yiancar - 7/10/11 at 7:51am
post #3930 of 4234
Nice build!

Are you running with or without the negative feedback?
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