[LV26]

Hi
 
My Bijou done!
Amazing sound.
Need listen more... need some tube burning (50 hours I think)
 
Will inform later.
 
 


 

 

 
THANK TO ALL WHO HELP ME WITH THIS AMP!!!
 
Bulk photos:
http://postimg.org/gallery/4b4au5w6/
 
== With Best Wishes
Victor

 

[ev13wt]

Very nice work!!!! Looks really nice!

 

[LV26]

Very nice work!!!! Looks really nice!

Thanks
BTW - open design for my build was your idea!

 
-- Regards
Victor

 

[bhjazz]

Victor - That's a nice-looking build - Congratulations!  Hope it sounds great.  Keep us informed as it gets burned in. 
 
Brian

 

[ev13wt]

Thanks
BTW - open design for my build was your idea!

-- Regards
Victor

It looks very nice, I like being able to see the tubes when it gets dark it will glow nicely.

 

[hey-cameron]

Anyone ever try the Bijou with AKG K1000s? Have any comparisons to other K1000-friendly amps?
 
Cameron

 

[Johnthurston]

I'm making progress on my Bijou
 
The power supply was finished a few days ago and is comfortably driving a test load. I had a few hours of depression when all of the AC input was perfect but I wasn't able to detect any output from the power supply. But after stepping away from the bench for a bit, I realized I had neglected to switch to DC when measuring the output

 
The amplifier boards are built and have received a quick cleaning. Next up is wrapping them in a basic case and wiring them up for a smoke-test.
 
I'm currently thinking about a bleed resistor for the power supply. I know that some folks will permanently install a high-value bleed resistor and accept the steady power-loss during normal operation. Is there a reason not to incorporate a bleed using a DPDT mains-switch? If the switch is rated for +250v, use one pole to switch the hot line of the mains to the power supply and the other pole to connect the bleed resistor to ground (on the opposite throw, of course). My thinking is I can achieve both a fast bleed and low power loss with a minor complication in wiring.
 
Now that I've written that, it dawns on me that I may not be able to find a switch rated for +250vDC (even at the low current it would be seeing).

 

[LV26]

  I'm making progress on my Bijou
 
The power supply was finished a few days ago and is comfortably driving a test load. I had a few hours of depression when all of the AC input was perfect but I wasn't able to detect any output from the power supply. But after stepping away from the bench for a bit, I realized I had neglected to switch to DC when measuring the output

 
The amplifier boards are built and have received a quick cleaning. Next up is wrapping them in a basic case and wiring them up for a smoke-test.
 
I'm currently thinking about a bleed resistor for the power supply. I know that some folks will permanently install a high-value bleed resistor and accept the steady power-loss during normal operation. Is there a reason not to incorporate a bleed using a DPDT mains-switch? If the switch is rated for +250v, use one pole to switch the hot line of the mains to the power supply and the other pole to connect the bleed resistor to ground (on the opposite throw, of course). My thinking is I can achieve both a fast bleed and low power loss with a minor complication in wiring.
 
Now that I've written that, it dawns on me that I may not be able to find a switch rated for +250vDC (even at the low current it would be seeing).

Hello, Johnthurston
 
My congrats with progress on Bijou.
I just finished my build way
I think you will be happy with buid and sound

 
I can`t understand why you need bleed resistor. For safety reason?
With 100k resistor you need some minutes for discharge PSU.
250/100k = 2.5 mA.
If you choose 10k for fast discharge (for example) you will have extra 25 mA load for PSU.
And you can have a problem with Regal Mods.
 
+
 
Good engineering practice is using DP mains-switch for break two AC lines.
I think some safety standards request this as mandatory.
 
I not sure that bleed resistor is a good idea.
 
Everything should be made as simple as possible, but not simpler. // Albert Einstein



So.. don`t complicate

 
-- Regards,
Victor

 

[Johnthurston]

... I can`t understand why you need bleed resistor. For safety reason?

It isn't so much a question of 'need' as of 'want'. I can't see any reason to leave those caps charged if it is simple to discharge them.
Sure, I can look around for a suitable resistor every time I open the case, but it seems simpler to just build it in and be done with it.
 

With 100k resistor you need some minutes for discharge PSU. 250/100k = 2.5 mA.
If you choose 10k for fast discharge (for example) you will have extra 25 mA load for PSU.
And you can have a problem with Regal Mods.

 
Which is why I was hoping to have the bleed connected only when the amp was switched off.
 

Good engineering practice is using DP mains-switch for break two AC lines. I think some safety standards request this as mandatory.

Can you offer any of those safety standards for reference?
 
I'm in North America where I'm working with single-phase 120VAC. In my polarized, grounded, NEMA-15 outlets, the ground lead is at the same potential as the 'neutral' lead. Using a double-pole switch on the mains (to disconnect both the 'hot' and the 'neutral') is going to leave exactly the same potential exposed on the ground lead as using a single-pole switch would leave on the 'neutral' lead. I'm not seeing any significant danger here. What am I missing?
 
But the whole question may be moot. In studying the Mouser catalog, I'm having trouble identifying a switch I like which is also rated at 250vDC

 

[LV26]

  I'm in North America where I'm working with single-phase 120VAC. In my polarized, grounded, NEMA-15 outlets, the ground lead is at the same potential as the 'neutral' lead. Using a double-pole switch on the mains (to disconnect both the 'hot' and the 'neutral') is going to leave exactly the same potential exposed on the ground lead as using a single-pole switch would leave on the 'neutral' lead. I'm not seeing any significant danger here. What am I missing?
 
But the whole question may be moot. In studying the Mouser catalog, I'm having trouble identifying a switch I like which is also rated at 250vDC

Hello.
1) Not all outlets polarized
2) There are many outlets in Europe, Asia, Africa, etc. which Not polarized.

 
3) I think you can findout in UL and CSA standard. I haven`t direct info, but you can see Delta 06AB2D Power entry module datasheet.
(http://www.digikey.com/product-detail/en/06AB2D/1144-1009-ND/3830632)
 
 
-- Regards,
Victor
 
P.S.
Discharging caps require only few minuts.
How often you need to do this? And why?
I just finish with my Bijou and never has such issue.

 

[flatbroker]

Some Bijou porn for a Monday night.

1st Bijou build.  Regal's mod w/ 6N6P's and 6922's.  1/8" aluminum plate on Cherry chassis.  Allied 6K56VG Xformer.  Paralleled 80mfd ASC poly output caps.  Sounds good.

2nd Build.  Paralleled 80mfd GE motor run caps.  270FX Xformer.

Unbelievable dynamics.  
 
Only noise on either build with HD600's or DT880's(600) starts at 4/5 volume with no NFB.  Build 2 is the best I have ever heard with HD600's.  DT880's bass is great, but they are still a little too bright for me.  Build 1 is good, but the ASC caps are a little grainy on the top end.  Yea that's a Sansa Clip Zip as the source.  It's dac is good enough to leave the USB dac in the drawer.  24/96 with rockbox.  Meier crossfeed.  No netbook.  Everything fits in the DT880 softcase. 

 

[LV26]

Hello,
Nice build.

 

Only noise on either build with HD600's or DT880's(600) starts at 4/5 volume with no NFB

Uniform noise? 50/100 (60/120) Hz?
New tubes? If yes you need 50-100 hour for "preheating".
Try connect Volume and NFB shafts to star ground point.
On my build noise disapear after some time (was very very low level at max volume)
Shafts are not connected with star ground.
 
-- Good Luck.
 
P.S.
I need wait for this week for finish heating my Bijou.
Then need check PSU voltage and internals.
Will inform ASAP.

 

[flatbroker]

No 60Hz or 120Hz hum at all, just some soft 12-14kHz hiss.  Very faint, but noticeable.
 
I probably had 30 hours on build 1.  I stole its base and tubes for build 2.  

 

[LV26]

No switching electronics near Bijou?
LED lamps, etc.

 

[flatbroker]

No. I keep it in a quiet corner away from everything. Mobile phone, within range, messes with it though.