[adamus]

it matters.

look on the schematic, the there is a voltage divider that puts about +40vdc bias on the heater lines. This is required if you look at datasheets (although anyone doing ampheads mods is not doing this).

You could either parallel them for 7 amps (which means you will probably have too high a voltage). ot just just one (ez81 ~ 1amp, 2x 6dj8 ~ 0.6amp, 2X 6n6p ~1.6amp = 3.2amps @6.3v.

If the tranformer runs a bit hot, then parallel them (taking care of phase).

 

[breizheau]

After a break, i have decided to start again to work on the Bijou. But this thread now is loooooooooong.
I am sure not sure to know all the updates about this amp. Exept the "Amphead's Heater Mods" and "Reagl's mod" that i have found on Cavalli website.
What about the capacitors ?????? Could you do a "shorcut" for the different tests already done about values, caps, brands please ?

Olivier

 

[pabbi1]

Does anyone have observations about using Grados, or other low impedence phones, with the Bijou?

 

[adamus]

I do, but it may be controversial.

I thought it was bad with grados, didnt like the sound at all.

with high impedance phones the bijou is lovely and impressive. With low impedance i think sohaII or the CTH actually sound 'better' (subjective opinion only!)

 

[regal]

Quote:

Originally Posted by breizheau /img/forum/go_quote.gif After a break, i have decided to start again to work on the Bijou. But this thread now is loooooooooong. I am sure not sure to know all the updates about this amp. Exept the "Amphead's Heater Mods" and "Reagl's mod" that i have found on Cavalli website. What about the capacitors ?????? Could you do a "shorcut" for the different tests already done about values, caps, brands please ? Olivier

As mentioned earlier use this amp with 300 ohm or higher headphones. Remove the NFB resistor. Then for the large output caps use 100uf motor run oil caps bypassed with russian Ky40 1uf caps. Both caps are found on ebay for cheap, sound is hugely improved over using electrolytic caps.

 

[GWorlDofSPACE]

Guys,
I was wondering how to configure the bijou PSU to deliver 300V anode power 100mA?
Can I just connect a 310-320V transformer? Has someone experimented whit higher anode voltage? Is I know you get different flavour of sound not?

 

[adamus]

why?

00ma @300v over 4 tubes = ~ 25 per tube = something like an EL84 (which would want a bit more current.


not a bijou anymore.

 

[GWorlDofSPACE]

Understand... I am thinking to make an tube 6j8d output for my future DAC.
The PSU from Bijou is very good and the EZ81 can deliver 150mA. I need 100mA.

 

[adamus]

why do you need 100ma?

100ma @ 300 v = 30watts?

sure your calcs are correct?

6dj8 typically run 1-10ma. are you running many?

 

[breizheau]

Quote:

Originally Posted by regal /img/forum/go_quote.gif As mentioned earlier use this amp with 300 ohm or higher headphones. Remove the NFB resistor. Then for the large output caps use 100uf motor run oil caps bypassed with russian Ky40 1uf caps. Both caps are found on ebay for cheap, sound is hugely improved over using electrolytic caps.

Thx. I'll do ASAP. I still have to find time to work on it.

 

[mugdecoffee]

Quote:

Originally Posted by adamus /img/forum/go_quote.gif I do, but it may be controversial. I thought it was bad with grados, didnt like the sound at all. with high impedance phones the bijou is lovely and impressive. With low impedance i think sohaII or the CTH actually sound 'better' (subjective opinion only!)

I very much agree. I think my HF-2s sound better out of my iPod than my Bijou. I also agree about the CTH. Just built mine and it drives them quite well.

 

[regal]

Quote:

Originally Posted by mugdecoffee /img/forum/go_quote.gif I very much agree. I think my HF-2s sound better out of my iPod than my Bijou. I also agree about the CTH. Just built mine and it drives them quite well.

I agree also, The Bijou was my dream amp when my facorite headphones were Sextetts (600 ohm) and Senns (300 ohms), then I heard Grados for the first time and fell in love, but the Bijou just wasn't a good match for them. I built a SOHA II with a high tail current mod and it does a great job with Grados.

 

[rolotube]

Quote:

Originally Posted by pabbi1 /img/forum/go_quote.gif Does anyone have observations about using Grados, or other low impedence phones, with the Bijou?

HD650's (300 ohms) sing beautifully with my Bijou, K701's (62 ohms) are, at best, ordinary. As noted by regal, the latter work better on the SOHA II but don't capture the magic of the Senns, at least not to my ears.

 

[UKToecutter]

Quote:

Originally Posted by pabbi1 /img/forum/go_quote.gif Ok, caps packaged for all who gave me an address - James, Randy, Husky - need mailing info. Again, just donate the $$$ directly to Head-fi. Still over 100 left...

Pabbi1.

Just reading through the thread and came across this.

Do you have any of these caps left???

 

[pabbi1]

Quote:

Originally Posted by rolotube /img/forum/go_quote.gif HD650's (300 ohms) sing beautifully with my Bijou, K701's (62 ohms) are, at best, ordinary. As noted by regal, the latter work better on the SOHA II but don't capture the magic of the Senns, at least not to my ears.

Mine too... hd600, hd650 and hd800.

Quote:

Originally Posted by UKToecutter /img/forum/go_quote.gif Pabbi1. Just reading through the thread and came across this. Do you have any of these caps left???

I do indeed - just ping me with an address.