[MoodySteve]

Quote:

Originally Posted by mugdecoffee /img/forum/go_quote.gif True. You could add one of AMB's e12 boards as a failsafe. After poking around, I think this is a capacitor multiplier done with an opamp. Even if the cap's sound still made it through the buffer, this circuit would allow the use of much smaller and higher quality film caps. With the cost of large film caps or high quality bypass caps being rather high, this somewhat complex solution might be justified. It could be made as an addon board so you wouldn't have to mess with the original boards besides shorting the output caps.

I'm not sure the ε12 is usable with the Bijou - what would you power it with and still retain the DC protection?

 

[runeight]

Interesting idea, but ... the e12 is probably not fast enough for certain failures that are rare, but could occur. Also, you'll need to think about the reference for the e12. It is normally referenced to ground or a virtual ground. If you use your virtual ground the e12 will be floating at 125V along with its power supply. Certainly doable, but extra work.

Is the output of the opamp going to be at 125V? Is it a high voltage opamp? If not, where do its rails come from? Etc. Just asking because, like so many things, I don't understand yet.

 

[Ant1Xr1st]

Some idea about OCL (output capacitor less) Bijow. (See pic.)
In microcap works fine.

Any comments?

[size=xx-small]*sorry 4 my english[/size]

 

[amphead]

Interesting, maybe Runeight can evaluate your circuit. Cheers

 

[adamus]

I regal modded my bijou last night.

its made quite an impact, the mids have got bigger and bass has more authority, it seems to have sped things up a little. this is with the 6dj8. With the 6n1p i dont hear much difference.

Bijou + regal mod + bugle boy + 6n6p is a very good amp.

my PS with the Rcore transformer didtn bat an eyelid, 250v solid.

has anyone used boutiques as the coupling caps (c3 and c4). My brain says... why bother, the signal is then going through a big electrolytic (bypass with a nice cap).

anyone notice a significant improvement?

 

[regal]

Quote:

Originally Posted by adamus /img/forum/go_quote.gif I regal modded my bijou last night. its made quite an impact, the mids have got bigger and bass has more authority, it seems to have sped things up a little. this is with the 6dj8. With the 6n1p i dont hear much difference. Bijou + regal mod + bugle boy + 6n6p is a very good amp. my PS with the Rcore transformer didtn bat an eyelid, 250v solid. has anyone used boutiques as the coupling caps (c3 and c4). My brain says... why bother, the signal is then going through a big electrolytic (bypass with a nice cap). anyone notice a significant improvement?

Thanks, which do you prefer the mod+BB's or the 6n1p's ?

 

[adamus]

bb's by a country mile.

 

[fishski13]

Quote:

Originally Posted by adamus /img/forum/go_quote.gif bb's by a country mile.

i need to try these. sorry, i'm too lazy to search, where's best place to buy?

 

[adamus]

no idea, a mate gave me my pair as payment for some work on an amp.

 

[cyteen]

Has anyone got suggestions as to values to optimize the circuit for 6n1p.

 

[adamus]

its on the cavalli audio website.

 

[rolotube]

Quote:

Originally Posted by fishski13 /img/forum/go_quote.gif i need to try these. sorry, i'm too lazy to search, where's best place to buy?

BB's are readily available but be prepared to pay - the genuine article isn't cheap. There are reports of inferior copies being peddled by some tube dealers so it might be wise to stick with reputable firms. I got mine from pcX. They periodically have discounts & currently have 20% off which softens the blow a bit. The 6N23P may also be worth considering. There's been some recent discussion of this tube in these pages. IMO, its close to the BB in sound quality for 25-30% of the cost.

 

[rolotube]

Quote:

Originally Posted by adamus /img/forum/go_quote.gif I regal modded my bijou last night. its made quite an impact, the mids have got bigger and bass has more authority, it seems to have sped things up a little. this is with the 6dj8. With the 6n1p i dont hear much difference. Bijou + regal mod + bugle boy + 6n6p is a very good amp. my PS with the Rcore transformer didtn bat an eyelid, 250v solid. has anyone used boutiques as the coupling caps (c3 and c4). My brain says... why bother, the signal is then going through a big electrolytic (bypass with a nice cap). anyone notice a significant improvement?

I'm running the same configuration in my Bijou with the same results. Its an excellent combination.

C3&4 - I'm using M-Cap Silver/Oil with significant sound improvement over stock MKP's, but any quality film cap should do a similar job. Which one will depend to some extent on what "type" of sound you're after. C3&4 replacement has been discussed a fair bit in these pages. C5 can also be replaced with a film cap for another worthwhile improvement. Bypass is then not necessarily needed; one less cap in the signal path should be better.

 

[runeight]

Quote:

Originally Posted by Ant1Xr1st /img/forum/go_quote.gif Some idea about OCL (output capacitor less) Bijow. (See pic.) In microcap works fine. Any comments? [size=xx-small]*sorry 4 my english[/size]

This circuit might actually work. I'd like to hear how you do. I've been working on something similar for the Bijou II. But different.

A few things that you probably already know:

1. The e12 will not be fast enough if you get any kind of HV arcing in the O/P section.

2. The regulators will not regulate that well under the heavy current draws that the Bijou might make compared to an active regulator. This is not at all terrible, just something to know.

 

[viction]

I have finished stuffing my boards and am now wiring everthing up. I found a diagram on audiologica for wiring the volume potentiometer but can't find anything for the NFB. The diagram on Cavalli's website is a little vague. TIA.