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Bijou All Tube Futterman Headphone Amplifier - Page 100

post #1486 of 3981
10/3/08 at 11:27am
Quote:
Originally Posted by runeight View Post
Dantes, this will shorten tube life and cause the tubes to draw much more current than what the PS is expecting.

For 6922 the range of heater voltages (on the spec sheets) is 6.0V to 6.6V. This will be similar for the other tubes.

Is there a way you can make it lower? Decreasing the heater voltage will also help with the B+ because it will reduce the current drain by the amp boards.
I will try to wire the transfo with a different configuration but this will lower the primary to 240V.

In other hand, this transfo make some audible noise. I think i will change it. But it's not easy to find an equivalent to the hammond 370 in france.
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post #1487 of 3981
10/3/08 at 1:14pm
What transformer are you using? I have forgotten.
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post #1488 of 3981
10/3/08 at 2:23pm
huhu, i do not tell you the model because i do not know myself
The only thing writen on it it's "Vedovelli" and all voltage informations.

It's an old one from an old dead equipement, but it is OK.
It have a lot of wirering possibility.
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post #1489 of 3981
10/3/08 at 4:16pm
Quote:
Originally Posted by adamus View Post
I would quite like to lick that.

ferrari, isnt it also you that has a stock of super expensive russian tubes to go in there?
If you are talking about this, ...yes!
However, with 6N1Ps (at much lower cost) in the front end this amp sounds great too.
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post #1490 of 3981
10/3/08 at 5:38pm
Here is mine.

The case is not finished and it will not be as beautifull as some seen here, but it works not too bad

The box was a power unit of an old Sun server.
Just the size... not many room to work in fact

I'am happy, it's my first diy project

Do not pay attention to the mess in the box


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post #1491 of 3981
10/3/08 at 7:22pm
nice industrial look there
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post #1492 of 3981
10/3/08 at 7:43pm
Quote:
Originally Posted by Dantes View Post
Here is mine.

The case is not finished and it will not be as beautifull as some seen here, but it works not too bad

The box was a power unit of an old Sun server.
Just the size... not many room to work in fact

I'am happy, it's my first diy project

Do not pay attention to the mess in the box
Sun is my ATF for salvage cases, as evidenced by my m³ builds in 911 cases.

Ron, the suspense is killing me - how does the Bijou look in that case?
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post #1493 of 3981
10/4/08 at 12:04am
Quote:
Originally Posted by Ferrari View Post
If you are talking about this, ...yes!
When you put those 6H30-DR's in...are you running stock, or with Regal's mod? I read many posts back that those tubes need to be run with more current then the original build provides. Regal's mod (5mA?) may not even be enough to extract the most from them. My Bijou is running stock at 1mA and my 6H30's (JJ's, not the DR's) don't sound as good as the 6N1P's.
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post #1494 of 3981
10/4/08 at 2:16am
Quote:
pabbi1 writes: Ron, the suspense is killing me - how does the Bijou look in that case?
The Bijou looks quite good in the large case. The parts/boards just seem to go in obvious places in the layout, for an organized and roomy appearance. It might look good with a black epoxy paint finish, if you mask the boards well with newspaper and tape. Then either a wooden or metal front panel. I will take pictures, when the amp boards are mounted. My wife just received a digital camera awarded to her from a health-care company where she works.;-)
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post #1495 of 3981
10/4/08 at 2:24am
Quote:
Originally Posted by amphead View Post
The Bijou looks quite good in the large case. The parts/boards just seem to go in obvious places in the layout, for an organized and roomy appearance. It might look good with a black epoxy paint finish, if you mask the boards well with newspaper and tape. Then either a wooden or metal front panel. I will take pictures, when the amp boards are mounted. My wife just received a digital camera awarded to her from a health-care company where she works.;-)
Well, I thought the Bijou would look good in blue, with the wood fromt panel, like the Blue Hawaii... with a metal badge made from your vector logo file... ;-)
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post #1496 of 3981
10/4/08 at 2:31am
Yeah, blue with wood panel should look awesome. That's why I haven't done any overt cosmetic work, so that you can customize the way you have in mind. Well, tomorrow I have a long drive once again......
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post #1497 of 3981
10/4/08 at 4:26am
Quote:
Originally Posted by huskydawg9 View Post
When you put those 6H30-DR's in...are you running stock, or with Regal's mod? I read many posts back that those tubes need to be run with more current then the original build provides. Regal's mod (5mA?) may not even be enough to extract the most from them. My Bijou is running stock at 1mA and my 6H30's (JJ's, not the DR's) don't sound as good as the 6N1P's.
Non of both!
As I mentioned it earlier, this amp is build with a personal touch (same as my SOHA II).
The amp and its PS are modified to make them more capable to run the 6H30-DR (and 6N1P-EB) at the appropriate higher current bias.

Without criticizing the design (I understand the design goals/compromises very well), but running 6H30-DR at the stock 1mA is not worth the tube and the money (better is to give the money to homeless folks).
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post #1498 of 3981
10/4/08 at 12:15pm
Yes I agree Ferrari. The original design had a power budget in mind and was running the 6922 a little light. A high current tube like the 6h30 is running almost starved for current. But, the regal mod (5mA) puts it at a better op point, still a bit below where it might like to run. It will be interesting to hear results.
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post #1499 of 3981
10/4/08 at 12:27pm
Quote:
Originally Posted by Ferrari View Post
As I mentioned it earlier, this amp is build with a personal touch
The amp and its PS are modified to make them more capable to run the 6H30-DR (and 6N1P-EB) at the appropriate higher current bias.
.
Care to share your mod to run the 6H30's? Alex mentioned that the PS would have to be tweaked to get the current bias up to where it needs to be.
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post #1500 of 3981
10/4/08 at 5:29pm
Quote:
Originally Posted by huskydawg9 View Post
Care to share your mod to run the 6H30's? Alex mentioned that the PS would have to be tweaked to get the current bias up to where it needs to be.
Alex (runeight) and I are talking about increasing the quiescent current in the input/phase splitter stages of the Bijou in order to get a better operating point for tubes like 6N30-DR and NOT over PS tweak.
There is nothing to tweak with the PS though. It has its own limit and that’s what we have to live with!

To run the 6N30-DR in my build, I am using use a heavier transformer (250V/250mA; 6.3V/6A) and 2 PS (one for each channel) and set the quiescent current in the input/phase splitter stages to ~ 7.5-8mA.
Obviously, this is far beyond the spec of the Bijou design and unreachable for an amp with a PS based on a Hammond 270DAX or something like that.
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