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Old 14th January 2010, 09:59 PM   #101
juma is offline juma  Serbia
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200mW per one BF862 is OK, and here you won't have more than 130mW (especially when you don't have to worry about thermal drift).
I prefer to keep small signal circuits as compact as possible and this way Gates are too exposed for my taste. OTOH those are line level signals and there shouldn't be much of a problem. Let's see how it works - you have a nice box and shielded transformer, I guess it'll be all right.
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Old 14th January 2010, 10:23 PM   #102
njepitt is offline njepitt  United Kingdom
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Default Working!

Hi Guys,

Well, at least two out of the four buffers are working - one didn't work when I tested it, but it's probably something simple since two are OK. (I didn't check the fourth yet... I wanted to listen for a while first...)

In the end I managed to get the boards out and switch the 1k for 10R without nasty band-aid type solutions, although it was pretty hard work.... Maybe that'll teach me to check things more thoroughly...

All off-board wiring inside is strictly temporary, just good enough to test whether things work, since it'll all have to be redone after the crossover section is done. Nonetheless, I've been listening to the music I use to check new projects (Artur Pizarro playing Beethoven Piano Sonatas, Elisabeth Schwarzkopf singing Strauss, among other things), and it sounds very good indeed! Right now I'm testing it with the mini-Aleph-J juma helped me with (which is also BF862!); I'll have to wait to try it with the F5 in the living room, which is where it's really intended for.

I've included two photos of the box closed up - I'm using 10-turn wirewounds for left and right volume, hence the complicated knobs. One switch for on/off, the other for choosing between two inputs. The hole in the middle is for a LED to show power, when I get around to it... I've decided there is no reason that hifi equipment has to be black or silver, so I decided to use what in the UK we call "British Racing Green" (probably people from other places don't call it that ) but in the end it looks a little like a piece of army surplus equipment... Oh well... (Next time I'll use fire-engine red...)

As always, any comments on the build are most welcome. I'd be particularly grateful for any suggestions on how to economise space, since I am beginning to think I'll have space problems for the crossover section. (Posts about that stage will be in the corresponding thread on the B1 crossover.)

Cheers

Nigel
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Old 14th January 2010, 10:37 PM   #103
eLarson is offline eLarson  United States
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Quote:
Originally Posted by njepitt View Post
Hi Guys,

... I've decided there is no reason that hifi equipment has to be black or silver, so I decided to use what in the UK we call "British Racing Green" (probably people from other places don't call it that ) but in the end it looks a little like a piece of army surplus equipment... Oh well... (Next time I'll use fire-engine red...)
...
Actually we do. Well, okay, I do--I can't speak for the other 299,999,999 people in the US.

Anyway, it looks very nice, indeed.
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Old 15th January 2010, 07:58 AM   #104
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The dials look way too cool! Did you break 'em of combination locks?
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Old 15th January 2010, 08:14 AM   #105
massimo is offline massimo  Italy
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Quote:
Originally Posted by njepitt View Post
...
I've decided there is no reason that hifi equipment has to be black or silver, so I decided to use what in the UK we call "British Racing Green" (probably people from other places don't call it that ) but in the end it looks a little like a piece of army surplus equipment... Oh well... (Next time I'll use fire-engine red...)
....
Absolutely famous all over the world and that will be the colour of my next Aston Martin!

But pls leave red to Italians and our Ferrari! Even if few people know that the "official colour" of Maranello team is yellow. Red was the racing colour for all the Italian cars, as well as white (and later silver) for the German ones, blue for French, etc.
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Old 18th January 2010, 04:48 AM   #106
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glossy white spray will make it look elegant
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Old 18th January 2010, 12:12 PM   #107
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can i ask a stupid question? whats the VAC rating of the transformer used. ~.~
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Old 18th January 2010, 12:24 PM   #108
brianco is offline brianco  Ireland
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Was your repair what one might refer top as a "Pitt Stop"?

(My old Maseratis were each finished in Italian Racing Red with natural light tan interiors....BRG did not suit them and Irish Emerald Green was even worse. THey always used to say that only the Gods should wear green or flaunt emeralds!)
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Old 18th January 2010, 12:35 PM   #109
njepitt is offline njepitt  United Kingdom
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Originally Posted by chchyong89 View Post
can i ask a stupid question? whats the VAC rating of the transformer used. ~.~
It's not a stupid question, although maybe someone else has a better answer for you.

I am using one transformer for four output buffers and up to 14 symmetrical buffers - you can see the planned circuit on the thread about the B1 active crossover if you're interested. For this I have a 3A trafo, at 24 -0 -24, which comes out to 144 VA. I should point out, however, that a 2A trafo would likely have been enough, and that here in Brazil trafos are sold by current rating, not power rating, so these values may be a bit misleading. (Also, I tend to overengineer...) If you are planning a stereo preamp like juma's original design something much smaller should suffice.

Cheers

Nigel
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Old 18th January 2010, 12:40 PM   #110
njepitt is offline njepitt  United Kingdom
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Quote:
Originally Posted by brianco View Post
Was your repair what one might refer top as a "Pitt Stop"?

(My old Maseratis were each finished in Italian Racing Red with natural light tan interiors....BRG did not suit them and Irish Emerald Green was even worse. THey always used to say that only the Gods should wear green or flaunt emeralds!)
Whoooaaaa.... I know it's OT, but tell us more!!
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