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Old 19th April 2007, 06:17 PM   #401
steenoe is offline steenoe  Denmark
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Quote:
Originally posted by apassgear



Wait and see to when those Fostex are really broken in.

Good to see you back after some nice vacationsÖ

Cheers
Thanks a lot Tony. I know the Fostex drivers needs a long breake in time. Mine are probably not fully broken in yet, but I felt it was fair enough to compare amps on them, nonetheless? Here is another shot from the Azorer's.

Steen


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Old 19th April 2007, 06:56 PM   #402
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Steen,
Don't feel bad about the quote thing. It's counter-intuitive. You'd think you'd be able to choose from the Reply screen, since that's what you're doing. Nope, gotta choose before you go in, Oh, well.
Caps: People fixate on the rolloff frequency as though it's a brick wall filter. Ain't so. A 6 dB/oct filter starts rolling off ages before the formal -3dB point, And then there's the phase shift to worry about.
Or you could peek in Nelson's stock room and note that he buys 220uF caps by the metric ton. If it's handy, sometimes that's the part you use.

Grey
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Old 19th April 2007, 07:28 PM   #403
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Quote:
Originally posted by MiiB


If this is the case the 22uf should be sufficient. At least if simulations are just a little right. 22 uF is app 2 Hz bandwith.

I suspect there may be other reasons for selecting big caps other than bringing frequency response down to 1/10 Hz
The larger the caps, the longer the delay for turn-on thump.

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Old 19th April 2007, 08:03 PM   #404
MiiB is offline MiiB  Denmark
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Steen did you get any fish at azorerne.

Got three yesterday in Mariager.

22 uf would make it feasible to use some better Caps. After all they are in the signal path.

I know from experience what is does in loudspeaker design to go from EL.caps to film types. Even if it's costly for larger values for midrange filterening.
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Old 19th April 2007, 10:13 PM   #405
massimo is offline massimo  Italy
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About coupling caps, any suggestion for a specific brand/type?

Maybe a NP cap could be a good choice, such as the N or Nx series from Black Gate.....
Or the ubiquitous Panasonic FC or the new FM?
BTW, does anybody know that Panasonic released a new series "for Audio" available from Farnell?
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Old 19th April 2007, 10:15 PM   #406
Vix is offline Vix  Yugoslavia
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Steen, F4 is a terrific amp, no doubt. I thought I envy you about an amp. Not that much. Azorer's are better! If only we could combine the magical sound of F4 with that natural beauty. That would be heaven.

p.s. I hope moderators don't mind you posting more pictures from your vacation!
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Old 20th April 2007, 12:41 AM   #407
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Quote:
Originally posted by massimo
About coupling caps, any suggestion for a specific brand/type?

Maybe a NP cap could be a good choice, such as the N or Nx series from Black Gate.....
Or the ubiquitous Panasonic FC or the new FM?
BTW, does anybody know that Panasonic released a new series "for Audio" available from Farnell?
You canít go wrong with FC but itís a good idea to test BG standard or the more pricy Nís.
Iíve heard mix reactions to FMís as coupling caps, thou itís an excellent spec lytic.

But in the end itís a personal thing or taste and will also depend on the other components your system has, so let your ears be the judge.

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Old 20th April 2007, 06:18 AM   #408
steenoe is offline steenoe  Denmark
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Quote:
Originally posted by Nelson Pass


The larger the caps, the longer the delay for turn-on thump.

The F4 behaves very civilized on turn-on
Regarding the cap's; I used Panasonic FC's in the F4 with good results (as you figured out by now ) I am not sure if there is a lot to be gained from using more expensive caps. When restoring the NS10 preamp, I used only BG N's in the signal path. I am sure that was a good choice, since it sounds like mountainair in an early morning Just like Keb' Mo's voice, if you know what I am talking about Blues does
Vix, sorting out the 600+ pictures makes me want to go back to Sao Miguel. Unfortunately it was too windy to go fishing, so I didnt catch any Marlin this time. Next time I will!
MiiB, is Mariager Fjord your homewater? Its one of the most beautyful places in DK.

Steen
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Old 20th April 2007, 07:16 AM   #409
massimo is offline massimo  Italy
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Steenoe, as you're one of the few who already have built an F4, what do you thnk if I send you (for free, of course) 4 pcs new Pana "for Audio" 220uF/35V ?
Do you have time to try them and report us how they do sound?
They are quit small and I'm pretty sure they fit in any pcb.
If you accept, drop me a mail with you complete address.
I'm just curious about them and I don't any audio gear using EL caps as coupling caps where to test them by my own.
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Old 20th April 2007, 07:37 AM   #410
cviller is offline cviller  Denmark
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Wow, nice holiday pictures steen. Welcome back!!

Quote:
Originally posted by NP
I have an abstract interest in the acceptance of the F4, but it's
bandwidth is not the part that will influence that - it is the total
lack of voltage gain. It's a surprisingly good sounding piece,
but very few consumers will find that out.
I'm very interested in how the consumers react to this amp too - and I don't even have money evolved...
It is more like a building block than an actual power amp. Everytime I plug it into my system I'm startled on how wonderful it sounds and when I get all excited and want to turn up the volume, I get disappointed cos it won't go any higher. (well I just have to build myself a preamp)

It has been very hard for me to explain to family and friends that this amp has no voltage gain - it just seem too abstract for non-techies. But I guess firstwatt's audience are very competent buyers who know how to interpret specifications and look at the nice illustrations in the manual.
It would probably be a bad call to put in a full page advert in stereophile along with a review - sure you'll sell amps, but I'm afraid that would attract buyers that don't understand what they have bought.
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