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Old 25th March 2005, 10:38 PM   #1
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Default Best class A for millwatts

I知 getting close to building high efficiency speakers (100 dB) in horns, to give about 105 dB. It値l be active from 250 Hz up, ie mids and treble.

的n every amplifier those first few watts, or milliwatts, are the best sounding watts
So 15 watts is plenty, 8 enough, and mostly playing at about 0.3 watt.

The guy that sold me the horn flares suggested a headphone amp.

Of the Pass designs, which is best for that power level, and what would an approx all up cost be? (I知 also considering a tube amp)

ZEN V1/ the light bulb version/ a mini A? Aleph-X on batteries?


Thanks
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Old 26th March 2005, 06:51 AM   #2
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Default Mini A or Aleph-X on batteries?

Come on, at least 100 (?) of you must know more about Pass designs than me.

Who use speakers of > 100 dB ?

Which more likely or should be better, the Mini A or Aleph-X on batteries?
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Old 26th March 2005, 07:17 AM   #3
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Dunno about the Pass designs, but you could give Kevin Gilmore's 1W Class A discrete amp a try

http://headwize.com/projects/showfil...lmore3_prj.htm
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Old 26th March 2005, 07:40 AM   #4
Henrik is offline Henrik  Denmark
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One of the Son Of Zen variations would be verry nice or just a SOZ.
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Old 27th March 2005, 12:09 AM   #5
grataku is offline grataku  United States
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What impedance do you need to drive?
The balanced line stage + a follower or a current source SOZ amp would work depending.
What driver is that you are going to use?
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Old 27th March 2005, 02:07 AM   #6
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Antness, thanks
(I should perhaps have made this clearer) although mostly playing at about 0.3 watt, 15 watts is plenty, 8 enough ie about 10-15 watts is the target.

grataku
It痴 for mids and treble in a horn, all nominal 8 ohms:
From 200 about 800 Hz will be the JBL 2202H, 100 dB & nominal 8 ohms.
800+ will either be a compression driver (older JBL/ P.Audio/ BMS); or a PHL 1040 & and Esg1. The PHL minimum impedance is 6.2 ohms, the Esg1 is a pretty flat 7 ohms; a P.Audio BM-D750 nominal 8 ohms.

How would a SOZ compare with a mini Aleph??

Thanks!
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Old 27th March 2005, 01:35 PM   #7
grataku is offline grataku  United States
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It seems to be a question of the harmonic distortion character of the amp, the aleph is SE so you get mostly second, the SOZ is balanced so you get third (harmonic).
I never built an aleph and went directly to the alephX so I can't tell. There's been alot of talking about this @ here.

Besides the amp type you should look at output mosfet type, too.
In that freq range maybe the irfp240 is your best bet the miniA comes with the irfp044 that maybe better for subs. you should definitely compare
If you are talking bi-amp with high eff your number can be scaled down to 2W enough 4W plenty.
Your system could endup looking very cool with tiny amps driving huge speakers.
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Old 27th March 2005, 09:45 PM   #8
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Thanks! Grataku
Very interesting re the harmonics characters of the amps.

I致e done some searching on output mosfet type here at diyA pass labs, but except they池e the same package size, no answers yet:

Is your suggestion of the irfp240 based on electrical or aural characteristics?

Presumably I壇 need a different number of output stages??
How would that be calculated?

鍍iny amps driving huge speakers:
May become tiny amps with mid size heat sinks driving substantial speakers creating (via horn loading) huge sounds
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Old 28th March 2005, 05:26 PM   #9
angel is offline angel  Norway
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Quote:
Originally posted by antness
Dunno about the Pass designs, but you could give Kevin Gilmore's 1W Class A discrete amp a try

http://headwize.com/projects/showfil...lmore3_prj.htm
That amp is for 500mW into 32 ohm.. It can barely deliver 2mW into 8 ohm..

Although, if someone has a suggestion for a set of transistors with similar specs to the output transistors, but with a higher current capacity, I guess one could use a CFB for the current gain stage and get a decent output.

2mW is a bit low for me.. But I would very much like to see some nice sub-10W designs apart from the SoZ (low damping plus my current speakers equals muddy sound, unfortunately).
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Old 28th March 2005, 07:22 PM   #10
grataku is offline grataku  United States
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Angel,
if you add the patented Pass CCS with AC current gain to the SoZ you should get over the low damping problem.
However, if you complain about muddy sound the soz is probably not for you.

rick,
everything within the measured +/- 0.05 THD is ultimately based on aural consideration, I think.
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