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Old 2nd October 2002, 09:20 PM   #11
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Obsession with symmetry and matching is a natural
part of being an audiophile.

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Old 2nd October 2002, 10:43 PM   #12
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In someway a wrong obsession.

Energy lost into chaos (random) is totally waisted.
Energy lost into (near ideal, not optimal) symmetric circuitry will cause (return as)harmonic (ie. ordened) distortion.

Total chaos is in my eyes even a way too lose entropy in the universe.
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Old 3rd October 2002, 01:01 AM   #13
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Thumbs up I like Symmetry.

Only I think of things like:
  • Raquel Welch
  • Sophia Loren
  • Various other beauties
In high school I had a strange Analytical Geometry teacher who perverted my mind with very womanly examples of symmetry during his lectures...

Later,
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Old 3rd October 2002, 01:49 AM   #14
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I use MPSA42.
I use ZTX450 too.
I use 2N6517 too.
All matched.

I have only one power amp. So, I use the above three
simply to replace in turn, whenever I get to feel boring.
Its fun of soldering and re-soldering. Yeah...it is indeed.

If it is NPN transistor,
if it has big enough CE, CB and EB breakdown voltage rating,
if it works hard-saturated, and
if it has a base-emitter potential of about 0.66V,
which one?, does not matter. This is my lesson from a book and
the articles of Nelson Pass.

Cowanrg...



I was teaching a shark how to swim...
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Old 3rd October 2002, 02:07 AM   #15
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jh6you,

It seems like any respectable BJT will do in this situation. I have even built a test circuit using the venerable 2N2222 in place of the ZTX450/MPSA18 for the Aleph current source. Worked pretty good with a hfe of ~125.

I wonder what the minimum hfe would be in this situation. I might tinker with this tomorrow if I get some time.

cowanrg,

8-100W Class A Amplifiers?! I hope that your climate control system is up to the task. Don't each of these amplifiers idle near 400W?

Later,
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Old 3rd October 2002, 03:24 AM   #16
cowanrg is offline cowanrg  United States
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hehe, yeah, 8 aleph2's.

but 6 of them are going to be in a theater, and the other 2 in a listening room. they wont all be together. i know i know, its nuts. but hey, i want to do it. and its only 300 watts of heat :-)

Quote:
Originally posted by stadams
jh6you,

It seems like any respectable BJT will do in this situation. I have even built a test circuit using the venerable 2N2222 in place of the ZTX450/MPSA18 for the Aleph current source. Worked pretty good with a hfe of ~125.

I wonder what the minimum hfe would be in this situation. I might tinker with this tomorrow if I get some time.

cowanrg,

8-100W Class A Amplifiers?! I hope that your climate control system is up to the task. Don't each of these amplifiers idle near 400W?

Later,
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Old 28th May 2005, 11:04 PM   #17
Coulomb is offline Coulomb  England
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So did we ever decide what the best choice would be?

BC546
BC550
MPSA18
MPSA42
2N2222
ZTX450
ZTX550
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Old 28th May 2005, 11:27 PM   #18
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cowanrg,

So You're the one responsible for global warming and climate change? Shame on you.
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Old 29th May 2005, 03:57 AM   #19
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I just hope you have a dedicated line rated at 120 VAC @ 30 amps or a 220 VAC dedicated line rated @ 15 amps just for the power amplifiers. You will need at least 10 awg wiring to the outlets @ 115 VAC. Six channels of Aleph 2 is about 1800 watts constant draw which is a tad too close for a 120 VAC, 20 amp circuit. A 120 VAC 20 amp circuit may not be safe if the run is long. A long run could be a fire hazard due to heat dissipation in the wiring. It looks as if your best bet is either a 120 VAC 30 amp circuit or wire the Alephs for 220 VAC and run a 220 volt line (if your trannies have dual primaries). I also hope you have at least 150 amp service or better in your home especially if you electric appliances. All in all though, having 8 Aleph 2's is not a bad problem to have.
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Old 29th May 2005, 04:59 AM   #20
cowanrg is offline cowanrg  United States
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wow, brought back from the dead huh!

i have since scaled back my designs for my main system and will probably only include 2 aleph2's, in addition to my 2 aleph3's i currently use. i dont have the time, money, or energy to finish off all my cases that i have right now. i will be just finishing two of them, and leaving the others for another project.
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