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Old 27th February 2013, 06:22 PM   #1
daly2k is offline daly2k  United States
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Well I don't know if I have to apologize or not but I fell off the DIY wagon and bought a used pair of XA100.5 power amps. Yes I know that I built a pair of x amps from this thread which were actually a converted pair of Aleph 200's I had built in 2001. I also have built the Pass/Thoroguard A75 which I am retiring after 23 years of faith full service-it is starting to hum and I suspect the poor caps.


The question I have is that I have bi amped line arrays. I also bought about 6 years ago a Pass X350.5. The idea is to have an all class A driven loudspeaker.

I am now beset with do I use the 350.5 to drive the tweeters as for sure it will never leave class A or use it on the mid/woofs where it just might happen? Crossover is at 2700hz.

By the way my wife was never impressed with my metal work or that the enclosures were mounted on dolly wheels.

When I wanted to rebuild the X amps using a stripped engine small block V8; put the tranny in the oil pan and the outputs in the heads with the input board on the manifold she was ready to call the doctor. Of course I would use the politically correct chrome covers.
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Old 27th February 2013, 06:47 PM   #2
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Originally Posted by daly2k View Post
..........
I am now beset with do I use the 350.5 to drive the tweeters as for sure it will never leave class A or use it on the mid/woofs where it just might happen? Crossover is at 2700hz.

.....
not really enough info

wee need you to cover other possibilities , same as more info about spks and amps - are you using just these two amps , is there subwoofer (needing an amp or two ) etc .

off course it looks as blasphemy using so potent amp just for tweets , when you can have smaller - more economical one , and in same time most probably sweeter sounding


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.......... Of course I would use the politically correct chrome covers.

in that case , most possible is that Doc would be on your side ; all men are weak on chromed covers
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Old 27th February 2013, 06:58 PM   #3
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Just my 2 cents, but try both ways. I would use the XA100.5 on top and the X350.5 on the bottom.

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off course it looks as blasphemy using so potent amp just for tweets
He's right. But, you have to do with what you have, right?
I use a 5w for 120Hz to 20k.
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Old 27th February 2013, 08:07 PM   #4
daly2k is offline daly2k  United States
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I have line arrays, each speaker has 12-5inch ribbon tweeters and 12-5inch eton cone mid/bass with a ported output. Useful output is down at about 45hz.
These speakers are crossed over to subs at about 60hz. The subs have built in 300 watt class AB plate amps and their own cross over controls plus volume.
The line arrays are biamped at 2700hz @ a slope of 48db/oct.

My issue with my home built X projects is the relative DC offset varies especially while the amps are heating up so I don't use them for the tweeters.
I use them on another hard working system.

I listen to music from 75-85 db so I think I have more than enough power. I also built a passive outboard xover for the line arrays at 24db/octave and 2500 hz.

To protect the tweeters I can put about 50 uf of cap. in series with the +/- signal outputs of the tweeter amp but I don't like doing this. I love the class A Pass sound and my wife can live with the design of the factory amps.

I enjoy working on electronics during the winter months but prefer being outside during the summer. The factory amps have very low relative off set at less than 5mv. My tweeters do have an impedance matching xformer and in theory should be immune to dc but I am trying to be safe. thanks for the feedback. dave
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Old 27th February 2013, 08:19 PM   #5
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Hm, U definitely have to apologize!

Kiddin; U cant focus on class A, B or whatever in that way. There are AB-amps that are totally usable in your setup. U could build a good AB-amp and compare to a bad A-amp untsoweiter. There are several ways to move distortion out of an amps window of operation.

Last edited by siouxiebuff; 27th February 2013 at 08:26 PM.
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Old 27th February 2013, 08:27 PM   #6
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that turntable is absolute junk, you better send it over to the east coast and I will 'recycle' it for you!
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Old 27th February 2013, 08:45 PM   #7
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if you like both amps , especially 'cause you owe them already , then just try which one you prefer on top , and keep like that

sweet dilemma

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Old 28th February 2013, 02:35 AM   #8
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Put the 350.5 on the bottom.

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Old 28th February 2013, 10:39 AM   #9
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Quote:
Originally Posted by daly2k View Post
the Pass/....... A75
Mr Norman Thagard (turning 70 this year)

Nothing wrong with Edelbrock/block, "edel" means noble.
(how much for the antique Rorschach gun in the window ?)
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Old 28th February 2013, 11:09 AM   #10
Jay is offline Jay  Indonesia
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Of course I would use the politically correct chrome covers.
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Originally Posted by vdi_nenna View Post
Just my 2 cents, but try both ways.
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Originally Posted by Zen Mod View Post
just try which one you prefer on top , and keep like that
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Put the 350.5 on the bottom.
Of course, if your ears have no idea which one is good at which, then use the politically correct decision, which is what NP sayz...
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