Well, I finally did it...WOPL

Z

Zach C.

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Put the White Oak driver board in my 700B...er...WOPL 1000. :)

I am very pleased.

Better bass definition and extension.
More detail
WAY less noise. No hum, whatsoever, and I can barely hear anything with the volume knob maxed out and no source playing with my ear pressed against the speaker.


It's amazing what all that headroom does for dynamics and clarity at even moderate levels. You often her people say that most solid state amps sound pretty much the same when used within their limits. I think there is some truth to this. But, I also believe that most folks grossly overestimate what is "within their limits." There is a very noticeable difference going from a PL300 II to the WOPL, and the 300 ain't exactly crap.

Right now, it's just hooked up to some DIY 6.5" MTM towers in the kitchen. Might be a while before it gets moved to the line arrays, due to logistical issues.

Good stuff.


WOPL 2.jpg WOPL 1.jpg
 
Z

Zach C.

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laatsch55 said:
The 300 was the quietest and best amp from a THD & N standpoint.
Click to expand...
The 300 is a nice amp, but it just doesn't have what the WOPL1000 has.

Dayum the bass is good. Not exaggerated, just really good.

I keep asking myself if it's the low output impedance, or the stiff supply, or the huge watatge reserves, or...

I saw something where a guy was saying these amps had wimpy power supplies. Smallish caps sure, but the trannies are massive.

My suspicion is that this is why the caps could be smaller. No need to store huge amounts of current when you can just get more off the line.

I feel like I remember reading in Randy Sloan's book that you really only needed enough to smooth the ripple from the bridge to the point of your amp's power supply rejection ratio, as long as your transformer was up to snuff. Maybe I dreamed that though.

Thoughts?
 
laatsch55

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Randy's formula was 1,000 uf per 10 volts of rail voltage PER RAIL. The reason the low end is so good is because it's frequency response is only down .13 db at 10 hz. Oh, and all the above ...
 
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Looks really good there! Only one thing - on the DC protect I see those white wirewounds for the Z networks. If you still have the two 10 ohm pairs that were in there, suggest you put those back in place of the WW's.

Here's a pic from a 700 I did awhile back showing them... tie them in parallel then stand one side up, other side you may need to extend the lead a lil..

done4now.jpg
 
laatsch55

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Good catch Jer. Zach, get the white 4.7 ohm off the zoebel. They are very inductive and lead to oscillations......
 
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De-ja-vu we've been here before but the problem was not well understood then.........it is now.
 
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Zach C.

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laatsch55 said:
Randy's formula was 1,000 uf per 10 volts of rail voltage PER RAIL. The reason the low end is so good is because it's frequency response is only down .13 db at 10 hz. Oh, and all the above ...
Click to expand...
So, you're saying that Sloan's formula works out to what Carver did, of twice that?

I could just go look, I guess. :)
 
premiumplus

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Nice work, sir! Very clean. Did you isolate the input jacks from chassis ground and follow Joe's suggested grounding scheme?
 
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Zach C.

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jbeckva said:
Looks really good there! Only one thing - on the DC protect I see those white wirewounds for the Z networks. If you still have the two 10 ohm pairs that were in there, suggest you put those back in place of the WW's.
Click to expand...
Thanks for the compliments fellas. And, especially thanks for the heads up on the zobel thing.

Some of you may recall that I had quite a bit of trouble getting this amp to come up when the DCP board was installed. I did the Gepetto ground rewire and added snubber caps on the bridge and bypass caps on the backplane, and this straightened things up. Wish I'd done those things one at a time, but I didn't.

It would come up fine with the original zobel in place, but would not settle without it (open output) or with the DCP installed.

Since it wouldn't come up "open" I don't think the wire wounds were hurting me, and I'm not getting any excessive idling temps, but that's good to know.

I do still have the original zobel, so I'll be fixing that soon.

I appreciate the compliments even more since I keep thinking it should be tidier in there. I'm a bit of a slob myself, but I want my work to be top notch on anything I touch. A desire for perfection that probably stems from mommy issues. :)
 
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Zach C.

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premiumplus said:
Nice work, sir! Very clean. Did you isolate the input jacks from chassis ground and follow Joe's suggested grounding scheme?
Click to expand...
I did.

I should also add that there were zero issues when installing the driver board other than a bad connection to one of my dummy loads that had me scratching my head for a minute. Both channels showed output on the scope, but one was much lower voltage than the other, for obvious reasons.

One other thing...Are you guys biasing these on the high side of spec? I noticed that mine wants to run right at .45 with the trim pot centered, and will only just get to .35 with it minimized. I went with .45

While I did get her pretty warm yesterday, the idle temp seems fine. I'm driving 4r speakers and never did get the volume control much past half, but that's still asking for a lot of current. Come to think of it, IDK what that Nikko pre-amp puts out voltage-wise. I might not even be close to full output. Hmmmmmmm

I may have to upgrade either the power cord or the wiring to the the outlet. I was getting dimming lights on the meters when turned up. :) :) :)
 
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Zach C. said:
I was getting dimming lights on the meters when turned up. :) :) :)
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From my experience, dimming meters mean the heat protections will soon activate. Bias is probably a little too hot or you need some more cooling
 
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Zach C.

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Northwinds said:
From my experience, dimming meters mean the heat protections will soon activate. Bias is probably a little too hot or you need some more cooling
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That could be, but I was getting it after the amp had cooled completely, and I had just turned it back on and turned it up a bit. Like I said before, I'm using 4r speakers, but the VU meters weren't even hitting -3dB.

I'll play around with it a bit and find out. That'a gonna have to wait, though. The wife just got up. I think she may object.

Pretty sure I'm going to need fans regardless. I am a whiny little bitch when it comes to fan noise, and you can't pump out the jams all of the time. Anybody know of a good temp regulated controller I could build/ buy?

Or is that a new Phoenix product? :)
 
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Zach, Joe linked us to a PWM variable speed setup quite awhile ago. I've found If I need fans, I ain't gonna hear them F*&^%$# anyway....
 
laatsch55

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Larrt showed Me that yeARS ago. If you are shooting for no fans with a 4 ohmload, triplethe cooling area
 
laatsch55

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Zach, if you are going to bias them past 400, replace R38, R39 with 15 ohm 1 watt 1% metal film resistors.. You can go to 525 then.
 
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