phase linear 400

MusicSteve

MusicSteve

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Gepetto said:
The voltage sag you observe with increased power output is a function of the quality of the load regulation of the transformer, the line cord and the AC mains service coming into the amp and is the main determinant of how the voltage drops with load. The resistance in the transformer windings has the largest effect, followed probably by the other two (I have no idea if you are running the amp on a wimpy extension cord, for example).

The capacitor value is a secondary effect since it is recharged every 8.3 msec by the transformer.

If you are driving the amp that hard to have the voltage droop ~6V (12V down on both rails), then you are also running into clip sooner (that is about 7.5% load regulation of the transformer). Flat-lining due to clipping will show up as noise in the higher frequencies.
Transformer load regulation is a function of the physical size of the transformer and the internal window size, which limits the size of the wire you can coil around the core. PL had to make some practical choices in that area and settled on the size they did for both the 400 and 700. You notice that the frame size on the 700 is much larger than the 400 in order to achieve a similar load regulation specification at 700W that the 400 does at 400W.
The control board is fine to much, much lower voltages (the regulated voltages are +/-15V). Clipping at the rails is your primary limiter.
Click to expand...
Joe
What is the Normal Transformer load regulation and running all the way up to Clipping.
If the Voltage drops to much (high current) and will cause problems to the transformer? or other components? (I use fans and always keep it below 110 degrees) Transformer seems to be a normal temp but I have not put a temp probe on it.

I also know that my speaker Impendences is low causing some of the problems and I have been adding resistors to increase it (I will run a impedances test Later to see what it really is)
 
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George S. said:
So we try to build them with a 15 or 20 amp IEC socket, 15 or 20 amp line cord. I use 14 AWG wire on the AC runs, but 16 AWG appears adequate. Use mil-spec PTFE/Teflon silver plated wire.
Insulate the transformer bolts, and use a heavy duty contractor grade power strip if your going to use one.
Don't think I experienced voltage sag at punishing sound pressures yet, but I haven't had a meter on the rails. My house does have good wiring, but it hasn't been specifically wired for multiple WOPLs. That's a future project.
The original PL cord is good for lamps, not amps.
Click to expand...
Thank George
I'm running from the inside the wall are14awg than I run a 12AWG to a power strip (only 14awg) than the original PL cord
don't think this is the problem since I normally have 2-PL 700II w no problems, except for power up and will trips the 15amd house breaker 1 of a 50 times (I just make a Soft start and I can tell they are working good )

It would be nice to see what you get from your + - DC rail. (might be a good test) I also saw your post about the 4 bolts and I have some SS bolts from work , don't know if their long enough but its on the list. I also tightened the bolts up which were loose.
 
laatsch55

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George S. said:
So we try to build them with a 15 or 20 amp IEC socket, 15 or 20 amp line cord. I use 14 AWG wire on the AC runs, but 16 AWG appears adequate. Use mil-spec PTFE/Teflon silver plated wire.
Insulate the transformer bolts, and use a heavy duty contractor grade power strip if your going to use one.
Don't think I experienced voltage sag at punishing sound pressures yet, but I haven't had a meter on the rails. My house does have good wiring, but it hasn't been specifically wired for multiple WOPLs. That's a future project.
The original PL cord is good for lamps, not amps.
Click to expand...
I've documented some SERIOUS voltage sag at times...but...ya know...someone had to do it..
 
MusicSteve

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laatsch55 said:
I've documented some SERIOUS voltage sag at times...but...ya know...someone had to do it..
Click to expand...
LOL I'm also taking it to the Extreme. And it sounds amazing until I hit the Tweeter rip sound lol
Did you have the Tweeter rip sound?
w all the room treatment and the speakers I made Dead, requires more Power. but has amazing sound stage and w the New board added even more Dynamic Range.
 
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#2,305
If you do find big caps work you, you can always add spacers between the chassis and faceplate along with longer bolts. Happy experimenting!
 
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Thinking maybe the best way to test this is on the bench with a proper load bank, distortion analyzer, signal generator, and scope.
Those may well be high frequency oscillations your hearing. Distortion.
Also have to rule out the rest of the system.
 
gene french

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George S. said:
So we try to build them with a 15 or 20 amp IEC socket, 15 or 20 amp line cord. I use 14 AWG wire on the AC runs, but 16 AWG appears adequate. Use mil-spec PTFE/Teflon silver plated wire.
Insulate the transformer bolts, and use a heavy duty contractor grade power strip if your going to use one.
Don't think I experienced voltage sag at punishing sound pressures yet, but I haven't had a meter on the rails. My house does have good wiring, but it hasn't been specifically wired for multiple WOPLs. That's a future project.
The original PL cord is good for lamps, not amps.
Click to expand...
how does one insulate the transformer bolts??
i have not installed one in the chassis yet...it has not arrived....
 
MusicSteve

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George S. said:
If you do find big caps work you, you can always add spacers between the chassis and faceplate along with longer bolts. Happy experimenting!
Click to expand...
Not a option for the 700II cap to the 400II , their no room and I can buy the same value 15kUF for the 400II which will fit from Joe) I did use the old 700II Caps & than switched to the Newer 700II caps.
 
MusicSteve

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gene french said:
how does one insulate the transformer bolts??
I have not installed one in the chassis yet...it has not arrived....
Click to expand...
When your done, Buss out the each bolt to Ground and check and make that it is open (when I do mine I will only do one bolt at a time I don't want to to open any of the steal shanks) I also might use a brush to get the rust out I hope theirs is none LOL . also George said to use Stainless Steal Bolts
 
gene french

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MusicSteve said:
When your done, Buss out the each bolt to Ground and check and make that it is open (when I do mine I will only do one bolt at a time I don't want to to open any of the steal shanks) I also might use a brush to get the rust out I hope theirs is none LOL . also George said to use Stainless Steal Bolts
Click to expand...
i can do that too....lol
thanks....
i am curious why georges transformer and rectifier without caps measures 80v,,,,and mine is only 60v....
i think i will add caps before i read voltages again....
should be easy to pick the best one...
 
MusicSteve

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gene french said:
i can do that too....lol
thanks....
.
Click to expand...
Gene and George
I pulled one bolt out and I would have to drill hole's in both transformer covers and it still might not work?

So its a no go for me , yours might have bigger holes.
So for me I don't want to take the change of loosing up anything in the inside the transformer (metal and Varnish) I did tighten up the bolts and they were a little loose.
 
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