Bridged Phase Linear series ll

[grapplesaw]

Need to get some mineral oil to fill this.

 

[grapplesaw]

I could not wait
Soooo After full power testing is now done. We are short of the 750 Watts I hoped for. Very low THD+N at .12% unweighted at 1k. Will test higher frequency when the wet load bank is done

got 55volts or 378 Watts into 8 ohms. Did not heat up or blow up. Serious drop on rail voltage, so we passed the power supplies ability to charge the 18,000uf caps. Still makes a great amp in stereo or as a bass mono driver.

 

[grapplesaw]

I think it’s time to put David Bowie through it

 

[laatsch55]

Good work Glen!!!

 

[grapplesaw]

I could not wait
Soooo After full power testing is now done. We are short of the 750 Watts I hoped for. Very low THD+N at .12% unweighted at 1k. Will test higher frequency when the wet load bank is done

got 55volts or 378 Watts into 8 ohms. Did not heat up or blow up. Serious drop on rail voltage, so we passed the power supplies ability to charge the 18,000uf caps. Still makes a great amp in stereo or as a bass mono driver.

Just was thinking and I had this running through the varic supply so will hope for better results when I test again. Right now playing Grover Washington and working great.

 

[laatsch55]

I am a bit confused, Lee told me 400 and 700s could not be bridged BUT you could just use one channel a get a little bit more power??

Ron, years ago I probably did say you couldn't bridge a PL...

 

[bill7621]

Need to get some mineral oil to fill this.

If you go by a electric substation and see a crew working there, they might be able to give you some if you ask nice.

 

[grapplesaw]

If you go by a electric substation and see a crew working there, they might be able to give you some if you ask nice.

Thanks for the idea. Walmart has it at $2 a quart so that may be easiest for me.

 

[grapplesaw]

Tested the amp again tonight with it plugged into a wall socket. Got 68 volts output before l blew the main fuse. So that is 578 Watts. Very low distortion
Do not want to push the transformer over spec fuse at this time. Good enough for me.

 

[laatsch55]

Both channels driven?.

 

[grapplesaw]

Both channels driven?.

Lee I have the two channels hot leads (red and white binding posts) making a mono channel. There is no connection to the black binding posts whatsoever. So this is the bridged setup. Could get more out of it but this is enough at this time

 

[grapplesaw]

Oh ya. The input is through a Y cable so both channels are equally driven and both meters read the same

 

[laatsch55]

I think I have it now Glen.
What was the rail voltage at thatoutput??

 

[grapplesaw]

I think I have it now Glen.
What was the rail voltage at thatoutput??

Did not measure it as it is alll buttoned up. Should be closer to 80 volts on each rail.

When I get the load resistor finished I will run it up again and do a full spec on it. Still not sure if I will try more than a 10 amp slow blow fuse. It has fast blow 10 now. It looked like it would have gone to 700 or so Watts. The input voltage was between .7amd.8 volts so the control board is not stressed. I put in Joe’s capacitor setup with 100 volt caps totaling 18,000u each rail and a 40amp Bridge rectifier. It has Don’s DCP as well. So only worries are transformer and possibly the outputs.

When end it is bridged the amp sees a 8 ohm load as 4ohms hence the large power increase

 

[laatsch55]

In theory, it should quadruple the output. Each channel amplifying only the top or bottom half. So, if it's close to 700 , it's closer to 4 times than 2 times....interesting...

 

[Northwinds]

Pretty nifty!

 

[WOPL Sniffer]

Damn Glen, These things dwarf the caps we use in the 700 wopl's...... I'm gonna need a bigger Chassis. I hope to work on my Mono Boards in the next couple days.... Just got a few components to change out. They should really Kick some ass in the 700 configuration. The 2 big torroids, and these big monstrosities, should help keep the rail voltage up and steady. I see a "Brown Out" happening soon.

 

[Skratch]

Are you gonna soft start these?

 

[grapplesaw]

Go big or go home they say Perry

 

[THD+N]

My stock 700 Series ll that I tested in mono (years ago) put out 1100 Watts RMS into a single 8 Ohm load. This mono test was easy to implement with the AP System One because you can invert one channel from the AP to the amp. Then you simply use the 2 amp "hot" outputs for your load.

I used 8 amp fuses for the rails and I think I bumped up the main line fuse to 12 or 15 amp for the mono test. This info is in the 700B service manual. Nothing in the 700B about mono, but only regarding the supply and line fuses.