The Smoked 400

[laatsch55]

Always wanted to see if a 901 could stand a 700 .

 

[derek92994]

Always wanted to see if a 901 could stand a 700 .

I dont think the 700 would reach clipping point on those but they do have a lot of drivers in them.

 

[Fishoz]

Is it possible to clip just one speaker? One of the Penguins developed a distortion in the woofer. Visual inspection of the woof all looks good. I haven’t tried to troubleshoot yet...thought it was room vibration at first...ruled that out.

 

[laatsch55]

Is it possible to clip just one speaker? One of the Penguins developed a distortion in the woofer. Visual inspection of the woof all looks good. I haven’t tried to troubleshoot yet...thought it was room vibration at first...ruled that out.

Yep....

 

[grapplesaw]

I dont think the 700 would reach clipping point on those but they do have a lot of drivers in them.

Well I can tell you after 45 years the 901’s are still running. We have a series one run them and would take them outside and run them thill the amp over heated Did that for 16 or so years. Now they sit waiting to get hung from the ceiling in the shop and of coarse a 700 to drive them. The 901’s are so heavily boosted in the lower frequencies that it is easy to wind them up on a 700.

 

[Billboard]

901s are reported to be able to handle being plugged directly into a wall outlet 120v. That’s 170 volts p/p.

If I ever come across a set of 901s I am not trying that. But they could probably hold their own against a pl700

 

[derek92994]

I can't wait to hear the results

 

[oldphaser]

The little lovely is back on the horns..

Lee,

Now that you've repaired the amplifier.....
Did you ever get a chance to re-test the amplifier at rated output both channels driven 20Hz-20KHz?

Ed

 

[laatsch55]

No, I have not Ed..

 

[laatsch55]

After repairing the D board , things were not right. Had problems on the backplanes, namely 3 shorted 21195's and 1- 21196.....along with their associated emitter resistors. I have also changed out the D board for a G board. Powered up fine , offset.000 both channels, bias steady at 380 mv.

 

[laatsch55]

The little copper heatsinked beauty is back on the horns!!

 

[BlazeES]

Nice!

 

[FredR]

The little copper heatsinked beauty is back on the horns!!

If your are ever interested in fabricating copper heatsinks for a 700 let me know.

 

[laatsch55]

I built 2 sets of those Fred....

 

[FredR]

I built 2 sets of those Fred....

If you want to do a larger run I'll finance it.

 

[Gepetto]

If you want to do a larger run I'll finance it.

I have priced it prior and everyone backed away when price was given. Other than the copper appearance they won't gain any advantage over the aluminum black anodize. Unless they are black oxide finished, you will lose to the aluminum.

If you want them, I can have them run.

 

[laatsch55]

Fred, I figured I had 600.00 per set in em. Kinda pricey.

Amen Joe...

 

[Gepetto]

Fred, I figured I had 600.00 per set in em. Kinda pricey.

Amen Joe...

And you don't have the black oxide finish on them. For a run of 48, they were ~$115 each, copper/black oxide.

You cannot laser copper so they have to be punched which is a contributor to cost.

 

[laatsch55]

Joe, what was the emissivity difference after anodizing copper?

 

[Gepetto]

Joe, what was the emissivity difference after anodizing copper?

Rough and tough, black anodize aluminum is 0.77-0.82 and black oxide copper is ~0.78. Different sources have slightly different measured results but these are the ranges.

For forced air situations, copper is superior due to higher conductivity than aluminum. The PL amp situation is typically radiating.