What the Hell is This????

[laatsch55]

Thank you for finally posting sir! Will qwe see your build in a thread?

 

[Gepetto]

I saw that too, probably a few of the amps have them installed

All of them do Lee...Hanley installed them for all the amps they used on the Aerosmith tour. Kind of a crappy implementation but it was only rock PA so who would notice.

 

[laatsch55]

What were they trying to accomplish in particular?

 

[grapplesaw]

Thank you for finally posting sir! Will qwe see your build in a thread?

I will start a thread when I get started. Got to sort out what are best RCA inputs , bridge rectifier setup And main power caps - I have some panasonic 100 v 18000 uf 85*c but though of getting some higher voltage ones and use the panasonic in 400 build. Any help would be welcomed

 

[Gepetto]

What were they trying to accomplish in particular?

Hum rejection from ground loops.

 

[laatsch55]

We have a 700 PS cap group buy going. A basic 50 amp BR is now standard. I like the standard Switchcraft RCA jacks. I have installed some high dollar MBL's that were 200.00 a pair but the point of diminishing returns reared it's ugly head there...

 

[laatsch55]

Hum rejection from ground loops.

Common in PA setups?

 

[grapplesaw]

Common in PA setups?

The problem I find is marring the new with old. I have option of either balance or unbalanced out puts off my preamp. There is 8 db difference in line level between the two. I also and going to try a processor for crossing over the pre into three frequencies and then feed those into three amps. With the processor working best , lowest THD, in balanced output I need to reduce the input level to the Phase Linear with either transformers or a opamp setup. I do not know how much noise the opamps would add. The ones you have may be very dirty but they could be as easily be very clean. You could test them out with your gear for fun or trash them I guess.

Can you let me know on the group buy for caps. Please PM me how to get in.

 

[laatsch55]

Contact the Nav, he's ridin herd on that project..

 

[laatsch55]

The problem I find is marring the new with old. I have option of either balance or unbalanced out puts off my preamp. There is 8 db difference in line level between the two. I also and going to try a processor for crossing over the pre into three frequencies and then feed those into three amps. With the processor working best , lowest THD, in balanced output I need to reduce the input level to the Phase Linear with either transformers or a opamp setup. I do not know how much noise the opamps would add. The ones you have may be very dirty but they could be as easily be very clean. You could test them out with your gear for fun or trash them I guess.

Can you let me know on the group buy for caps. Please PM me how to get in.

So you are going through an electronic crossover.....that should have level controls for the outs to the amps....correct?

 

[grapplesaw]

So you are going through an electronic crossover.....that should have level controls for the outs to the amps....correct?

Yes you can turn the output level down , but that's the rub. If I turn down the levels from it then I cannot get the lowest THD from that unit. The line transformers will do that without any additional signal to noise loss at the amp input.
I am going to try it out and have some fun testing the setup. I will let you know how it works after setting it up. I hope it works well.
You probably have read this article and although old I think still current on the whole idea.
http://www.rane.com/note145.html

 

[laatsch55]

Looking forward to your results. What do you have for equipment? Will you be able to measure these changes?

 

[laatsch55]

That link is good reading...

 

[grapplesaw]

Looking forward to your results. What do you have for equipment? Will you be able to measure these changes?

Nothing like what you have Lee. I have old HP331 a distortion analyzer, a Hp 652a signal generator and a Tektronix 465 Oscilloscope. Just bought a Sencore LC77 Sencore Auto-Z Capacitor - Inductor Analyzer. All work well if you take the time. I am looking at some PC analyzer programs but do not have a clue as to what works well. Have you looked into any?

The new dbx PA2 managment system has a condenser mic used with pink noise to measure and balance the three channels with 1/3 octave equalization. If it works I will have +/- 1/2 db from 30 hz to 10,000 and 4 th order crossover I think I can hear 1-1 1/2 db change in sound but that could be a stretch these days so counting on the new age stuff. It's all just for fun so we will see. With electronic crossovers now you delay any output to match and balance the offset that is detected

 

[laatsch55]

Dude , what you have is nothing to sneeze at. It's all good stuff. A good PC based analyzer is Daqarta, check that out.....very handy.
I agree a fella should be able to hear a 1-1/2 db change....gonna be interesting...keep us in the loop. What's your name? grapplesaw is a lot to type evertime a salutation is in order...

 

[grapplesaw]

Dude , what you have is nothing to sneeze at. It's all good stuff. A good PC based analyzer is Daqarta, check that out.....very handy.
I agree a fella should be able to hear a 1-1/2 db change....gonna be interesting...keep us in the loop. What's your name? grapplesaw is a lot to type evertime a salutation is in order...

Glen
From north of the 49th

 

[NavLinear]

Glen
From north of the 49th

Glen,

It's good to see you posting here and from what I read you have some good old school test equipment. If you're interested in the group cap buy send me a PM and I'll add you to the list.

Welcome again - Nav

 

[Northwinds]

Glen
From north of the 49th

49th Parallel or 49th State? Welcome Glen!

 

[gadget73]

Common in PA setups?

and big installs, yeah. It lets you run really long cables too, which is needed when you have hundreds of feet from mixing console to the amp rack. Regular unbalanced cables will tend to pick up more noise, and/or they have enough capacitence that it just smashes the highs.

 

[grapplesaw]

49th Parallel or 49th State? Welcome Glen!

We are near Vancouver BC,