Sutton's Phase Linear, White Oak 500

[Skratch]

Should be here Thursday. It is taking a ride around, Gillette then sheridan then billings last i tracked it it was in south dakota.

 

[Skratch]

Correct

 

[laatsch55]

It's a matter of semantics. Mark that is not a true bridging. A bridge takes and converts one channel to amplify the positive half of the sinwave and the other channel to amplify the negative half of bvthe sine wave so when you put them together by running just bthe positive outs of the left and right you have a complete sine wave, albeit 4 times more powerful.

There was a heck of a blizzard in that neck of the woods, may take a couple days to get straightened out.

 

[Skratch]

I now understand about bridging. Thanks Lee Are you getting any snow, Its cold here today but it is going to be in the high 40's by the weekend. I don't know about you but the older I get the more I hate winter.

 

[laatsch55]

Wellllllll........ I'm in Phoenix by the way and I don't think snow is in the forecast, at home however there is 5 inches on the ground and more on the way. Each New Years down here we add another day. We are up to 9 days. I nthink we should double the rate.

 

[laatsch55]

Lee, if you have the mounting brackets for those monster caps, I'm interested. Let me know.

Having said that, there is a point of diminishing returns for increasing the cap size. The point of the caps is to smooth out the DC ripple voltage as it comes off the bridge rectifier. The + caps do this by charging on the voltage ramp-up (even though it is small) and then slowly discharging as the voltage ramps back down, the - caps do the opposite. The caps discharge so slowly that the voltage does not have time to drop and the DC ripple is removed. At some point the caps are discharging slower than they need to and not accomplishing anything except looking cool.

That's how I understand it.

Mark

Mark, I do have the brackets for the 100 volters, standard 2 inch. Large caps do help in the very large voltage and current swings inherent in large transients.

 

[Skratch]

Lee I received the board from you today, looks good. I am putting the goodies I got with it in tonight. Will probably put it in this weekend. Thanks Mark

 

[laatsch55]

Lee I received the board from you today, looks good. I am putting the goodies I got with it in tonight. Will probably put it in this weekend. Thanks Mark

Very Welcome Mark!! Hope all goes well!!

 

[mlucitt]

Lee, in your 900 watt amps, you maybe right. But I'm talking about the puny 400. Try this experiment: With the amp warmed up and no input signal (but inputs and outputs connected) turn off the amp and start a stopwatch. Let me know how many seconds you get until you hear the pffffft sound (you will have to disable your CD Output Protect board). I'll try it when I get my amp back together.

My theory is that anything more than about 2 seconds until the caps completely discharge is redundant because one cycle lasts .016 of a second and you get 2 cycles because of the rectification so the interval between ripple peaks (bumps really) is .032 of a second. How much can your caps discharge in 32 milliseconds? I'm just sayin'...

 

[laatsch55]

True Mark, and I'm not qualified to argue further. In fact, G. Randy Sloan's rule of thumb is 1000 uf for every 10 volts of rail voltage PER SIDE(+/-).
So in the case of the 400 you're looking at 16,000 total.

 

[Gepetto]

The full wave rectification period between charge deposits at 60 Hz is 8.333 milliseconds by the way. 1/60 = 16.666 milliseconds and there are 2 charge periods with full wave rectification (one for the positive half of the AC cycle and one for the negative half) leading to the charge deposit on the caps every 8.333 milliseconds. One of the advantages of larger caps is the ripple reduction that they afford, esp at higher frequencies which means the amp has a better chance of rejecting these input disturbances given the power supply rejection ratio inherent to the amp. The biggest advantage I have seen is replacing OLD dried out caps with NEW vital caps. Modern caps are generally made better and have much lower ESR than the old ones used 30+ years ago. This help in the high frequency rejection department helps the amp out in the area that it can least defend itself.

 

[laatsch55]

I knew there was more to it, Thanks Joe!!

 

[stuwee]

Just to prove I was here!!!! This is Lee!!!

 

[laatsch55]

Now it's not!!

 

[Skratch]

Hi When identifing small signal transistors do you look at them from the flat side?

 

[laatsch55]

You mean a a standard to identify pinouts?? Yes, with leads down.

 

[Skratch]

Thanks Lee

 

[laatsch55]

Welcome Sir.

 

[Skratch]

I am from the old school where almost anything was idiotproof, could only put the tubes in 1 way, everything was standardized. That was the thinking 50 years ago. With the small transistors some are pinned out one way while the others are pinned out another. What was the reasoning for this? I am sure there was alot of thought behind this?????

 

[laatsch55]

To try and appease the OEM's and on certain projects with machine insetion it was easier to change pinouts that reconfigure the machines, I'm guessing.