Sutton's Phase Linear, White Oak 500

[mlucitt]

Lee,
Check this out, at least the guy bought Joe's cap kit. But there is a bad connection in the meter wiring (notice the meters are pegged low until he moves the faceplate) and now the whole world knows the guy has funky wiring in his amp:
http://www.youtube.com/watch?v=7e0Sq5uQ ... re=related

 

[laatsch55]

So............if it's vertical the meters work!!!! Choice!!!!! Needs to back off the hold down screws and put in the Laatsch Special aluminum plates!!

 

[laatsch55]

Joe,
The 40mm caps should fit easily because there is no aluminum casting in the way, I can see through to the transformer windings!

I just made my Mouser order and I didn't order any caps (except for the main board) so please add (4) of the 40mm x 50mm 8200uF 100V to your order and send it to me when you get a chance. Let me know the cost and if it is still the same as the 16.8k uF setup, I will place an order on your website.

Mark

If you can see the transformer windings a couple of those 22,000 100 volters should fit. I've done 2 like that.

 

[ksrigg]

Mark,

Could you use a pair of these? They are 2 1/2" in diameter and 4 1/2" tall....If they will fit in a 400 that would be awsome...I have enough to do Kevin's, the one I am building on my end and yours....

Let me know...

 

[ksrigg]

I finally snagged a 400 to attempt ressurection. Now I'll have everything but the Mouser order. Everything else is either in hand or on it's way (except the ability) to make this beauty work...The faceplate looks a little rough and I'll have to paint the trannie and the meter bezels, but it just spoke to me (or the price did....free shipping), so we are off to see the wizard.

http://www.ebay.com/itm/Phase-Linear-40 ... 8601101376

 

[laatsch55]

That's a good one to practice on.

 

[Skratch]

DUMB QUESTION???? Has anyone ever tried to make a mono amp out of a 400. Pull the drivers and parallel the outputs from the other channel, Disconnect the 1 channel from the driver board and make a new faceplate with 1 VU meter and change the resistor for the VU meters.

 

[mlucitt]

NO! You cannot do that. Here is the language from the PL 400 Service Manual, "NEVER EVER EVER BEGIN TO THINK ABOUT PARALLELING THE TWO CHANNEL OUTPUTS TOGETHER TO FORM A MONO AMP! The amplifier can be bridged at the inputs to form a mono amp provided that the speaker load driven is 8 ohms or greater in nominal impedance."

The amp was not desiged to become a mono amp.

I'm just sayin'...

 

[mlucitt]

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

 

[laatsch55]

Skratch, the 400's CAN BE BRIDGED........BUT...AND THIS IS A BIG BUT>>>>>> it has to be done in the input section with a bridging adapter ala Rod Elliott's ........AND .....It will quadruple the power.....BUT>>>>>>>>>>> you are limitedc to an 8 ohm load, any less and the amp will eat itself. The only reason for tbhat amount of power.........well ok ........ another reason for that amopunt of power is to drive difficult loads to mind bending levels.........not generally an 8 ohm load application. I have intended to bridge one of my remaining 400's just to prove it can be done, then a 700 if that pans out.

 

[laatsch55]

Speaking of bridged amps. the early 700 Ser iwas bidding on with the 4 outputs per rail , was eventually bought by Ed Blackwood. In our correspondence back and forth this particular 700 was a FACTORY BRIDGED AMP. The driver board is unlike anything he has seen. It has 4, yep 4 discreet channels and more point to point wiring than a 200 watt tube amp. He has sent pics and when I get home, with his permission I will post em. It is a very intriguing set up. He wants to get it working although Dean has said the chances are slim as the factory had very little luck in that regard. Why would he want to fight a losing battle like vthat ya say?? Other than the fact almost everyone says it can't be done( i love that about Ed) To see what it cranks out in wattage!!

 

[Skratch]

I am running my 400 bridged at the inputs now. Coming out of my SUB OUT on my Ashley crossover I have a "Y" and feed both left and right. My subs are 12 ohm. Wouldn't paralleling just the other 6 outputs and connecting the 2 speaker out wires together basically be adding more output transistors. You would have 12 per channel instead of 6. A 700 has 10 per channel?

 

[laatsch55]

You are about to toast your 400. The amp should not be bridged at the inputs!!!@!! Very dangerous game you are playing there Mark. The bridging should be done where global negative feedback is introduced in the V/A stage, NOT at the inputs. Ands yas gotta remember the 700 is a 700 because it has +/- 100 volts on the rails, additional outputs does not mean more power, just more current sharing.

 

[laatsch55]

When you connect the 2 speaker out wires, you will need plenty of parts. Is this the one with the XPL-910's??

 

[Skratch]

I have been running it with the inputs bridged for years. The amp hardly even gets warm after driving it hard for hours.

 

[laatsch55]

How are the speakers connected??

 

[Skratch]

No This one I bought new in the early 70's. It has 909's in it. The one I want to play with is the one that I am getting the board from you.

 

[laatsch55]

Did the board get there yet???

 

[Skratch]

8 ohm Dual voice coil in series which ohm out at 12ohms. I have a pair and one is connected to the left out and the other is connected to right out. I had the voice coils paralleled which gave me 3.5 ohms and the amp ran fine but it ran very warm, not hot

 

[laatsch55]

Then it is not bridged, you are splitting a mono signal and driving two separate speaker systems, one from the left and one from the right... correct??