Hi from Australia

R

Richard Lewis

New Around These Parts
Joined
Nov 6, 2020
Messages
6
Joined since I have a 700b to restore. I purchased it second hand way back last century and used it running subs in some PA systems, in a rack sleeve with fans and an external DC protector. It ended up with fatigue cracks in the case that were repaired by inserting aluminium angle behind the faceplate.
Put it in storage when I got some higher powered and lighter amps.
The look of the silver face and big meters had me thinking of restoration one day.
Then while browsing on the bay I came across White Oak replacement chassis and I ordered one which has now arrived.
It's certainly an excellent piece of engineering.
I also got the Watts Abundant internal DC protection board.
I plan on installing the DCP first so I can use the amp while I accumulate bits and pieces to go the whole hog (even though in my situation that could take some time).
My thinking is new control board, then new upgraded power supply caps. Then backplane and meter lights.
Possibly also a nice clean new faceplate. IMG_20210111_134019592_HDR.jpgIMG_20210111_134030317_HDR.jpgIMG_20210111_134019592_HDR.jpgIMG_20210111_134030317_HDR.jpg
Amp in storage unit
 
Welcome Richard, glad the chassis made the long trip to Australia and that you are pleased with it.
 
Gepetto said:
Welcome Richard, glad the chassis made the long trip to Australia and that you are pleased with it.
Click to expand...
Just figuring out what to order next. Shipping time was pretty good to the far side of the world in these strange times. Surprisingly the last hundred miles from Sydney me took about ten days.
 
Richard Lewis said:
Just figuring out what to order next. Shipping time was pretty good to the far side of the world in these strange times. Surprisingly the last hundred miles from Sydney me took about ten days.
Click to expand...

Back planes and the G1 control board............... Get ready to launch the rocket.
 
Second that...doing the backplanes BEFORE the control board would save a lot of work...
 
WOPL Sniffer said:
Back planes and the G1 control board............... Get ready to launch the rocket.
Click to expand...
Just hit my first snag. After only twenty two years service my Weller soldering station has decided not to work anymore. I'm thinking that since I have retired and on a reduced income now that I will go the control board next and install it quasi while saving for the backplane. The other thing in the back of my mind is that renewal of the power supply caps could increase in priority once I measure the rails...I live near the start of the power supply grid in our State and when I was doing PA work my Furman power distribution would regularly show over 260 volts AC supply. We were nominally 240 back then and dropped to nominally 230 now but I recall it still being around 250 volts last time I had the meter in my drive rack.
If it takes me time, then that's the way it is but even if it is a long journey the first step has been taken.
 
There is another fella on here from Oz, 250-to 260 is not a problem...sure helps the rail voltage..
 
Richard, your logic is sound. Those big power supply caps are well past their life expectancy of 15-20 years. If they decide to let go, you will have a big mess on your hands. The caps are our first recommendation, then you can upgrade as you wish; knowing your power supply is safe.

Welcome to Phase Linear heaven.
 
If the ripple (AC) voltage on the caps at idle is less than 100mv they're not in terrible shape. mlucitt is right that life expectancy is less than 20 years. If the decision is to hold off on replacement , at least check the ripple voltage. If the caps are going to fail, at this point in their life it will likely be at turn on and could be catostrophic. A ruptured electolytic such as those in a 700B will fill a 5 gallon bucket full of confetti if they come apart.
 
I used to cringe every time I switched on my amplifier with the old filter caps still in. Replaced those and now, not so much. The expense and time were well worth it. Amp switched on, Anxiety switched off you know.
 
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