Johnny D's 700 Adventure

Re: Phase Linear 400

Ok just ordered 22K Adcom PS caps from Steve should recieve saturday or monday. Should I put .33 caps on transistor plane? Just got all the resistors from the NTE factory by me but he didnt have the PS caps in stock..
 
Re: Phase Linear 400

If your noise problem is cured , pass on the .33 caps.
 
Re: Phase Linear 400

replacing all the carbon resistors with 2% and 5% metal films, havent run unit yet but when I finish Ill let you know how it is. Carbons so far out of each other...
 
Re: Phase Linear 400

Hi John
Been trying to send you some email responses but the replies seem to bounce. Cryptic server error so I cannot tell why. Maybe you're over your limit or something with all the photos flying back and forth.
 
Re: Phase Linear 400

laatsch55 / Gepetto
I was at NTE factory earlier this week and Lance there set me up with link for crossing some of the output transistors and drivers for the 400/700b, http://www.nteinc.com/index.php, cross refrence the transistors. can you take a look at the pdfs and see if these are good subs? they have all the subs for 2sd555, mj15024, mj21196, mj21194, rca410, I even seen cross for the TIS97, might be another source for the outputs and drivers. coolest thing if they do work I can get from Lance, only 6 miles from my home... :)
 
Re: Phase Linear 400

question if I do a load sharing test on this, I dont have a 250 watt resistor for the output.
Biggest I have is 4 ohm 100w, can I use a 300w light bulb off the output terminals?
 
Re: Phase Linear 400

Hi John
If it ohms out in the 8 ohm ballpark it should work fine. It will increase in resistance as the filament heats up but it should do the trick if the starting resistance is not too low.
 
Re: Phase Linear 400

cool, Ill check some resistances of some light bulbs..
Did you look at some of those transistors....?
 
Re: Phase Linear 400

Hi John
I always go with the original manufacturers whenever possible, rather than going down the sub path.
 
Re: Phase Linear 400

I'll keep my mouth shut, or fingers pinned as the case may be!!
 
Re: Phase Linear 400

I do OEM parts too, but just wondered if they are worthy... well changed all the resistors, new normal/direct switch with new r/c network....grounds are all taken care of....just waiting the dc protect and PS caps.
question, should I bypass the PS caps with a .01/630v?
also should I use a new style line plug with the ground or keep the none polorized plug?
 
Re: Phase Linear 400

Hi John
No problem on the caps. They do no harm.

I do not recommend going away from the original power input scheme used by Phase Linear. It can lead to system ground loop problems that cause hum and are hard to debug.
 
Re: Phase Linear 400

so Ill stay with the original plug, on the early 700 and 400s they have bypass caps on the rails of the transistors, would that be the same as bypassing the PS caps?
On my 700b there are no bypass caps on the transistor back plane...I was ready they are for RF interference..
 
Re: Phase Linear 400

Yes it is the same John but putting them out on the backplane is more effective than at the bulk cap terminals. Putting them out on the backplane offsets the inductance in the wire runs out to the power transistor collectors (high side) and emitters (low side)

If you put them on the bulk cap terminals, you will not neutralize the wire run inductance effects.
 
Re: Phase Linear 400

ok great Ill use the value of the 700II series and put them on the backplane...let you know how it works, next chance I'll get to work on it is monday nite, waiting for parts..thanks joe
 
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