phase linear 400

Sunnbobb said:
nope To simplify the issue...whenever I hookup speakers, the DBT lights up.
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i got 2 junk speakers....one is a 4" full range that came out of someones ceiling...still in the mount...
the other is a 3" 2 ohm that has seen better days...one i scrounged....
when i hook up the 2 ohm speaker...the dbt brightens...
the 8 ohm ceiling speaker doesnt....and yes it visaed and versaed....
speaker probably shorted or something...
 
Sunnbobb said:
Well, still the same. hmmm
Click to expand...
the dbp board has a zobel network within...so you would cut out all of the existing network when you change out the posts for the dcp board...
with white oaks back plane kit...you would disable the zobel on the dcp board...

christine has been playing all afternoon now...since i figured out my problem...with a point in the right direction by mr. joe...
 
I'll do that if you think it's ok to run it with the bulb lit? The variac wont do above 70 Volts due to the draw when the speakers are hooked up.
 
Sunnbobb said:
I'll do that if you think it's ok to run it with the bulb lit? The variac wont do above 70 Volts due to the draw when the speakers are hooked up.
Click to expand...

With the variac all the way down and off, hook the speakers up and clip the DMM on the binding posts too.

Then bring the variac up and see what the offset does as you turn up the variac, Should only take a few seconds to see what is happening.
 
OK, I brought the Variac up to 45V, and the output reading was at 7 volts. It was rising as I increased the voltage from the variac. Just to double check, I disconnected the speakers, and the out put voltage dropped to .05V with the variac all the way up to 120V. BTW, I have a volt meter inline with the dimbulb tester so I can see exactly what the amp is getting. Thanks for your time with this.
 
Sunnbobb said:
OK, I brought the Variac up to 45V, and the output reading was at 7 volts. It was rising as I increased the voltage from the variac. Just to double check, I disconnected the speakers, and the out put voltage dropped to .05V with the variac all the way up to 120V. BTW, I have a volt meter inline with the dimbulb tester so I can see exactly what the amp is getting. Thanks for your time with this.
Click to expand...
Do you have an oscilloscope?
 
One further consideration. The previous owner wired in a couple of input potentiometers ala Series 2. I didn't mention them as I assumed the Amp was working prior to losing some transistors. Here are some pictures, I somewhat wonder if the input/output wiring is incorrect? I would remove them, however there are two holes in the faceplate for them. I did go ahead and put them back in the faceplate just to see if there was some sort of grounding needed, but the issue of the dbt still exists.
 

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gene french said:
please remember...i dont know much...
i still would like to make another suggestion...
remove top 4 outputs...test...next 4...test etc...kinda like the bring up protocol joe uses, except in reverse...
Click to expand...
I taught myself everything I know... and I still don't know anything! I brought it up that way, but I did not have the speakers hooked up, so I had no indication of trouble. I'll try it in reverse as you suggested, this time with speaker testing. Thx Gene.
 
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