The Phase Linear 400 Guinea Pig

[laatsch55]

You're not blowing 8 amp fuses are you?

 

[Northwinds]

You're not blowing 8 amp fuses are you?

Nope, have not blown a fuse in months. I just see the comment where Joe says your smoking 5A fuse at 240w and other things are getting hot so I wondered if I was damaging anything. I'm just worried as I was blowing 5A fuses LONG before 240w when I was running them before Jer said to switch to 8A. If you remember the conversation, I was blaming my preamp

 

[laatsch55]

And I still think there's something to that. To blow a 5 amp fuse when sine wave testing is like blowing an 8 amp fuse on music reproduction. Sinewave testing is a steadt state test, amplitude is steady until you change it. That's a lot harder to do than playing music.

 

[Northwinds]

Ok, gotcha. I did not realize you were doing a sine wave test therefore, I am still running somewhat safe then. The preamp has not caused me any issues since but the amp does heat up pretty fast when I am cranking. Starting to wonder if the published specs of my E-7127 being 8 ohms is wrong. It heats up so fast that I would think they are 4 ohm. As long as I have the monster box fan sitting on top blowing max speed when I am feeling loud, the amp performs flawlessly and the fins feel pretty cool. It just looks stupid as hell but blowing up the amp for not using it would be even more stupid

 

[laatsch55]

Measure the impedence with your meter..

 

[Gepetto]

OKay, what now. 240 wasn't near it's potential...

But it is right at the limit of a 5A fuse though Lee. If you want to push more out of it you will have to go to a 6A or 7A fuse.

 

[laatsch55]

Do you feel we have answered all your questions yet?

 

[laatsch55]

Isn't there supposed to be a trace here? Between 34,35?

 

[NavLinear]

Ok, gotcha. I did not realize you were doing a sine wave test therefore, I am still running somewhat safe then. The preamp has not caused me any issues since but the amp does heat up pretty fast when I am cranking. Starting to wonder if the published specs of my E-7127 being 8 ohms is wrong. It heats up so fast that I would think they are 4 ohm. As long as I have the monster box fan sitting on top blowing max speed when I am feeling loud, the amp performs flawlessly and the fins feel pretty cool. It just looks stupid as hell but blowing up the amp for not using it would be even more stupid

Ron - remember that speaker impedance varies over frequency so they could be dipping down to something less than 8 ohms. I don't know how much the E-7127 speaker impedance varies but that is something you should take into consideration.

 

[Northwinds]

Ron - remember that speaker impedance varies over frequency so they could be dipping down to something less than 8 ohms. I don't know how much the E-7127 speaker impedance varies but that is something you should take into consideration.

Sorry Dennis, I typo'd and extra 7, they are E-712's

http://reviews.cnet.com/separate-speakers/cerwin-vega-e-712/4505-7869_7-6899368.html

 

[NavLinear]

Isn't there supposed to be a trace here? Between 34,35?

Based on the schematic for the RevD board you should have continunity between R34L and R35L to the emitter of Q7L so there should be a trace between the resistors.

 

[Gepetto]

Isn't there supposed to be a trace here? Between 34,35?

On the backside Lee...

 

[laatsch55]

I think this was the beta board, so quasi was not the goal. Just wondered if Joe knew this.

 

[Gepetto]

I think this was the beta board, so quasi was not the goal. Just wondered if Joe knew this.

Beta board = production board Lee.

 

[laatsch55]

OK, then you moved it to the topside later?

 

[NavLinear]

Sorry Dennis, I typo'd and extra 7, they are E-712's

http://reviews.cnet.com/separate-speakers/cerwin-vega-e-712/4505-7869_7-6899368.html

I didn't see anything in the spec besides a nominal 8 ohm rating for your speaks. It seems to be rare to see a graph of speaker impedeance over the audio band but your speakers will vary from the rated impedance based on the frequency input. That is always a problem for testing audio amplifiers - you just don't know what speaker system they'll be hooked up to and what the impedance will be across the band so that is one reason for using a fixed resistance load for testing.

 

[Gepetto]

OK, then you moved it to the topside later?

No change Lee, Right channel has that interconnect on comp side of board, Left channel has it on the solder side. Same result.

 

[Gepetto]

OK, then you moved it to the topside later?

OK??

 

[laatsch55]

I have an early and late "D" board on the later one both interconnects are on the top, on the earlier they are top/bottom..

 

[Gepetto]

I have an early and late "D" board on the later one both interconnects are on the top, on the earlier they are top/bottom..

Hi Lee
I think you are looking at an A or C board. Both of those boards had the trace on the topside.

There has been only one run of RevD boards ever produced and there is one topside and one bottomside trace in this location on the RevD board and artwork.

Are you experiencing a problem?