Hifonics hercules vi

[enthusiast123]

Hello,
Does anyone know that the value of the resistor goes on R40A place? I know it's a difficult question, but to try.
Thank you in advance.

 

[Perry Babin]

If no one can answer your question definitively, post a photo of the entire board and a photo of the area where the resistor is/was located. It may be similar to a different amp.

 

[enthusiast123]

Ok thank you Perry, i will send photo as soon as posible.

 

[enthusiast123]

hifonics hercules vi

I hope you can see, someone put some resistor on that place, but I am not sure is it correct value.

 

[Perry Babin]

I don't have anything similar. Contact ZED Audio to see if they have any information on it.

Is the amplifier working properly?

 

[enthusiast123]

It is working, but it have 50-70mv offset and after twenty minutes of operating I measure on the R29, R30, R31 and R32 0,4mv bias and on the other side 0,0mv bias? I do not know is it normal?

 

[enthusiast123]

Idle current is normal 0,76v and it is not getting warm.

 

[enthusiast123]

The problem that happened, when I use its high pass output for front speakers amp, once when I turn the system on it passes high frequencies trough one channel and destroyed that channel on genesis amp, that is why I opened it to check everything.

 

[Perry Babin]

I don't see how you could have different bias voltage across the emitter resistors from one side to the other. I would expect the voltage across the resistors to be the same unless you have a leaky transistor that's causing excessive current through one of the resistors and no current is passing through the other 3 resistors.

 

[enthusiast123]

On all four resistors R29,30,31 and 32 i measure 0,4mv and on the other four R25,26,27 and 28 it is 0,0mv, not from the start, but after few minutes of listening.

 

[Perry Babin]

It may be just below the limitations of the meter. Set the bias to about 1mv across the resistors to see if it is more like what you'd expect.

 

[enthusiast123]

I raise the bias and now i have 1,0v idle cosumption.
R25 0,9mv
R26 0,8mv
R27 0,7mv
R28 0,7mv
R29 1,4mv
R30 1,9mv
r31 1,2mv
R32 1,7mv

 

[Perry Babin]

Disconnect the speaker or dummy load if you have one connected and see if the voltage across the resistors becomes more equal from one side to the other.

 

[enthusiast123]

Yes I just did it and now it is
R25 1.5
r26 1.4
r27 1.1
r28 1.2
r29 1.1
r30 1.7
r31 1.0
r32 1.5

 

[Perry Babin]

That looks better. I think it's OK. The combination of the load and the slight offset was causing one half of the transistors to switch off.

 

[enthusiast123]

I am very pleased with the sound it produced. Do you think I have to reduce offset a little because it gets warm faster? What do you think this resistor on R40a if it is not original resistance can it make some troubles? What do you think what happened when it fried that other amp trough the rca output?
Thank you!

 

[Perry Babin]

Place the black meter probe on the amp's main ground and the red probe on the output RCA shield. Do you read more than a fraction of a volt (AC or DC)?

With the probe in place, twist/push/pull on the transformer. Does the voltage reading ever go higher than a fraction of a volt?

Are you 100% sure that the speaker wires from the Hifonics never made contact with the vehicle ground?

I would not be concerned with R40A. From the way the flux looks, I'd guess the amp has been working perfectly fine with it for many years.

 

[enthusiast123]

I read 1,44v DC and 0,1AC volts, when I ckeck what you told me. Nothing is changing when i twist transformer.

 

[enthusiast123]

I am not sure if speakers wires were ever made a contact with vehicle ground, as I not the first owner, but as far as I am using it, it never happened.

 

[enthusiast123]

I recently recap the amplifier and use the same value with maybe little higher voltages, if it is good to mention.