Soundstream XXX-6500D - What is the value of R4?

[RiLoWa]

If anyone has a schematic that they could share with me, that would be great too.

 

[Perry Babin]

4.7 ohms.

email me

babin_perry@yahoo.com

 

[RiLoWa]

Thank you Perry.

I found some other obvious owner replaced parts that with the diagram allowed me to get the right ones in there.

 

[Perry Babin]

These amps (and similar amps) have a weak drive signal. The pulldown resistor (R6 and R21) is a 4.7k. I'd reduce it to at least a 1k. The most common symptom that this is a problem is the power supply FETs running hot at idle.

 

[RiLoWa]

Thanks for the tip.

For the record, I have installed the BD139 / BD140 combo as the drivers. Does that change your recommendation at all?

I placed an order for the power supply FETs, so I don't have those yet, but I did check the drive signal to this point and thought it looked good.

 

[Perry Babin]

The recommendation remains. If the FETs idle hot, drop them to a 330 ohm 1/4w.

 

[RiLoWa]

A couple of questions, this amp has 2K Ohm resistors that look factory installed at R5, R6, R20 & R21 instead of 4.7K. Was that possibly a revision to address that problem?

Should I still change out R6 and R21 since you may have assumed there were 4.7K ohm resistors installed at R5 and R20?

 

[Perry Babin]

That should be sufficient. If it is not (FETs getting hot at idle), reduce the value of those 4 resistors.