Marantz 4300 4400 Flyback P700 Sanity Check

[fishyswaz]

Hi,

Just a quick sanity check - are the attached schematic and board view the correct way of adding flyback diodes to the Marantz 4300/4400 P700 Amp boards adding 1N4007 diodes? From what I've read/worked out this should be ok hopefully. Thanks in advance.

 

[fishyswaz]

Bit of a bump, just in case anyone's there that can answer - no worries if not.

 

[Redkarter]

I think you have everything arranged correctly based on this photo.

By the way are you adding this to a 4400 or 4300? What kind of benefits did these provide?

 

[fishyswaz]

I think you have everything arranged correctly based on this photo.

By the way are you adding this to a 4400 or 4300? What kind of benefits did these provide?

View attachment 3219736

Sure looks like it in that photo (thanks for the reply btw).

Adding to a 4300 I've just brought back to life and serviced. The benefits are it adds output spike protection to the reciever, although I belive it'll only protect at certain frequencies and there's a chance it'll effect the output of higher frequencies of the amp, not sure about this though using 1N4007's. I'm in two minds about adding it at the mo, I might have a bit of a look with/without through my scope and distortion meter.

 

[Redkarter]

Sure looks like it in that photo (thanks for the reply btw).

Adding to a 4300 I've just brought back to life and serviced. The benefits are it adds output spike protection to the reciever, although I belive it'll only protect at certain frequencies and there's a chance it'll effect the output of higher frequencies of the amp, not sure about this though using 1N4007's. I'm in two minds about adding it at the mo, I might have a bit of a look with/without through my scope and distortion meter.

Id like to hear the results of what you find with them added. I considered adding them to my 4300 awhile back but didnt and figured I could always add them later if I was compelled.

Not sure what you're hoping to get out of your 4300 but I found adding uprated driver transistors (mje15032/33) increased the output close to an original 4400. The latter has a slightly higher rail voltage but a stock 4400 and my upgraded 4300 both start to majorly clip around 37.5 volts through my 8 ohm load, with a 1khz signal.