Replacement of IRF730 for Sonic Frontiers SFL-1

[Tubenstein]

My friend and I also own a Sonic Frontiers SFL-1 and these are the questions we want to ask:

Is any MOSFET out there considered as an improvement of IRF730 for
direct replacement. My Sonic Frontiers SFL-1 hybrid has a IRF730 in
there.

What about 2N6768 and STP7NK40Z?

The Sonic Frontiers actually based on the design of Curcio Daniel II,
and Curcio has MTP3N40 for the same position instead of IRF730. I have
no idea the sonic character between both MOSFET. However, it should be
something out there better than both since transistor technology is
very mature today. Should be more linear, less noise and lower
distortion than the IRF730 and MTP3N40! Or you suggest stick with either IRF730 or MTP3N40?

Any suggestions are welcome!

 

[almamorphous]

Hi there,

I'm having the same question concerning the IRF730 replacement in order to reduce background noise.
Anyone can help?

Thanks

 

[Tube_Dude]

Hi there,

I'm having the same question concerning the IRF730 replacement in order to reduce background noise.
Anyone can help?

Thanks

Any MOSFET is noisy, not a good choice for a preamp... 😉

 

[almamorphous]

Hi Tube Dude!
Thanks for the reply!
Not a good chance then in reducing the background noise of the SFL-1... :-(
Abraço,

Hugo

 

[paul_peraic]

Actually there is a way to lower the noise and that is go back to the original Motorola Mosfets totally different pre-amp with the IRF-730 .

 

[stocktrader200]

DN2540 enhancement FET is very low noise. comes as TO92 and TO220, I am using the TO220 for crossover distortion elimination.

 

[almamorphous]

Hi there. Thank you for your reply.
I did not however, understood your answer. Can you elaborate more please? What can be used in the Sonic Frontiers SFL-1 to replace the original IRF730 Mosfets?

 

[analog_sa]

No. At least not without a substantial redesign.

 

[almamorphous]

Ok. That's what I suspected.
How about changing it to the IRF740? Would that make any difference?
Thanks

 

[paul_peraic]

Motorola MTP4N40E

 

[Mark Tillotson]

The IRF730 only has a gate-source breakdown voltage of +/-20V, I'd expect +/-30V would be a much more robust spec here, and its not uncommon to find high voltage MOSFETs with this rating. STP7NK40Z for instance.

 

[Mark Tillotson]

Motorola MTP4N40E

Obsolete by the look of it, and has a higher on-resistance.

 

[almamorphous]

Is it a direct replacement?