100W Ultimate Fidelity Amplifier

[xrk971]

You may find that jFETs work better for switching duty.

There was a Thread some years ago in which was mentioned an alternative switching arrangement that eliminated the distortion due to any non linearities across the switch.
I wish I could remember these things !

I have a bunch of J113's - could those work? I also have 2SK170's but saving them for a real input stage amp use. Could they be wired front to back in same way as the above circuit and driven in same way with gate voltages?

 

[AndrewT]

jFETs get wired a bit differently, but still use two in a back to back format.

See if you can find that discussion on alternative switch arrangement.
Maybe another can give you a better pointer/clue.

 

[mlloyd1]

andrewt,

was this something by bcarso that you're thinking of?

mlloyd1

 

[ravpreet420]

just idea not tested

 

[ravpreet420]

not tested

 

[xrk971]

Neat - could 2SJ74 work? How much voltage needed for +v?

 

[ravpreet420]

A simple J-FET switch is easy to accomplish. The use of a P-channel J-FET is required. The more common N-channel will not give the same results, especially fading. A common device is the 2N5462 or the J176 or J177
voltage=12 to 15V

 

[sajti]

Why not use special IC for input selector?

http://www.diyaudio.com/forums/solid-state/97171-best-sounding-analog-switch-ic-input-source-selector.html

Sajti

 

[apexaudio]

Use 4066

 

[AndrewT]

andrewt,

was this something by bcarso that you're thinking of?

mlloyd1

Sorry, no memory.
But I seem to think three or four Members were involved in the discussion and they seemed to agree that the alternative was a better solution for switching audio signals.

 

[mlloyd1]

the folks that make the mcintosh gear had some preamp models that used jfets for switching audio signals. take a look in some of their schematics for some known tested and well-working circuits.

i'll come back later with some link pointers ....

mlloyd1

OK, made it back before timeout


look at this preamp schematic: McIntosh C34V preamp; page 9 has an example. njfet is 2n4392 or pn4392, still available and not ridiculously expensive.

 

[thimios]

the folks that make the mcintosh gear had some preamp models that used jfets for switching audio signals. take a look in some of their schematics for some known tested and well-working circuits.

i'll come back later with some link pointers ....

mlloyd1

Years ago(1990?) in the Elektor cmos preamplifier used cmos and op amp in input and out, as source switches.
I will try to find the boards.

 

[mlloyd1]

yep, cmos and dmos analog switches are popular, especially now that the on resistance can be made VERY low and reasonably flat. jfet switches were popular before the cmos switches became as good as they are now.

mlloyd1

 

[ravpreet420]

i am wanted to make 4.1 home theater ,which amplifier circuit is best for this,i am wanted to high sound is crytal clear sound.

 

[andrewlebon]

FH9

Thinking of making a 5.1 amp 5 CH will be FH9 sub channel will be 900 watts
classd

 

[xrk971]

I agree that FH9 is an excellent choice for multi channel amp as it is easy to make, cost effective, and sounds great. What are you using for 900w sub channel AndrewLebon?

 

[andrewlebon]

FH9

Small class d module for subwoofer i will use

 

[xrk971]

Small class d module for subwoofer i will use

Oh I almost forgot you are the thread starter of one of the most popular threads in Diyaudio:

http://www.diyaudio.com/forums/class-d/166214-ucd-25-watts-1200-watts-using-2-mosfets.html

You know all about high power class D amps.

 

[sumeshak]

FH9: Help

Dear Sir,
Thank you so much for the support extended so far..
I wish to do FH9 after a long break...Can you tell me the post with latest layout?
Can I use irf2520s also?


Regards,
Sumesh

I agree that FH9 is an excellent choice for multi channel amp as it is easy to make, cost effective, and sounds great. What are you using for 900w sub channel AndrewLebon?

 

[xrk971]

Dear Sir,
Thank you so much for the support extended so far..
I wish to do FH9 after a long break...Can you tell me the post with latest layout?
Can I use irf2520s also?


Regards,
Sumesh

Here are Gerbers I used:

http://www.diyaudio.com/forums/soli...imate-fidelity-amplifier-746.html#post4718255

Change drivers to ksa1381/ksc3503 and power rail caps to 63v and run at 53 rails for FH9HV. Sounds even better.