JFET input, MOSFET VAS, LATERAL output = Perfect!!

[lineup]

Dr. EM
Unfortunately I have not the exact spice models for those lateral.
I would rather use components I can play with in SPICE

But I have these models:
ECX10N20 ECX10P20
And I have used:
ECF20N20 ECF20P20
ECF10N20 ECF10P20

MiiB.
I use HEXFET this time IRFP240/9240
And they need at least, I have a feeling, 10 mA
and as the MOSFETS are ZETEX ZVP/ZVN3310A = TO-92, 625mW
they do not safely take 35v x 10 mA = 350mW
Well, at least they would get hot.

MY rule of the thumb is at least 5 mA for Laterals and 10 mA for HEXFET
But, yes, I have seen less current in use. Also by Nelson Pass.

2SK170 takes 40 Volt.
I did not think about, forgot, that maybe a cascode would be in place.
Say the power supply puts out, at some time, 2x40 VDC

[lineup]

Originally Posted by ontoaba

Umm., could you explain that MOSFETish? What kind is it?

Some amplifiers using MOSFET will exhibit distortion with mostly 2nd harmonic
and then nicely falling higher harmonics.
This is how TUBES do, too.
In this case MOSFET can come closest to the TUBE SOUND.
It has been descibed as 'warm sound'.
The opposite would be clean, analytic, sound.
But far from all MOSFET amplifiers have mostly 2nd harmonic.

Regarding my published amplifiers in this topic
they have so low THD distortion, that they probably NOT add to sound at all.
But if such amplifier does, it could be a MOSFETish or TUBE sound.

[GregH2]

Lineup,

I like the simplicity of this design.

Just before I saw this thread I was working on the design of something very similar in LT spice, but mine had a BJT ltp input. I ended up giving up as I had trouble getting the bias and DC offset set up as the resistor values are always very critical and hard to tweak in the software.

Anyway, if you feel like taking the design a little further I would like to see a version with lower rail voltages and class A operation using IRFP240/IRFP9240 and ZVN/P 3310. All of these parts are available from digikey.

As usual, love your work!

[MiiB]

Sworfish.....do you have the Zetex LT-spice models..??

I you do will you post them here or in the spice forum..?

[Jay]

Originally Posted by ontoaba

This one using cheapo MOSFETs, but this prototype is best sounded that I have, and best sounded among all amplifiers I ever tried and heard. I listen it almost all few day long (still play when I sleep) without listening fatigue. Best sound reached when driving headphones directly (most beautiful high frequency), but my motorola earpiece burned by this amp when crack input from bad connector happen. Finished in last few days.

Hi Ontoaba,

You just built an amplifier, not even "finished", and a prototype with bad components, but think that it is the best sounding amp you have ever heard and tried!!

The chances are, you are still far away from the "best", or the amp tricked your ears

[Jay]

Originally Posted by ontoaba

This one using cheapo MOSFETs, but this prototype is best sounded that I have, and best sounded among all amplifiers I ever tried and heard. I listen it almost all few day long (still play when I sleep) without listening fatigue. Best sound reached when driving headphones directly (most beautiful high frequency), but my motorola earpiece burned by this amp when crack input from bad connector happen. Finished in last few days.

Hi Ontoaba,

You just built an amplifier, not even "finished", and a prototype with bad components, but think that it is the best sounding amp you have ever heard and tried!!

The chances are, you are still far away from the "best", or the amp tricked your ears

[ontoaba]

Originally Posted by Jay

Hi Ontoaba,

The chances are, you are still far away from the "best", or the amp tricked your ears

I'll more like this amp if it really could trick my ears. BTW, I am never heard very expensive tube amps.
I am still using some metalfilm resistor and pp caps and the vas using 2Ssc3956e/2sa1541e. They aren't really bad.


Hi, lineup.
I have problem with the real sound belong to, tubeish, mosfetish, or modern ampish?
Most good sounded modern amplifiers makes my ears sick before reaching 3hour listening with my audax loudspeakers, but it last longer with many small loudspeaker in series-paralel.

[GregH2]

Originally Posted by MiiB

Sworfish.....do you have the Zetex LT-spice models..??

I you do will you post them here or in the spice forum..?

Sure, here they are:

Zetex ZVN3310A + ZVP3310A LT Spice models

[lineup]

This is slightly different version to previous.
Can it be more simple than this to get hifi?

1. One JFET 2SK170 with current feedback
2. Two IRF610 and IRF9610 for volt amp
3. Two IRFP240 and IRFP9240 for current out
Sum 5 transistors!!!!

The amplifier makes like 50 Watt with THD ~0.050%
Image shows 40 Watt out at THD 0.015%
At 1 Watt THD is so low as 0.00068%

[MiiB]

You could also keep the fine zetex mosfets and let them drive a pair of Laterals that has only half the input capacitance... I like this circuit concept....