Pass X250 concept ?

[acaudio]

Hi guys,
nice to see that the discussion is again flamed up.
My circuit with that Jfet cascode had, so far as I can remind, absolute no DC offset. I was running it without any capacitors in the signal way. I can agree Cheff, the sound was pretty well fast with deep bass. In the pas time I was on weight up what better, Aleph P or this. The time should show us. My project is on ice, but I´ll continue as soon as my horns are build.

Good luck!
Adam

 

[Nelson Pass]

Those are particularly nice horns. I take it those are FE166 ES?

 

[acaudio]

Those are particularly nice horns. I take it those are FE166 ES?

Thank You Mr. Pass!
I´m using FE206E, driven by F1.

Best Regards
Adam

 

[Nelson Pass]

I was fooled by the magnet size

 

[ANALOG GUY]

My completed schematic

1.Balanced source. (convert from Function Generator)
2.Balanced input module without de/increse gain.
3.Se input module with 10k potentiometre

Many guys mail me about my posted @ solidstate, Yes it's same schematic.

I have some problem with simulation when I use ZVN/P 3310 instead IRF610/9610 it's has more DC out on (drain+drain) output (0.5-1V) or I'll change source resistor from 1k to 221 ?

Help me please,I used 10.48mA each IRF610/9610.....too much ?

Thanks
analog guy

 

[CheffDeGaar]

Just a few pics of the prototyped beast :

The "whole" setup, quickly breadboaded, wires everywhere, and absolutely no noise

 

[CheffDeGaar]

A closer look...

 

[CheffDeGaar]

Top of the pops...

 

[lumanauw]

Is there any way to not-use K389-J109, replacing with other "easy to get" transistors, without sacrificing the performance?

 

[CheffDeGaar]

Haven't tried, so can't tell about better or worse performance. And you'd better match the fets.

 

[lumanauw]

And you'd better match the fets.

I would be very lucky if I even can buy the non matched parts I still have K389 BL's but don't have any J109(GR or BL or V or anything)

In my fuzzy memory, Mr. Pass sometimes ago (very long ago) seems to write it is the OL gain + CL gain + feedback ratio that matters very much. This is when he was asked why he uses Mosfets for X1000 and X600, and uses these UGS Jfet modules for smaller X amps.

Since I'm still learning, is it true that these ratio's that makes the "sound", not because it is built by Jfet or Mosfet or Bipolars?

 

[jam]

Cheff,

......................just one question. Since you take feedback to the sources of the differentials, does it still qualify as a true x-amp?

Regards,
Jam

 

[jam]

............sorry! I missed a couple of connections .....you are correct.

Jam

 

[Adams_Leo]

I don't know about the Panasonic polypropylene--I was using the 10uF polyester. It's no real surprise that polypropylene sounds better than polyester, but I needed larger values in order to get the frequency rolloff down.

Grey

EDIT: You want the schematic? No problem. Remind me when I'm at home and can get to it.

would you please share the line stage schematic?