Berning P-1 Preamp

[kmtang]

Hi,

I am just wondering if anyone could have idea on the gain and output impedance of the Berning P1's line stage. The schematic is per attached.

This circuit seems a good performer with lots of local feedback to minimise the distortion.


Thanks in advance.

Johnny

 

[SY]

Wow, where did you find one of these? I had one built into a PAS-3 cabinet many moons ago. The distortion performance was OK, nothing special. Output impedance was roughly 10-15K, again, nothing great- 12AX7 is a pretty weedy output tube.

 

[kmtang]

Hi SY,

Good to hear your comment. I built the Matisse Atom line amp with some modifications to make it sounds better.

My friends love the Marantz 7 line amp and they built or building the same. I am just hoping to build another model that might be better. I have looked at the schematics of the Conrad Johnson, Audio Research, Jadis and many others. I am not excited with them much.

Do you have any recommendations???

Thank you,
Johnny

 

[audiousername]

The main line stage section would have an output impedance of the vicinity of 1K and a gain of around 7 (17dB). Keep in mind that although the output impedance is quite low, this isn't really suitable for driving heavy capacitive loads since it the output stage won't be able to provide the current - it only has about 1mA running through it.

EDIT: Whoops, I missed the votlage divider at the output 🙁

So the gain provided would actually be around 4.8 and output Z probably around 8K from calculations.

 

[SY]

If you like exotic, try the line stage from the Berning TF-10.

Jason is right, BTW, the source Z is something like 8K.

 

[kmtang]

Hi SY,

Do you have the Berning TF-10 schematic? Do you mind post it so that I could take a look.

Thanks,
Johnny

 

[rfbrw]

http://www.davidberning.com/tf-10.htm

 

[kmtang]

Purist II Line amp

What about the 3 stages 12AU7 line amp? Seems a very good design.

I have got this schematic from www.normankoren.com

JOhnny

 

[kmtang]

Purist II Line amp

Here's the schematic