Balanced Zen v. Borbely SE Balanced

[Pete Fleming]

Here's another comparison request (don’t you just luv ‘em!)

I’m wondering if anyone has compared the Balanced Zen Line Stage, by Mr Nelson Pass, with the SE Balanced Line amp (EB-2000/402) by Mr Erno Borbely?

While I’m have an (increasing) admiration for the work of Nelson Pass, I am attracted to the idea of using JFETs instead of MOSFETS in a pre-amp. Indeed Mr Pass acknowledges the superiority of JFETs in certain low level applications.

Incidentally, to ascertain the performance of a “passive pre” in my system I soldered a couple of resistors in my interconnects as a voltage divider, and connected directly into my amp. Obviously I can’t alter the volume, however (as my CD player has two pairs of outputs) switching between the pre-amp and the attenuated leads demonstrated the affect of the pre-amp on the signal. Just a thought for those considering going down the passive path, but wanting to see the effects before spending a lot of money on a stepped attenuator. An alternative would be to make a series of “piggyback” RCA plugs of different values, with a female and male RCA connected via an attenuator.

Cheers,

Pete

 

[jam]

Pete,

Both designs you mentioned are excellent, I have a slight preference for the Pass. I would current current source the circuit as suggested by Nelson(but try it both ways). The Borbely design, could be improved by replacing the follower, with for exmample, a single ended mosfet.

Have you considered using a shunt volume control?

Jam

 

[Pete Fleming]

Think Mr Pass will get the nod

While I like the idea of using JFETS, I haven't been able to easily locate the devices used in the Borbely design, so I think the Pass project will get the nod.

I'm designing the pre-amp as a modular concept so can easily replace the gain stage. I'm presently collecting data to use the same typology as the "Balanced Zen", except with JFETS.

Cheers,

Pete

 

[jam]

Pete,
The use of j-fets is probably not necessary as noise should not be a problem for the signal levels involved (they would be if you were building a phonostage).
Also you would need a buffer since j-fets might not handle the current levels required and you will be forced to use a follower.

Jam

 

[Pete Fleming]

Thanks for the heads up

Yes these were exactly the things I was looking at, just going through spec sheets to see if I could find something suitable.

Always worth pondering though.

Cheers,

Pete

 

[UltimateX86]

!up

Bosoz with 30V rail vs Borbely SE Balanced ??

http://www.borbelyaudio.com/eb2000402.asp

thx

 

[Nelson Pass]

They're both nice circuits. Maybe you should
try both.

 

[UltimateX86]

hi

It is possible to use a symetric PS for pushpull ?

one could remove the output capacitor ....

or then to use an output like the kaneda

http://www.bonavolta.ch/hobby/en/audio/kaneda_p.htm

thx