The E80F preamp


Based on this schematic from the Svetlana website

What Svetlana says about this:

Figure 3 shows the EF86 in triode connection. When this is done, the resulting triode is among the lowest-distortion electronic amplifying devices ever made. Typical second-harmonic distortion with 10v RMS output is on the order of 0.05%. This result is achieved without any negative feedback, so this circuit is an excellent choice for high-end audio design. The voltage gain will be about 25 in this connection, making it suitable for line stages:

Hey...isn't this what we all are looking for?

What I did and did not do:

Leave out cathode bypass electrolitic cap (works fine and sounds even better without)
At the output I used a 1M resitor (parrallel over the cinch terminal)
Use first class components, you only need a few of them.
I used 2Watt tantalum resistors from Audionote and copperfoil output caps also from Audionote.
Use a E80F tube, after a few days you will hear why...
The input selector and volume control (100K) I use are from DACT.
For the power supply (230Vdc) I used an old fashioned GZ32 and CLC for general rectification and an other LC per channel.
For general rectification I used a Philips Electrolitic (16+225F) bypassed with Xicon 0,470F/630Vdc caps.
For each channel I use one half of a 2x 220F Black Gate WKZ/350Vdc.
The general choke is 30H and the two other chokes are 20H.
Everything hard wired in solid silver.
Kondo-san could not have done it better...

I love simple things...and every time I use simple topologies I get rewarded with some real music reproduction.
I was a convinced for more than 25 years that a preamp has absolutely no use, because the output voltage of a cd player or phono amp is high enough and does not need to be amplified before entering the power amp...well I was wrong.
I have heard lots of high end preamplifiers and my passive solution was most of the time the better solution unless K's of  euro's/dollars were spend....
With this preamp you prevent loosing musical details at the beginning of the audio system...once lost, they can NEVER be recovered.

schematic click here.

inside views:

  visitors since 5th  November 2004