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+225µF) bypassed with Xicon 0,470µF/630Vdc caps.
For each channel I use one half of a 2x 220µF 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.
visitors since 5th November 2004