Leak Varislope II.

Ian's last piece of kit is a Varislope 2 (technically a late Varislope II Stereo) to match the Stereo 20.

On thing I find a little odd about the Varislope, is it's use of EF86 pentodes instead of, say ECC83's.... anyway. 

One EF86 has been changed in the past. If Ian can detect one side souds a little "different" to the other, I'll find 2 new matching valves.

It's chock full of horrible, sticky visconal capacitors. On with the gloves!

One cap has been replaced in the past, and it's the same vintage to those in the Stereo 20, 1979.

The preamp consists of an EF86 gain stage, followed by a Baxandall tone control, and another EF86 stage, where you can vary the response of the tone controls, and negative feedback.

After the capacitors are evicted, I check through all the resistors. Unbelievably, only two cathode resistors are outside of specification. 

Studying the circuit further, it appears the EF86's are run close to starvation mode at around 250uA, great for gain, not so great for distortion. 

Does this matter? Nah, on test it sounds great... :)