|
Posts: 8
Joined: August 30, 2009
|
| Model: | St20 | | Category: | Amplifier (Tube) | | Suggested Retail Price: | whatever you can agree to | | Description: | small pp EL84 stereo 'power' amplifier ideal restoration /tweak target | | Manufacturer URL: | Not Available |
Leak stereo 20: replace all couple-caps with MKT or MKP. Check PSU electrolytics. Replace GZ34 with 2 1N4007 plus 100 Ohm in series to the first electrolytic condensor. Check all resistors, many will not have the spec values. Now it is a really high end amp.
With good loudspeakers, even Magnepan MG IC, no feedback is the best sounding. Just remove V-1, disconnect it-s anode resistors and then connect the input to the entrance condensor of the Schmitt phase splitter.
Sensitivity is the same as with feedback. This procedure is easy reversible if your loudspeakers are underdamped by bad design, Magnepans (IC) are 5 Ohm at all frequencies, so these have no problems at all.
The Varislope is bad, replace anode/screen/cathode resistors by standard 100 Kiloohm/390 Kiloohm/ 1 Kiloohm and give them 250 volt by a separate power unit. ( the outlet on the Leak stereo 20 will drop too much because the EF86 will draw 2mA now.
| Product Weakness: | After 5 years all kinds of problems, hum, hot transformers because of leaking capacitors, bad minimal PSU capacitors and bad resistors, many loose their values especially in the phasesplitter, the EL84 cathoderesistors. Renewal makes it a completely new amp, because the transformers are good and the circuit also. | | Product Strengths: | Very good new in 1967.<br> |
Associated Equipment for this Review:| Amplifier: | leak stereo20 | | Preamplifier (or None if Integrated): | modded varislope pre | | Sources (CDP/Turntable): | cd phono | | Speakers: | Dali 606 Magnepan IC | | Cables/Interconnects: | 4 mm | | Music Used (Genre/Selections): | everything that swings | | Room Comments/Treatments: | rugs, curtains | | Time Period/Length of Audition: | 1967 -2009 | | Type of Audition/Review: | Product Owner |
|
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2009, Audio Asylum, all rights reserved ]
[ Go Green ]
[ Take5 ]