Stax stax ESL-F81 - please help

Hey thanks for all the info. How do I get to the fuse and RC network resistor? Do I need to take off the top plate of the box? I cleaned the beck from the deteriorated foam and never replaced it. Do they sound best with or without this foam?

I listen only near-field and at low volumes, they are my late night speakers, so I am looking for something to drive them to SPL 90 or so, but with warmth and clarity.

Yes remove the top wood plate. All the electronics are bolted to the bottom side of the plate.

The input fuse is located on the RC network board. Replace with a 2A normal blow fuse. Check the resistance on the RC network resistors, (2) 12 ohm/2 watts. They may be visibly burned or not. Likely these have failed. If they have not failed I would still highly recommend they be replaced with (2) 12 ohm/10 watt or higher. Fly these large resistors off the board to allow for cooling. Make sure they do not touch anything. The resistors get extremely hot.

The foam on the rear protective cover is always rotted. If you have the speakers out from the back wall at least 3-4' the missing foam will have no impact. If they are close to the back wall some rear wave damping is helpful. A light weight foam or fabric will do.

A good tube amp in the 60-100 watt range should work well with your requirements. The ARC D70 works nicely with these speakers. Articulate, open, warm, it mates well with the seductive, soothing quality of the Stax. $700-$900 on the used market in good shape. With any TC tube amp use the highest output tap possible.

If I decide to go with OTL tube amp what should be ideal specs? Any amp suggestions? I just want to see what the market is.

I have F-81's and Stax DA100M Amps which work very well together. The DA100M's were designed and built to drive the Stax F-81's. However, I have found that my Radford TT100 Solid State/KT88 Valve Hybrid actually drives the F-81's better than the DA100M's! In fact the Radford is one of the most amazingly dynamic and staggeringly powerful 100W amplifiers I have ever come across. it's a true audio work of art. The Stax amps can run out of power at higher volumes causing significant distortion on more complex programming which is both annoying and potentially damaging. I have never had this problem with the Radford driving the Stax. My advice would be to truely make the Stax sing you need a powerful Valve amp. OTL would probably work well. Good luck and have fun experimenting.

This thread is out of date but I may as well chime in. First, pay attention to Kentaja, he fixed my Stax F83's (which did indeed have blown resistors and consequent panel damage). This is a man who knows his business. Second, the amps I've been using to drive them are the Futterman OTL3a.s They are a magnificent match, but the amps run out of steam in the bass, where the impedance drops (unusual for an ELS). I ended up using a subwoofer, with a steep crossover at 100Hz. I couldn't be happier now. These amps are still available used if you try hard. An incredible combination.