Eico ST-70 integrated amp

The power amp circuit is a good design- enough so that others in high end audio make power amps that are the same circuit.
If this amp is indeed stock, other than to see that it works, don't run it until the power supply filter capacitors have been replaced! Those capacitors, if original, will be loading the power transformer for more than it was designed for and so it will run hot, eventually damaging the power transformer (which smells very bad when it burns up!).

You really don't want this to happen! Replacement of the filter capacitors will probably run around 250.00 or so.

If that amp is properly refurbished its very nice. I'd look on ebay to see what they are going for; if unrestored you'll be at the lower end of that price range. Good Luck!

The filter caps look original, they're Spraigue.
It looks like filter caps with similar specs can be had for around $40 each.  Same uFD rating, slightly higher voltage rating.

Maybe I'll give it a shot, I'm fairly handy with a soldering iron.

Good! The Sprague parts were good but long past their freshness date :)  If you can so the work yourself you can save a lot. You can find aluminum can-style 'multi-caps' at CE Distribution (www.cedist.com)  Many of them are made on the same machinery as were used to make the originals.


One tip- be careful about where the grounds are hooked up on the filter caps. Often the caps are mounted on phenelic insulators that are riveted to the chassis (those are available from CE as well); sometimes you can get into ground loop issues if you don't get the wires tied to the grounds of the filter caps back in the same spot.


The Eicos were not particularly neat inside but they are otherwise laid out pretty well. I've seen people go nuts trying to see how neat they could make them and the results have been very impressive. Eico didn't use very nice coupling caps- this is one way the amp can be noticeably improved. Have fun- don't zap yourself!!

Thanks.
CE had a couple, one that that looks reasonably like the original, but the temp rating is way below the originals.  They had a JJ Electronics one that specs better, but needs a clamp mount.

I seem to remember an old saying something about keeping one hand behind your back at all times when working with tube amps.

Check pricing here:
https://www.hifishark.com/model/eico-st-70

I’ve a number of EICO amps and they sound very good. Use K40y PIO coupling caps.

They had a JJ Electronics one that specs better, but needs a clamp mount.

Those are good parts and hold up well. Its not that hard drilling the mounting holes for the clamps. The clamps are 1 3/8" diameter.