[Nomad]

When I was studying electronic subjects at the Uni back in the day, I remember reading that most capacitors have a "Best use before" date. It really depends on many factors but one should start to be suspicious with around 10 years old gear (in theory although in real life things seem to be better). Anyway it is still a concern. A real one.

I guess the question here is if it is really worth to get (for quite a lot of money, unfortunately) amps like the Stax SRM-T2 or the Senn HEV90, considering this issue?

Same could be said for some other gear like old DACs, CDPs, etc They usually don't age very well, but I wouldn't mind to get some Stax DACs, for example.

Any experiences/thoughs on this?

 

[facelvega]

Yes, I get the impression that cap decay is a big issue in vintage solid state receivers, but I think a lot of us try to ignore it as much as we can. (I do too.) I don't think the DAC thing is an issue-- old CDP's tend to die from mechanical issues before the DAC's give up.

 

[nikongod]

big hint regarding woverhyped crap in the line below:
vintage caps are largely sought because of a particular sound signature. not because they sound like the music being played...
big hint in the line above.

another note: film caps dont deteroriate anywhere near as fast as electrolytics. if the amp has caps IN the signal path, they are (hopefully) films, and probably good. these will have a MUCH larger efect on the sq than the psu caps.

guitar amps that are supposed to sound like they were built in 1940 should have caps from 1940. high-fi amps should peobably use a nicer cap.

regarding a t2: the caps are mostly generic ones, and easily replaced by ones that are significantly better in most respects except for the wallet factor.

 

[Carl]

You're only likely to find electrolytics in the power supply (well, you'd hope), and if they go, just replace them with something better, unless you're keeping the amp as a museum piece. Some black gates or cerafines are hardly likely to make the amp sound any worse.

 

[Rob N]

But the HEV90 can still be serviced by Sennheiser

IMO if the equipment is less than 20 -25 years old then probably the caps will still be okay.If you're talking about early 1970's or earlier then replacing them would be advisable.

Having said that I've had unmodified equipment from the 1960's that was perfectly okay

 

[billinkansas]

I've had several Fisher tube amps from the 1960's, most of which still played decently, but ran quite hot and threw an occasional spark. The two that I'll be keeping have been restored by Terry DeWick of TN. He sends back a whole bag of questionable caps, etc. They do sound better, but most importantly I don't worry about burning the house down.

If it's worth keeping, it's worth restoring. A refurb usually costs $2-300, a little more on a receiver if you want the tuner aligned.

 

[Duggeh]

I used to have an old Quad 303 amp. Replacing the old capacitors in that made no end of difference to the sound.

 

[Uncle Erik]

I poked around with old tube radios for about 10 years before vacuum tubes eventually brought me to hi-fi and Head-Fi. Capacitor condition varies widely depending on how old they are and what they're made of. If you have any gear with wax/paper caps, you want to get those out of there. Especially the electrolytic ones. Yeah, I know they supposedly have "audiophile" qualities, but I've also seen them smoke and catch fire. Unless a piece of gear was made in the last 10-15 years, I replace all the caps. Seems the safest way to go.

If you haven't done it before, it's not bad at all. You just locate the caps and swap them out. I always upgrade the power rating (e.g. going from a 50v cap to a 250v cap, if it's available and it fits) too.

Also overlooked are resistors. Again, many people like the sound of carbon comp, but I've seen those smoke off, as well, and take out a tube or two with them. If a resistor isn't a modern one or a wirewound, it goes as well.

Yes, all this can be a bit of work. But the gear works properly afterwards and doesn't give me any trouble.