[Shadorne]

Just wondering what is the typical expected lifespan before it becomes advisable to re-cap? Warranty runs 20 years but surely with all that heat coming off these amps, the electrolytic ones in the audio path (not so worried about the power supply as these amps are so overbuilt that some degradation there probably won't matter) will slowly degrade. Just wondering when does this start to become something that is worth checking?

[rmurray]

 I have a 4bst that's 12 years old. I would like to know that too :

[Shadorne]

I have a 4bst that's 12 years old. I would like to know that too :

Exactly the reason I ask. I have a 99 and a '00 "pro" model making them 13 and 12 years old respectively. These amps are beautifully built but I don't expect that Bryston will have solved the inherent problem that all electrolytic caps do age and dry out (even when not used) and they also tend to age more quickly under stress from high levels of heat. Perhaps the question would be better asked in overall terms of hours and age and when is it considered advisable to have them re-serviced?

(FWIW I have personal experience re-capping a 19 year old but good amplifier (not Bryston) and it definitely made a difference - highs were less rolled off after the caps were replaced - probably a coupling capacitor was getting long in the tooth)

[spinner]

Perhaps there are better caps available as well.

[James Tanner]

Hi folks

I will ask engineering. I know it is based on operating temperatures vs lifespan expectation.

James

[Shadorne]

Hi folks

I will ask engineering. I know it is based on operating temperatures vs lifespan expectation.

James

Thanks James.

I read somewhere that Bryston have produced something of the order of 30,000 4B-ST so my guess is your engineering will have a "rule of thumb". For others reading this I want to be clear that electrolytic capacitors are used in nearly all analog audio applications so lifespan of these items will affect nearly all amplifiers and this is not a reflection on Bryston build quality, which everyone knows is second to none.

[Stilgoe]

Hi folks

I will ask engineering. I know it is based on operating temperatures vs lifespan expectation.

James

Any answers on this? Are caps covered in the 20 warranty then?

[James Tanner]

Any answers on this? Are caps covered in the 20 warranty then?

Engineering tells me the caps are rated given their temperatures for 50 year life span.

james

[spinner]

  James if one changes them would newer ones be somewhat finer or would they be identical to originals?

[James Tanner]

  James if one changes them would newer ones be somewhat finer or would they be identical to originals?

Identical if all is working as it should.

james

[rmurray]

 Now that says a lot about military spec Brytson build quality. Proud to own a 4Bst :

[Elizabeth]

Engineering tells me the caps are rated given their temperatures for 50 year life span.

james

Good to know. And what is typical of Bryston IMO. Fifty years.. OK!

[alexone]

Good to know. And what is typical of Bryston IMO. Fifty years.. OK!

...49 years would be ok, too

al.