Ok I own and love my Exposure XV integrated, but it is gettiung up there in age so I descided to replace the large power supply caps (4x10000uf/63v). While I was doing the recap I noticed a small blue ajustment pot inside the amp and I am wondering what it was for, i later found out it was to ajust the voltage for the output stage. Now I would really like to know how to check to make sure it is withion spec and ajust it if need be. The amp is nearly 15 years old and its possible that it has drifted out of spec and I would like to make sure. The problem is, I emailed Exposure with my question and they basically gave me no answer. I asked around and also came up without an answer. Now can anyone help me with this or point me in the right direction to someone that can?? Its just really bothering me that I cant check to make sure the amp is within spec, I dont know why it just does!!!
Frank

It'll be a bias adjustment pot, for which you'll need a given setting (measured current draw, or a stated voltage drop across the emitter resistors) to measure and aim for. Alternatively, it is possible to adjust bias by measuring the %THD in the output watching the crossover residual, and adjusting the pot for the minimum.

If you don't have the info /equipment though then leave it alone - it's entirely possible to bugger things right up fiddling here. If the pot's been left undisturbed since setting at manufacture it's unlikely to far off - certainly less than trying to 'do it by ear' would achieve!

Its not a bioas pot according to Exposure???

That's a little surprising, though it could be for offset adjustment then. The point remains - unless you're sure, leave it alone.

Yes I know I wont touch it unless I canm find out for sure how to adjust it. Id really like to find out to make sure its up to snuff.

Send it to exposure

They will charge more than the amps worth! i think recapping was in the neighborhood of $250 or so! It cost me about $30 to do it myself

They will charge more than the amps worth! i think recapping was in the neighborhood of $250 or so! It cost me about $30 to do it myself

But if you do it wrong, you'll have a non-working amp!

Exactly! Cheap is expensive!

the amp works fine, i just wanted to check it

Ok I own and love my Exposure XV integrated, but it is gettiung up there in age
They will charge more than the amps worth! i think recapping was in the neighborhood of $250 or so! It cost me about $30 to do it myself
Frank,

Considering the pleasure it has given you over all these years, would you not say it deserves to be pampered a bit if you intend on keeping it another ten? Having it serviced by the factory is an investment, as it will immediately increase its value somewhat - not necessarily the $250 you will have paid.

If you look at $250 over another 10 years' benefit, it's only $25 per year. I would consider it money well spent. Exposure will certainly do other stuff to it to optimise the performance whilst it's with them.

If $250 is not within your budget, that's another matter.

What other stuff will they do to it?? Its already been recapped??

I'd say there were more than 2 capacitors in your amp. ;) There may be other stuff I don't know about.

there are 4x10000uf/63v

And thats the only thing that Exposure changes when you send it for service, i already spoke to them about it.

And thats the only thing that Exposure changes when you send it for service, i already spoke to them about it.
in that case, you have just saved yourself $220.

I must say I'd be a lttle disappointed at what you get for $250, in that case. Transport costs will eat up a lot of it, but even so....

So how much better did the amp sound after your self-recapp? I understand that Exposure amps are less prone to the cap degradation that Naim amps are. I ask because I am considering purchasing an Exposure amp that is 10-12 years old and wonder how much of the sound has gone. Thanks.

I don't understand why an Exposure amp would be any less prone to capacitor degradation that would a Naim one.

Martin?

Doesn't make sense it would be any less prone than any other amp.

I was on an install once with naim along. Naim/Linn front-end feeding a 52 and Krell 600 monoblocks into Apogee Duettas(???..the big ones). I whispered to my buddies, "why does this sound like sh*te, I don't remember krells or apogees being this bad." My friends from naim whispered back "aged filter caps in the 600's supplies." The new owner loved the system regardless; I think it had something to do with her winning the system from her husband in a recent divorce battle;-)

I am reminded of a pair of dead Apogees that have been rotting away in a local dealer's damp and musty smelling shop basement for years.

Multiple, and rather violent looking, long knife slash wounds to the diaphrams.

Perhaps she simply didn't want anyone to have these in the divorce settlement?

Craig

LOL...or someone had severe room problems;-)

Craig.

Exposure amps do indeed require a re cap ( of big main ps caps) less frequently than some amps, in particular naim, who recommend replacement every 10 years of use.
If you send a 10 year old amp to exposure, they will not routinely change the big bhc aerovox caps unless there is somthing obviously wrong. I suspect it is the design of these caps . Also, exposure amps run generally cooler than naim most of the time. Electrolytic cap life is proportional to the average temperatures they are exposed to. I read that somewhere.

I sent my 21 pre amp back to factory for repair and service a couple of years ago. It was 9 years old. I had to ask specifically to get the big caps changed while it was at the factory. They were not going to do this as amp was meeting spec in all areas after repair.

Having said all this, I still got 4 bhc caps sent to me from Exposure, and replaced the ones in my 10 year old 18 super mono's.


Mark.

Thanks Mark,

I also found this thread (http://pinkfishmedia.net/forum/showthread.php?t=9766) helpful - especially so, Martin Clark's contribution within post #13 (http://pinkfishmedia.net/forum/showpost.php?p=88914&postcount=13).

Craig

When I asked Densen about recapping a B-100 they said the caps will last at least 20 years and not to worry about it.

If that's the case and you have already changed these caps then I suggest you either (a) leave well alone or (b) find a reliable local repairer
(:rolleyes: I know...) to just give it a check over for which he won't charge anything like $250.

Changing PSU caps is IMO the first thing you should do if modding/buying SH old amps. If they go pop they will take out the rectifier as a minimum.

BTW I don't think a SS amp is old till it hits 20-25 years.;)