advertisement


Exposure 3 c**k up.

the loaf

pfm Member
Hi,
I have an exposure 3 preamp and about a year ago managed to accidentally plug in a non phono source into the mc phono input not once but twice! There is now a constant background noise/hum on all inputs . It appears that the preamp does not function unless the mc stage (looks like a card easily removeable) is in it's rightful place.
Can this mc stage be fixed and / or can the pre be modified to function without a phono stage ? ( Apologies can't download pics and I am not an engineer) .
Thanks.
 
Really, really unlikely that overloading the phono stage a year ago causes a fault today.

You haven't specified the exact model/year, but the current 3010 has an input that is either aux/mc/digital, the latter two with optional cards. So it's highly likely you can convert the phono input back to line. You will probably need a 'jumper' of some form to replace the card, and that might be a cue to call Exposure or a dealer.
 
Plugging a non MC source into phono input will not do any harm. It is also unheard off for a pre to need the phono card in place for other inputs to work. Yes it can be repaired and yes it can be wired to have no phono stage and instead an extra line input if required. Probably wants a rebuild, getting rid of original dodgy tantalum caps in the process. One of these gone short is most likely problem.
 
Plugging a non MC source into phono input will not do any harm. It is also unheard off for a pre to need the phono card in place for other inputs to work. Yes it can be repaired and yes it can be wired to have no phono stage and instead an extra line input if required. Probably wants a rebuild, getting rid of original dodgy tantalum caps in the process. One of these gone short is most likely problem.
And what would you use to replace those dodgy tantalum caps ?
 
Just out of curiosity, what makes tantalum caps dodgy and what makes the other mentioned electrolytics NOT dodgy. I wanna learn.

(popcorn....)
 
Just out of curiosity, what makes tantalum caps dodgy and what makes the other mentioned electrolytics NOT dodgy. I wanna learn.

(popcorn....)

Apart from them having a poor performance on THD they have an unfortunate tendency to go short circuit when they fail and this can often take out other components. I seem to recall reading in another Exposure thread on pfm that Exposure themselves now recommend this course of action in repairing older units. I don't know if they've stopped using them on new builds or not.
 
dirty...sonsof.....

On that note, anyone heard the new 5010 monoblocks??

Thanks for the clear explanation Jez. Makes sense.

Out of curiosity, can you give an example of a line of amps whose internal parts usage are....exemplary?
 
dirty...sonsof.....

On that note, anyone heard the new 5010 monoblocks??

Thanks for the clear explanation Jez. Makes sense.

Out of curiosity, can you give an example of a line of amps whose internal parts usage are....exemplary?

What I'd prefer to do is to point out just how unimportant parts "quality" is to sound quality! The design of the circuit, the topology, is by far the most important thing with the layout also important. Parts quality is not even 5% of the total when it comes to sound quality. A good design will still sound excellent if quite literally built from second hand parts removed from 30 year old TV's and video recorders! A poor design will not be made any better by "silver foil and polypropylene capacitors made only under a full moon", fancy resistors, or anything else.

Reliability can be affected by parts quality but even then the type of part chosen and precisely how it is used are more important than "quality" by a huge margin. eg using a 1W resistor when 1/4W is being dissipated is good practice and better than using better "quality" resistor of 1/2W rating generally.
 
What I'd prefer to do is to point out just how unimportant parts "quality" is to sound quality! The design of the circuit, the topology, is by far the most important thing with the layout also important. Parts quality is not even 5% of the total when it comes to sound quality. A good design will still sound excellent if quite literally built from second hand parts removed from 30 year old TV's and video recorders! A poor design will not be made any better by "silver foil and polypropylene capacitors made only under a full moon", fancy resistors, or anything else.

Reliability can be affected by parts quality but even then the type of part chosen and precisely how it is used are more important than "quality" by a huge margin. eg using a 1W resistor when 1/4W is being dissipated is good practice and better than using better "quality" resistor of 1/2W rating generally.
According to these comments, the ones I witnessed lately for contemporary hi-fi gears are Sugden and Luxman pure class A amps.
Both of the use standard parts but they will use a high wattage resistor when needed.
And both sound very good IMO if you like that sound signature.
 


advertisement


Back
Top