PSB 50MKII

[GrahamJohnMiles]

I'm just auditioning a pair of these speakers and searching online I found a reference to a crossover modification using Vishay bypass caps. I can't find anything more than this casual reference, does anyone have any further information or links available?

 

[esldude]

Do not know any particulars. Usually bypass caps are sized 5% or 10% of the cap being bypassed. So if you look inside and know the value you know what value bypass is needed. If it were a 10 microfarad cap, then you might bypass it with a 1 microfarad cap by putting the cap in parallel with the larger cap. This helps the sound of large bipolar electrolytics when you bypass them with a smaller value film cap of higher quality.

 

Don't know about Vishay caps having never used them, but their resistors are very worthwhile parts for improved sound quality.

 

Of course if you change values of crossover parts you slightly alter the crossover response. Might be better to keep it to 5% for bypassing.

 

[GrahamJohnMiles]

Thanks for the response that gives me an idea of how to approach the mod.

 

 

[esldude]

http://www.canuckaudiomart.com/details/119047-psb_50_mkii_speakers__mint_condition__will_ship/

 

Ad on some of your speakers. Fellow mentions a Vishay Roderstein bypass mod. He describes using all .01 microfarad caps for bypass. I have doubts they would make much difference in a crossover. The bypass to main cap ratio is not in that 5-10% range. In my own experimenting it takes at least 2% to make much of any difference. 5% or a bit more makes plenty of difference.

 

He also links to this site:

http://www.humblehomemadehifi.com/Cap.html

 

It appears to me this second site was not bypassing, but completely replacing which will of course do the most good. Also costs the most money. I haven't used all the caps on this guys list. Of the few I have used I would find most of his subjective descriptions of how they sound pretty much spot on with my experience of them. As he mentions film caps do take awhile to break in and sound right.

 

You might be in a place where replacing the big caps (if they are bipolars) with lesser film caps a good improvement. You also might bypass the big lower priced film caps with some excellent smaller caps. Doing it this way you can have all the values add up so the crossover response is not changed at all. In smaller speakers it also will matter about how much room you have. Film caps will be physically much larger than bipolar caps.

 

Of course if you really want to become part of the lunatic fringe, you could move the crossover outside the speaker so room isn't an issue. Then use better wire from the new crossover board to the drivers. This is not a bad idea and will improve sound a bit more. I don't know if this is something you would consider or how it might 'look' in your use of these speakers. Just a thought.

 

[GrahamJohnMiles]

Thanks for the interesting suggestions. I might resist the temptation to tinker. I went through all that years ago, replacing caps, resistors, rewiring components etc. It can be fun but my golden ears are getting a little tarnished these days so subtle differences might not be worth the effort.