RE Designs LNPA-150 Amps Info On Large Blue Caps and Other Needs

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audiojem

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I recently bought a pair of the late Dan Banquer's RE Designs LNPA-150 power amps I'm trying to find some info regarding replacing the 2 big blue caps on this site Dan recommended to replace every 15 years and I know these are older than that.
So my questions on how can you tell (no leakage) or is it an age thing.
What brand do I use, i have seen a few different pictures some of the blue caps were shorter, thicker/wider then the ones in mine are a thinner taller blue caps made by General Electric and can't read value somewhere i thought 33,000 something.
Is there anyone who might still own one who could take a picture of the inside of your amp or if there are any DB or RE Designs
Genius here who can help?
Thanks In Advance
AJ

richidoo

The amps are very overbuilt using best of the best components so even tho he mentioned doing preventative maintenence the caps are probably still ok and youre better sticking with originals until there is an operational problem. You would need to remove them to test for age caused diminished capacity. I would guess knowing Dan the little bit I did that his caps will last longer than 15 yrs.

When you replace them just make sure the repiacements have equal or larger temp rating, equal or larger capacitance rating, equal or larger voltage rating, pinout size and can size that fits the amp and choose a very high quality cap brand like panasonic nichicon etc.  I like to use Nichicon KL low leakage in general if the other parameters fit. Panasonic makes great quality caps too. Try to use same exact part if possible to preserve his voicing.

Using caps of voltage rating too low can cause accelerated demise from higher heat. I would say stick with same capacitance rating as the original caps.

Iirc AC member mgalusha had these amps and probably knows as much as anyone about them.
Hope this helps

audiojem

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So i posted inside shots of of my my 150's, my serial # are 1031 & 1032, these are the blue caps and I'm trying to find the Vishay resistors that were a option can anyone point those out to me?
Thanks In Advance
AJ










timind

Remove the strap from one of the caps so you can get a look at it. The value is probably printed on the cap, just not visible now. Of course, be sure the amp is unplugged and has been off for for a few minutes. Hopefully, Dan put some bleed off resistors in there. I say hopefully, because I don't see them.

As richidoo says though, if the amp is 15 years old, the caps are most likely fine.
 

audiojem

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I will do that.
Here are some better shots for the Vishay search.
Thanks
AJ










mgalusha

The large caps are spec'd as 33,000uF. The output of the power supply is 40.5V, so the caps are almost certainly rated at 63V, do not go lower. I would suggest Mouser or Digikey for caps like these, look for 105* C rating, low ESR/high ripple current and of course they will need to physically fit in the straps. Other sizes could be accommodated but you may have to buy or make a suitable strap. Be very aware of the polarity, they are not the same, one side is the positive rail and the other is negative. If you have an ESR meter, you could measure the caps and compare that to what new ones are spec'd at, they are likely OK but all electrolytic caps will eventually dry out.

There are bleeder resistors in circuit, it should be safe after few minutes but measure and be sure!

audiojem

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Mike
Thanks for your help.
AJ

deanr

AJ, did you ever locate the Vishay resistors?  My LNPA 150 amps are supposed to have them too.  Did you look in the side heatsink modules?

deanr

Here is a picture of one of the big caps in my LNPA-150 amp with the band moved so you can see the specs.

I haven't found any place that stocks these, although Mouser has some made by Vishay that are very close.
From the various inside pictures I have seen, it looks like Dan used a few different types of caps.

deanr

I believe I have found the Vishay Bulk Metal Foil resistors.  They are the golden yellow pieces in the photo below.

I was looking for black rectangular components, so the packaging for these was new to me.
Here is a link to a Vishay document that mentions them:
http://vishaypg.com/docs/63149/vshzvscz.pdf

poseidonsvoice

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Excellent sleuthing deanr. Looks clear now that the Vishay Z-foil resistors on this amp are the yellow type, not the “naked” type (TX2575, etc...).

Thanks,
Anand.