Hovland musicap meltdown...

[jarrods]

I've been playing with my newly constructed 4344's this past week and the 2405H on the RHS stopped working. As it turned out the 1.5uF (EXPENSIVE) Hovlad cap in series with it went open circuit. Now i doubt if i thrashed it to over the 100V is it rated at :-)

Anyone else had these Hovlands die? I'm concerned about long term reliability if i get 1 failure in the first week.

jarrod

[Robh3606]

Wow that's a bit strange. I would contact them and ask if they want it if they have a website. I work in the High Rel Space business and we screen parts all the time. Typically caps are conservatively rated and can actually survive a bit more without failure or damage. When we screen them they get burned in between 1.5-2.5 times their rated voltages with no real issues. Sounds like a manufacturing defect. Could be the lead/wire attachment. Unusual for them to go open??

Rob:)

[grumpy]

Very odd unless there's a lead problem. Shorting
or blowing up are more likely scenarios, but
even that is more typical for old or abused
polarized caps. Then again, marginal parts can
die early (test ok initially , but a bit of stress
brings out a defect)...hence Rob's and similar
industries burn-in procedures for quality
assurance.

Could you describe how the cap was tested to
be "open"? (e.g., used a different cap and the
2405 was happy again... an ohmmeter won't
tell you much).

-grumpy

[jarrods]

I popped a bipolar electrolytic from my hobby junk box across with a couple of alligator clip leads and the 2405H sprung back to life*. I have clipped the offending Hovland off the pcb and sent it back to partsconnexion.com for replacement under warrenty.

btw here is an old thread that had a pic of the PCB....

http://audioheritage.org/vbulletin/showthread.php?t=2574

*note: when i say "sprung back to life" let me quantify that it made noise. hmmm i was a bit sceptical about all this capacitor stuff.. to me a 1.5uF cap was just that - 1.5uF. i can tell you that a 28cent electro sounds NOTHING like a Hovland.

[Ian Mackenzie]

Bad Luck,

Try a Jaycar 1.5 polypropolyne 1.5 uf speaker cap any bypass with 0.01 polystyrene. Not a Hovland but it will make do for now.

Ian