Recently I have blown an SR Orange and Purple fuse on a tube swap, powering up after the new tubes are in. I know that these fuses are “sensitive” , and I wait several minutes after powering down before extracting the tubes, setting them, and powering back up. This has happened only on the BHK. Ideas?
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Possible that the fuses are not the time slow blow type?
Did this happen on the pre amp or power amps?
The only time my SR fuses blew was with the preamp on
while powering up my former Parasound A21 power amp.
The inrush current draw must have gotten through to the
preamp…
Just wondering if a similar situation happened with your BHK…
Best wishes
Are these BHK amps? In mine I removed my Orange fuses after they kept blowing on inrush current. I’ve moved to Purples and upped the value slightly. My suspicion is that the fuses aren’t spec’d correctly and are undervalued.
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It happens on the BHK Pre only, and they are slow blow.
I know that SR’s fuse ratings may be suspect as you have suggested but I am hesitant to “over rate” fuses for the obvious reasons.
One detail remains…was BHK preamp on while power amp
was being powered on?
Best wishes
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The BHK Preamp has a strong inrush from cold. I accidently bounced the power switch on it one day and caused a fuse to blow. The aftermarket fuses should be rated properly with what they cost.
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I have very slightly increased the capacity of aftermarket fuses to accommodate inrush current.
The very expensive “pop” of the fuse is one reason that audiophile fuses are the last thing to spend money on imo.
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I wonder if a few hours of tube burn-in would have prevented it from happening. If that is the case, though, it serves you little to know now.
To be clear, it blows on power up with the preamp only. An in-rush current issue. I will probably go slightly higher on the SR rating and hope for the best. What’s another $200 bucks. Thank you all for suggestions.
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Well that helps rule out a possibility…
If your BHK blew on inrush go back to the SR seller. I’ve received replacements for the problem. But the seller insisted on a higher value. FWIW I’ve never replaced a HiFiTuning fuse in 6 years. They work like champs and power all 10 rails in my BHK 300’s.
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Kind of weird that the tubes would cause it. I think it’s a good idea to have some cheapos on hand to make sure everything is OK. Testing with $200 is no fun.
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Do you generally power up your preamp after your amp(s)?
Best,
-JP
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Hey john2213…
Yes my sop is to fire up my amp 1st and let it draw it’s inrush
then power up my sources…
Doing so for me is a safety precaution for my sources…
Just me perhaps…
Thanks for asking
Best wishes
I power up my BHK Pre first, and then 5 secs later it sends trigger to the 250 (L&R) and 700 (Center). I haven’t had any issues so far.
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This thread has me wondering what the overall consensus is on exact value, aftermarket fuse swaps, or value+, factoring fuse build tolerances or lack thereof.
It is my general practice to turn on the source and preamp before amps. I have recently swapped tubes in a BHK pre without blowing a fuse. Granted I have a factory installed fuse but I have never blown an audiophile fuse in solid state or tube gears.
I would recommend the opposite.Your sources do not need protection.
But the amp could conceivably be damaged from a source being powered on.
Actually have been doing this for years…never a problem…
Power up
Preamp, sources, amps
Power down
Amps, sources, preamp
This is always how I have been taught avoids unwanted “thumps” and other nasties
Best,
-JP