P5 fuse blows

Hi Guys,

First of all, I greet everyone who writes so cheerfully here! I just signed up. I am a long-time PS audio fan who started with the P500, meanwhile had a PS-Audio GCPH (the first with a remote control! Even before it was in series). and P5 owner for 8 years. Now comes the reason why I logged into the PS-Audio Hot-Spot:
Last night I was sitting on the couch and suddenly the light went out … KLACCKKK! The fuse from the circuit where the light and the stereo system ran over it had gone out (one gigawatt G-C20A). The entire stereo was on, but no music was playing. After checking everything I found no mistake. I then put the P5 on the table and checked it. The fuse had blown. A new one is quickly inserted and switched on with no devices connected. Immediately the fuse blown again. The P5 wasn’t hot (it never gets, just a little warm), nothing smells burnt. Then I took off the lid and checked everything visually. There is absolutely nothing to be seen that suggests a short circuit or the like. The capacitors all look ok too. Then I switched on all amplifiers etc. of the stereo system individually via an extended power cable to see whether a device was defective. All amplifiers fine.
What do the experts say, has something like this happened before, and where could the mistake be?

High fidelity greetings, Geramond

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Welcome Geramond! Great to hear you’ve been a long-time PS fan! if it blew right away with nothing connected to the back and the fuse value was correct, I’d suspect a short circuit somewhere. Did you make sure to match the same fuse value?

Hello James,

Thanks for the answer! the fuse is the correct one with> 3A slow <. I have now given the P5 to an electronics engineer friend of mine who works in the audio sector. He checks everything. He was also amazed that although the fuse blows immediately when you switch it on, you cannot see any (optical) damage. Let’s see what he finds. Is this type of failure known with the P5?

Greetings, Geramound

Great, thanks for letting me know. Let’s hope your friend can find out what’s going on. I wouldn’t say it’s known necessarily. There are too may things that could possibly cause this. Ranging from very simple to needing a new regen assembly. Let’s hope it’s the former though.

I may be mistaken…but I don’t think P5 uses a T3a fuse but a T5a
on my P12 it is a T5a T= slow blow.

Save that the P12 is a newer version of P5 I’m thinking fuses values
are the same.

If indeed the P5 fuse value is T5a then no wonder your P5 is blowing it’s
T3a fuse on power up…

Hopefully James will reply…

His profile says Germany so the lower amp rating of the fuse is probably correct for 230 volts.

Can confirm he’s in Germany and running the correct fuse for his 230V unit.

hi guys,

The way davida writes it is correct! I just spelled it wrong! It should be a 3A fuse! This is what it says in the German operating instructions on page 12. From the first day there was a 3.15A fuse from AHP in the P5, that is for almost 8 years. This is how I got the device and so far I have never had problems with the backup.
I’m curious if someone has ever had this problem with a P5. This topic is still new and hardly anyone will have read it, let’s see …

Greetings, Geramond :blush:

Did you find the cause?

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The same problem with my friend´s P5. What is the result?


one side of the output stage transistors was completely cracked. The regenerator block was replaced which was expensive. Why that broke I don’t know. The P5 was actually only lightly loaded. I don’t use it anymore after the repair. The device is here only for decoration.

Greetings, Geramond


Hello Geramond,

Thank you for mail! My friend will not be very happy with this report…

He is not rich man and new PSAudio product are too expensive.

What do you using instead PSA for better electric power?

I have P10 and it is working ok until now.

Greetings, Franta

I just tried another fuse and it blows the moment I put the power button on , so I don’t know what’s the problem; someone has an idea ( PS Audio’s staff )???

If you’re trying it with nothing plugged into the P5, that’s not a good sign. Likely something in the regen that has failed. Likely needs to be repaired.

I live in Quebec, Canada. Where do I go for repair ?

Same here. Had a brief short and now she won’t power up with nothing connected :grimacing:

No visible damage so I did a test using an ammeter in place of the fuse and Variac to throttle the AC power. It draws full 5 amps with only 30 volts in so dared not go higher. Couldn’t see anything overheating. Anything else I can check before sending it across the border?

My P10 is doing exactly the same. I had the regen boards changed, it powered up for a couple of minutes ok (with a few things connected). I then put all my plugs in, powered up and the fuse blew. Replaced the fuse, blew again. Disconnected everything and the fuse still blows immediately on power up.

I too would really appreciate someone in PSA indicating the likely problem.

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Wow. Whatever you do don’t bypass the fuse like I did. This thing draws insane current before even powering up. There must be an internal short somewhere. In my case I suspect a relay is stuck in a bad state from a power surge - there are 5 large black relays on the Output/Relay board. I don’t know if that part was replaced when you did your Regen boards.

The last time this happened to me with another amp it was the mains transformer shorted due to age, but it was very obvious because it would get hot immediately.

I too fear that it might be the transformer.

I have a P10 and it blows the fuse of my preamp every time I power it on.
One is the fuse in Parasound JC2. Dac is ok. CD PLayer is also Ok.
If I plug the preamp directly into the wall the fuse does not blow.

Any help would be much appreciated!!!