Fuses blown, need help Identifying proper replacements

[opimax]

Hi,

I recieved my Perreaux amp last week and last night got it working, problems w/unusual connections , needed to make my own which turned out to be no problem w/input from Perreaux tech support.

Last night late I am smiling as I hear music w/test speakers , portable CD player for 30 minutes. This morning after reading the paper hook up to main speakers once before moving and finalizing connections, etc.

1 side is blown! Started checking everything on the small speakers(l20t3 ). Short answer 2 rail fuses are bad, swapped with the other 2 channel sounds fine again, BIG, BIG relief!!

Now the questions please

Amp has written on it by the fuses "8 amp, 15 amp blow." the fuses that are in it are Lucas 5 (then small print "continuous") 10A. Seems to me that theses are too small by design. I have never heard of this style. The only other thing I have heard of is "slow blow" are these the same thing? If not would Radio Shack have them or are they specialized and if so recommendations where to buy

Thanks much

Mark

[Thom]

This won't answer your question but may explain a bit. I'm unfamiliar with said amplifier and fuses. For maximum protection continue your quest for information. Some fuses are rated at current they can carry with no ill effect. Some fuses are rated at current they should disappear at. Some fuses have very special time X current curves. Usually there is quite a bit of discretion available in replacing a fuse but if you want the fuse that will let you get the most before it becomes history and at the same time offer as complete of protection as a fuse will give you in the application then what will work becomes much narrower. I hope there was something in there for you. I'm sure a fuse number would have been more helpful.

[SEAWOLF97]

Hi,

I have never heard of this style. The only other thing I have heard of is "slow blow" are these the same thing? If not would Radio Shack have them or are they specialized and if so recommendations where to buy

Thanks much

Mark

Since you are in contact with Perreaux tech support , ask them. I would never use "slo blo" in audio gear.

When I was getting tech support from Ohm's president , we blew fuses left and right , working to THE SMALLEST that was usuable and not blow often.

[opimax]

Thanks both for the replys.

I do understand both replys I will continue w/Perreaux but being the impatient child I still am I want something today and no answer from Perreax is expected till Mon or Tuesday. I will do my Bicycling today past some high end shops in Bethesda and see if they "know" the correct answer.

For the 2-3 days I am waiting this is what I am thinking.
10 amp regular quick blow or even and 8 based on 5 blows at 10 that was in there and the writing on the amp of 8 blows at 15


Any thoughts...

Mark

[Allanvh5150]

Hi Mark,

Depending on the amp model you have, it must be a big one, the fuses you want are just standard 1 1/4" glass fuses. Dont use slow blow. If the amp says "8Amp", go with that. The 15 amp blo rating was is confusing to say the least. Also, depending on how loud you run your system, you could just put 5amp fuses in there for a little extra insurance. I have had a lot of experience with the older Perreaux amps and I have never seen a rail fuse blow, unless someone put a very low load on it or a dead short. I have only ever seen the Mosfets fail "open", which is very good for your system. Any info that you want, give me a yell and I will see what I have. Hope this helps.

Allan.

[opimax]

Allan

Thanks for the response. I went and purchased 10 amps for the main. I purchased both 6 and 8 for the rails starting with the 6. All of the fuses showed old age and some burning of the paper Lucas used internally. I have not seen Lucas fuses for sell here in the States thinking they might be very old.

Seems "warm", not at all familiar w/different amps but this seems accurate to what I think warm would be. I like it.

2 other issues, not liking the fan so I would think i will disable it, per a few people including Pereaux support. The other is the gigantic thump when turning off, this has to be tamed whether normal or not.

Oh and trying to find out if there is a face plate that is not rack mounted

Mark

[SEAWOLF97]

. All of the fuses showed old age and some burning of the paper Lucas used internally. I have not seen Lucas fuses for sell here in the States thinking they might be very old.

Back when I drove English sportscars equipped with Lucas electrical running gear , Lucas was know as the "Prince of Darkness"

In fact the old joke goes..

Q. Why do the English drink warm beer ?

A. because they have Lucas refrigerators ...


Lucas quality really improved about 10 years ago (when they started rebadging BOSCH parts and selling as their own)

[hjames]

Back when I drove English sportscars equipped with Lucas electrical running gear , Lucas was know as the "Prince of Darkness"

Ah, you're just saying that because you never tried Moto Morelli parts!

[BMWCCA]

Or, perhaps, Magneti-Morelli?

[hjames]

Or, perhaps, Magneti-Morelli?

There ya go makin' sense of it all ..
hey I never let accuracy get in the way of good drinkin' !

[Allanvh5150]

Hi Mark,

Out of curiosity, wht model Perreaux do you have? I am pretty sure they were all rack mount.

Allan

[opimax]

Hi Allan,

It is a 6000b. only 2 issues left , disabling the fan and turn off thump. the fan I can deal with the thump I need help with

Mark

[Earl K]

It is a 6000b. only 2 issues left , disabling the fan and turn off thump. the fan I can deal with the thump I need help with

Mark,

If that was my amp, I would worry most about the "thump". It sounds to be a discharge wave that includes a large amount of DC based energy. This could eventually cause damage to your speakers. I'd suggest that you take your speakers "offline" before shutdown and replace them with an 8 ohm load resistor before powering down the amp ( until this thump is minimized ). I'd go with a 20 watt / 8 ohm resistor ( fwiw ).

- This discharge thump is ( IMO ) what's causing your rail fuses to prematurely blow. I think the amp overall needs some maintenenace & tweaking in the area of all the internal DC offsets .

- I'd recommend you register at the diyAudio website . Once a member, create a thread listing your amps problems. "Anatech" ( Chris ) is a moderator there who's a very skilled tech. / who "may" just respond to your query with some self-help directions ( if you want to open up your amp ) .

[opimax]

Earl,

I agree the thump is an issue, I thought that is what I posted,

let me clear something. The fuses don't blow on a ongoing bases, they blew only one and that was after the 1st time I used it. The fuses were 5 amp and 8amp is what is printed. I used 6amp this time, I do have 8 amp available. the old ones were very old.

All that being said I have only turned it off 3 times , 2 thumps 1 not. My unit is kept on currently, it is no big deal to leave on. On the otehr hand I want all my equipment "right" so I will happily follow your suggestions, athough in my usual slow process . I am also waiting for next response from Perreaux on the manual, I will be asking them about the thump also if I haven't already

[Allanvh5150]

Hi Mark,

It is unusual for these amps to make a thump, on or off. Does it still do it when you turn the attenuators right down? Putting a timer circuit and a realay to disconnect the speakers would solve the problem as well.

Allan.