Leak Stereo 30 Plus mains fuse

[Goodizzy]

I have been using one of these in my system for some time now and recently had a fault whereby I was getting hum on startup from both channels. The amp has never been recapped nor pushed hard, but had been run thru two 4ohm EMI DLS529 speakers. (not best pairing)

Before recapping and going down the full on troubleshooting route, I gave it a good air clean and cleaned all switches with contact cleaners. I am ready to hook it back up and turn it on when I noticed that both the AC and DC fuses were fast blow 1.6A fuses! After consulting the literature it seems the AC fuse is listed as 1A time delay. However, since I am running it at 130V being in the US, should I increase that to 2A? Thanks for any input- I love this amp!

[GrimJosef]

Curiously the circuit, available here http://44bx.com/leak/leak_ccts.html, shows a 1A mains fuse for the 30 Plus and a 0.5A one for the straight 30. The latter is described as Slo-Blo but the former is not. There is no alternative rating given for different mains voltages.

I would never increase a fuse rating over the manufacturer's recommended value unless I was certain it needed to be done. If you don't get regular 'nuisance blowing' with the recommended fuse then I'd stick with it.

Cheers,

GJ

[Goodizzy]

Thank you, I actually have both amps but the germanium 30 has been sitting on the bench a long time, haha. Thank you for the reply, I will stick a 1A slow blow in there.

['LIVEWIRE?']

Point taken about correctly rated fuses, GJ, but as, in round figures, this amp. is being run from half the UK mains supply voltage, then surely, it will draw roughly twice the current than if run from 230/240VAC, which should require a higher amperage fuse. As you no doubt know, most dual-voltage amplifiers, etc., do specify higher amperage fuses for 12v than for 240.

[Goodizzy]

As per another thread I had started on the Components section regarding the BS1362 plug fuses...I suppose the proper thing would be to hook an ammeter up and measure how much it is drawing.

As I stated originally, the fuse in the AC mains positions was the wrong rating. It was rated at 1.6A, while the schematic calls for 1A. It is worth noting too that the schematic is drawn to 240V on PT primary. 2A might be a safe guess, but just a guess none the less?

[GrimJosef]

Originally Posted by 'LIVEWIRE?'

Point taken about correctly rated fuses, GJ, but as, in round figures, this amp. is being run from half the UK mains supply voltage, then surely, it will draw roughly twice the current than if run from 230/240VAC, which should require a higher amperage fuse. As you no doubt know, most dual-voltage amplifiers, etc., do specify higher amperage fuses for 12v than for 240.

Point taken about the variation of current with supply voltage. But the circuit I referred to shows a single mains transformer primary with multiple mains voltage tappings. The fuse is shown as 1A at the same time as the 110V tapping is shown as selected. The 48V DC supply, which powers the whole amp except for a 'Lilliput' panel lamp, has a 1.6A fuse in it. So the amp power can't exceed 77W. Making some small allowances for the lamp and the transformer inefficiency, 1A and 110V for the primary seems about right. If the 1A fuse persistently blows in the US then we might want to investigate the possibility of increasing it. But why would we risk it otherwise ?

Cheers,

GJ

[Trevor]

The amplifier is fitted with a small transformer I would be amazed if it was more than 60 Va so a 1 amp fuse would be a sensible choice 120 volts 1 amp = 120 Va it should be enough
Trev

[Goodizzy]

Thank you!