Just got a Rogers LS5/8 system

[RufKutz]

OK then I got a problem!

One of the amps is not outputting to the tweeter properly. The tweeter will sound for a bit and then crackle and cut out.

The problem is definitely the amp, I've swapped speakers and cables and everything and the fault stays with the amp.

I've got everything with me at home but our family is on self isolation for the next two weeks!

Is this the kind of thing I might be able to fix myself with a soldering iron and gritted teeth or should I wait and get it fixed by someone who knows what they're doing??

I hope you're all keeping safe and healthy and have nice speakers nearby to help u through these difficult times!

[mole42uk]

You need to get the amplifier to a qualified engineer. The Quad amps were modified and are known to have issues which we know about. The BBC test gear is helpful too…

[Bobsound]

I had a similar problem with one of mine. It turned out to be a 15mfd tantalum capacitor on the frequency splitting pre-amplifier unit.
Bob

[RufKutz]

nice one Richard - I'll send you a private message!

[Radio Wrangler]

Originally Posted by RufKutz

The problem is definitely the amp, I've swapped speakers and cables and everything and the fault stays with the amp.

Can you swap power amps inputs from the crossover board and then you can tell if it's the crossover board or the power amp.

If it's the power amp, the number-one first diagnostic of the amplifier itself is the DC offset voltage on the output after you've checked power supplies and fuses. and checked that signal is reaching the amp.

Rocket science isn't involved. Care and thought will get you there. Transistor audio power amps have some dirty tricks to lead the unwary up the garden path if an orderly approach isn't taken.

Take care. These pages hold many tales (well, as much as they are prepared to admit!) of people whose slip with a probe blew more bits up and set them back to worse off than where they started.

David

[mole42uk]

It’s difficult to swap power amps in the AM8/16 because, in addition to the active crossover which is connected with a wiring loom, the HF power amp is modified to restrict output to the tweeter.

[RufKutz]

OK well I am definitely in need of a qualified engineer then! Can anybody recommend someone? I'm based in Manchester (not that that really matters at the moment...)

[Radio Wrangler]

Yes, it's the sort of job that needs the right equipment to apply signals at chosen frequencies and follow them through the system. At least you have one good side to compare the bad one against. That will help a lot.

David