Hey guys!
I have been using my dads old A60 Amp and a pair of Mission Renaissance 737r for a few years now - pretty good match up actually, beats most of the modern ones my friends buy in volume and clarity!
Anyway, a while ago the amp just died and we got it repaired - I'm guessing it was the fuses being blown.
But they did not quite fix it, as now there is another issue - the right output makes the speakers sound like they have been turned up too loud and distorted.
I'm not sure how to really describe it properly, but the closest sound I can come up with is this: Someone has turned their speakers up too loud and they've blown and now sound distorted continuously at any volume.
It is a problem with the AMP (right output) not the speakers. The speakers sound fine when connected to the left output, but when switched to the right the above symptoms happen.
I'm hoping its something obvious that you guys will recognise straight away because I don't have much experience with this kind of thing at all!
Thanks 🙂
I have been using my dads old A60 Amp and a pair of Mission Renaissance 737r for a few years now - pretty good match up actually, beats most of the modern ones my friends buy in volume and clarity!
Anyway, a while ago the amp just died and we got it repaired - I'm guessing it was the fuses being blown.
But they did not quite fix it, as now there is another issue - the right output makes the speakers sound like they have been turned up too loud and distorted.
I'm not sure how to really describe it properly, but the closest sound I can come up with is this: Someone has turned their speakers up too loud and they've blown and now sound distorted continuously at any volume.
It is a problem with the AMP (right output) not the speakers. The speakers sound fine when connected to the left output, but when switched to the right the above symptoms happen.
I'm hoping its something obvious that you guys will recognise straight away because I don't have much experience with this kind of thing at all!
Thanks 🙂
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The service manual is free at Service Manual free download and search for Cambridge-A60 amp.pdf but you don't sound like you have the necessary experience to dabble inside safely. Perhaps it's something simple like a leaky capacitor, you could look for stains on the board and/or bulging capacitor cases, but can't you take it up with whoever 'fixed' it and get them to do it properly?
PS. I had one of these with a wooden case around 1980, it sounded great at the time compared with anything of similar to double the price - fond memories. I had to build a Crimson Elektrik kit (still working) a year or two later to better it.
PS. I had one of these with a wooden case around 1980, it sounded great at the time compared with anything of similar to double the price - fond memories. I had to build a Crimson Elektrik kit (still working) a year or two later to better it.
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Have had a look through the service manual already. The serial number of this amp (~27,000) implies that the capacitor problem was fixed in these models.
I did have a look inside and test a few things but, yeah, I'm not that experienced. I am currently studying electronic engineering at uni but not that far into it yet - and I don't want to break it!
The people who repaired it said they don't know much about these Amps but will try and have a go for us - it wasn't a proper repair service, just a 'we will try our best', so we can't really complain. They got it half working!
I will have a look at the capacitors and see if they look bulged / or leaking.
Thanks for the reply!
I did have a look inside and test a few things but, yeah, I'm not that experienced. I am currently studying electronic engineering at uni but not that far into it yet - and I don't want to break it!
The people who repaired it said they don't know much about these Amps but will try and have a go for us - it wasn't a proper repair service, just a 'we will try our best', so we can't really complain. They got it half working!
I will have a look at the capacitors and see if they look bulged / or leaking.
Thanks for the reply!
Ok, I've found something interesting out.
Firstly if you don't know - each output (right and left) has two plugs each, red and black.
I was playing around with the outputs while keeping the balance/pan in the center. I noticed if I hold the red plug from the right output (the dodgy one) onto the red plug from the left output - or just plug it into the left - while keeping both black plugs in the correct sides. The right speak sounds perfect!
So this means it is the red output that is causing the issue - or something connected to it within the amp. Does that narrow it down to anything you guys might be able to pick out?
I can actually use both speakers fine if I do this - having both black plugs in the correct place but having both red plugs running out of the same working output - would this causing any potential issues?
Thanks!
Firstly if you don't know - each output (right and left) has two plugs each, red and black.
I was playing around with the outputs while keeping the balance/pan in the center. I noticed if I hold the red plug from the right output (the dodgy one) onto the red plug from the left output - or just plug it into the left - while keeping both black plugs in the correct sides. The right speak sounds perfect!
So this means it is the red output that is causing the issue - or something connected to it within the amp. Does that narrow it down to anything you guys might be able to pick out?
I can actually use both speakers fine if I do this - having both black plugs in the correct place but having both red plugs running out of the same working output - would this causing any potential issues?
Thanks!
The black outlets are common earth - It makes no difference which you connect either speaker to. You have simply connected both speakers in parallel on the one (still working) channel and yes, It could work OK if mono is acceptable and and you don't use it as loud as it can play, since the load is twice as much on the remaining amplifier. It is gamble though, with no accurate detail as to what is actually wrong, we can only guess.
Note that stereo sound is from 2 different sources and now you only have half the information - both channels from the preamp should be mixed to mono before connection to the amplifier or you will soon be annoyed with half-stereo rather than mono sound. Music will be missing some instruments, tonal range and the sound generally weak.
You should be looking for a repairer who actually does know one end of an amplifier from the other. I don't think you will be able to tackle a repair though, as the learning curve is steep and you need equipment plus at least some experience inside audio gear to hope for a reasonable outcome. Believe it or not, yellow pages directories are good at finding services and if you are in suburban UK, there will be at least some within reach.
Note that stereo sound is from 2 different sources and now you only have half the information - both channels from the preamp should be mixed to mono before connection to the amplifier or you will soon be annoyed with half-stereo rather than mono sound. Music will be missing some instruments, tonal range and the sound generally weak.
You should be looking for a repairer who actually does know one end of an amplifier from the other. I don't think you will be able to tackle a repair though, as the learning curve is steep and you need equipment plus at least some experience inside audio gear to hope for a reasonable outcome. Believe it or not, yellow pages directories are good at finding services and if you are in suburban UK, there will be at least some within reach.
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