View Full Version : amp warm up?
skimminstones
25-02-2015, 22:33
When i first got my nad c320bee amp about 5 yrs ago i remember it taking about 30 mins to start sounding good. Gradually its taking longer and longer to do so now. Im at the point where its a huge noticeable difference after 90-120mins of playing when the music sounds much better. Volume gets louder, bass is fuller and more defined and much better clarity in general. ive tried to keep an open mind over the last few months about this and tried to make sure its not something im imagining but its definitely there. Its almost like a switch is turned on and the music goes from quite cold and hollow to what i mention.
Should it really take almost 2 hours for an amp to start sounding good or is it a sign of an imminent faliure?
walpurgis
25-02-2015, 22:39
Sounds like it needs a recap. The old ones are probably getting tired.
Sounds like it needs a recap. The old ones are probably getting tired.
+1
skimminstones
25-02-2015, 22:53
havent the foggiest about electronics and wouldnt have a clue what to do. Been thnking about changing it anyway so maybe this is the prompt i need.
walpurgis
25-02-2015, 23:03
If you liked the amp when you first had it, a recap (capacitor replacement) could well have it singing like new. There may be one or two AOS members who could help you with this. I'd suggest outlining the situation in the Blank Canvas area, you may get a good response.
skimminstones
25-02-2015, 23:27
having just watched a quick youtube video on changing a capacitor, is it as simple as sourcing the same ones and soldering them in? If so, any good places to buy them? and also a soldering kit?
walpurgis
25-02-2015, 23:41
having just watched a quick youtube video on changing a capacitor, is it as simple as sourcing the same ones and soldering them in? If so, any good places to buy them? and also a soldering kit?
Ah Ha. Now you're getting the plan!
You need to look inside the amp and check access. Some you need to do a lot of dismantling, others have a single PCB that you can reach by removing top or bottom covers.
Then you need the right soldering iron (irons?). A small one for the fine work and a bigger one for meatier soldered joints (probably). Check the required temperature for the solder and ensure the soldering irons are up to it.
Practice soldering before embarking on such a project. It's not hard, but you need to get used to it. As you've seen there are tutorials online. Clean metal is the key!!
eBay should provide the caps.
A desoldering suction gun will help lots too. they aint dear tbh, or u can use braid. Maplins should be able to help you out re soldering gear. some decent kits there with different size tips for doing the job.
walpurgis
25-02-2015, 23:50
I prefer braid. Cheap'n easy. It works.
skimminstones
26-02-2015, 00:06
http://www.ebay.co.uk/itm/40w-Soldering-Iron-Kit-Set-4-Piece-Solder-Station-Stand-Desoldering-Pump-/111579214864?_trksid=p2054897.l4275
Something like this ok for a soldering kit?
I'll open the amp tomorrow and have a look, if it doesn't look too difficult I may give it a go. I've been thinking about changing it and been looking at some roksan amps but even if I do decide to change it would be interesting to know how to work on an amp anyway.
walpurgis
26-02-2015, 00:13
Something like this ok for a soldering kit?
Certainly cheap. Why not?
[QUOTE=skimminstones;624316]http://www.ebay.co.uk/itm/40w-Soldering-Iron-Kit-Set-4-Piece-Solder-Station-Stand-Desoldering-Pump-/111579214864?_trksid=p2054897.l4275
"Something like this ok for a soldering kit?"
In short - no.
I would avoid it like the plague if you want your life to be reasonably trouble free and light hearted
having just finished an extensive recap and replacement of transistors in a vintage pre and power amp I would say without any hesitation that a kit like that will lead to premature baldness and an iressistable urge to chuck the amp (and everything within reach) out the window after prolonged screaming at high octave
during my journey I made the huge mistake of buying some cheap 'leadfree' solder exactly like that in the listing from a local DIY shed and it left my crying with anguish in no time flat. also the 'soldering iron' looks way too thick, clumsy and too high a rating and will most probably scald the tracks off the PCB within milliseconds (if it doesn't electrocute you). The solder suction pump looks to be made entirely from plastic and may decide to melt the first time it gets near anything warmer that a hair dryer.
Take some time and scout around for some slightly more decent kit - certainly a lower wattage and finer soldering iron and 60/40 tin+lead solder - and a solder pump that is at least vaguely composed of metal parts.
skimminstones
26-02-2015, 10:28
In short - no.
I would avoid it like the plague if you want your life to be reasonably trouble free and light hearted
having just finished an extensive recap and replacement of transistors in a vintage pre and power amp I would say without any hesitation that a kit like that will lead to premature baldness and an iressistable urge to chuck the amp (and everything within reach) out the window after prolonged screaming at high octave
during my journey I made the huge mistake of buying some cheap 'leadfree' solder exactly like that in the listing from a local DIY shed and it left my crying with anguish in no time flat. also the 'soldering iron' looks way too thick, clumsy and too high a rating and will most probably scald the tracks off the PCB within milliseconds (if it doesn't electrocute you). The solder suction pump looks to be made entirely from plastic and may decide to melt the first time it gets near anything warmer that a hair dryer.
Take some time and scout around for some slightly more decent kit - certainly a lower wattage and finer soldering iron and 60/40 tin+lead solder - and a solder pump that is at least vaguely composed of metal parts.
is there a kit that youd recommend?
I opened the amp up this morning expecting to find some blown capacitors or something but it all looks fine. Do they just wear out then rather than blow? There also looks a lot of them so how do you know which ones would benefit from replacing? or is it a case of replacing every one of them?
http://i98.photobucket.com/albums/l241/londonguy/CAM00564.jpg (http://s98.photobucket.com/user/londonguy/media/CAM00564.jpg.html)
I'd consider just replacing the PSU caps as a first step. They are the 4 in the bottom right corner of your picture. The two black and two blue ones. You should replace them with capacitors with at least the same value of voltage and capacitance, but there might be a benefit in going for something slightly larger (larger values, not physically larger, as you don't have too much room to play with). Can you read the values on the 4 capacitors and post them here. The values will be something like: 4,700uF, 63v. also, if you can, give us the height and diameter of these 4 caps, and also the available height in the case.
Hope this helps.
If you're not familiar with soldering take care. Removing components from circuit boards needs to be done with care and the right amount of heat plus you'll need a solder sucker. It's easy to knacker the solder pads.
skimminstones
26-02-2015, 11:19
I'd consider just replacing the PSU caps as a first step. They are the 4 in the bottom right corner of your picture. The two black and two blue ones. You should replace them with capacitors with at least the same value of voltage and capacitance, but there might be a benefit in going for something slightly larger (larger values, not physically larger, as you don't have too much room to play with). Can you read the values on the 4 capacitors and post them here. The values will be something like: 4,700uF, 63v. also, if you can, give us the height and diameter of these 4 caps, and also the available height in the case.
Hope this helps.
cheers, ive plugged it all back in for now as im off work today and wanted to listen. At the weekend ill open it again and have a look for those values. Im in too minds whether to bother really, im thinking of changing the amp as id like something a little less powerful on the bass but then i am quite interested in having a play and learning how to do this as well.
could be a project for you when your bored. and a nice way to learn new skills too.
is there a kit that youd recommend?
Personally I use a 12 watt Weller for lifting components on PCBs - it has a nice fine point, replacements tips are easy to get and I've never knackered a track since getting it; cost about £20 on t'bay. A stand is handy with a sponge (use damp to clean the tip). I always use sucker first to get the most solder off and then braid to clean up the track before fitting new parts
If you do want to cut costs this kit don't look too bad and includes all the necessary (and 60/40 solder)
http://www.ebay.co.uk/itm/25-Watt-Electronics-Soldering-Iron-Kit-Stand-Solder-Desolder-Accessories-25w-/151599613237?pt=LH_DefaultDomain_3&hash=item234c0a8535
Would still prefer a metal tubed sucker though - I'm reet clumsy with an iron ;)
I totally agree that the PSU is great place to start - particularly as its on its own board and looks pretty easy to lift out for access ....
Would still prefer a metal tubed sucker though - I'm reet clumsy with an iron ;)
I totally agree that the PSU is great place to start - particularly as its on its own board and looks pretty easy to lift out for access ....
I understand the concern, but I've used an 'Antex' brand, plastic bodied solder sucker for years, and it has worked just fine.
Good man! Get stuck in buy good solder too and as has been said "be careful".
This thread needs pictures by the way.
I have found the cure for slow amp warm up.I have not turned mine off for eight years,it sounds fine every time i use it.I suppose it's just a habit i got into when i was a naimite,i see no reason to turn it off,got to give the solar panels something to do all day.:D
walpurgis
26-02-2015, 19:38
What about when you go on holiday Alan?
Haselsh1
26-02-2015, 19:41
My Rotel's take around thirty minutes to really warm up and when they do the treble smooths out into this gorgeousness. When I need the power amps recapping I shall get a pro to do it, there is no way I am attempting it.
Hate to say it,but English pensioners without a passport and a jack russell,just don't go on holidays.Everyday is a holiday in our house.:lol:I have three amps permanently powered up and they all sound fine,don't even turn off my Bantam gold in the workshop.
I opened the amp up this morning expecting to find some blown capacitors or something but it all looks fine. Do they just wear out then rather than blow? There also looks a lot of them so how do you know which ones would benefit from replacing? or is it a case of replacing every one of them?
Don't do it, if you have no experience this is not the amplifier to practice on, sure you'll gain experience and learn something new, especially if it goes wrong! There are enough trade members on the forum who could do it for you for at a reasonable cost with guaranteed success.
If you are determined to go-ahead then practice soldering on some scrap PCBs or electronics kits, not your amplifier.
walpurgis
26-02-2015, 20:24
Hate to say it,but English pensioners without a passport and a jack russell,just don't go on holidays.Everyday is a holiday in our house.:lol:I have three amps permanently powered up and they all sound fine,don't even turn off my Bantam gold in the workshop.
Well I'm an English pensioner without a passport and a Lurcher who does go on holiday (in the UK) and does turn his amp off! :D
Ah yes,but have you got a water bed????:rolleyes:;)
Ninanina
26-02-2015, 21:12
Well I'm an English pensioner without a passport and a Lurcher who does go on holiday (in the UK) and does turn his amp off! :D
I'm not a pensioner but I do have a passport and a yearning for another sight hound (lurcher, whippet or greyhound!) and I go on holiday in the UK and I have to turn my amp off as I was advised to as it uses valves....
My Oto takes a little while to sound right though, probably about 15-20 mins...
walpurgis
26-02-2015, 21:22
Ah yes,but have you got a water bed????:rolleyes:;)
No, but I've had a few Leaks! ;)
Ninanina
26-02-2015, 22:38
No, but I've had a few Leaks! ;)
:rfl::rfl:
Mine gets switched off too although the amps previous owner told me he left it on standby. If I can't get it sounding right it may never be switched on again :D
Apart from any warm up time, I believe electrical devices are most at risk of an internal failure at the point of powering up which in theory should mean leaving them permanently on might help reduce the risk but I'm too much of a worrier and wouldn't sleep if I'd left a 15yr old amp switched on while my kids are upstairs.
No, but I've had a few Leaks! ;)
No worries,i keep a puncture kit handy..Sounds like you need a nappy..:lol:
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