"Serviced" bugbear

[Twincam]

I was just looking through some ads on eBay and whenever I see the words serviced I always take it with a pinch of salt. I've seen many ads now on eBay that really get too me. There is an amp on there claiming serviced but the pics show, a very corroded transformer wire, a couple of dodgy leaky caps a cracked resistor and a resistor that looks like it's badly overheated, patently this amp easily went through its service lol! What a joke.

Because serviced to me means an amp has been brought up to date so it's ready to use reliably. So I expect ancient power supply capacitors to be changed, the bias checked and adjusted. And any other components that could be an issue in the near future changed.
And guess what the ads show the inside of an amp that hasn't been touched since who knows when.
Serviced to some must mean it was looked at and deemed ok.
It's like saying the car has been serviced and all someone has done is check the coolant and oil levels despite how old the oil, filter and anti freeze is.

I know some components last a long time and maybe the filter caps are in good working order but if the amp is over 20+ years old there is surely no way a good amp tech would let old caps be left in there. It's well known large caps have a lifespan. The amps I'm looking at are 30 - 40 years old, they need changing the bias needs to be checked.

So I'm left thinking "serviced" means bullshit.
I know some amps are actually serviced, but most "serviced" amps ain't and it's a con to people who don't know better to raise the price and sooner rather than later the new owner will have to foot the bill, and be left wondering why his serviced amp needs a service so soon.

I will also add I'm not saying your 20+ year old amp needs servicing but it is worth noting that for reliability and longevity a proper service is a good thing. So not looking to pick a fight with folks who own older non serviced amps.

Always ask questions when buying an amp.
Rant over

Edited May 18, 2016 by Twincam

[gary mac]

I look at it as entertaining reading though. It's fun reading between the lines and gauging the level of bull.

There's a jazz bass on there at the moment and the seller is detailing how the nut has been replaced with one fashioned from a toothbrush. The price for said Jazz, £12,000.

Hopefully you won't get too wound up and stressed, may be avoid trawling the ads for a while.

[casapete]

I saw a 1x15 speaker cab recently advertised on eBay, claimed to be recently serviced.
What's that all about then? Checking the input socket, and maybe speaker terminals?!!

[Phil Starr]

I've been banging on about this for some time. I'll probably continue until it becomes the accepted wisdom because I hate to see people ripped off.

YOU CANNOT SERVICE AN AMP

an amp contains no serviceable parts. There's nothing to top up, tighten up, tweak or adjust. There is no routine maintenance.

your car has lots of moving parts and its reliability depends upon lubricants and filters that need periodic replacement. It also has safety critical components that ought to be checked periodically, which is why there is a list of things to check and when which makes up a servicing schedule. No such thing exists for amps, check your manuals if you don't believe me.

Now things break down and wear out, just as they do on a car but your service doesn't cover that.

Now if you are running vintage gear then you might want it rebuilt, all the capacitors, pots and sockets replaced or a re-valve but that's the equivalent of rebuilding a car, a major task that can cost much more than the original amp.

Now I'm sure there are other amp techs out there who will do a service if you push them hard enough. They may open her up Hoover out the accumulated dust and check for scorching, maybe even spray some switch cleaner on the bits they can reach. (Though I avoid this if there is no fault because it can disturb dirt that wasn't causing problems) what they are doing is offering a bit of placebo effect though. A bit of reassurance to a nervous customer.

Some smart Alec is going to point out the odd vintage valve amp that needs the bias tweaking every now and again or that you could have the valves checked but for most of us there is no point in checking an amp that is working faultlessly.

[Beer of the Bass]

Regarding things like replacing electrolytic capacitors on old amps, I found it interesting reading through John Chambers' website. He's an amp tech with decades of experience and the site is a mine of information for anyone interested in these things. I noticed that he does not routinely replace capacitors in old amps unless they have visibly deteriorated or the amp isn't working correctly. This seems quite different to the prevaling wisdom nowadays, but it's evident that he knows his stuff.
I do tend to go through any older amp of my own and replace them, but I realise this is like the guys who strip down old Morris Minors in their garage - tinkering as an end in itself.

[luckydog]

[QUOTE] Beer of the Bass said:

Regarding things like replacing electrolytic capacitors on old amps, I found it interesting reading through John Chambers' website. He's an amp tech with decades of experience and the site is a mine of information for anyone interested in these things. I noticed that he does not routinely replace capacitors in old amps unless they have visibly deteriorated or the amp isn't working correctly. This seems quite different to the prevaling wisdom nowadays, but it's evident that he knows his stuff. [/QUOTE]

I agree - however the likes of us are in the minority, and it's almost heresy to suggest !

I don't routinely change caps either. By way of servicing vintage gear, I reform electrolytics at rated voltage using a method similar to factory formation - then test for leakage current and original rated capacitance. For interstage coupling caps on valve gear I simply check for leakage current - undiagnosed faults of this nature are more common that faulty electrolytics IME, and replace where faulty. For cathode decoupling caps generally I reform them and test for value and leakage current if time permits, or sometimes replace the output stage one (if present) routinely if its easy.

This preserves authenticity and detects ageing or failing caps without replacing original good parts.

I suppose it is proper 'servicing', and actually takes longer than replacing caps wholesale which I really don't like to see done.

LD

[NickD]

If I'm buying something 'serviced', to me that means that it works properly. After years of using a bigger rig I recently dug out my old Trace combo to find that years of neglect had left it crackly and horrible, with volume jumping and dropping at random. After taking it to a tech it now works exactly as it did the day I bought it 25 years ago, and if I were to sell it I would probably use the word serviced in that context.

[luckydog]

I think it's reasonable to think that 'serviced' implies the equipment is in servicable condition ie fit to use with a reasonable expectation of reliabilty. Whatever it takes to get there......

LD

[Twincam]

[quote name='Beer of the Bass' timestamp='1463563283' post='3052280']
Regarding things like replacing electrolytic capacitors on old amps, I found it interesting reading through John Chambers' website. He's an amp tech with decades of experience and the site is a mine of information for anyone interested in these things. I noticed that he does not routinely replace capacitors in old amps unless they have visibly deteriorated or the amp isn't working correctly. This seems quite different to the prevaling wisdom nowadays, but it's evident that he knows his stuff.
I do tend to go through any older amp of my own and replace them, but I realise this is like the guys who strip down old Morris Minors in their garage - tinkering as an end in itself.
[/quote]

The thing is old caps can work ok but for how long? And people think there serviced amp is going to be good for another 20 odd years which it won't be.

The other thing people don't seem to test for is a caps esr rating which is from my understanding a better way of evaluating a cap.

[Twincam]

[quote name='gary mac' timestamp='1463548604' post='3052158']
I look at it as entertaining reading though. It's fun reading between the lines and gauging the level of bull.

There's a jazz bass on there at the moment and the seller is detailing how the nut has been replaced with one fashioned from a toothbrush. The price for said Jazz, £12,000.

Hopefully you won't get too wound up and stressed, may be avoid trawling the ads for a while.
[/quote]

It ok I'm not stressed or wound up, slightly irritated maybe.

A toothbrush? Is it an old bone one? Ivory? Please don't tell me it's plastic.

[3below]

[quote name='Twincam' timestamp='1463574015' post='3052433']
It ok I'm not stressed or wound up, slightly irritated maybe.

A toothbrush? Is it an old bone one? Ivory? Please don't tell me it's plastic.
[/quote]

At £12,000 it should be made from unobtanium at the very least

[Beer of the Bass]

[quote name='Twincam' timestamp='1463573833' post='3052431']
The thing is old caps can work ok but for how long? And people think there serviced amp is going to be good for another 20 odd years which it won't be.

The other thing people don't seem to test for is a caps esr rating which is from my understanding a better way of evaluating a cap.
[/quote]

I guess there's also the question of how much bench time is really justified for an amp of a given value, bearing in mind that anyone who isn't into DIY pays by the hour to have their amps worked on. Perhaps on premium-valued vintage gear it would be worthwhile to test every part, but I've always had the kind of B-list valve amps that would be hard to shift even for a couple of hundred quid (although I note there are some people on a mission to slowly push up the prices). Many of those are good, solid amps, but a few hours of time from an experienced tech would be getting close to the market value of the amp. Taking a pragmatic approach to that sort of lower valued gear, it may make more sense to assess the functionality of the whole unit and deal with any problems as they occur.

Edited May 18, 2016 by Beer of the Bass

[Twincam]

[quote name='Beer of the Bass' timestamp='1463577261' post='3052472']


I guess there's also the question of how much bench time is really justified for an amp of a given value, bearing in mind that anyone who isn't into DIY pays by the hour to have their amps worked on. Perhaps on premium-valued vintage gear it would be worthwhile to test every part, but I've always had the kind of B-list valve amps that would be hard to shift even for a couple of hundred quid (although I note there are some people on a mission to slowly push up the prices). Many of those are good, solid amps, but a few hours of time from an experienced tech would be getting close to the market value of the amp. Taking a pragmatic approach to that sort of lower valued gear, it may make more sense to assess the functionality of the whole unit and deal with any problems as they occur.
[/quote]

Yes I see where your coming from. The only issue I have with dealing with problems as they occur is that if something fails big time, then it can cause a lot more work.
But I'm not really taking issue with anyone whom chooses to only replace certain parts themselves or techs that leave in older components as such. It's only the people who imply the amp is serviced. When it's not, it may of been looked over and deemed ok right now but the amp is pretty much original and who knows when something of age will let go.

I think prices are going up naturally. But also folk are realising the more obscure or b and d brands stuff Can be pretty good or modded and some of the crap or lower end of yesteryear actually can have there place and is retro cool or something. Especially as the better or more well known stuff is higher priced and not as readily available maybe. Also going through that time when people long for 70s stuff they had when younger. Then it will be the turn of the 80 and 90s and what were cheap trace heads will be worth quadruple what they are now lol.

Edited May 18, 2016 by Twincam

[taunton-hobbit]

There is a firm on fleabay that alleges its stuff is serviced & cleaned. I had the pleasure of buying from them once (only once) - what arrived took days to clean the rexine (on a smallish head) and a specialist to sort out the disgusting state of the innards (& replace the caps, which needed attention & had clearly not been checked).
This is not what I understand 'serviced & cleaned' to mean.....
Caveat Emptor, I suppose........

[luckydog]

[QUOTE]Twincam said:

The thing is old caps can work ok but for how long?[/QUOTE]

Well, at risk of heresy, if they are made well and conditioned well they'll typically see us out for sure.

I don't see evidence for, nor theory supporting a general ageing issue.

In relatively recent times there have been some well dodgy quality issues with electrolytic caps that might have led to fairly sweeping generalisations. Check out the great capacitor plague of the noughties [url="https://en.wikipedia.org/wiki/Capacitor_plague"]https://en.wikipedia.org/wiki/Capacitor_plague[/url]

But actually, well made caps age very well IME and for good reasons, especially vintage ones.

Not saying this to be controversial, but to suggest examine the hard evidence rather than take any unevidenced statements as fact on the subject - including mine !

Ever the heretic.....

LD

[Twincam]

[quote name='luckydog' timestamp='1463604771' post='3052820']


Well, at risk of heresy, if they are made well and conditioned well they'll typically see us out for sure.

I don't see evidence for, nor theory supporting a general ageing issue.

In relatively recent times there have been some well dodgy quality issues with electrolytic caps that might have led to fairly sweeping generalisations. Check out the great capacitor plague of the noughties [url="https://en.wikipedia.org/wiki/Capacitor_plague"]https://en.wikipedia.org/wiki/Capacitor_plague[/url]

But actually, well made caps age very well IME and for good reasons, especially vintage ones.

Not saying this to be controversial, but to suggest examine the hard evidence rather than take any unevidenced statements as fact on the subject - including mine !

Ever the heretic.....

LD
[/quote]

Well some caps do age well. But there is massive evidence to suggest that certainly after 30 years of use the power caps particular don't do as good of a job they once did even if they . I've had a few fairly old amps now and everyone of them has had at least one of the larger filter caps replacing. And commonly on amps it's one of the first things to go and need replacing.

[Dad3353]

Most often, big filter caps will show physical signs before failure, typically bulging and/or leakage. Many caps have 'escape vents' that pop if there's a build-up of pressure inside. Often, these caps are spec'ed close to top limit. Other than that, if there's no sign of deterioration, it changes nothing to swap 'em out; new caps can fail, too. My Hiwatt and Fender still have their original caps, with no symptoms. I'm well qualified for changing them, and wouldn't hesitate if there seemed any risk, but for now, all is well.
Still, if I'm not heard of for a few weeks, maybe someone could come and pull me free from the smoke-filled room, please..?

Edited May 18, 2016 by Dad3353

[Beer of the Bass]

I've recently changed out the filter caps on my Dynacord head, but one of them had failed years ago and been sloppily replaced with two marginally rated caps positioned right where the hot air rises from the power valves, with the wiring to them running across lots of the audio wiring. So it felt quite reasonable to sort that and refresh the ones in the bias supply too while I was at it.
I had a bit of a learning experience with one particular amp I had several years ago. It came to me with a loud hum - first I changed the main filter caps to no avail, as it turned out to be the one in the bias supply. Then I ended up chasing a crackling noise in the power amp. I had replaced most of the resistors in the power amp and replaced and re-wired the output valve sockets before I figured out that the noise was from one of the power valves, which I had just assumed must be OK as they were new. So, I had a quiet, working amp at the end of it but it occurred to me that I had replaced many more parts than might have been necessary, and someone with a bit more experience would have been more methodical and addressed those specific issues right away.

Edited May 18, 2016 by Beer of the Bass

[luckydog]

[QUOTE]Twincam said:

.............after 30 years of use the power caps particular don't do as good of a job they once did [/QUOTE]

Well that is certainly widespread belief, but my point is that ain't necessarily so. I did say it was heresy ! Sure caps sometimes fail, but that really doesn't mean all will, and for good reason.

IMO it's best to examine, re-condition and test vintage caps, rather than routinely replace them. Or just not worry. The vast majority are fine IME, and surgery is often worse than the disease. Obviously if they test faulty or are ruptured, they have to be replaced, but not routinely.

LD