US Amplifier Servicing

MintyGreen

Hey,

Just thought I'd post this here in this forum as it may be the most appropriate as I need some advice about getting a guitar amp serviced in the UK.

I bought the amp in 2018 from a reputable maker of boutique amps in the US and had it shipped over. The amp was built to UK specifications with a UK power transformer and plug. 

I've had no problems with the amp apart changing the power tubes when they started to go. It's been very reliable and have gigged with it numerous times. The one issue is that it does have a bit of rattle on a low note. Also recently I noticed that the headroom on the amp was a bit lower than normal so I took it to an amp tech in the UK to look at. 

Unfortunately the amp tech said that he could not work on the amp due to the way the amp was constructed, as the chassis is exposed underneath the tubes. They also said that the amp would never conform to British Standards and therefore if they worked on it and something was to happen, they could liable. 

The amp maker is a very good one and I know that some of their amps have been sold to some of the best musicians in the world. I doubt that they would make an amp that was unsafe, but I can understand the amp technicians position up to a certain point, and ultimately it's there decision whether they chose to provide a service or not.

However, I'm in an invidious position in that my options seem to be to either contact the maker and see if they will provide an out of warranty service, which would involve shipping it at expense, finding another amp tech or trying to diagnose and fix the problem, which is probably dangerous and not advisable.

Any advice or suggestions would be greatly appreciated.

Also, curious to know what the position is regarding public liability of amp techs, just in the sense that I know many of them will be working on vintage amps that would have no chance of meeting a British Standards test or getting a CE mark. Even after servicing and repair - for example removing the death capacitor and making sure the amp was properly grounded, I know that some of these amps would not pass those types of electrical safety tests, yet they continue to be repaired and sold on the vintage market.

ICBM

Welcome .

Do you have any photos of the area in question? Even if it does have exposed parts it’s probably not impossible to build some sort of housing or cover for it - I’ve done that for a couple of vintage amps which had exposed terminals on the transformers.

US regulations are quite a bit different and much less strict than EU/UK ones, so it is quite possible that it could be built well and to the relevant standards there, but not here. The tech is correct that he can’t legally work on something which doesn’t conform to the standards without accepting liability for it. Some have “looser” interpretations of the regs than others though…

(Before you ask, I’m no longer doing repair work so this is not a sales pitch!)

RiftAmps

If I'm honest, it's doubtful that the amp was built to meet UK/EU regs (many UK builders struggle to achieve this!), so it really should not have been sold into this market. Many US 'boutique' built amps fall foul of our regs and in my experience, the builders tend not to care.

Unfortunately the amp tech said that he could not work on the amp due to the way the amp was constructed, as the chassis is exposed underneath the tubes. They also said that the amp would never conform to British Standards and therefore if they worked on it and something was to happen, they could liable.

Yes, he would indeed take on the liability should anything happen after he'd worked on it. It's the same with garages, cars, and surgeons. It's why we have insurance. This does not mean, however, that the amp needs to be brought up to mnfr'ing spec, but simply (I'm using this term very loosely) that it needs to be made 'safe'.

Also, curious to know what the position is regarding public liability of amp techs, just in the sense that I know many of them will be working on vintage amps that would have no chance of meeting a British Standards test or getting a CE mark. Even after servicing and repair - for example removing the death capacitor and making sure the amp was properly grounded, I know that some of these amps would not pass those types of electrical safety tests, yet they continue to be repaired and sold on the vintage market.

From the Electrical Equipment (Safety) Regulations 2016: Great Britain

"Products which are repaired, refurbished or exchanged without changing their original performance, purpose, or type, are not considered ‘new’ and therefore do not need to be recertified and remarked.

However, the above assumes that the appliance respected the appropriate regulations at the time of its manufacture .



More reading - https://www.gov.uk/government/publications/electrical-equipment-safety-regulations-2016/electrical-equipment-safety-regulations-2016-great-britain

ICBM

RiftAmps said:

Yes, he would indeed take on the liability should anything happen after he'd worked on it. It's the same with garages, cars, and surgeons. It's why we have insurance. This does not mean, however, that the amp needs to be brought up to mnfr'ing spec, but simply (I'm using that term very loosely) that it needs to be made 'safe'.

I would actually say that a good understanding of proper electrical safety is more important than slavishly following the regs (although you should still know what they are) in many cases, especially with vintage amps - some of which were not even compliant with the standards when they were made, including some quite well-known manufacturers. It’s very rare to find one that can’t be made safe - the closest would be an old AC/DC amp (not the band!) with direct mains rectification, like some very early Selmers. You can still fit a normal transformer if you’re determined enough and want to spend the money though.

RiftAmps

ICBM said:

RiftAmps said:

Yes, he would indeed take on the liability should anything happen after he'd worked on it. It's the same with garages, cars, and surgeons. It's why we have insurance. This does not mean, however, that the amp needs to be brought up to mnfr'ing spec, but simply (I'm using that term very loosely) that it needs to be made 'safe'.

I would actually say that a good understanding of proper electrical safety is more important than slavishly following the regs (although you should still know what they are) in many cases, especially with vintage amps - some of which were not even compliant with the standards when they were made, including some quite well-known manufacturers. It’s very rare to find one that can’t be made safe - the closest would be an old AC/DC amp (not the band!) with direct mains rectification, like some very early Selmers. You can still fit a normal transformer if you’re determined enough and want to spend the money though.

I agree to an extent, but I do not want to ever stand in a Coroner's Court explaining why I didn't follow the regs!

ICBM

RiftAmps said:

I agree to an extent, but I do not want to ever stand in a Coroner's Court explaining why I didn't follow the regs! 

Nor me. It was one of the parts of my decision to stop doing repairs - too many people asking for 'originality' and hence 'value' over safety or regulations... especially concerning things like Bulgin mains plugs, which I refused to leave in place.

RiftAmps said:

From the Electrical Equipment (Safety) Regulations 2016: Great Britain

"Products which are repaired, refurbished or exchanged without changing their original performance, purpose, or type, are not considered ‘new’ and therefore do not need to be recertified and remarked.

However, the above assumes that the appliance respected the appropriate regulations at the time of its manufacture .

Where I feel there's a little room for interpretation is exactly in whether something (other than crappy mains connectors that shouldn't ever have been mains-rated in the first place!) should be altered if it did pass the regulations when manufactured, and is safe to any reasonable standard, but doesn't now.

But I don't worry about that any more...

Modulus_Amps

Presumably the amp does not bare any CE or UKCA markings?

There are loads of amp makers in the US and the UK and EU that do not build to a high enough standard. Most of them can be made safe though. There will be UK amp techs that would look at this for you, those that would take an interest in the amp and have the time to work through it and the ability to make a plan re the safety side.
Really though to give you proper advice we need to know:
where are you?
what amp is it?
Photo's of the chassis and wiring?

I know loads of amp techs or could look at it for you, but I would not want to do so if it is a complete turd.

ecc83

There is of course a lot more old electrical gear about than just guitar amplifiers (think of the stuff done on "The Repair Shop") and I think the burden of safe repair lies with the service tech? If he or she is satisfied that the equipment has been brought up to a safe standard then they should be fine. If the equipment subsequently causes injury or worse then the tech should be able to show that it was in a safe state when it left them and their qualifications and reputation would be an important consideration.*

Naturally the nature of any incident would be investigated and an examination of the equipment would need to be made.

*There are of course many unqualified and inexperience people in the electrical and electronics repair world.

Dave.

Modulus_Amps

 A repair tech can not be expected to bring any product up to full compliance. Yes they must do a safe repair.

If the equipment never met electrical safety standard in the first place liability would always go back to the manufacturer or importer.

Refusing to work on it is the smart thing to do, though in my mind it would be better to make it safe or skip it rather than put it back out there to be a hazard.

MintyGreen

Thanks for all the information and responses - I'm going to try and do a bit of troubleshooting my self to start, there isn't much wrong - there is some low end buzzing, and a slight loss of headroom, plus one preamp tube has a bit of rattle. For the low end buzzing I'll try a different speaker, and also take the amp and speaker out of the cabinet, as the buzz could be coming from the cabinet itself. I'll try a different set of power tubes as well and put a new preamp tube.

After that I'll try a few other amp techs, I assumed that they would be of the same position.

goldtop

Why not post more details/photos and get some practical answers?

ecc83

goldtop said:

Why not post more details/photos and get some practical answers?

Amen to that brother!

MintyGreen

ecc83 said:

goldtop said:

Why not post more details/photos and get some practical answers?

Amen to that brother!

I'd prefer to keep the makers details anonymous just out of courtesy. They've been extremely helpful when I bought the amp and have been good in answering any after sales questions.

ecc83

MintyGreen said:

ecc83 said:

goldtop said:

Why not post more details/photos and get some practical answers?

Amen to that brother!

I'd prefer to keep the makers details anonymous just out of courtesy. They've been extremely helpful when I bought the amp and have been good in answering any after sales questions.

Fair enough.

Dave.

goldtop

MintyGreen said:

ecc83 said:

goldtop said:

Why not post more details/photos and get some practical answers?

Amen to that brother!

I'd prefer to keep the makers details anonymous just out of courtesy. They've been extremely helpful when I bought the amp and have been good in answering any after sales questions.

Then all we can do is guess that the amp tech you went to wasn't having a bad day. 

There aren't many amps which can't be made safe and reliable by an open and problem-solving mind.

ICBM

MintyGreen said:

I'd prefer to keep the makers details anonymous just out of courtesy. They've been extremely helpful when I bought the amp and have been good in answering any after sales questions.

Can you take a photo of the area in question without showing enough of the outside that the amp is identifiable?

MintyGreen

Ok so I did some troubleshooting myself - safely as possible of course. I removed the back panel and removed the chassis from the cabinet and mounted this on blocks separately. I changed the speaker over and then checked the nuts of the screws holding the speaker to the front of the cabinet. It seems that there was some buzzing coming from the speaker not being mounted tightly enough.

I put the old speaker back in and then tested the amp again. It seems that the rattle on the low frequencies was coming from the chassis not fitting correctly into the cabinet. Unfortunately the cabinet has taken a couple of knocks and the pine cabinet is a bit delicate, which means that the chassis can't be completely screwed in tightly to the cabinet on one side, as the screw thread has chewed too much of the screw hole. With some adjustments I've been able to get the chassis to fit reasonably well and most of the rattle has gone. Additionally I swapped out the 6L6s and the preamp tube which was causing some rattle on a higher frequency and the amp sounds as it should.

So in summary, it seems that the remaining rattle is due to the cabinet, as there isn't any rattle when the chassis is outside the cabinet. However I'll still need to get a tech to make sure that the chassis can fit properly in the cabinet and that everything is secure. Hopefully that should be the solution.