Question New TT hum -is this normal?

LawlB

Standard Member
I really could do with some help. I’m not technical above plugging in and turning on.

I purchased a demo Thorens TD350 Turntable which came with a 1 year warranty after reading some good reviews.

I have connected it up to a new Arcam SA30 which when connected together, results in a very noticeable and loud hum. Low volume not auditable but anything around normal family room listening is very noticeable. I don’t have my music loud, so it’s not a small noise that’s heard at maximum volume. It’s a loud hum and normal listening levels.

The Thorens does not have an earth connector but the Arcam does.

Tried new or different cables, connectors, different speakers, placement changes, rooms, different wall sockets and so on. No change whatsoever.

Emailed dealer, who said that hum can be problematic to detect followed by;

“Unlikely to be a fault with the tonearm and wiring but more a system mains hum earth loop hum, sometimes too many earths cause a ground loop causing more noise in the system this is why star single point earthing is desirable”.

Not a great place to be left given I have no idea what to do now.

Tried earth cable from Arcam and touched around Thorens, made no difference until I touched the centre metal spindle. Touching anything else made no difference. Touching the earth cable to the spindle reduced it by about 50%.

The hum was whether the TT was turned on or not, but as it connects to a MM specific connection, I didn’t feel safe plugging into a different connection.

I would appreciate some advice particularly whether this is an acceptable outcome for new kit, or if the hum I describe is an expected outcome of any expensive turntable set up or if in actual fact, it does suggest that there is an issue with the turntable.

I should just add, no hum when TT disconnected from the Arcam or when anything else like CD is connected, just the TT.

Not used vinyl since a tower system 30 years ago. It feels so much has changed.

I have a couple of short videos but wasn’t sure how to upload..

thank you.
 

Gray3

Active Member
It is neither normal nor acceptable to have the level of hum you have described.
The fact that 50+ people have viewed your question so far and chosen not to answer, doesn't surprise me though (easy solutions are jumped on early).
What is normal, is that a cartridge is extremely sensitive and susceptible to electromagnetic sources.
Looking at all you've tried, the important part of your story is that you've relocated the TT, even to different rooms.
Could you try a different amp? (not that I think that's the problem).
If you are 100% certain that it's always been well away from mains transformers etc.,........
For obvious reasons, this is not a good time, possibly the worst in history, but here's what I think you should do:
You're within warranty, contact the dealer again. Tell him you're not completely satisfied with his 'unlikely' to be faulty response and that you will get it, together with the Arcam (assuming that he supplied it) back in to him for testing at the earliest opportunity.
Not what you want to hear I know, but if anyone's got a better solution, maybe they'll give it.
Good luck for a satisfactory outcome.
 
Last edited:

DT79

Well-known Member
If it doesn’t have a captive interconnect, then try different ones (brand/model). Some times a component can get earthed through the interconnect if it has a screen which is connected at both ends.
 

LawlB

Standard Member
It is neither normal nor acceptable to have the level of hum you have described.
The fact that 50+ people have viewed your question so far and chosen not to answer, doesn't surprise me though (easy solutions are jumped on early).
What is normal, is that a cartridge is extremely sensitive and susceptible to electromagnetic sources.
Looking at all you've tried, the important part of your story is that you've relocated the TT, even to different rooms.
Could you try a different amp? (not that I think that's the problem).
If you are 100% certain that it's always been well away from mains transformers etc.,........
For obvious reasons, this is not a good time, possibly the worst in history, but here's what I think you should do:
You're within warranty, contact the dealer again. Tell him you're not completely satisfied with his 'unlikely' to be faulty response and that you will get it, together with the Arcam (assuming that he supplied it) back in to him for testing at the earliest opportunity.
Not what you want to hear I know, but if anyone's got a better solution, maybe they'll give it.
Good luck for a satisfactory outcome.
 

LawlB

Standard Member
Thanks.
No the Arcam came from a different dealer.

At my normal listening levels, I could live with the 50% reduction when the earth cable was attached, but there is no external connection post.
I have emailed the dealer and will wait and see.

what worries me is the dealer is suggesting loud hum, or any hum as normal.
 

oscroft

Member
what worries me is the dealer is suggesting loud hum, or any hum as normal.
Yep, there's clearly an earth issue here. I always thought a tonearm needs to be earthed either through a separate earthing wire or through one of the RCA grounds. As there's no separate earth, I wonder if there's a fault and there's no earth via RCA ground either? Maybe something has become disconnected during its demo days, perhaps by someone fiddling with it in ways they shouldn't?

There should be no audible hum at all from a turntable, and at normal volumes it should be totally silent apart from what's on the record. So I wouldn't accept even the 50% hum reduction, and I'd return it
 

Gray3

Active Member
If it doesn’t have a captive interconnect, then try different ones (brand/model). Some times a component can get earthed through the interconnect if it has a screen which is connected at both ends.
In his original post he said he's 'tried new or different cables'.
 

Gray3

Active Member
Thanks.
No the Arcam came from a different dealer.

At my normal listening levels, I could live with the 50% reduction when the earth cable was attached, but there is no external connection post.
I have emailed the dealer and will wait and see.

what worries me is the dealer is suggesting loud hum, or any hum as normal.
You're right to be worried.
It would be possible to open up the TT and connect to an earthing point but don't.
It's not your job to make corrective modifications and you'd invalidate the warranty.
I've got a (decades old) Thorens TD-160S. It cost a fraction of what you paid and is hum-free.
No way you should live with a 50% reduction in the hum. 100% is what you must have.
You're doing the right thing.
Good luck.
 

Khazul

Well-known Member
Are they all connected to the same mains outlet? (Ideally yes).

All my turntables (technics) are completely hum free whatever I have them connected to (Yamaha Hifi Amp and AVR, Pioneer DJ mixer, NI DJ audio interfaces etc).

The dealer is talking utter bollox and trying to fob you off. Do not accept and perhaps even keep such as written evidence of deliberate deceit should this all turn sour.
 

oscroft

Member
Gulp, I've only just seen the price of a Thorens TD350.

You should have absolute hum-free perfection for that kind of price, and any dealer who says hum is in any way acceptable is a scoundrel.
 
I really could do with some help. I’m not technical above plugging in and turning on.

I purchased a demo Thorens TD350 Turntable which came with a 1 year warranty after reading some good reviews.

I have connected it up to a new Arcam SA30 which when connected together, results in a very noticeable and loud hum. Low volume not auditable but anything around normal family room listening is very noticeable. I don’t have my music loud, so it’s not a small noise that’s heard at maximum volume. It’s a loud hum and normal listening levels.

The Thorens does not have an earth connector but the Arcam does.

Tried new or different cables, connectors, different speakers, placement changes, rooms, different wall sockets and so on. No change whatsoever.

Emailed dealer, who said that hum can be problematic to detect followed by;

“Unlikely to be a fault with the tonearm and wiring but more a system mains hum earth loop hum, sometimes too many earths cause a ground loop causing more noise in the system this is why star single point earthing is desirable”.

Not a great place to be left given I have no idea what to do now.

Tried earth cable from Arcam and touched around Thorens, made no difference until I touched the centre metal spindle. Touching anything else made no difference. Touching the earth cable to the spindle reduced it by about 50%.

The hum was whether the TT was turned on or not, but as it connects to a MM specific connection, I didn’t feel safe plugging into a different connection.

I would appreciate some advice particularly whether this is an acceptable outcome for new kit, or if the hum I describe is an expected outcome of any expensive turntable set up or if in actual fact, it does suggest that there is an issue with the turntable.

I should just add, no hum when TT disconnected from the Arcam or when anything else like CD is connected, just the TT.

Not used vinyl since a tower system 30 years ago. It feels so much has changed.

I have a couple of short videos but wasn’t sure how to upload..

thank you.
This may sound daft? Been into HiFi for over 50 years and recently had the same problem. Like everyone else suspected an earth loop. Couldn't understand why? As like with your setup, my turntable had no Earth lead, to connect to the Amp's earth terminal. Eventually checked the cartridge and found the left and right channel Earth connections crossed over. Reversed them and the hum disappeared.
 
Last edited:

Gray3

Active Member
See Ron's post above... just check that wire colours correspond to coloured markings on the cartridge. (Though if they were to be wrong, the dealer would be as worryingly incompetent as he was dismissive)
I trust that I'm right to assume the cartridge was fitted to the TT when you bought it!
You can see what others are saying here.
You are being very reasonable about this - which is a good thing.
The last thing you want to do is go back in 'all guns blazing' only for him to test and find silence!
Let's face it, there couldn't have been a hum while he was demoing it could there?
Take my advice. Don't make the point that you're not technical (no need to tell him that you swapped speakers 😉).
Before going back with it, tell him you'd like to be present for the his testing.
(As an Electronics Service Engineer, I've been between retailer and customer and have seen things from both sides).
On a brand new item, proved to be faulty within 30 days of purchase, you would normally have the right to your choice of refund or replacement (and not be obliged to accept any repair unless you wanted to).
Your personal warranty arrangement may have been different on ex-dem? but I'm sure he will want you to be a satisfied customer.
Perhaps you'll report back here with the eventual outcome.
 
Last edited:

DT79

Well-known Member
In his original post he said he's 'tried new or different cables'.
Whoops. I was half asleep when I read the post.
 

RugbyAl

Well-known Member
I have a rega which is not fitted with its own earth lead, instead earthing through one of its channel grounds. This suffered badly with hum. As my amp has no phono input I use a separate phono pre amp. To cure my hum, I connected a phono earth lead (bought on ebay) to the phono preamp earthing post. The other end was then connected to the earth pin of a regular 3 pin plug (no other wires connected). This was then plugged in to an extension lead which also had the amp and phono amp plugged in and bingo - silence!

I believe another forum member has done the same with similar results and it is perfectly safe as long as only the earth lead is connected to the earth pin in the plug.

Try the same with a lead from your SA30 earth post?
 

daddy999

Active Member
I use a Rega P3 with my Yamaha amp using its built in phono stage with no hum at all, again no earth lead required, I would suggest this is probably an earthing issue.

However, I had a exactly the same issue with a Technics slp1200 with an ortofon cartridge and a Rotel amp years ago. I changed the cartridge to Goldring, moved the turntable away from the amp....no more hum. I would go back to the dealer, ask to try a different cartridge for free, if that doesn’t fly, return the whole turntable for full credit and buy an alternative. Perhaps a Rega.
 

LawlB

Standard Member
That is everyone. I have emailed the dealer and waiting for a response. just to say, the Arcam SA30 came from a different dealer and sounds above expectations.

i should also add that I purchased the TT a couple on months ago having taken my time to decide on an amp. It was only upon connecting them up for the first time did I find out to my horror, the hum.

i will keep reporting here any updates and do consider that a return to the dealer will be necessary, though I am unaware if anyone will be available to look at it with the Covid19 restrictions but I will know the answer to that in a day or two.

cheers everyone.
 

The latest video from AVForums

AVForums Movies Podcast: Which is the best decade for horror movies?
Subscribe to our YouTube channel

Full fat HDMI teeshirts

Support AVForums with Patreon

Top Bottom