Can you help diagnose the problem with my Hifi?

Pointless Bores Me

Novice Member
Firstly, I know the best way to get to the root of this problem would be to simply replace different parts of my hifi one by one until I find out what the issue is, however that isn't easy given current circumstances, and I don't have any spare amp or speakers lying about!

Firstly here's what I've got:

Nad C320 BEE amp
Tannoy Revolution DC6 speakers
Google Chromecast

The problem with my hifi is intermittent (with it being a problem for 90+% of the time), whereby sound quality drops suddenly significantly. Instead of sounding how it has for a number of years, the sound will become harsh and disjointed, as well as being much quieter and so I need to turn the volume up much more than I normally would (which can then sound harsh). The intermittent problem doesn't drop in and out regularly and is more case of it will be rubbish for days/weeks but then once every now and then it will sound as it should (briefly!).

For a while I thought I was going mad until one day I was listening to the house of the rising sun and it started switching between sounding good (noticeably clear and loud) and bad (whereby it will suddenly sound rubbish and quiet) suddenly and abruptly within the same song. This was a relief as I knew I wasn't going mad!

At first I thought it would be the chromecast that was the problem, so I bought a new one (new and boxed) off ebay and a new rca lead to hook it up to my amp. I then switched between each chromecast as a song was playing and there was no difference between them, so I don't think it's that.

The speaker wire is QED I think that Richer sounds terminated with banana plugs in the shop - I've plugged these into the different inputs at the back of the speakers (there are 4 on each speaker) but no luck.

I know that this is a long shot, but due to the nature of the problem (very sudden dramatic increase or decrease in sound quality) does that point in any way towards where the problem might be (e.g. speakers, speaker cable or amp), or possibly rule anything else out (e.g. because it is so sudden a change it is unlikely to be an issue with the speakers)? The next step I am thinking would be to try different speaker cable (the current ones I am using are QED I think, which have banana plugs that Richer sounds did themselves in store when I bought the amp circa 2005), and after that bite the bullet and replace the amp and/or the speakers, but I'm obviously reluctant to replace anything that might be working ok.

Any advice much appreciated!
 

John7

Well-known Member
To me, it sounds like a problem with your amplifier. From your description it could be a dry joint, a failing component or a dodgy relay.

Don't know how long you've had it but it will more than likely cost more to investigate and repair it than buying a new model, unless you know a friendly electronics engineer who can give you "mates rates"!

Here's a basic budget amp for a good price..

Amazon product
or a more expensive amplifier brand


For what it's worth, I have a Tibo PA150 power amp driving my rear Atmos channels and it does a good job and is well built for the price
 

Joe Fernand

Distinguished Member
AVForums Sponsor
No need to replace speaker cables - simply power off the Amp, disconnect the cables and check the terminations are good.

Ideally you do need a second Source device to at least eliminate the Source, you could also try plugging the Source to a different Input on the Amp and possibly switch out the Source > Amp interconnect whilst you are testing things out.

Not being able to try a different Amp or Speaker pair does make it tricky trying to isolate where the issue is - if it is on both channels then it is more likely the Amp which has the issue.

Joe
 

Paul7777x

Member
First, because it’s cheap, buy a new connector for the CCA. A cheap one for a couple of quid from eBay will be fine, it’s to check against the current cable.

And chop off the bananas from your speaker cable and use bare, newly stripped bare copper into the binding posts on both amp and speakers.

It’s unlikely, but possible the fault lies there.

If not, then a dry joint on the amp is next up. You can remove the casing and see if there’s an obvious wiggle to the speaker outputs.

If they’re easy to get at, running a soldering iron over the contacts may be enough to get a new flow.
 

Paul7777x

Member
Ps, also make sure that the connectors between the pre-outs and power amp-in are in one piece and sitting properly.

Also check any soldering connection between them is good when you have the lid of the Nad.

And, as mentioned above, try every input on the amp.

Ps, is there any crackle on the volume pot at any time you use it? Or does the problem change if you spin the volume a bit?

Finally, and least likely, does the problem alter if you disable (or enable) the tone control defeat button?
 
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Timmy C

Distinguished Member
This is a longshot but are you certain the problem is on both speakers? If not I wondered if the lf/hf coupling links on the back of one speaker might be loose, assuming the Tannoys have them. I'm pretty sure it would have been clear it was just one speaker causing the issue but thought it worth mentioning just in case.
 

Pointless Bores Me

Novice Member
Thanks for the quick responses guys really appreciate it! Lockdown has been a lot tougher since my hifi started playing up

No need to replace speaker cables - simply power off the Amp, disconnect the cables and check the terminations are good.

Ideally you do need a second Source device to at least eliminate the Source, you could also try plugging the Source to a different Input on the Amp and possibly switch out the Source > Amp interconnect whilst you are testing things out.

Not being able to try a different Amp or Speaker pair does make it tricky trying to isolate where the issue is - if it is on both channels then it is more likely the Amp which has the issue.

Joe

Sorry if I didn't explain it properly but I think I already did that with buying a new chromecast? I bought a new rca cable for the new chromecast too so I had 2 separate sources with 2 separate cables and it still sounded the same, which should mean it isn't the source? Pic:

IMG_20210315_182828_resized_20210315_064009800.jpg


@Paul7777x - There is a slight cackle immediately after I lower the bass or treble on the amp, but that lasts less than a second and there doesn't seem to be any cackle otherwise. In regards to the tone defeat - it's still the same whether it's on or off

I've decided to start with opening up the amp and having a look (as opposed to starting by cutting the speaker cable). First thing I noticed was - WOW there's a lot of dust! I bought this in 2005, think I opened it up once a while back but must have been a good ten years. Quick google check it seems compressed air is the best way to clean this? Are there any other ways I can clean this dust? Pics:

IMG_20210315_182552_resized_20210315_063306733.jpg


IMG_20210315_182651_resized_20210315_063307070.jpg


Around the speaker inputs nothing seems loose, although there is plenty of dust:

IMG_20210315_182642_resized_20210315_063306026.jpg


There are also a noticeable couple of marks on the top of the inside where something has got warm/burned out?

IMG_20210315_182527_resized_20210315_063307387.jpg


Finally, to my untrained eye, are whatever it is these arrows are pointing to ok to be rusty like this:

InkedIMG_20210315_185544_resized_20210315_065907010_LI.jpg


Again guys, thanks for your help with this it's much appreciated
 

Paul7777x

Member
That is indeed one filthy amp. But I’ve seen worse.

A paintbrush (gently) and a vacuum cleaner simultaneously will do the job.

I can’t really see the rusty bits in the photograph properly, they’re a bit dark.

As for the soot and ‘burn’ marks, again I’ve seen worse in properly working amps.

If not the speaker cables then I’m at a loss.

The fact that there is crackling on the potentiometers though means they are on the way out (at least) and could well have intermittent contact and only on a small patch at a time.
 

John7

Well-known Member
The marks on the inside of the lid are where the heat from the Toroidal transformer has concentrated the dust - nothing to worry about. The rusty looking bits are just glued on RF shields around sensitive components.

As I suspect - you have quite a few relays in there - the black rectangular block near the speaker terminals is one. It prevents speaker thump when switching the amp on. If the contacts are worn and pitted, you will get signal breakup on the affected channels.

You also appear to have a relay on each input of the amp. You could try connecting the Chromecast to another input, in case the relay of the ones you have it connected to are worn.

Just seen you tried that....
 
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Paul7777x

Member
It’s a bit hard to tell, but at this bit of the circuit, there seems to be significant overheating on the opposite side of the board, but you’d need to remove the whole thing to see what (if anything) has burned out. But it does look suspect.


3786BAD9-052A-4169-BC2C-7ECED18291EE.png
 

Paul7777x

Member
Ps, if it’s not one of the relays (as John 7 says) and it’s not the speaker cable or the pre/power connectors then it’s not really worth messing about with it.

You can get another for around a hundred quid.
 

John7

Well-known Member
That looks like capacitor electrolyte leakage....

There's a number of things that could be causing the issue (relay contacts, capacitors, cracked resistors, dry joints) etc.

To be fair I think the OP's had his money's worth after 15/16 years, probably time to retire it and invest in a spanking new amp (or as you say, a newer replacement from the 'Bay)!
 

Paul7777x

Member
That looks like capacitor electrolyte leakage....

There's a number of things that could be causing the issue (relay contacts, capacitors, cracked resistors, dry joints) etc.

To be fair I think the OP's had his money's worth after 15/16 years, probably time to retire it and invest in a spanking new amp (or as you say, a newer replacement from the 'Bay)!

Yup. Any repair would be throwing money away in the long term I’d say.
 

Pointless Bores Me

Novice Member
That looks like capacitor electrolyte leakage....

There's a number of things that could be causing the issue (relay contacts, capacitors, cracked resistors, dry joints) etc.

To be fair I think the OP's had his money's worth after 15/16 years, probably time to retire it and invest in a spanking new amp (or as you say, a newer replacement from the 'Bay)!

Haha yea I think it's fair to say it's had a good innings! Remember saving up for it when I got my first job, about 180 I think it was from Superfi. Happy days

I'm happy to buy a new one I just didn't want to buy a new one and then find it's my speakers that are the problem.

Are there any amps any of you would recommend with this sort of set up? Had my eye on the Marantz PM6007, partly because it has you can control the bass and treble (I know this is frowned upon but I live in a flat and sometimes I need to take the bass down a bit) or possibly the Rega Brio as I hear it's good and lively (which I like), but open to ideas, and would try ebay. Again thanks for all the help
 

blotbolt

Novice Member
It wouldn't be the broadband input to the Chromecast? If the bitrate dropped, would the quality not drop off horribly?
If you are feeling brave, tap or prod various items with an insulated screwdriver.
I find usually potentiometers and switches are often to blame.
Usually mechanical parts....
 

Pointless Bores Me

Novice Member
It wouldn't be the broadband input to the Chromecast? If the bitrate dropped, would the quality not drop off horribly?
If you are feeling brave, tap or prod various items with an insulated screwdriver.
I find usually potentiometers and switches are often to blame.
Usually mechanical parts....
I wouldn't have thought it's the broadband mate just because 90 percent of the time it sounds rubbish, whereas I'd probably expect the broadband to drop in and out here and there but mostly be OK (unless anyone knows any better)?
 

Paul7777x

Member
Haha yea I think it's fair to say it's had a good innings! Remember saving up for it when I got my first job, about 180 I think it was from Superfi. Happy days

I'm happy to buy a new one I just didn't want to buy a new one and then find it's my speakers that are the problem.

Are there any amps any of you would recommend with this sort of set up? Had my eye on the Marantz PM6007, partly because it has you can control the bass and treble (I know this is frowned upon but I live in a flat and sometimes I need to take the bass down a bit) or possibly the Rega Brio as I hear it's good and lively (which I like), but open to ideas, and would try ebay. Again thanks for all the help

If you fancy a Marantz, I’d go for the 6006 used. Still new enough to be problem free and a useful bit less cash than the newer model.

But if you can afford the stretch, I’d go for one of these.



Or, if you’re happy with used then this is a splendid thing.


All of the above will be a revelation with the Tannoys compared with the Nad (even when it worked :smashin: ).

The Nait being my first choice.

An interesting review here. He has his head up his arse a bit, but it gets the message across.

 
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[email protected]

Active Member
If you can localize it to one speaker I’d reverse them and see if the problem.follows the speaker or stays with left or right. It’s probably not the speaker, but a bad internal connection could possibly do it.
 

RBZ5416

Distinguished Member
I'm too lazy to read the whole thread in detail but if CC is the only source, I'd try another that isn't dependent of WiFi. As you have RCA to 3.5mm cables for the CC, you could try your phone headphone output, assuming you don't have one of those that have done away with it. Failing that an old DVD player with analogue out?
 

jonno73

Active Member
Totally sounds like the amp to me.

(At a stretch, dodgy wifi into the chromecast, but the error sounds too consistent really to be that).

there’s one on eBay now for £89 btw...
 

Pointless Bores Me

Novice Member
Totally sounds like the amp to me.

(At a stretch, dodgy wifi into the chromecast, but the error sounds too consistent really to be that).

there’s one on eBay now for £89 btw...

That's what I thought (or at least hope as I've ordered a new amp!). I've been working from home and the WiFi been fine, plus the sound is crap most/all of the time now. Fingers crossed and I'll see how the new amp is
 

Pointless Bores Me

Novice Member
Ok so the Naim Nait arrived this morning.

Firstly, the banana plugs I've got on my speaker cables aren't suitable I don't think!? They are very loose when plugging into the amp and come out easily. This is them:

Banana Plugs.jpg


Am I right in thinking that I need to use BFA plugs or terminate them somehow with the speaker plugs that came with the amp? Pic:

Naim plugs.jpg



As opposed to cutting the banana plugs off my current speaker cables, for piece of mind I think I'd prefer to buy new speaker cables. If I do will I need them terminating or can I just cut them at the ends and put them in the speaker plugs? If anyone has got any recommendations or advice that would be great (less than £50 preferably)
 

Paul7777x

Member
You simply need to remove the cap from the Naim connectors and solder your speaker cables into the groove at the top of the connector.

They have to be soldered though.

Ps, what NAIT is it?
 

Paul7777x

Member
PPS, ypu can place a small screwdriver between the springy parts of the body of your current bananas and (gently indeed) expand them. That will make it a tight enough fit to use until you get the Naim connectors soldered up.

They would have been a tighter fit when new.
 
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Paul7777x

Member
Ok so the Naim Nait arrived this morning.

Firstly, the banana plugs I've got on my speaker cables aren't suitable I don't think!? They are very loose when plugging into the amp and come out easily. This is them:

View attachment 1477998

Am I right in thinking that I need to use BFA plugs or terminate them somehow with the speaker plugs that came with the amp? Pic:

View attachment 1477999


As opposed to cutting the banana plugs off my current speaker cables, for piece of mind I think I'd prefer to buy new speaker cables. If I do will I need them terminating or can I just cut them at the ends and put them in the speaker plugs? If anyone has got any recommendations or advice that would be great (less than £50 preferably)

Also, terminated Naim NAC speaker cable is preposterously expensive. Truly obscene.

This is essentially the same stuff. So, buying this and snipping of the plugs to show new copper and soldering one end to the naim plugs will be your best bet, if it’s an older Nait.


If it’s the Nait 5 I mentioned earlier in the thread, then any speaker cable at around 2.5mm cross section will do the job. Including the cable talk too of course.
 

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