Question Denon PMA600NE Dilemma

[Al ears]

Thanks and I agree with you.

Situation not ideal I realise but it sounds like even trying yet another amp would lead to the same scenario.
Poor design on Denons part.

 

[David F]

Situation not ideal I realise but it sounds like even trying yet another amp would lead to the same scenario.
Poor design on Denons part.

I also found it unusual that I couldn’t find any other reports or instances of this when searching the internet.

 

[Al ears]

I also found it unusual that I couldn’t find any other reports or instances of this when searching the internet.

Presumably they don't expect anyone who has a turntable with a built in phono preamp would want to connect it to the phono inputs on the amp and that anyone who wanted to use those inputs wouldn't buy a turntable with a built in phono stage.

 

[Gray]

I know but he will be going round in circles trying to determine if it is the turntable itself or the phono stage in the amplifier. There's no easy way of determining that.
Perhaps the only way is to switch the amp to a line input before you want it to go into auto standby, or better still save electricity and switch it off manually.

The TT can be taken out of the equation - once we consider the (varying) symptoms (when it isn't even connected).

 

[My2Cents]

The TT can be taken out of the equation - once we consider the (varying) symptoms (when it isn't even connected).

He stated at least twice that the amp does go to standby if nothing is connected to the phono input.
I'm wondering if he has the ground lead connected 'cos he never mentioned that little detail.

Incidentally, the shorting pin plugs (which actually come installed in the phono sockets) are only used if the phono inputs are not in use (try plugging an RCA plug in when there is a shorting plug already in the hole).
So I still don't get why you wanted him to try that with the TT plugged in.
If this is not a case of 'user error' then it looks like Denon needs to do a firmware update.
Yamaha USA has a customer service number that connects you to a tech. in around 2 minutes. It's so much easier to explain a problem and get a solution using spoken words rather than an e mail (to a third party 'specialist')

 

[Gray]

Firstly may I say that I really appreciate all the advice and assistance I’m receiving and secondly, my apologies if my original post was possibly confusing.

This morning I connected the turntable to the amplifiers Aux input, moved the turntables switch from Phono to Line, selected Aux on the amp, started then stopped the turntable and after 30 minutes the Auto Standby functioned correctly.

I then put the amps Input selector to Phono with the connections still as above and once again the Auto Standby function worked.

Should I now try the same but with the supplied short circuiting plugs fitted to the amplifiers Phono terminals or is this really not necessary?

Looks like I’ll be leaving the turntable switched to Line and connected to Aux if I want to use the Auto Standby function!

Don't worry about causing confusion David, you're merely being specific about a confusing problem

In view of the outcome of the tests you did this morning, shorting the phono inputs would not now prove anything more than you have done.

In your very first post you said that, as a double-check you had nothing but mains connected to the amp - and the auto standby worked as expected.
At other times it did not.
If you can repeat that same test and the auto-standby doesn't work, then there is obviously a problem with the amp.

The shorting plugs are designed to kill any stray noise within the phono amp - so Denon may well suggest fitting those as part of the conclusive testing.

Do that. Fit the shorting plugs in the phono inputs. Have no other signal cables connected.
If the amp does not go into standby - report that specific test to Denon.

If you confirm it to be an intermittent problem, make sure you tell them that.

As far as I'm concerned, you will have done all that you can.....the ball will be in their court.

 

[My2Cents]

Are you noticing any difference in sound quality between the 2 phono pre-amps (Dual vs Denon)?
Both are fairly mediocre and neither will get the best from CS429.
Once you have worn out the Ortofon Red (1000 - 1500 hours) you may consider replacing it with a better cartridge and a dedicated phono pre-amp (e.g. Cam. Audio's Alva).
No more worrying about auto standby and the phono inputs and better sound!
Of course, you will have to switch off the pre amp manually when done listening

 

[Gray]

He stated at least twice that the amp does go to standby if nothing is connected to the phono input.

With nothing but mains connected to his amp, the auto-standby function did not work.
He retested:
With nothing but mains connected to his amp, the auto-standby function worked.

What's your theory on that?

And of course I didn't want him to, or suggest that he shorted out the RCA inputs while the TT was plugged in 😆

 

[My2Cents]

With nothing but mains connected to his amp, the auto-standby function did not work.
He retested:
With nothing but mains connected to his amp, the auto-standby function worked.

What's your theory on that?

And of course I didn't want him to, or suggest that he shorted out the RCA inputs while the TT was plugged in 😆

Yes, I thought I was reading contradictions too. I had to double up on my psych. meds. as I thought I was going even more crazy.

 

[Al ears]

The TT can be taken out of the equation - once we consider the (varying) symptoms (when it isn't even connected).

That's the point, and it has been proven, the turntable cannot be taken out of the equation as he wishes to use it. He has shown that it will function as expected in the Aux socket and using the turntables phono stage.
There is obviously an issue with using this particular turntable in the Phono inputs but impossible to prove whether it is an issue with deck or it's interaction with the amps inbuilt phono stage.
Unless the OP can try a turntable without an inbuilt phono stage we will never know the issue but he cannot do this or it would defeat the whole point of an auto shut off for a turntable because the LP being played would end before the auto shut off had a chance to kick in....

 

[Gray]

That's the point, and it has been proven, the turntable cannot be taken out of the equation

I meant the TT can be ruled out as the cause of the issue - because the issue variously happens, or not, with nothing (other than mains) connected to his amp.

The amp is the problem.
Of course he should be able to use his TT in any way that he chooses. But the amp does not allow him to use it direct from the cartridge - because the amp has an (intermittent) problem when its input is set to phono.

If he can recheck and confirm the auto standby to be intermittent - with nothing connected.....Denon need to know.

Using David's findings, maybe Denon can do similar tests on their current batch, that's up to them - but he needs a resolution.

 

[My2Cents]

I meant the TT can be ruled out as the cause of the issue - because the issue variously happens, or not, with nothing (other than mains) connected to his amp.

The amp is the problem.
Of course he should be able to use his TT in any way that he chooses. But the amp does not allow him to use it direct from the cartridge - because the amp has an (intermittent) problem when its input is set to phono.

If he can recheck and confirm the auto standby to be intermittent - with nothing connected.....Denon need to know.

Using David's findings, maybe Denon can do similar tests on their current batch, that's up to them - but he needs a resolution.

He clearly stated (at least at one point) that the amp does go into standby when nothing is connected, even when the phono source is selected. I would try another TT which has no phono pre amp onboard (if he can borrow one).
Evidently, the Denon believes that it is still receiving a signal, even when the TT is not playing anything (even when the Dual's on/off switch is 'off')? I wonder, if he actually unplugged the Dual from the mains power completely would the Denon go to standby?
I highly doubt that Denon are going to do tests on a budget amp. that has probably sold perhaps 10's of thousands of units worlwide... even if a few hundred users did complain of the same problem.
I see no USB connector on the amp that would allow for any firmware updates anyway.
I would be calling a product specialist on the phone, they have a number on their web site.

 

[Gray]

He clearly stated (at least at one point) that the amp does go into standby when nothing is connected, even when the phono source is selected.

He certainly did say that 👍
I could be wrong but I'm pretty sure that at another point he also said that, in the above scenario, it didn't go into standby.

Perhaps he can clarify that, because it's obviously crucial to the elimination process.
(Clarification / certainty of the fault symptom is necessary - and certainly before any further contact with Denon).

 

[David F]

Denon PMA600NE Dilemma (Part II).

1. Thank you all again for your responses. As I previously posted, the Auto Standby function of the Amp did perform correctly when the Turntable was On with Line selected and connected to the Amp Aux input. To confirm or otherwise, the following was carried out:

2. Amplifier - On, Amp Input Selector – Phono.

a. No connections (except B&W Speakers).
Auto Standby – YES.
b. CD Player On, connected to Amp CD Input.
Auto Standby – YES.
c. CD Player On, connected to Amp CD Input, Optical 1 & 2 connected.
Auto Standby - YES.
d. Turntable On, Line selected, connected to Amp Aux input.
Auto Standby – YES.
e. Turntable On, Phono selected, connected to Amp Phono input.
Auto Standby – NO.
f. Turntable Off, Phono selected, connected to Amp Phono input.
Auto Standby – NO.
g. Turntable Off, Line selected, connected to Amp Phono input.
Auto Standby – NO.
h. Turntable Off, Phono selected, Audio Cable disconnected at Turntable.
Auto Standby – NO.
i. Turntable Off, Phono selected, Audio Cable disconnected at Amp Phono Input.
Auto Standby – YES.
j. Turntable Off, Phono selected, Supplied short circuiting plugs fitted to Amp Phono input connectors.
Auto Standby – YES.
k. Turntable Off, Phono selected, Audio Cable connected at Turntable & Amp, Turntable unplugged from Mains Supply.
Auto Standby – NO.

3. The examples above, h. i. and j. are to me contradictory. Is the opening or closing of the actual Phono input connectors making the Amp believe there is or there is not a signal being received? If so, why does h. not function but i. and j. does when i. is an open input and j. a closed input? I have double checked to make sure this is correct.

4. I obviously have two options, use the Phono input without the Auto Standby function or use the Aux input with and does it really make a difference which? Even the internet gives conflicting opinions as to whether Phono or Line is preferable. If I decide to use the Line/Aux input, should I leave the Short Circuit Plugs in the Phono input connectors?

5. Although this Denon amplifier may be considered to be a “Budget” amplifier in the Audiophile world, it’s more than adequate for my requirements. I’ve played a diverse mix of music types: Gustav Holst, Vivaldi, Cass Elliot, Willie Nelson, Jeff Wayne’s WOTW, Traveling Willburys, Fleetwood Mac, John Lee Hooker, Andrea Bocelli, Dire Straits and more. With it connected to my 20+ year old B&W 601 S3 speakers, the quality of the sound reproduction is really very good, well to my ageing ears it is!

Since the Auto Standby function takes thirty minutes to kick in or not it’s taken me a few days to compile this. I shall look forward to all your replies but it is now time to get back to the real business of playing some actual music.

P.S. - must also get back to visiting the Village pub, we’ve been missing each other!!!

 

[Gray]

Denon PMA600NE Dilemma (Part II).

1. Thank you all again for your responses. As I previously posted, the Auto Standby function of the Amp did perform correctly when the Turntable was On with Line selected and connected to the Amp Aux input. To confirm or otherwise, the following was carried out:

2. Amplifier - On, Amp Input Selector – Phono.

a. No connections (except B&W Speakers).
Auto Standby – YES.
b. CD Player On, connected to Amp CD Input.
Auto Standby – YES.
c. CD Player On, connected to Amp CD Input, Optical 1 & 2 connected.
Auto Standby - YES.
d. Turntable On, Line selected, connected to Amp Aux input.
Auto Standby – YES.
e. Turntable On, Phono selected, connected to Amp Phono input.
Auto Standby – NO.
f. Turntable Off, Phono selected, connected to Amp Phono input.
Auto Standby – NO.
g. Turntable Off, Line selected, connected to Amp Phono input.
Auto Standby – NO.
h. Turntable Off, Phono selected, Audio Cable disconnected at Turntable.
Auto Standby – NO.
i. Turntable Off, Phono selected, Audio Cable disconnected at Amp Phono Input.
Auto Standby – YES.
j. Turntable Off, Phono selected, Supplied short circuiting plugs fitted to Amp Phono input connectors.
Auto Standby – YES.
k. Turntable Off, Phono selected, Audio Cable connected at Turntable & Amp, Turntable unplugged from Mains Supply.
Auto Standby – NO.

3. The examples above, h. i. and j. are to me contradictory. Is the opening or closing of the actual Phono input connectors making the Amp believe there is or there is not a signal being received? If so, why does h. not function but i. and j. does when i. is an open input and j. a closed input? I have double checked to make sure this is correct.

4. I obviously have two options, use the Phono input without the Auto Standby function or use the Aux input with and does it really make a difference which? Even the internet gives conflicting opinions as to whether Phono or Line is preferable. If I decide to use the Line/Aux input, should I leave the Short Circuit Plugs in the Phono input connectors?

5. Although this Denon amplifier may be considered to be a “Budget” amplifier in the Audiophile world, it’s more than adequate for my requirements. I’ve played a diverse mix of music types: Gustav Holst, Vivaldi, Cass Elliot, Willie Nelson, Jeff Wayne’s WOTW, Traveling Willburys, Fleetwood Mac, John Lee Hooker, Andrea Bocelli, Dire Straits and more. With it connected to my 20+ year old B&W 601 S3 speakers, the quality of the sound reproduction is really very good, well to my ageing ears it is!

Since the Auto Standby function takes thirty minutes to kick in or not it’s taken me a few days to compile this. I shall look forward to all your replies but it is now time to get back to the real business of playing some actual music.

P.S. - must also get back to visiting the Village pub, we’ve been missing each other!!!

Now there's some comprehensive testing ✅
Somewhere in 2a-k above there will be a diagnosis......when we get time to read it....

......what, precisely, is the signal cable between your turntable and the amp?
And have you got a separate earth cable connected between the turntable ground and the amp's 'signal ground'.

 

[Al ears]

Now there's some comprehensive testing ✅
Somewhere in 2a-k above there will be a diagnosis......when we get time to read it....

......what, precisely, is the signal cable between your turntable and the amp?

Unfortunately I think it's one of th ose things he'll never get to the bottom of unless he can scrounge a different turntable, one without an inbuilt phono preamp....
However, that may defeat the objective anyway as he obviously its fully automatic functionality

 

[nopiano]

On reflection, I’ve managed to enjoy Hifi systems of various configurations for over 50 years now, and I’ve always switched them off manually - by power button or remote. I’m amazed they even fit an auto standby feature!

 

[Gray]

On reflection, I’ve manage to enjoy Hifi systems of various configurations for over 50 years now, and I’ve always switched them off manually - by power button or remote. I’m amazed they even fit an auto standby feature!

Yes, I've had quite a few amps over about the same time period (half a century 😱).
My current Cyrus is the first I've had with an auto-standby feature - but it can be disabled.

When enabled it goes into standby after 20 minutes. I thought I might as well leave it enabled.....based on the theory that I'd never leave it idle for that long without switching it off.
....of course, the first time I returned to the room (after it had been idle for longer) I wondered why it was in standby mode 🙂

I can see why they do it - now that standby has to use so little energy - there's quite a difference in consumption when idle, even if it isn't as bad as class A.
Having said that, I've currently got the function disabled.
Like you, I've never had any problem switching amps off at session end 👍

 

[Gray]

Unfortunately I think it's one of th ose things he'll never get to the bottom of unless he can scrounge a different turntable, one without an inbuilt phono preamp....

His latest round of tests suggests the cause is not due to the turntable's inbuilt phono preamp - but there's no doubt that a test turntable - with a cartridge known to be correctly wired (and grounded) would be handy...

His tests also show that, as we might well expect, open ended phono cable (disconnected at TT end) is enough to hold the amp out of standby. This means that there is obviously still at least as much noise pickup when the cable is connected direct to his cartridge.

 

[Al ears]

On reflection, I’ve managed to enjoy Hifi systems of various configurations for over 50 years now, and I’ve always switched them off manually - by power button or remote. I’m amazed they even fit an auto standby feature!

The fact he has a fully automatic deck says something otherwise you'd have to get up every 20 odd minutes to pick the tonearm up anyway......

 

[Gray]

3. The examples above, h. i. and j. are to me contradictory. Is the opening or closing of the actual Phono input connectors making the Amp believe there is or there is not a signal being received?

Yes, that's precisely what's happening.
A phono preamp has a very high gain - its inputs are very susceptible to noise pickup....which is why it's a good idea to fit the shorting plugs whenever phono inputs are unused (and why I was making my own before they were ever supplied).

If so, why does h. not function but i. and j. does when i. is an open input and j. a closed input?

You're thinking logically....your comprehensive testing and multiple 30 minute waits were not in vain .

The centre contact in the RCA socket is the sensitive part.
In your test (i) the surrounding screen of the RCA socket was enough to keep noise pickup below the auto-standby threshold level.

In your test (j) you're connecting screen to centre directly, killing noise pickup dead - so no problem for AS to work.

In your test (h) however, you've got an open-ended aerial for the noise...noise that's enough to hold off the AS trigger.
Short those open ends and you will find the AS works.

Now to the crucial part:
You've proved that, when those open ends are connected direct to your cartridge (when phono / line switch is set to phono), there is (must be) at least as much noise present as in your test (h).
That should not be the case. Once it isn't.....your problem is solved.

Check that your cartridge is correctly wired and that a separate wire is securely connecting turntable to Denon ground terminals.

And just to answer your question in number 4:
Any conflicting opinions on the internet would (should) have been based on listening tests by those with the opinions.
Soon you'll be able to make your own valid comparison between the phono preamp in your turntable and the one in your Denon amp and then stick with what you prefer - with the auto standby function working as it should.