Hi guys,

I am a newbie turntable user and have a question for you.

Each time I start or stop my turn table mechanics with my amp still
powered on I see my woofers giving a low frequency boom. This is guess
is the sound picked up by the tone arm etc.

I can actually see my woofers breathing in and out when this happens.

Do you think I am #@$king my speakers up, should I turn down the amp or
pull the volume down before starting/stopping my TTable? Or should I
just not worry?

Any advice will be greatly appreciated.

Cheers

Max

In article . com, max
graff wrote:
Hi guys,

I am a newbie turntable user and have a question for you.

Each time I start or stop my turn table mechanics with my amp still
powered on I see my woofers giving a low frequency boom. This is guess
is the sound picked up by the tone arm etc.

I can actually see my woofers breathing in and out when this happens.

You do not say what turntable or amp you are using (nor amp or cartridge).
What you describe seems quite unusual to me. It should not occur. Not
something I've ever encountered with various systems I've used.

Assuming that you are *not* leaving the stylus on the record at the time...

Do you think I am #@$king my speakers up, should I turn down the amp or
pull the volume down before starting/stopping my TTable? Or should I
just not worry?

It would concern me. The obvious avoidance is to wind down the volume
level. Or to switch to a different input. However I would then certainly
regard this as a 'fault' and try to fix it. Difficult to know if it will do
any damage as we don't know enough about your system.

Does you 'turntable' happen to include its own (RIAA) pre-amp for its
cartridge, and you then connect into your amp via a line-level input? That
is the only possible cause that immediately occurs to me. If so, it may be
that the amp built into the turntable is being switched on and off, and
this generates a LF 'thump'. If so, it is a poor design, or is poorly
matched to your amplifier, or there is a fault.

Given more details of your system it may be possible to identify some other
possible reasons.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Hi Jim,

My system is a Pro-ject Debut III connected to a NAD PP2 phonostage
which in turn is connected o a Maranrtz 6500 OSE Integrated Amplifier.
I am using JBL S312 floor standing speakers.

Do you think there could be something wrong with the NAD or the
turntable?

Cheers

MB

In article . com, max
graff wrote:
Hi Jim,

My system is a Pro-ject Debut III connected to a NAD PP2 phonostage
which in turn is connected o a Maranrtz 6500 OSE Integrated Amplifier. I
am using JBL S312 floor standing speakers.

Do you think there could be something wrong with the NAD or the
turntable?

Afraid I am not sure.

To clarify: When you said the problem shows when stop and start the TT, you
are leaving the NAD phonostage switched on throughout? i.e. the problem
can't be due to the NAD being powered on/off?

The symptom you describe is one I associate with something like a preamp
which has a single power rail. When switched on/off this may cause a
'thump' as the dc levels change and settle. This isn't something I'd
normally expect when a TT is switched on/off as all that normally does is
cause the TT to begin or cease rotation.

Other sources of 'thumps and waggles' for the speakers might be when you
lift or lower the stylus and it makes/breaks contact with the record
surface, or if the record/deck have a lot of rumble. But these don't seem
to fit with the behaviour you describe - unless you are including
lifting/lowering the stylus as part of 'start and stop the TT'...

I know that some TTs do include pre-amps, from what you say, that isn't the
case in your system.

At present I can only say that there does seem to be an odd problem, but it
isn't clear to me what the cause may be. Perhaps someone else will
recognise it.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

On 2 Jan 2007 17:39:42 -0800, "max graff" wrote:

Hi guys,

I am a newbie turntable user and have a question for you.

Each time I start or stop my turn table mechanics with my amp still
powered on I see my woofers giving a low frequency boom. This is guess
is the sound picked up by the tone arm etc.

Just speculating, but I would check whether any interference
suppression components across the switch or the motor are damaged.
(This is assuming a mains-operated motor.)

The usual warnings and disclaimers about opening mains operated
equipment apply. If you are in any way unsure, leave well alone!

--
Chris Isbell
Southampton, UK

On 2 Jan 2007 17:39:42 -0800, "max graff" wrote:

Hi guys,

I am a newbie turntable user and have a question for you.

Each time I start or stop my turn table mechanics with my amp still
powered on I see my woofers giving a low frequency boom. This is guess
is the sound picked up by the tone arm etc.

I can actually see my woofers breathing in and out when this happens.

Do you think I am #@$king my speakers up, should I turn down the amp or
pull the volume down before starting/stopping my TTable? Or should I
just not worry?

Any advice will be greatly appreciated.

Cheers

Max

What exactly is it you are doing when this happens? Are you flipping
the start-stop switch on the turntable, picking up the stylus from the
record, or what exactly? It is hard to diagnose this without the fine
detail, I'm afraid.

d

--
Pearce Consulting
http://www.pearce.uk.com

Hi Don,

I hear the low-frequency 'dhub' when I lift/lower the stylus when the
amp is connected.

Some time I can also hear it when I have left the amp on and powered
off the NAD phono amp.

I thought it was an Amp problem and switched connection to my old Denon
PMA 250 (2-channel) and the problem still exists. I guess this is the
dilemma of using analog equipments.

As Jim suggested I have decided to either lower the volume down to 0 or
change the source before changing the vinyl sides or while
starting/stopping the equipment.

Thanks to all for helping me out.

Cheers

MB

On 3 Jan 2007 23:15:00 -0800, "max graff" wrote:

Hi Don,

I hear the low-frequency 'dhub' when I lift/lower the stylus when the
amp is connected.

OK - that one is easy. You need to sort out your technique for
raising/lowering the stylus. You have too much sideways movement at
the moment, which is forcing the stylus over. That causes the low
frequency signal in the sub.

Some time I can also hear it when I have left the amp on and powered
off the NAD phono amp.


That was as Jim suspected - you are hearing bias conditions flying
around during voltage changes.

I thought it was an Amp problem and switched connection to my old Denon
PMA 250 (2-channel) and the problem still exists. I guess this is the
dilemma of using analog equipments.

As Jim suggested I have decided to either lower the volume down to 0 or
change the source before changing the vinyl sides or while
starting/stopping the equipment.

Thanks to all for helping me out.

Cheers

MB

No problem - the volume control is the tool of choice here.

d

--
Pearce Consulting
http://www.pearce.uk.com

In article .com,
max
graff wrote:
Hi Don,

I hear the low-frequency 'dhub' when I lift/lower the stylus when the
amp is connected.

Ah! That is quite different to your initial description which was about
"stop or start the turntable mechanics".

Such behaviour isn't uncommon and is caused by the stylus being moved as it
makes/breaks contact with the LP surface. It is 'harmless' provided you
lift or lower the arm with due care. i.e. slowly and vertically.

As Jim suggested I have decided to either lower the volume down to 0 or
change the source before changing the vinyl sides or while
starting/stopping the equipment.

That should be fine. :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Jim Lesurf wrote:
In article .com,
max
graff wrote:

Hi Don,


I hear the low-frequency 'dhub' when I lift/lower the stylus when the
amp is connected.


Ah! That is quite different to your initial description which was about
"stop or start the turntable mechanics".

Such behaviour isn't uncommon and is caused by the stylus being moved as it
makes/breaks contact with the LP surface. It is 'harmless' provided you
lift or lower the arm with due care. i.e. slowly and vertically.

I don't remember suffering from that problem. Perhaps Max's phono
preamp design omits the RIAA 50.05Hz corner, and the IEC 20Hz one.
The thump when switching the preamp on or off is normal.

--
Eiron.