Not Valves but you might be able to help tuner question

**Dave xxxxx** · September 12th 04, 05:20 PM posted to rec.audio.tubes,uk.rec.audio

I a Magnum Dynalab FM tuner the Etude have very large roof aerial

Everything works very well apart from BBC Radio 4 93.5

When ever I have that channel on, there is a hum from the speakers

Is there an electrical fault, that could cause it?

--
Dave xxxx
www.davewhitter.myby.co.uk

Music is Art - Audio is Engineering
Steam is Fun

**Sander deWaal** · September 12th 04, 05:39 PM posted to rec.audio.tubes,uk.rec.audio

"Dave xxxxx" said:

I a Magnum Dynalab FM tuner the Etude have very large roof aerial
Everything works very well apart from BBC Radio 4 93.5
When ever I have that channel on, there is a hum from the speakers
Is there an electrical fault, that could cause it?

Try to disconnect the ground lead to the mains.

Music is Art - Audio is Engineering

Thou art a Pinkerton worshipper?

Steam is Fun

Until it comes out of your ears.

--
Sander deWaal
"SOA of a KT88? Sufficient."

**Dave xxxxx** · September 12th 04, 05:45 PM posted to rec.audio.tubes,uk.rec.audio

Sander deWaal wrote:
"Dave xxxxx" said:

I a Magnum Dynalab FM tuner the Etude have very large roof aerial
Everything works very well apart from BBC Radio 4 93.5
When ever I have that channel on, there is a hum from the speakers
Is there an electrical fault, that could cause it?

Try to disconnect the ground lead to the mains.

do you mean the one in the power lead?

Music is Art - Audio is Engineering

Thou art a Pinkerton worshipper?
:-) NO !

Steam is Fun

Until it comes out of your ears.

Its ok coming from my trains
http://www.davewhitter.pwp.blueyonder.co.uk/trains.htm

**Sander deWaal** · September 12th 04, 08:27 PM posted to rec.audio.tubes,uk.rec.audio

"Dave xxxxx" said:

Try to disconnect the ground lead to the mains.

do you mean the one in the power lead?

Yup.

Thou art a Pinkerton worshipper?

:-) NO !

Ok, so you're a sensible engineer ? ;-)

--
Sander deWaal
"SOA of a KT88? Sufficient."

**Stewart Pinkerton** · September 12th 04, 08:39 PM posted to rec.audio.tubes,uk.rec.audio

On Sun, 12 Sep 2004 17:45:58 GMT, "Dave xxxxx"
wrote:

Sander deWaal wrote:

Music is Art - Audio is Engineering

Thou art a Pinkerton worshipper?
:-) NO !

Quite right. I don't want 'followers', I just want people to truly
*trust* their ears, so that they base their judgements on what they
can hear when they don't *know* what's connected..........

--

Stewart Pinkerton | Music is Art - Audio is Engineering

**Sander deWaal** · September 12th 04, 08:51 PM posted to rec.audio.tubes,uk.rec.audio

Stewart Pinkerton said:

Music is Art - Audio is Engineering

Thou art a Pinkerton worshipper?

:-) NO !

Quite right. I don't want 'followers', I just want people to truly
*trust* their ears, so that they base their judgements on what they
can hear when they don't *know* what's connected..........

According to a certain mr. Ferstler, I *do* not know what's connected
in my system. This is all very confusing, you will note.

I think I'll try to find some peace of mind in religion, and thinking
of becoming a cathode follower. Patrick Turner seems to benefit.

See:
http://epistolary.org/84.html

--
Sander deWaal
"SOA of a KT88? Sufficient."

**Wally** · September 12th 04, 06:03 PM posted to rec.audio.tubes,uk.rec.audio

Sander deWaal wrote:

I a Magnum Dynalab FM tuner the Etude have very large roof aerial
Everything works very well apart from BBC Radio 4 93.5
When ever I have that channel on, there is a hum from the speakers
Is there an electrical fault, that could cause it?

Try to disconnect the ground lead to the mains.

What makes you think it's a mains or earthing problem if it only happens on
one station?

--
Wally
www.artbywally.com
www.wally.myby.co.uk

**Sander deWaal** · September 12th 04, 08:28 PM posted to rec.audio.tubes,uk.rec.audio

"Wally" said:

Try to disconnect the ground lead to the mains.

What makes you think it's a mains or earthing problem if it only happens on
one station?

Modulation hum on weak reception, poor AM rejection?

--
Sander deWaal
"SOA of a KT88? Sufficient."

**tony sayer** · September 13th 04, 07:35 AM posted to rec.audio.tubes,uk.rec.audio

In article , Sander deWaal
writes
"Wally" said:

Try to disconnect the ground lead to the mains.

What makes you think it's a mains or earthing problem if it only happens on
one station?

Modulation hum on weak reception,

Eh?, can you explain that please?.....

poor AM rejection?

--
Tony Sayer

**Sander deWaal** · September 13th 04, 03:18 PM posted to rec.audio.tubes,uk.rec.audio

tony sayer said:

Try to disconnect the ground lead to the mains.

What makes you think it's a mains or earthing problem if it only happens on
one station?

Modulation hum on weak reception,

Eh?, can you explain that please?.....

poor AM rejection?

Depending on the design and alignment of the IF section, weak
reception may cause AM modulation outside the range of the limiter.
Hum may enter via the mains/ground leads and interfere in the
limiter/detector stage.

I've seen this problem with some not-so-badly-regarded tuners.
Removing the safety ground from the plug (assuming it's there, you
have all 3-prong plugs in the UK, right?) may solve the problem in
some cases.
That, or there's another ground loop somewhere.
Sometimes external antennas are grounded as well for safety reasons
(lighning!), and a cable system is always grounded but may show huge
potential differences with the mains gnd.

Following the thread though, it seems that the OP suffers from
crossmodulation or some such, because he's located so close to the
xmitter.
Apparently, a Magnum Dynalab is no better than a middle class FM tuner
in that regard.

--
Sander deWaal
"SOA of a KT88? Sufficient."