On Thu, 28 Jul 2011 12:53:39 +0100, Jim Lesurf wrote:

Maybe we should do some 'blogging' more about audio. So if anyone is
interested, I've spent the morning saying a fond farewell to my
c25-year-old ESL63s and installing a new pair of 2805s as their
replacements. My main initial impressions a

Jim,

I hope that you have better luck than me! I am currently on my fourth set
of 2805s. All of them have developed internal arcing - one of the latest
pair started doing this as soon as they were installed.

Regrettably, it looks very likely that I will be going back to my forty-
year old 57s. This is a great pity because in all other respects the
2805s sound wonderful.


Chris.

In article , Chris
Isbell
wrote:
On Thu, 28 Jul 2011 12:53:39 +0100, Jim Lesurf wrote:

Maybe we should do some 'blogging' more about audio. So if anyone is
interested, I've spent the morning saying a fond farewell to my
c25-year-old ESL63s and installing a new pair of 2805s as their
replacements. My main initial impressions a

Jim,

I hope that you have better luck than me! I am currently on my fourth
set of 2805s. All of them have developed internal arcing - one of the
latest pair started doing this as soon as they were installed.

Well, the bad news is that when I switched them on this morning one speaker
didn't power up. :-

Fuse had blown. I tried another similar fuse and this also blew. The
speakers had worked fine all yesterday.

I went direct to source and have been discussing it with Quad this morning.
I'm told that this is probably the mains transformer and a new one is on
the way. I'll know more once I've had a go at trying that. They said that
if I have any problem or doubts they'll send someone out to fix it. But -
since they know I'm an engineer who knows which end of a soldering iron
*not* to hold - it is a job I can probably sort out myself more quickly if
I prefer. If so, that suits me as it also gives me an excuse to learn a bit
about the innards. Its a chance I'd have preferred not to have needed so
soon, though... I'll decide when the transformer and info on how to do the
replacement arrive.

How did the arcing show up and what were the symptoms, etc?

I've had an assortement of repetitive clickings and buzzings at times in
the past from 63s and 988s. But this always passed after a day or two and
my understanding is that it is fairly normal. It didn't cause a shutdown or
problem beyond the faint noises when not in use.

Regrettably, it looks very likely that I will be going back to my forty-
year old 57s. This is a great pity because in all other respects the
2805s sound wonderful.

For me the worry is that I no longer have the 63s. So am now reliant on the
2805s for the main system. The 63s were showing their age in various ways.
In particular a level of hum/buzz from the speakers that had slowly been
getting louder over the last year or two. I guess various caps needed
replacement. But (perhaps unwisely) decided that after 25 years it was time
to try the new version rather than have a refurb.

Oh well, the 988s still sound good, and I can use headphones or my ancient
cone-and-box speakers (Armstrong 602s) for a while.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 29 Jul, wrote:


I went direct to source and have been discussing it with Quad this
morning. I'm told that this is probably the mains transformer and a new
one is on the way. I'll know more once I've had a go at trying that.
T... I'll decide when the transformer and info on how to do the
replacement arrive.

A couple of replacement transformers arrived this morning. Along with some
63mA fuses. The next step is for me to go out and buy some curtain rod as
this is a tool required to take apart the 2805s! 8-

Nice to see that Quad have remained as of old in various ways. The parts
were sent asap, with apologies and helpful advice. And dissassembling /
assembling their equipment tends to be a bit 'around the houses'.

I still remember how funny it seemed at the time how you had to open and
close the box of a 405! The 2805 seems like that on steroids. :-)

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article ,
Jim Lesurf wrote:
I went direct to source and have been discussing it with Quad this
morning. I'm told that this is probably the mains transformer and a new
one is on the way. I'll know more once I've had a go at trying that.
T... I'll decide when the transformer and info on how to do the
replacement arrive.

A couple of replacement transformers arrived this morning. Along with
some 63mA fuses.

[snip]

Bit of a worry a mains transformer failing - and the maker putting their
finger on the problem immediately? If it is indeed just a transformer and
not a SMPS?

--
*Real women don't have hot flashes, they have power surges.

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Dave Plowman (News)
wrote:
In article , Jim Lesurf
wrote:
I went direct to source and have been discussing it with Quad this
morning. I'm told that this is probably the mains transformer and a
new one is on the way. I'll know more once I've had a go at trying
that. T... I'll decide when the transformer and info on how to do
the replacement arrive.

A couple of replacement transformers arrived this morning. Along with
some 63mA fuses.

[snip]

Bit of a worry a mains transformer failing - and the maker putting their
finger on the problem immediately? If it is indeed just a transformer
and not a SMPS?

Transformer. The circuitry is essentially the same as the 988/989 series.
And apart from the changes to the limiting arrangements and some tidying
up, much like the 63s. Ye Olde Fashined transformer technology.

AIUI the diagnosis is on the basis that nothing else would blow the fuse so
quickly at switchon. I did wonder if it was some busted diodes or caps in
the voltage multiplier stack. But there are some 220k resistors in series
between them and the transformer. So it isn't obvious how anything at HV
would draw so much primary current. If they'd accidentially fitted much
lower resistor values, maybe. But the speaker worked on the first day
without any sign of problems.

The LV side isn't much more than a 555 and a few odds and sods. To me the
only obvious candidate there would be if the LV winding's rectifier bridge
has failed. Possible, but not something I'd expect unless they had chosen a
piddle-power surge current rated bridge. Or just dead unlucky, (That sounds
like me, though! Sod's Law still rules KO. :-) )

In reality, of course, *anything* may fail without warning. And it may just
be a dead insect that was trapped as a stowaway and has now fallen across
the power wires somewhere inside the box.

However at present I'm just proceeding 'as recommended'. If it turns pun
out *not* to be the transformer and a new one just blows another fuse my
understanding is that they'll send an injuneer with a bigger box of tricks,
or replace if necessary. As things stand I'm happy to see if I can change
the transformer and if that fixes the problem and it then works Ok, fine
with me! If not, there will be more contact, discussion, and acitivity...

FWIW I've now got the magic tool (a length of 6 x 12 mm baton) and poked
out the top plate and can see the next nut to be undone. However I'm going
to have my lunch and maybe water the garden before my next session of
semi-informed breaking and entering...

One of the things I'll ask them next week is wrt the shape of the assembly
that mounts the input connectors, etc. If the top of this had extended
another cm or two towards the speaker frame you could probably have space
to remove the lid of the box *without* all the other furtling around
because at present the brace fouls having to slide the top of the box back.
Maybe Quad just have a fetish about 'ultra long tools'... 8-]

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 30 Jul, wrote:
In article , Dave Plowman (News)
wrote:
In article , Jim Lesurf

Bit of a worry a mains transformer failing - and the maker putting
their finger on the problem immediately? If it is indeed just a
transformer and not a SMPS?

Transformer.

Finally got around to replacing the transformer this afternoon. The speaker
then powered up OK and would play music. Too soon as yet to know if it will
go wrong again or if my 'repair' has caused some other problem. But so far
so good. One nagging worry is that something else *caused* the transformer
to fail, so may do so again in the - perhaps near - future! Fingers
crossed...

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article ,
Jim Lesurf wrote:
On 30 Jul, wrote:
In article , Dave Plowman (News)
wrote:
In article , Jim Lesurf

Bit of a worry a mains transformer failing - and the maker putting
their finger on the problem immediately? If it is indeed just a
transformer and not a SMPS?

Transformer.

Finally got around to replacing the transformer this afternoon. The
speaker then powered up OK and would play music. Too soon as yet to know
if it will go wrong again or if my 'repair' has caused some other
problem. But so far so good. One nagging worry is that something else
*caused* the transformer to fail, so may do so again in the - perhaps
near - future! Fingers crossed...

Does the transformer sort of look marginal to your experienced eye, Jim?
Or does it vary from the average mains transformer in design - perhaps to
provide the HT? Just seems an unusual thing to fail - and for the factory
to put their finger on the fault instantly.

--
*Suicidal twin kills sister by mistake.

Dave Plowman London SW
To e-mail, change noise into sound.