General Forum

Re: Beocord 9000, recently acquired

chartz — Thu, 02 Jun 2011 06:01:52 GMT

Also look here: http://forum.beoworld.org/forums/p/30587/246646.aspx#246646

Re: Beocord 9000, recently acquired

Step1 — Wed, 01 Jun 2011 15:10:41 GMT

Just to add to Jacques good advice there is the spool clutch assembly which should be dismantled and checked for a crack in the supporting shaft this can have an adverse effect on operation. Look for a recent thread in the workbench section (page 2 or 3) regarding a Beocord 8000 (same mech) to see what I am talking about!

I also changed the playback and record head pcb headers for gold plated as my examples were not in the best shape.

Re: Beocord 9000, recently acquired

chartz — Wed, 01 Jun 2011 07:31:06 GMT

Hi Christian!

You should re-post on the Workbench or Vintage forums methinks. Many more people (including me!) are watching these!

See you there!

In the meantime, there are several things that would need attention.

On Tim Jarman's and Martin (aka Dillen) I dismantled the thing to clean everything, especially the motor pulley which will have black goo around it, hence provoking wow, and I fitted a new pinch roller. The tape path will have to be very clean too. It would be nice if you published pictures of you mech!

Tim says:

Check the brakes, there are three felt pads that act on the spool

carriers (best accessed with the cassette tray removed), they can get

gummed up with dirt and cause this sort of thing. After repair work they
can also get re-fitted wrongly, check this too. I assume that your
mechanical overhaul has included removing the spool carriers from their
shafts, cleaning away the horrible old grease and lightly re-lubricating
them? This is very important in all Beocords as stiffness here can cause
needless head wear.

Check the head azimuth and of course the Dolby level (if you are using
the NR function), if it still sounds dull there is a procedure for
checking the frequency response in the manual, it isn't easy but may be
worth doing.

Remember that Nakamichis on the whole have an incorrect frequency
response with rising treble (one of the many reasons that I don't use
them) as it sounds "good" in the showroom but makes them unsuitable for
use as a "reference" machine. The 9000 has a slighltly falling treble
characteristic too which highlights the effect hat you have observed.
The Pioneer CT-A9 and the Aiwa AD-F770 / AD-F990 both have perfectly
flat IEC frequency response characteristics when in good condition and
correct adjustment, these are far more suitable to use as reference
machines than any Nakamichi.

Also think of lubrication. The spools will have sticky grease, and the motor will certainly need the odd drop of Singer oil too!

Well that's I did on mine, and it worked nicely. The only person who can supply THE belts is Martin. All else is c**p. He is all dedicated to keeping B&O stuff alive and he's very nice and has the science and most importantly the parts you need! The pinch roller is rare, watch the Bay for an original one. I have a good spare one if you like.

Cheers,

Beocord 9000, recently acquired

ChristianThomas — Tue, 31 May 2011 14:05:38 GMT

Hi Guys

***This was originally posted on the Nakamichi forum, and it was suggested I reposted it here***

The Beocord 9000 is now turning and it works. Praise the Lord. I can hear
some great things, but only in parts. Otherwise it’s a pretty mixed bag,
and on some material I have felt my system really struggling to make sense
of things coming from it. In some ways it has taken me back to places I had
forgotten about, being truly awful on bad tapes. Not having Dolby A doesn’t
help – it has everything else up to HX-Pro (though where that is I can’t
immediately see) so a large number of recordings are going to be out of
bounds – and an FeCr setting doesn’t quite make it right.

Believe me, I am trying to like this deck, and I do hear some great things.
It is more detailed than the Bx-300, but I don’t have the feeling on speed
stability or sense of power of that machine. I’m not sure if the flat belt
I bought was new and if MikeM is reading this, perhaps he can tell me. I am
getting all sorts of modulation from time to time, and it’s really
intolerant of stretched or misused tapes. I’m building up my cassette
collection from charity shops so one can rarely tell their condition, but
these are the same tapes played on the BX-300.

It doesn’t sound to me as though it’s shagged out. In fact my suspicion is
that it has been underused. There isn’t that soggy, soft sound that I know
from amplifiers where the supply capacitors have really had their day. Nor
do I have the sense of a general roll off from the heads being worn. As I
say, while not really where I expect things to be nowadays – where we take
the top end for granted – it really seems pretty good up there given the
medium. In fact, if I could get the rest of it right I’m sure it wouldn’t
notice for a moment.

I wasted £3.99 on eBay for a service manual which I could barely read, only
to find they can be had for free at beoworld.com. From looking at the
innards, not the manual, it seems the head amplifier centres around a very
old TLO72 which would explain (to me at least) quite a bit of the sound. I’m
fond of this as an op amp because it’s sharp and lively and has plenty of
get up and go, but it’s not the finest thing around. It will sound cleaner
than many of the contemporary op amps and seems to be nicely balanced out
here. But it might also explain why I don’t feel the power and smoothness
in orchestral build-ups – and there really does seem to be a lack of bass in
this respect – though what is there is really quite good. But there are
polystyrene capacitors abounding in the signal path and this too (though I
have never tried them alongside a TLO72) would also give wonderful results
in all detailed ways.

It’s the modulation problems – and these can be right up into the lower
midband – the speed stability and the sheer crappiness on less than perfect
tapes (and I also get a feeling that this is not just the physically
imperfect but also less than ideal quality seems to be penalised more than
on the Nak) that really need sorting out. I don’t really know where to go
on this so would like to hand it over to the experts. I don’t believe the
machine is as bad as I’m hearing. I may not think it is yet a Nak beater
but I would like to give it a chance.

But nor do I think it is entirely the transport mechanism that is at fault.
I suspect that there are things going on – beyond it just needing a damned
good service – that only those in the know will know. I can get a new belt
for the flywheel, and the pinch roller rubber is slightly perished, but
instinctively I feel the problems run deeper.

I have some good kit here with which to test it, including an Audio
Precision analyser but really need some guidance as to what to do next, not
least knowing whether I can do it stand-alone or need some independent test
tapes. (The AP can make test tones that it can recognise -certainly on a
CD, so presumably on tape too, though I don’t have a lead to try it - and
then tell you the distortion as it picks up the fundamentals.) I suppose I
ought to be able to work out a mechanism by which one can tell the alignment
from this, or it must be in a paper somewhere, but guidance is always
welcome from those with experience. I am only too happy to share any and
all of my findings with the group as a whole – and tapes if it comes to
that. Incidentally, this is my attitude in all things, certainly to the
bounds of what is fair, though I won’t be making tapes all day.

Thanks for all your help so far. I know this is not a Nakamichi deck, but
it probably deserves a place in the Pantheon of good decks, even if not on
present showing.

Best wishes to you all

Christian Thomas

PS BTW, I am in the UK, unlike the majority here who seem to be in the US.
It means I have to miss out on an awful lot of good decks going free, but in
this instance it may have also a bearing on what you can ask me do on this
topic.