The Workbench

Re: Beocord 9000 sounds dull

yachadm — Wed, 14 Jul 2010 13:03:57 GMT

Jacques,

Good for you. Yes, sometimes we take the simplest things for granted.

Actually, I was following this thread with interest, because I wanted to see where the problem cause would reveal itself.

To tell the truth (and not to put you down at all), working daily in my lab, I have an automatic sequence of actions when kit comes in for repair.

Assuming a given tape deck powers on, the first 2 things I do is clean the heads with alcohol, and then degauss them. After that, I'll start on the technical bits.

So, you showed us how important it is to have a logical plan of action when tackling any repair!

Regards

Menahem

Re: Beocord 9000 sounds dull

chartz — Thu, 08 Jul 2010 06:22:51 GMT

Thank you Martin for your support, you are a friend indeed.

It's true the Beocord 9000 sounds different from the 6000/8000 series—mine were IEC later models—which deal with pre-recorded tapes (lots of them were recorded on Nakamichi-like set machines) better.

Now the transport works normally, I am impressed by speed stability because after all it's only a simple capstan mechanism. One can wonder what a direct driven, dual capstan B&O would have sounded like !

As an aside, I am amazed that the motor in the BC 9000 bears the exact same reference as the one in my BC 6000! Panasonic FG-SERVO 15VDC ref. MMX-5D2RSB (10 Aug79). It is the same motor, no doubt about it!

I am still looking for a good one... mine has disintegrated brushes and worn bearings.

Jacques

Re: Beocord 9000 sounds dull

Dillen — Thu, 08 Jul 2010 05:21:33 GMT

Would be a shame to delete it all.
Others will benefit from it and it's a perfectly good example of a case where the simplest thing can
drive you nuts because attention is focus'ed in all the wrong places.
It's also a perfectly good example to show that you should never give up.
Set it aside, wait a while and take a look at it with fresh eyes or ask a second opinion.
Don't forget, you came up with the idea of demagnetizing the heads yourself, that's very far from stupidity !

You did well !

Martin

Re: Beocord 9000 sounds dull

chartz — Thu, 08 Jul 2010 04:23:11 GMT

Hi,

How stupid can one be?

Well my stupidity has no boundaries...

I degaussed the head and everything is back to normal. It has now a few new caps and the deck is re-aligned (but it wasn't really out!).

Sorry to have bothered you. I'm retiring in a monastery.

Friar Jacques

PS. I'm so ashamed, can someone erase the whole thing please?

Re: Beocord 9000 sounds dull

chartz — Wed, 07 Jul 2010 14:05:35 GMT

Thank you both.

auric:

1) Have you replaced ALL electrolytic caps?

2) The trimpots are also suspect. They may look like they are in good condition but infact are not. Many are badly oxidized.

No, just the caps in the replay chain. The trimmers are good (tested) and not oxydized.

mediabobny:

Definitely try cleaning the heads with either a commercial wet-type cleaning cassette, or a Q-Tip dampened with rubbing (isopropyl) alcohol.

Already done of course.

I tried doing the adjustment procedure once more but nothing has changed. Recordings made on the Beocord are listenable, but on the soft side (unless Dolby is out when recording, in this case it plays fine) and it is unable to play pre-recordeds correctly with Dolby.

On my two Nakamichis these tapes play perfectly, with the same azimuth. Tapes recorded on the Beocord are too bright on the Naks, as expected. But the Naks are not bright sounding in themseves!

Jacques

Re: Beocord 9000 sounds dull

mediabobny — Wed, 07 Jul 2010 13:44:58 GMT

Definitely try cleaning the heads with either a commercial wet-type cleaning cassette, or a Q-Tip dampened with rubbing (isopropyl) alcohol.

Re: Beocord 9000 sounds dull

auric — Wed, 07 Jul 2010 13:28:47 GMT

Hi Jacques:

I haven't been following your thread so forgive me if this has been covered territory.

1) Have you replaced ALL electrolytic caps?

2) The trimpots are also suspect. They may look like they are in good condition but infact are not. Many are badly oxidized.

Derek

Re: Beocord 9000 sounds dull

chartz — Wed, 07 Jul 2010 11:17:25 GMT

Thank you Ron.

Do you think it's worth it to demagnetize the replay head?

Jacques

Re: Beocord 9000 sounds dull

langleyav — Wed, 07 Jul 2010 10:33:36 GMT

Prior to the 5000,5500,6000,7000 series of Beocords, B&O used the European equilization characteristic for their cassette recorders.

This means putting on more HF lift during the record process in order to reduce the HF level on playback, thus giving a better signal to noise ratio overall.

The result of this is to make recordings made with this equilisation sound overly bright on Japanese/American cassette players and recordings made on Japanese/American cassettte recorder sound dull on B&O cassette machines. The Dolby playback system exaggerates the situation with it's playback de-emphasis.

B&O appear to have changed to the more universally accepted characteristics as fron the 5000,5500,6000,7000 series of machines.

I have a Beocord 9000 myself which on its own I tested flat to within 2db up to 18khz!!

Ron

Re: Beocord 9000 sounds dull

chartz — Wed, 07 Jul 2010 10:20:52 GMT

Still nothing. One funny thing, when I approach a finger next to the head wires (Dolby in), treble is restored... When Dolby is out, it makes no difference. I tried changing the value of the head capacitors +/- but the effect is subtle at most.

I'm running dry here. Please help me!

Jacques

Beocord 9000 sounds dull [solved]

chartz — Tue, 06 Jul 2010 10:06:55 GMT

Hello,

I finally solved the flutter issue. Piano now sounds very pure.

The last problem is the relatively dull sound on playback (both channels). Treble is extended (there's detail) but it lacks impact; possibly in the 8-12 kHz region. I know it isn't a bright sounding deck, but it doesn't sound right!

The tapes recorded on the BC 9000 replay fine (including treble energy) on my other decks, so calibration does its job, and azimuth is properly adjusted. Pre-recordeds sound very dull on the BC too unless Dolby is out. Not so on BC 6000 and 2200.

I tried to alter Dolby level and the playback head frequency response, following the service instructions, but it didn't help.

Any ideas then? Magnetized head?

Jacques