The Workbench

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

yachadm — Tue, 10 Feb 2009 12:07:33 GMT

Martin,

That sounds like a great project!

Next to the mains transformer is a bank of the 4 large capacitors - ROEderstein EGM (now Vishay, but the EGM series is discontinued)

2x 6,800uF/50V 30x40mm (I'd like to put in 8200uF here, but I'm not sure if it would overload the Bridge and Power Supply)

1x 2,200uF/40V 22x40mm (for this one only, I found a Vishay BC 120ATC series replacement - blue sleeve - not yet installed)

1x 10,000uF/25V 30x40mm

These capacitors are absolutely space limited, and for the 6,800uF and 10,000uF, I have had a real problem finding good quality substitutes to fit.

The original EGM units have apparently long since finished their lifetime, and sound is deteriorating.

I would be very interested to see what you come up with as replacements for these capacitors.

Upgrading these caps, and changing the OpAmps are the last projects I'm thinking about on my BC9300.

Menahem

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

Die_Bogener — Tue, 10 Feb 2009 11:21:01 GMT

Probably this friday i get a BC9300 for rebuild and cap/opamp upgrade.

Maybe i make a workshop, at least i will take some pictures and a material list for the upgrade.

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

yachadm — Tue, 10 Feb 2009 05:15:01 GMT

Hi Martin,

Regarding your BC9300 OpAmp upgrade - I'm going to give it a try, and see how it sounds.

Which OpAmps did you use (I was thinking of the OPA2134)?

SMD or TTH?

How many OpAmps are there on the circuit - 2 or 3?

Did you need to add any coupling or compensation capacitors to prevent oscillation, or was it a straight replacement?

Menahem

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

Die_Bogener — Tue, 23 Dec 2008 12:38:22 GMT

Sorry, i have not seen an open 9500... but i own a BC9300.

The BC9300 uses a STK Hybridchip for the poweramp. I think, the older 9000 is using a modified BM5500 power amp, but this i dont know for sure... haven't seen it open.

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

jc — Tue, 23 Dec 2008 12:28:52 GMT

The poweramp of the BC9300 the same as BC9500? That would surprise me as the spec's show a frequency range from 70 Hz upwards compared to 50 Hz in case of the 9500. My experience is that the 9500 sounds way different and beter than the 9300 (with beovoxes that is).

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

Die_Bogener — Sun, 14 Dec 2008 12:36:00 GMT

Sorry, no...

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

Peter — Sun, 14 Dec 2008 12:30:07 GMT

Martin, have you seen the boards in a 9500? Are they Philips components or far eastern?

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

Die_Bogener — Sun, 14 Dec 2008 09:57:01 GMT

The BC9300 is more or less a BC2500, just with one way communication.

The tape drive, tape controller and radio are 100% compatible with the BC2500. There is just a new cpu board and a different cd drive installed.

The power amp and the power supply are similar to 9000 and 9500, but i think not identical.

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

lausvi — Sun, 14 Dec 2008 06:40:03 GMT

How will BC9000 rate in point of view of capacitor quality? Seeing the pictures of BC9300 it looks surprisingly different to my 9000 - a lot more separate boards and wiring.

Is there any experience if the BC9000 has some caps that 'should' be replaced by now to enhance something in audible / performance range? I am about to take mine apart to fix the classic problem with the muting relay.... replace it!

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

Peter — Sun, 14 Dec 2008 05:02:05 GMT

Afraid I have given my 9500 to a friend so cannot do pictures! Tim has rebuilt a 9500 following lightning damage so will know. I'll find out for you.

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

yachadm — Sun, 14 Dec 2008 04:17:53 GMT

Hi Peter,

I've never seen the inside of a BC9500, so I don't know.

If you have close-up, high resolution pics of the BC9500 PCB's, I'll take a good look for comparison, and let you know.

I don't know when B&O started sourcing Korean components, but that was, without question, a severely retrograde step.

The only ROE components in my entire BC9300 are the large Power Supply filter caps - that's it!

If they'd switched from Philips BC to Panasonic, Nichicon, or Nippon Chemicon, I wouldn't have a gripe against them, but Samwha? What a disappointment!

I severely doubt that, even if B&O had specced Japanese components as OEM, they would have used the top-of-the-line parts such as the FM or HE series which are now installed.

Menahem

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

Peter — Sun, 14 Dec 2008 03:54:37 GMT

Am I right in thinking that the boards in the 9300 are essentially the same as those of the Ouverture? Was the 9500 better specified as far as components are concerned?

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

yachadm — Sat, 13 Dec 2008 12:52:29 GMT

Hi Martin,

Here below, you can see all the new Nichicon and blue Vishay BC axial capacitors on the Amplifier board, but I didn't get around to replacing the 4558 OpAmps yet.

I actually have a Philips CD650 (TDA1541) with the original 4558 OpAmps, and I added DIP sockets to be able to try out many different OpAmps.

I tried at least 20 different types, including OPA2134.

I bought some Brown Dog SMD to DIP adapters to try out the SMD units.

There were some which caused oscillations, especially the AD797A, and I added bypass caps to solve that, but at the end of the day, only the OP275 was better than the 4558, and actually not much better.

So I concluded that the 4558 is a very good OpAmp, and not really worth the trouble to start changing.

Having said that, I am always tinkering, and maybe I might just have to try a series of replacements for the fun of it!

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

Die_Bogener — Sat, 13 Dec 2008 12:23:05 GMT

Hi Menahem,

you should also replace the caps on the preamp section. And replace the 4558/LF353 smd opamps also. That sounds really nice :)

Yes, i have an audiophil BC9300 too...

Martin

Re: BC9300 Tape Belts replaced and Capacitor Upgrade

yachadm — Sat, 13 Dec 2008 11:58:04 GMT

I replaced the 3 belts, and the Tape works perfectly again.

I'm a repeat customer of Atlantic Systems who supplied the required parts:

2732101 Large flat belt 8.0" X .196 X .031
2732085 Medium Round Belt 5.8" X .070 X .070 ( 1.8mm )
The Small Round Belt 2.7" x .070 x .070 ( 1.8mm ) was supplied by MarrsCommunications

I also replaced the CD Door belt 3.4" x .070 x .070 ( 1.8mm )

While I had the BeoCenter open for about 3 weeks waiting for the belts, I decided to do a project I'd been thinking about for a long time.

Except for the large ROE Power Supply capacitors, B&O used Korean Samwha capacitors throughout this unit. Obviously cost was a big consideration, but IMHO, not acceptable. I remember that I paid close to GBP2000 for this unit new, and I just can't accept that B&O could not justify the purchase of Elna or Philips BC capacitors, instead of these Korean units.

So, I decided to redo the entire machine - about 70 capacitors total.

All capacitors of 4.7uF or smaller, were replaced by Wima MKS2 and MKP capacitors.

All other capacitors were replaced by Panasonic FM, and Nichicon HE, depending on what values were available.

Needless to say, a substantial improvement in sound resulted, and FM stations are much more stable.

A highly recommended upgrade for those of you with the BC8500 and up series.

Menahem Yachad