BeoGram

Re: Beogram 6000 Muddiness with CD-4

cozza — Thu, 06 Dec 2007 19:19:24 GMT

Nice to be of assistance. Glad the re-cap worked out in the end!

Re: Beogram 6000 Muddiness with CD-4

Peter — Wed, 28 Nov 2007 18:20:40 GMT

My Beogram 6000 is in Bellac so not used. I do however have a project coming up!! I'll keep you all posted!

Re: Beogram 6000 Muddiness with CD-4

yachadm — Wed, 28 Nov 2007 16:44:04 GMT

Hi Peter

No argument that the SMMC20CL+ Cartridge is a large part of the sound quality, but I'd highly recommend doing a proper recap (if you haven't already done it), on the CD-4 PCB, the Control PCB, and the 4 Large Power Caps.

The new caps are certainly responsible for the high-quality sound actually getting from the SMMC cartridge to the Beomaster amplifier, without any audible distortion.

Regards

Re: Beogram 6000 Muddiness with CD-4

Peter — Wed, 28 Nov 2007 16:02:27 GMT

Well done! I might have to get a SMMC20CL+ from the sound of things!

Re: Beogram 6000 Muddiness with CD-4

yachadm — Wed, 28 Nov 2007 15:58:22 GMT

Hi Cozza,

Thanks for the pointer!

You were 100% right - I'd concentrated on the Electrolytics, and discounted the possibility that the Tantalums could be at fault (Naive!!!)

I got out my ESR Meter, and here's what I found, after a patient examination of every single tantalum on the PCB:

0.22uF/35V actual ESR 92 Ohms, should be 12 Ohms - replaced with Panasonic Polypropylene.

0.47uF/35V actual ESR 22 Ohms, should be 8 Ohms - replaced with Wima Polypropylene.

1uF/35V actual ESR 18 Ohms, should be 4 Ohms - replaced with another tantalum.

All the rest of 1uF are high at about 6-7 Ohms, but I didn't have any more Wima Polyesters, so that will have to wait for the next stage.

But, anyway now, the BG6000 has zero distortion, no muddiness, and if I may say so myself, incredibly excellent sound.

I've actually become addicted to this turntable, playing my Enoch Light CD-4's non-stop all day, revelling in the pure sound which I've been missing for so many years.

I'd go so far as to say that this turntable, properly restored and adjusted, has very few equals in the world.

BTW, best tracking weight for the SMMC20CL+ appears to be about 1.5 Grams.

I've invested about $95 in parts (not including my patient labor) to get to this stage, where I am very satisfied with it.

It's really a pleasure to listen to such unadulterated, natural sound!!!!!

Regards

Re: Beogram 6000 Muddiness with CD-4

cozza — Tue, 27 Nov 2007 15:37:19 GMT

Have you checked all the tantalum capacitors (the red ones) on the CD4 pcb? Sometimes they can fail (mostly short circuit) although I have seen some odd faults cause by bad tantalums which have gone intermittent.

Re: Beogram 6000 Muddiness with CD-4

Peter — Mon, 26 Nov 2007 11:39:28 GMT

A stylus balance is a small device which will measure the tracking weight. B&O do one which is a little weighted see-saw but you can buy digital ones etc for ever increasing amounts of money! Try altering the tracking weight by half a gramme each way and see what it sounds like. Pick which is best!!

Re: Beogram 6000 Muddiness with CD-4

Peter — Mon, 26 Nov 2007 11:36:58 GMT

I think you are probably finding why CD4 didn't catch on!! There are some good ones on very heavy vinyl but I suspect the muddiness is the combination of the recording and the CD4 decoder. Not really sure where to go with this one. I got my 6000 system working just so I could say I did, didn't think that much of it and went back to stereo! The BG6000 is lovely though. I am actually quite impressed with the RIAA in it which in my view is possibly a bit better sounding than that in many Beomasters.

Re: Beogram 6000 Muddiness with CD-4

yachadm — Mon, 26 Nov 2007 11:26:17 GMT

yachadm:
Here is a picture of the CD4 PCB

Re: Beogram 6000 Muddiness with CD-4

yachadm — Mon, 26 Nov 2007 11:25:23 GMT

Here is a picture of the CD4 PCB

Re: Beogram 6000 Muddiness with CD-4

yachadm — Mon, 26 Nov 2007 11:18:52 GMT

Hi Peter,

Thanks for the reply.

I am using my trusty BM3400 (I don't have have a BM6000, and I'm not really interested in it anyway ;-) )

Of course I've upgraded it!! All the electrolytics to Nichicon Muse (from PercyAudio) - they aren't that much more expensive than the Panasonic FM series anyway. And the 1uF's to Wima Polyester. The power caps were a bit larger than the originals, so I had to forego the metal strap, and hot-glued them to the chassis. See attached photos.

What is a stylus balance?

Peter at Soundsmith claims that the SMMC20CL+ responds to 50kHz!!!

I haven't got around to listening to any stereo records, but if I switch the CD4 switch to OFF while listening to a CD4 LP, the muddiness disappears completely, but there is a definite loss of high-frequency sound. (Should I maybe be looking for something else on the CD4 PCB?)

I bought some sealed NOS CD4 LP's on ebay a while back, and opened them for this special occasion, so they should be in the best possible condition.

Re: Beogram 6000 Muddiness with CD-4

Peter — Mon, 26 Nov 2007 10:45:36 GMT

I am sure the cartridge will be fine. Couple of observations:

1. You will lose the top end compared to a stereo recording - the CD4 format only goes up to 15kHz. - I cannot hear 15kHz so no problem for me!

2. CD4 records are notoriously fragile. One play with a heavy tracking cartridge will wreck a record despite it looking perfect. I have very few that sound reasonable!

3. Have you upgraded the capacitors in the CD4 decoder board? Wouldn't come as too big a surprise if this made a difference - knowing you you probably have!

4. The tracking weight is usually not bad and I normally adjust the last bit by ear anyway. I do however usually use a stylus balance anyway to get to the standard weight and with the SMMC range, I think this is sensible as they are likely to be a little different to the originals.

5. The SMMC20CL+ is actually not really designed to be a quad cartridge though it will be the best you can get now a days. I would be interested to see what its frequency response was like up the 45kHz!

What is it like with stereo records? Are you using it with a BM6000 or a 3400? The 6000 is not what I would regard as the best amplifier B&O made, though it looks wonderful. I certainly found that the 3400 sounded better.

Beogram 6000 Muddiness with CD-4

yachadm — Mon, 26 Nov 2007 05:46:02 GMT

Hi all,

I have just received my new Soundsmith SMMC20CL+ for my BG6000.

Playing a CD4 record (in excellent condition) with the CD4 switch ON, there is a very faint muddiness detectable.

Assuming that the cartridge is not defective, what adjustments should I be looking to make, in order to eliminate this?

How accurate is the tracking weight indicator on the tonearm?

Regards

M Yachad