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Hi all, has anyone else had this problem? I have a working 8002 the seems mechanically great, but playing an LP give a highly distorted sound. I swapped cartridges, bought a new cable.... Nothing has worked. Any idea at what is happening?
thanks in advance for your opinions and experience.
Al
Hi,The phono signal travels through the tonearm and out to a preamp through a muting relay. It is possible that relay I causing the problem. Also make sure you have checked the tracking force of the tonearm using an external scale (not just the slide indicator on the tonearm).
-sonavor
Sonavar,
Thanks. I'm not an engineer, so I can't offer much technical feedback, but here's what I've tried:
I used the slider to increase the tracking force by a small amount... maybe 0.10g and it fixed it, but only for one album side, then the distortion came back. The good news (possibly) is that there may not be anything wrong with it except that it has not been played in years and it's possibly dirty???
I looked in the manual, but couldn't find how to stop the platter and lower the arm to the Track Force Scale manually.
I appreciate all the help, I really want to get this beautiful machine working again!
Yes, there isn't much real estate at the edge before the platter to check the balance. What I do is remove the top platter and position my tracking force gage as shown in the picture below. It sounds like your problem could be with incorrect tracking force setting though. If the turntable has never been worked on then it will, at some point, require some restoration to the inside. But for now it sounds like it just needs some calibration of the tracking force.
I did what you recommended and the slider seems accurate! I've tried tracking forces between 1.0g and 1.6g but the distortion remains. What I can't explain is why I was able to eliminate the distortion for an entire album side when first moved the slider to a heavier setting? Any thoughts?
What about the Beogram suspension? Did you make sure the three floating chassis suspension locking screws are in the correct position and not locked down for transport?
Your issue is starting to sound like a cartridge problem. What is the history of your two cartridges? If they are both used cartridges then it is possible that both could have suspension problems. It is very common for those MMC cartridges (used by the Beogram 8002 and other Beograms of that period) to have suspension problems now (Twenty to Thirty years later). The suspensions can be repaired though. Here are a couple of Beoworld threads that discuss MMC repairs for the series that is used by the Beogram 8002: MMC Pickup Repair, MMC1 vs MMC2 Sonic Differences-sonavor
Regarding the Beogram 8002 floating suspension...Here is a picture of the transport screw locked into place (bottom part of the picture). In the unlocked position the silver screw head should be screwed down so it is below the opening of the round plate and the plate should be free to move. When all three lockdown screws are unlocked the platter and tonearm assembly should move up and down together independent of the Beogram cabinet.
I checked the platter suspension and its floating freely with all transport screws below the round plates. As for the cartridge, I replaced temporarily the mmc2 with a new mmc4 that was sealed in the box. Same results with distortion.
One possible clue that I haven't mentioned is that the album side that played beautifully without distortion was a bit warped and the cartridge tracked it well. I tried to replicate this intentionally but it didn't "fix" it like that one time.
What possible problem would tease me with glorious sound for twenty minutes and then become unlistenable. The distortion is huge, especially in the midrange, it's not something anyone could get used to, it's really harsh.
I have several working Beogram 8002 turntables including one I bought new back in 1983 and can assure you that those turntables should sound beautifully. Something is definitely out of order with either the signal path or your cartridges. Note that even a NOS cartridge sitting in a box could possibly be suspect. It isn't likely but could still be bad. The odds of two bad cartridges is also unusual but possible.The signal path is simple. There is no active circuitry between the cartridge and the turntable output connector. There is just the DIN connector, the muting relay and the cartridge mount that can affect the signal. Between those three things I would suspect the muting relay. The fact that you were able to get twenty minutes of distortion free sound also lends itself to a switch problem (like the relay). You could bypass it temporarily per the wiring diagram I posted and see if the isolates (or eliminates) the problem.
AudioNutCase:As for the cartridge, I replaced temporarily the mmc2 with a new mmc4 that was sealed in the box. Same results with distortion.
When you say new, do you mean new old stock, or newly refurbished?
AudioNutCase:What possible problem would tease me with glorious sound for twenty minutes and then become unlistenable. The distortion is huge, especially in the midrange, it's not something anyone could get used to, it's really harsh.
Since suspension failure of the cartridges is as much a result of age related deterioration as it is 'wear' (in fact probably more so), perhaps you had one failed cartridge and one that worked for one side but then failed the next time it landed on a record?
As sonavor said, the only other component in the chain is the relay, but it would seem unlikely for both channels to work to start with and then suddenly fail in this manner as they are separate contacts within the relay (and from your description of the distortion it doesn't sound like a relay 'chatter' issue).
Martin.
...and just one more thought - what is the 8002 plugged into? ie can we rule out a problem with the pre-amp or amplifier?
Kind Regards,
Dear Detectives,
I've tried two phono cables, two preamp's, a standalone mm phono amp, and a Beomaster 6000. All connections yielded the same distorted results.
if it was the suspension on the cartridge (or both of them) how do we account for that full side of gorgeous sound I mysteriously experienced? It was a sudden change, with nothing else different... Except for that one weird aspect that the record was not sitting fully on the spindle so it looked like it was warped but made beautiful music with great sound staging and imaging and detail.
visually, the suspension on both carts look good, but I will check with a microscope. Anything I should be looking for up close?
i don't have the skills to bypass the relay and I don't want to practice on this beauty.
Thinking about your problem I remembered that I have on occasion experienced the Beogram 8002 MMC2 cartridge setting down on a vinyl record in an unusual manner. Unusual sound due to the stylus not landing correctly in the groove. Visually it appeared to be playing the record but the sound was kind of scrambled/distorted. Hitting Pause then Play again (sometimes more that once) would get the cartridge to properly set down into the groove. This hasn't happened very often but it is the only thing I can think of that might fit your scenario barring you having bad cartridges or a bad muting relay.
How many vinyl records do you have available to try? You said the one you are using is warped. Do you have any good condition LPs?
I would add ''very" to distorted. I'll try your pause/play trick and see if it works.
I have lots of good LPs (I think around 2000) and four turntables including this one. I get the same distortion on every LP I've tried. But I'm not giving up! The 8002 is a modern design masterpiece and I really want it to work... I really appreciate you guys helping me. I wish I could find someone in San Francisco who knows this table like you two.
Would a bad muting relay be fixable by any good tech or do they need to know B & O?
The muting relay is pretty easy to get to but someone does need experience in opening up the Beogram. It actually opens up like an automobile hood. You can see pictures of internal repair work on the first Beogram 8002 I restored back in 2012. The fourth picture down the thread shows the small board with the muting relay in the rear left hand side. So it is easy to get to with the Beogram in its service position. Just be aware that to put the Beogram in its service position the three floating suspension spring clips have to be removed (as well as two small screws on the left underside of the Beogram case). For a tech that is familiar with the brand it is an easy job.
The muting relay doesn't break the signal path, it grounds the signals when muting, so bad relay contacts would cause lack of muting rather than distortion.The distortion will have to come from the cartridge and/or its cleaning/alignment, the record or external amplifiers.I have seen one case of intermittent connection inside the cartridge socket causing a "chopped" kind of sound in one channel. butI doubt this to be the case here since I take it the distortion you experience is in both channels ?You are not using an antistatic mat or similar, - are you? (Never use antistatic mats on a Beogram).
Martin
The usual culprit in these scenarios is the cartridge. To be fair, there is little else it could be. If the turntable is not turning at the right speed, you would notice wow but not distortion. Even at the wrong weight, the arm is really just a tube holding the wires for the cartridge and you can play a deck with locked suspension - it is just a bit microphonic. You need to try a cartridge that you know works!
Peter
Martin, Thanks for your input.
No, no record mat. The distortion is equal in both channels. And what you said about the Muting Relay makes sense, which leaves me with the possibility that both the MMC2 and the MMC4 (which was never used and sealed in B & O packaging) have identically bad suspension and cause the identical type of distortion... frankly, this seems like a longshot to me, but after all the discussion, what's left in the signal path that it could be?
Peter, thanks. Is there any way to check the cartridges? I would be bummed if I bought a third cartridge only to have the same problem.
B&O made adapters for their cartridges to work in non-B&O turntables. You could try and find one of those to test your cartridges in you other turntables. However, I would recommend buying a new or restored MMC cartridge from Soundsmith (USA) or Axel Schürholz (Germany). Another option is to send one of your MMC cartridges to one of the places above or to Benny Amina of Modular Electronics (USA) for repair of the suspension. I have used all three repair services successfully in the last two years. I would offer to test your cartridges on one of my turntables but that would only help if it turned out the cartridges were okay.
Sonavor, thanks for your generous offer. I emailed Peter Lederman at Soundsmith and asked his advice. Has anyone heard his SMM4 $200 cartridge? Maybe just getting one of those is the easiest path...
I have never heard one of the Soundsmith SMMC cartridges. My only experience is a suspension repair of an MMC1 cartridge. Even if you purchase a new cartridge I would consider getting your MMC2 cartridge suspension repaired (as long as the stylus is still good). The repair shop should be able to tell you if the stylus is good enough to warrant fixing the suspension.If you are looking to save money on the suspension repair and live in the USA then I would look to Benny Amina's service. He is very reasonable and did excellent work on one of my MMC2 cartridges. If you have time and don't mind risking shipping by US Post to Germany, Axel's service is good. I have had two MMC2 cartridges repaired by him. Both of those services are usually less cost than a Soundsmith repair.When it comes to the cosmetic results of the repair, Soundsmith is the best. I could not tell at all that the MMC1 cartridge had been opened up for repair. Both Axel and Benny have to cut open the cartridge to repair it and there will be a surgery scar on the bottom of the cartridge. Naturally that doesn't affect the sound and it doesn't bother me. I mention it just so you know what to expect when you get the cartridge back.
In all services you need to contact them ahead of time to make sure they know you are sending a cartridge for repair.
Well Detectives, Mystery solved.
I took action on all your suggestions and finally figured out that it's the suspension on the MMC2 that's faulty (feel free to say "I told you so!"). The way I found out was by going way out of bounds with the tracking force. At 2.00g, which is double the recommended force, the beautiful music came back almost completely... I say almost because now I have a low rider cartridge the body of which sometimes scrapes the record for a new type of noise!
So I ordered a refurbished MMC2 from Denmark to replace it and get me into music in the fastest way. Then, I may take your advice, Sonavor, and send the MMC2 lowrider and possibly also the MMC4 for suspension repair.
Thanks everyone for all the help. I'll report in on the quality of this Danish rebuilt MMC2 as soon as I get it (or after a break-in period, which new suspensions always need).
Good deal.If the Danish repairer is this place, then I believe your cartridge will be one that was repaired by Axel in Germany anyway...That is a good thing and you didn't have to worry about shipping your own cartridge.-sonavor
That's the one!