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At what vol level do you get rumble / flutter?

Hi everyone. I hope my Pro-ject Xpression has not started the dreaded rumble / wow / flutter problem. I recently tried a heavier MC Ortofon on my table and after switching it in and out (professionally done), my table will make the woofers rumble / wow / flutter as soon as my normal cartridge (Ortofon MC-3 turbo, HO MC) hits the record with the volume at about twice as high as my normal listening position, which is not party cranking levels, but twice as high is and that is where I see the rumble. Would you say this is normal for Pro-ject and similar tables? Will a Rega RP3 act similarly? Rest of system is posted and it is less noticeable with the rumble filter on. From what I remember, my table did not do this before the cartridge swap. Luckily, it is still under warranty.

TIA
sbrownnw
tobes's avatar
tobes
436 posts
 
Actusreus,

I do see your point, I probably didn't read your post above.
Like you say, it is probably a combination of factors at work here.
From memory the cartridges i mentioned above produced 'nervous' woofer pumping even on nominally flat records. They were verging on out of control with any ripple like warps near the start of the record - hence I found them unusable in that setup (and I returned them).
I suspect, for whatever reason, they had very pronounced resonance which was 'set off' by any subsonic content.

BTW, thanks for your kind words on my audio page, not sure its as deserving as you make out, but thanks.
tonywinsc
583 posts
 
If you can see the woofers pumping, then I would say that they are probably cycling at 0.5 Hz to 2 Hz. Note that 33 1/3 rpm is 0.56 cycles per second. So record runout, as I like to call it, ie. the eccentricity of the record grooves to the spindle could be generating a 0.56 Hz cycle. Some cartridges may mechanically filter out this low frequency side to side motion and perhaps some don't. Just a thought...
actusreus
733 posts
 
I meant to mention it in my last post - if anyone saw Fremer's "21st Century Vinyl" DVD, there was a great segment shot at Stirling Sound in NYC, and interview with the recently deceased, great George Marino. (What a loss to the community, by the way. Left us way prematurely. RIP George.)

Stirling uses a Neumann lathe to cut the master disc, and Marino was explaining the importance of isolating the lathe as it's essentially a turntable with a cutting "stylus," and any extrinsic noise can easily get transferred through the cutter and be embedded in the disc together with the recorded sound. They have the lathe on a slab of concrete and spring suspended. Even with this, I'm not sure you can isolate anything in Midtown Manhattan where Stirling is located, and it is certainly possible that many cutting lathes are not perfectly isolated and thus some of that unwanted low frequency noise does make its way into the vinyl.
sbrownnw OP
710 posts
 
@johnny, my table is at my dealer now. It has the lighter 65g counterweight for cartridges between 4-7 grams. How do I calculate the effective tonearm mass with this lighter counterweight (10g lighter that the factory 75g for 7-12g cartridges). I might have him put in a pair of 1 gram brass screws to bring the weight up a little.
sbrownnw OP
710 posts
 
I forgot to mention my turntable is on a custom steel wall rack bolted to the studs in my house but is in an audio cabinet (no doors). The section of the audio cabinet that houses the turntable has some of the back panel removed so the steel rack arms can come through. Could my problem be caused by this setup?

BTW, I put a new Vincent Pho-8 up against a new Pro-ject phono tube box II (my demo one was replaced under factory warranty after 1 channel got noisy) this weekend. The Pro-ject won out with better sound stage, realistic instrument sound and just overall more musical. I hope to upgrade the wall wart for the Pro-ject tube box. Would this one be a higher quality less noisy power supply?:

http://www.powerstream.com/EA1050.htm
EA1050A-61 16V 4A 5.5x2.5x11mm $57.50

Thanks everyone,

Scott
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