Bloodlemons
Well-Known Member
I did not realize this was a thread. Happy to help!
Technical Difficulties Thread
- Thread starter MikeH
- Start date
uvwxVinyl
Well-Known Member
Well I think the motor on my Dual 505 is dead or dying
Without the belt the shaft (where the pitch control is) doesn't turn. I can sort of give it push and you feel it trying to start and some torque but it won't continue turning.
I see replacement motor boxes on eBay and dual Fred. I think I should be able to disassembly and reassemble it...what do you guys think?
So after taking it all apart my motor turns by itself however it doesn't turn when I put this (yellow arrow) piece back. I believe that's the bearing and therefore the issue is probably lube.... Do you think I'm on the right track?
Can anyone recommend lube to use and how much?
siremobunny
Well-Known Member
Experimenting with a Vinyl Flat has brought to light what I think is maybe a turntable setup issue, or maybe just a fact of life when dealing with how a cartridge handles a very small and sudden warp on a record.
I flattened what was a very warped record to what appears at first glance to be pretty much flat...went to play it, and now get an audible thump in the speakers when the needle hits where I assume the warp was before (this didn't happen, of course, when the warp was large).
Closer inspection revealed that there is still the most miniscule of warp and the cartridge visibly gets rattled at this spot, syncing up with the noise...captured the video below...the noise doesn't really come through, but it's definitely there loud enough to hear from across the room
and a video of the effect on the speaker
I know i've seen this issue before on other records where it will last for a track or so and go away, but I've never actually looked at what's happening with the cartridge and wonder if this is maybe an issue with my setup or if there's any tactics to alleviate it.
Or maybe just a normal annoying thing that all turntables experience with records with tiny warps...however, whatever it is, it's making me gun-shy on trying to flatten any more records because I'm afraid that this will happen with all of them.
Any wisdom is greatly appreciated.
I flattened what was a very warped record to what appears at first glance to be pretty much flat...went to play it, and now get an audible thump in the speakers when the needle hits where I assume the warp was before (this didn't happen, of course, when the warp was large).
Closer inspection revealed that there is still the most miniscule of warp and the cartridge visibly gets rattled at this spot, syncing up with the noise...captured the video below...the noise doesn't really come through, but it's definitely there loud enough to hear from across the room
and a video of the effect on the speaker
I know i've seen this issue before on other records where it will last for a track or so and go away, but I've never actually looked at what's happening with the cartridge and wonder if this is maybe an issue with my setup or if there's any tactics to alleviate it.
Or maybe just a normal annoying thing that all turntables experience with records with tiny warps...however, whatever it is, it's making me gun-shy on trying to flatten any more records because I'm afraid that this will happen with all of them.
Any wisdom is greatly appreciated.
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Experimenting with a Vinyl Flat has brought to light what I think is maybe a turntable setup issue, or maybe just a fact of life when dealing with how a cartridge handles a very small and sudden warp on a record.
I flattened what was a very warped record to what appears at first glance to be pretty much flat...went to play it, and now get an audible thump in the speakers when the needle hits where I assume the warp was before (this didn't happen, of course, when the warp was large).
Closer inspection revealed that there is still the most miniscule of warp and the cartridge visibly gets rattled at this spot, syncing up with the noise...captured the video below...the noise doesn't really come through, but it's definitely there loud enough to hear from across the room
and a video of the effect on the speaker
I know i've seen this issue before on other records where it will last for a track or so and go away, but I've never actually looked at what's happening with the cartridge and wonder if this is maybe an issue with my setup or if there's any tactics to alleviate it.
Or maybe just a normal annoying thing that all turntables experience with records with tiny warps...however, whatever it is, it's making me gun-shy on trying to flatten any more records because I'm afraid that this will happen with all of them.
Any wisdom is greatly appreciated.
What is your turntable? What is your amplifier and phono stage?
Have you noticed this issue with other albums you have not flattened?
I have some ideas, but would like more info first to make sure I’m on the right track.
siremobunny
Well-Known Member
Turntable is Pioneer PLX-1000
Phono stage is Vincent Pho-8
Amp is Onkyo TX-8020
I have experienced this issue with records I haven't flattened, but not a large number of them. Just confirmed it with a few other records that I recalled having similar issues with. Common thread seems to be very very small warps in the record that jar the cartridge like in the video. The system seems to take on larger warps with no problem.
Some woofer pumping from subsonic energy (what you are seeing) is normal. You have more of it than I’d like to see. It also wastes amplifier power, as the woofers are being excited with no audible benefit.
The cartridge is a good match to the arm, so that’s not the issue.
The PLX-1000 is known for some examples having slightly loose arm bearings. I wonder if that is causing the issue. I’d like you to check. To do this, lift the arm gently off of the arm rest. See if you can gently move the arm forwards and backwards. Is the arm solid or do you feel any play? Do you hear a soft click? If you do, or if you especially hear a click, the horizontal bearings are loose.
Let me know if your PLX passes the test. The movement (if any) will be slight but obvious. A click is an automatic fail.
If it fails, it’s an easy fix. Mine were loose on my PLX straight from the box.
siremobunny
Well-Known Member
I'll check that out later tonight and report back. Thanks!
siremobunny
Well-Known Member
Sorry, I didn't end up getting to this today. Checked the tonearm, and the bearings seem pretty sturdy...not hearing any clicking or feeling any wobble. I believe you actually stepped me though tightening them when I first got the unit, but I wanted to make sure they hadn't loosened again.
The Denmarkian Wonder
Well-Known Member
Experimenting with a Vinyl Flat has brought to light what I think is maybe a turntable setup issue, or maybe just a fact of life when dealing with how a cartridge handles a very small and sudden warp on a record.
I flattened what was a very warped record to what appears at first glance to be pretty much flat...went to play it, and now get an audible thump in the speakers when the needle hits where I assume the warp was before (this didn't happen, of course, when the warp was large).
Closer inspection revealed that there is still the most miniscule of warp and the cartridge visibly gets rattled at this spot, syncing up with the noise...captured the video below...the noise doesn't really come through, but it's definitely there loud enough to hear from across the room
and a video of the effect on the speaker
I know i've seen this issue before on other records where it will last for a track or so and go away, but I've never actually looked at what's happening with the cartridge and wonder if this is maybe an issue with my setup or if there's any tactics to alleviate it.
Or maybe just a normal annoying thing that all turntables experience with records with tiny warps...however, whatever it is, it's making me gun-shy on trying to flatten any more records because I'm afraid that this will happen with all of them.
Any wisdom is greatly appreciated.
I also have some records that does that as well. Some have been in the Vinyl Flat and others haven't. At first i thought it was the VF but i also have some that's been flattened that don't have that "fluttering" part, then i thought it was the felt mat that covers the entire record so now i've started using the "donut" mat instead
In that case, I’d look seriously at the KAB TD-1200 tonearm damper. It’ll solve both issues. I ran one on my PLX-1000 and loved it.
KAB Electro Acoustics http://www.kabusa.com
www.kabusa.com
JohnnyCashFan
Well-Known Member
Certainly could be the motor. Those old units dry up and can seize as well if you are familiar with greasing/lubing it or have a local tech that is. Bill at Fix My Dual is a great resource for Dual parts, service, and questions. Welcome to FixMyDual
@siremobunny here’s a great explanation of what you are experiencing and why the TD-1200 works. Lifted from KAB:
All tonearms vibrate at the arm cartrige resonant frequency. This causes the speakers to motion in and out modulating the soundstage. Fluid damping stabilizes this behaviour and brings greater stability to the soundstage. Your amplifiers are also over reacting to this very low frequency signal and that can cause even more problems.
It would be better if we could call this behavior "Dynamic Ridgidity" for that better describes what is happening. Functionally when a tonearm reacts to the resonant frequency it produces a peak of output energy. This is seen as woofer pumping which is essentially the stylus over reacting to a small warp in the records surface. Fluid damping stops the stylus from over reacting. That is what is "damped". It all occurs at frequencies below 10 hz and has no impact whatsoever on audible dynamics. In otherwords, do not confuse damping of resonance with damping of dynamics they are not related in any way.
Above 10 Hz the arm is seen to be even more ridgid at any single point in time and as a result the stylus traces the groove with even more precision. The biggest sonic effect is to make the sound stage more "Still". This can be subtle to some, overwhelming to others. It all depends on your listening priorities.
zdkaiser
Well-Known Member
Not sure where to ask this question, but trying to properly set the dip switches on my phono preamp. I am using an Audio Technica 540ml cartridge.
Cart Specs: 47k ohm
Recommended Load Capacitence : 100- 200 pF
My phono stage is set at 47k ohms with a gain is set a 40 db for the MM cartridge.
With default settings, the phonostage has a capacitance of 47 pF.
Now I've read that RCA cables from the turntable can have a capacintence of 100 pF (or less). I have no way to measure this, but with the cable and the default preamp settings that'd put me at 147pF, perfect for the 540ml. I can also bump up the default 47 pF to 147pF on the preamp, but without knowing the cable capacitance that may put me over the recommedned 200 pF for the cartridge. Does it matter? Any advice?
Cart Specs: 47k ohm
Recommended Load Capacitence : 100- 200 pF
My phono stage is set at 47k ohms with a gain is set a 40 db for the MM cartridge.
With default settings, the phonostage has a capacitance of 47 pF.
Now I've read that RCA cables from the turntable can have a capacintence of 100 pF (or less). I have no way to measure this, but with the cable and the default preamp settings that'd put me at 147pF, perfect for the 540ml. I can also bump up the default 47 pF to 147pF on the preamp, but without knowing the cable capacitance that may put me over the recommedned 200 pF for the cartridge. Does it matter? Any advice?
Leave your phono stage as is. You are fine.
However, if you find the presentation too dull, you can increase your capacitance on the phono stage.
siremobunny
Well-Known Member
Do you know with these if the fluid in the damper needs to be changed out periodically? I watched a video on the installation and it doesn't look too bad, but I'm curious about the maintainance.
There isn’t any maintenance. And it’s not “fluid” per se. It’s more like goop. It’s easy to install.
siremobunny
Well-Known Member
oh what the hell, I'm gonna go for it. It looks like the one that fits the PLX-1000 is actually $20 less than the one you linked...
KAB Electro Acoustics http://www.kabusa.com
www.kabusa.com
thanks for the help
edit: I think that was a linking problem with their site, because when I tried to link the PLX one, it goes to the non-PLX one
The one you linked does not fit the Pioneer. Look at the red text in the center of the page.oh what the hell, I'm gonna go for it. It looks like the one that fits the PLX-1000 is actually $20 less than the one you linked...
KAB Electro Acoustics http://www.kabusa.com
www.kabusa.com
thanks for the help
siremobunny
Well-Known Member
yeah, it's something funky with their page...if you try to link to the right one, the link takes you.to the wrong one. Rest assured, I know which one I actually need (TD-1200)...lol
Okay so, question. On the occasions that I happen to get fuzz or crackle on an album, it's almost always coming through the left channel. In most cases, a second copy of the same vinyl either eliminates or changes where the fuzz may show up, but it still shows up left channel if the noise remains on a second copy. Anti skate doesn't affect it either way. So IF it's a very slight azimuth adjustment to perhaps move the stylus off the left channel groove wall, am I turning the tone arm towards the CENTRE of the album, or away from it? I always get this mixed up...