Record Doctor Low-Profile Record Clamp – Review
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To Clamp Or Not To Clamp – That Is The Question
I have often wondered whether a record weight or turntable clamp would improve my sound, so after about 40 years I took the leap and purchased the Record Doctor low profile record camp.
First you might ask why do I need anything to hold down my vinyl? Well let’s see what the turntable matts functions are:
- Stop the vinyl from slipping as the stylus traces those grooves that have peaks and valleys that can be as short as the wavelength of light
- Absorb the vibrational energy that the stylus reflects back into the vinyl as it traces those peaks and valleys
- Prevent any damage to the surface of the vinyl
- Help to dampen platter resonances
- Help isolate the vinyl from mechanical noise; bearing, belt and motor.
In order to effectively achieve points 1&2 above, the vinyl must be very rigidly attached to the turntable to prevent any form of slippage and be in ‘intimate’ contact with the turntable matt over ideally, its entire surface, so that any vibrational energy from the stylus, as it traces the grooves, is absorbed and doesn’t return to the stylus.
There are three ways to help keep your vinyl rigidly attached to your matt and turntable platter:
- Use a heavy weight
- Clamp it down using the turntable spindle
- Use a vacuum like the TechDAS turntables
A heavy weight placed over the record label might at first seem a simple and effective way to achieve this but some turntables, mine included, cannot support much additional weight without it adversely effecting its suspension system. Clamping uses the frictional force of the clamp against the turntable spindle to apply pressure to the vinyl label area rigidly holding the album in place. These clamps are generally quite low mass so have minimal impact on the turntables suspension system and do not damage the albums label.
NOTE: I do have to ask myself if firmly attaching the vinyl to the center spindle is actually wise. The spindle is in intimate contact with the bearing and platter drive systems so any vibrations created by them might be more easily transferred to the vinyl. On the other hand a loose fitting weight placed over the spindle that simply presses the vinyl more firmly against the turntable matt would not have such an issue. A quandary!
Despite the above note, I selected the Record Doctor low profile turntable clamp by Pangea Audio based upon its simple design, low mass and low cost, hoping that any additional transfer of mechanical vibration to the vinyl would not be significant as it was now in much more intimate contact with the platter matt that would hopefully absorb any additional energies. See Listening Results below.
I have read a number of comments regarding the potential benefits of using a high mass weight to the turntables rotational performance. Generally speaking these much heavier weights will:
- Add to the wear of the spindles thrust bearing and increase frictional losses
- Will not significantly improve the inertia of the turntable as much of its mass is centered close to the spindle
- Will put additional ‘start-up’ strain on a belt driven platter – not so much for direct drive
- You may need to adjust your suspension system to accommodate them. Some platter systems are rigidly mounted so this would not apply to them.
Ignoring my above note, I originally did not see any benefits of the heavy turntable weight over the clamp system, other than it is slightly quicker and less fiddly to put in place.
There are a large number of these turntable clamps available costing up to several hundred dollars. However, they all do exactly the same thing. The more expensive versions generally having refined finishes, additional features like level bubbles and may also be quite heavy being made out of solid brass, steel or aluminum. In all cases its job is the same, stop the vinyl from slipping at a microscopic level and hold it in intimate contact over its entire surface with the matt so as to transfer all its vibrational energy to the matt. As a side issue it can sometimes also help ‘flatten out’ slightly warped records.
A little care must be taken when selecting these clamps or weights to ensure that they are not too high (or too heavy), will allow you to close your turntable lid if you so desire and that your spindle is both high enough and the correct diameter.
I selected the low profile version (1.1″ high) as it was lighter, only 5.4 ounces, than the standard height version (1.75″ high & 6.9 ounces).
You must make sure that your turnable spindle protrudes enough to allow the clamp to grip it when the matt and vinyl are on the platter, especially for the thicker 180 and 200 gram pressings. It’s not just the spindles absolute height above the vinyl that matters. Some spindles, like mine, have their end rounded off and the clamp cannot attach itself to that smaller part of the spindle. You need about 1/8″ above the vinyl surface that is the spindles full diameter to get a good clamp. Spindle diameters are not all the same size either. The ‘standard’ diameter is 9/32″, which is 0.2813″, or 7.145mm, mine is approximately 7.2mm. It looks like this clamp model can support spindle diameters between approximately 7.1 and 7.3 mm.
(I had problems with 180 grams or thicker vinyl and had to ‘pack’ the clamping ferrel down so that it just protruded slightly being virtually flush with the clamps outer bottom phenolic surface that contacts the record label.)
Turntable Matts – A Quick Comment
Other than possibly for DJ work I have never understand why turntable matts are often referred to as slip mats. Slipping is the very last thing in the audiophile world that you want a matt to do. Also why some manufacturers claim that their matt is anti-static is unclear. Most matts are made of an insulating material like, cork, rubber, plastic, silicon, paper, felt etc. so are non-conductive and will if anything worsen any static issues that you might have. You would need to impregnate the matt material(s) with a conductive material like carbon in order to have any chance of reducing static. Something I haven’t seen offered.
It should be noted that different mats made from, rubber, vinyl, cork, silicon, felt, paper and various exotic compounds will impart their ‘own sound’ to the vinyl due to their varying absorption/support characteristics. In my case I found that the GEM Dandy Rubber Cork Compound Record matt from Osage Audio was my preferred choice after testing several including; the original Thorens rubber matt, cork, vinyl, plastic, felt and a few combinations.
NOTE: Some less expensive matts are known to shed dust/particles resulting in excessive vinyl cleaning and potential vinyl and stylus damage.
Remember that matt thicknesses can vary a lot and often exceeds 1/8″. So if you change it you may run out of spindle height. Also it’s worth noting that if the matt thickness changes then so will your cartridge/arm height. This will very slightly change your vertical tracking angle (VTA) and stylus rake angle (SRA). For some, these very small angular changes may also contribute to changes in the sound quality created by a different matt.
Finally, labels are often raised above the finished vinyl surface so these matts should include a recess for the label area. This should help ensure that the whole record stays in contact with the matt when clamped down, or not, see below!
The Listening Results
So did clamping my vinyl albums make any audible differences? Yes.
Attaching this clamp correctly is fiddly for my setup. The biggest challenges were attaching the clamp to my short turntable spindle and not over tightening it. Doing so clearly caused the record to be forced into the matts central recess causing the record to “dish” and lift its edge above the turntable matt, virtually removing the matts damping effect, a very bad thing! On second thoughts, maybe a matt with no central recess might be a better option or even just a simple weight if your turntable can support it. Something I may try at a later date after raising my turntables suspension.
Measuring the bearing rumble using S2T6 on The Ultimate Analogue Test LP produced no increase in level when the clamp was attached. A re-assuring result that the clamp was not transmitting any additional bearing or motor noise due to its rigid connection between the spindle and vinyl.
Three albums were used to test the sonic differences of adding this clamp:
- The Sheffield Track Record – Sheffield LAB 20 – 120gram
- The King James Version – Sheffield LAB 3 – 140 gram
- Dire Straits Brothers In Arms – Mobile Fidelity Original Master Recording, Limited Edition, 45RPM, 180gram
The sonic differences with and without the clamp are NOT earth shattering, but they are noticeable and can be summarized as follows:
- Very bottom end was tighter, especially noticeable on bass lines and kick drums
- Cleaner and “harder” impact from kick drums and toms
- Improved ambient detail
- Mid-range & vocals slightly smoother
- Trumpets, trombones and cowbell had less of an “edge”
- No significant effect on high frequency detail of cymbals etc.
I cannot stress enough that all but one of these changes are quite subtle. However, the improvement in bottom end tightness, reduction in coloration and kick drum impact was definitely a step upwards.
So will I continue to use the clamp? Unfortunately YES, despite it being a challenge to easily attach it to my turntable spindle and set just the correct amount of pressure. The problem is that my type A personality once hearing an improvement, will not let it go!
General Specifications (low profile):
Buy the Record Doctor record clamp here on Amazon.
For more information on turntables, arms and cartridges see the following posts:
Paul – I know you to be a careful, conservative and objective reviewer. That this $30 gizmo offers perceived improvement in a number of audible parameters is nothing short of astounding. I know improvements were “subtle” but still “improvement in bottom end tightness, reduction in coloration and kick drum impact” is remarkable. And especially so with systems costing many, many thousands of dollars, like yours. Too bad it took you 40 years to take this $30 leap!
Great review as always.
Hi Jerry,
They say all things come to he who waits! OK so I waited 40+years and I am still very surprised that I could hear any improvement, subtle or not, let alone one that I now need to keep in my listening routine. If my matt had no recess and I had a longer turntable spindle the clamp would be so much easier to use. Looks like I will be trying out a few new matts now.
In the near future I am going to make a simple weight that my turntable can support and try that to. Who knows, it might work just as well. I see another post on the horizon. It never ends!
Thanks for popping by and the comment.
Paul
Interesting
Hi Terry,
For me both interesting and surprising. Many of my albums are ruler flat like those I selected for the listening comparisons, so they were in good contact with my matt before I used the clamp. I had to be very careful not to over-tighten the clamp or you could watch the album edge rise off the matt perimeter….a little frightening. However with just sufficient clamp pressure it rigidly held the vinyl with no visible dishing. I definitely think that a matt with no central label recess may be be better bet……more tests and posts on the horizon.
Thanks for popping by.
Paul