Too high VTF?

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AliG

Too high VTF?
« on: 28 Jun 2008, 03:49 pm »
I have a Dynavector 20XH where the recommended VTF is 1.7g to 2.2g. But I found that the sound is a little too bright to my taste, I tried loading it at 2.4-2.5g and I thought it strikes the right balance.

But is this going to damage the grooves, or the stylus?

SET Man

Re: Too high VTF?
« Reply #1 on: 28 Jun 2008, 09:33 pm »
Hey!

    Many times I hear people including some vinyl experts say that too low VTF is worst than too high VTF. So, I think you will be OK.

   But! There are many factors that could make the sound too bright to you. I usually like to use set the VTF within the limit of what recommended by the cart manufacturer. This definitely will have effect on sound. But if you are setting it much higher than the recommended than the cart could bottomed out with some LP and won't track it probably.

   If you start hearing the sound especially on the high going in and out on some LP that are not perfectly flat... well none are anyway. Than it is likely that your cart could be bottoming out.

   AliG, have you try to resistive loading the cart? If I were you I would set the cart at 2-2.2g and try to calculate the loading for it? This will have an effect on the high respond curve.

   I see look at your cart spec and it seem like a good loading of anywhere from 1K to 2K. With your cart I will start around 1.5K first. :D

   When I was setting up my Benz Micro "ACE HO" cart I had a great help from people here especially from tvad4. Thanks guys :D

Take care,
Buddy :thumb:

AliG

Re: Too high VTF?
« Reply #2 on: 28 Jun 2008, 09:51 pm »
buddy.. my phono ony have 47kOhm loading. Do you know where I can buy 'reasonably priced' RCA loading plugs?? :wink:

Wayner

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Re: Too high VTF?
« Reply #3 on: 28 Jun 2008, 11:54 pm »
You've gone way beyond the recommended VTF. I would look at other set-up errors before adding more weight.

Wayner

SET Man

Re: Too high VTF?
« Reply #4 on: 29 Jun 2008, 01:01 am »
buddy.. my phono ony have 47kOhm loading. Do you know where I can buy 'reasonably priced' RCA loading plugs?? :wink:

Hey!

    I see... I think this is part of your cart/phono pre setup equation that might make the sound bright to you.

    With so many more affordable MC carts available today it is sad that most of the phono-pre that they will be use with don't off resistive loading options.

    Sorry I don't know who make those RCA loading plug. But than again if you get a pair and if they are made with cheap and bad RCA plug than it is likely will have some impact on sound.

    The best way still is to do this in the phono-pre. Luckily I'm a DIYer and it was pretty simple with my Audio Note M1 Phono pre of which does not offer resistive selection.... it is MM only and 47K is the default. I just popped the top off and look for those two 47K loading resistors on the phono-stage in my pre.  Take them out and put in a new one. I tried 1K, 1.18K and 1.5K and settled on the 1.18K for my Benz Micro "ACE HO" :D

   I don't want to stretch it but yes when it come to MC cart a correct or at least near the ideal resistive loading is definitely required for it to sound right on top end.

Take care,
Buddy :thumb:

bacobits1

Re: Too high VTF?
« Reply #5 on: 29 Jun 2008, 02:25 am »
I never have gone beyond the recommended VTF here.
Maybe VTA?

You can also make these.

A Quote from John Elison.

"One method is to use a Y-adaptor that allows you to connect loading resistors in parallel with your cartridge at the phono preamp input. You can get high quality, gold plated Y-adapters from Monster Cable. Then you would need to construct a load by soldering an appropriate resistor onto an RCA phono plug. You can buy resistors and gold plated RCA plugs at Radio Shack. You can probably also get gold plated Y-adapter at Radio Shack, too."



Den

AliG

Re: Too high VTF?
« Reply #6 on: 29 Jun 2008, 02:36 am »
Den, thanks for the pictures. Looks like I am now 'forced' to pick up a soldering station..

My turntable maker - VPI - recommend using VTF at 1/10th of a gram higher than specs. So I figure why not go 2/10th of a gram.. :wink:

I never have gone beyond the recommended VTF here.


YoungDave

Re: Too high VTF?
« Reply #7 on: 29 Jun 2008, 04:43 am »
I would definitely not attempt to obtain a dramatic change in sound characteristics by adding VTF.  I would suggest using a reasonable VTF, say, the high end of manufacturer's specs, to obtain freedom from mistracking.  I would then look into other, more likely, means of adjusting sonic characteristics.  It may be necessary to revisit many or all of the adjustments, i.e., VTF, VTA, impedance loading, azimuth - as an adjustment of one may affect others.  Eventually you might get the whole mess zeroed in pretty well.

What I'm saying is, leave the VTF at a reasonable level and look elsewhere to correct excessive brightness.

Your too-bright sound may be the result of incorrect resistive loading.  47k ohms is the most common impedance for phono preamp inputs, but mainly because it was a good impedance match for cartridges common long ago, and nobody's felt the need to change it now.  The utility of a 47k input impedance these days is that it makes the calculation of the correct loading of a modern cartridge a trivial matter.

47k, or even 1k to 2k, is way too much resistance for most moving coil cartridges.  Some carts work better than others into a wide range of loading combinations, but too high a load will generally permit a significant nonlinearity in freqency response, almost always in the form of a significant high freqency boost.  It may even permit ringing.  To tame this boost, the generally accepted "cookbook recipe" is to load 10 to 20 times your cartridge's output impedance.  I don't have the specs for your cartridge in front of me, but it seems the Dynavector MC carts run in 2 general classes: 5-6 ohms output impedance, which would like to work into a roughly 75-150 ohm load, and 30 ohms impedance, which would like a 300 to 600 ohm load.  Because 47k is so much higher than 600, it is negligible in the loading calculation, which does not need to be precise anyway.  You can just put a 600R resistor across the cable, as in a y-connector pictured in an earlier post, and be about where you need to be without any calculations.  To get exactly 600 in a 47k input, you would parallel a 608R resistor, but as a practical matter, I consider anything within 10% plenty close enough.

These are starting values (for the 5 ohm and 30 ohm carts, respectively), but get you into the ballpark.  You might try cutting the "cookbook" load in half, and then doubling it, to hear what difference it makes.   The values are not critical.  It's kind of like VTA - once you get it close, it's really hard to hear much improvement from further tweaking - some can hear it, but many of us just aren't able to hear a big difference.  As Harry Weisfeld says, eventually you should just quit tweaking the non-critical parameters and enjoy the music.

Bottom line - you'll probably get  better results by playing with loads first, and then fine-tuning VTA or VTF if desired

The above is only my opinion; it has worked for me over many years and many systems, but others may disagree.  That's OK, too.


AliG

Re: Too high VTF?
« Reply #8 on: 29 Jun 2008, 06:41 am »
YDY, thanks for the insight. I checked the specs of my cart, the output impedence is 150 ohm. So following your logic, the ideal loading is somewhere between 1.5k Ohm to 3k Ohm.


Wayner

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Re: Too high VTF?
« Reply #9 on: 29 Jun 2008, 12:42 pm »
As YoungDave mentioned, I would be suspicious of VTA. It is a characteristic of cartridges to sound high endish or schrillish with the ass end of the tone arm too high. VTA can be considered to be some what of a tone control by some, I tend to think there is only one true setting. That setting is a perfectly horizontal arm with the stylus on the record surface. Of course, there are several thicknesses of vinyl as you may have noticed, from the wimpy 120 gram to the brutal 200 gram. Picking a 150-180 gram album for this set up would give you a good average. I have made a "feeler" gauge out of a small thin mirror (only cause it's smooth) some plasticlay and a piece of wire. Put a wad of plasticlay on the back side of the mirror, bend a short "L" on the wire and stick the "L" into the platiclay base. The wire sticking out of the wad of plasticlay should be about 4" long. bend it around so it can touch the top of the tone arm near the headshell with the mirror on the surface of the record. Obviously, you want to use a crappy record for this and also the table motor is "off". As you move the feeler gauge down the length of the arm, you will quickly discover that the back end or front end of the arm is too high or low. Adjust as needed. Your sound will become 3 dimensional when you hit the sweet spot.



Wayner  :D

stevenkelby

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Re: Too high VTF?
« Reply #10 on: 29 Jun 2008, 01:56 pm »
Thanks for the tip Wayner. :)

Pity Rega arms are tapered. Any hints what to do there?

AliG

Re: Too high VTF?
« Reply #11 on: 29 Jun 2008, 02:04 pm »
my VPI tonearm is tapered too  :duh:

fsimms

Re: Too high VTF?
« Reply #12 on: 29 Jun 2008, 02:13 pm »
Quote
Pity Rega arms are tapered. Any hints what to do there?

Use a thread that contrasts with the arm and use some tape or clay to hold it on the centerline of the arm by eye.  You sould be able to get it pretty close.   Balance the arm to the proper tracking force.  Then level the thread with the gage.

Bob

bacobits1

Re: Too high VTF?
« Reply #13 on: 29 Jun 2008, 02:14 pm »
What I do here on my Rega is use 2 things for starters on VTA.
A lined index card and a small clock level. I place the clock level on the headshell portion and lower the arm slowly and carefully just so it hits the record. But, not all the way down because the cartridge will bottom out from the extra weight of the level. You can judge pretty close to level and recheck with the lined index card only judging looking at the headshell end because of the Rega taper. The rest is listening judgement.
 
Works for me.

The thread idea sounds good too. I'll have to try it.

Let me add I have VTA on my Rega 300. It is on a Basis 1400 table.


D
« Last Edit: 30 Jun 2008, 01:17 am by bacobits1 »

Wayner

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Re: Too high VTF?
« Reply #14 on: 29 Jun 2008, 07:02 pm »
Yes, I thought about this on my way to breakfest after I posted my thread. Bacobits and fsimms have good ideas too. At least you are aware that the tapered arm has a problem when using my technic. I also have a Rega P3 with the RB-300 tapered arm. What I did was use the feeler gauge on the top side setting it at the back of the arm, and then as I moved forward I noticed a gap, so I knew I was in the ball park. I measured the gap as best I could with a 6" steel ruler, then set the feeler gauge to go underneath the arm, setting it at the same spot at the back of the arm and hoping I ended up with an approximately equal gap up under the head. The is a faint "parting line" on the side of the tone arm (at least on mine) that should be at center. The only problem is that the Rega arm has no VTA! At least I know I'm close, anyway. Your also right if you think this is a clumsy method when you have a tapered arm. I will work on this to come up with an easier method. BY the way...how come no one has invented a level for doing this?

Wayner

Wayner

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Re: Too high VTF?
« Reply #15 on: 29 Jun 2008, 09:00 pm »
Now I have an idea to make the feeler gauge work with tapered arms. With a lead pencil, make a reference mark towards the back of the arm where the feeler gauge can still reach. Make a reference point towards the head stock. Get a caliper (available at ACE hardware for about $15-20 dollars. Measure the diameter of the arm at the fatter back reference point and keep that dimension in mind. Go to where you made your front reference mark. Get some narrow painters tape or masking tape and start going around the arm at that point, measuring often and wrap until you have the same diameter as the back reference point. Now you can use your feeler gauge and check both reference points. Remove tape when done. Watch out for your stylus when doing this!

Wayner

fsimms

Re: Too high VTF?
« Reply #16 on: 29 Jun 2008, 10:44 pm »
After all this talk, I got  inspired.   I set my VTF and wow what a nice difference!  Clearer and with less trebble sibilance.  I can now crank up the volume.  Surface noise is much better too!

Bob

mgalusha

Re: Too high VTF?
« Reply #17 on: 29 Jun 2008, 11:17 pm »
Amazing what the VTA can do. :)

One thing to keep in mind for those using a step up transformer with a MC cartridge. The impedance of the transformer is the square (or square root) of it's turns ratio. Many MC step up transformer are 1:10, so the impedance will be 100 time less than the load of the preamp. If the preamp is 47k the cartridge will see 470 ohms. Just something to keep in mind when picking loading resistors.

mike

bacobits1

Re: Too high VTF?
« Reply #18 on: 30 Jun 2008, 01:29 am »
The Dennison Soundtractor had a level with it like the one I used from the clock setup.
It had a V goove in it across its length to sit on an arm tube.
But, the same problem again it added the weight and bottomed the cartridge out.
It would defeat the purpose placing it further back toward the pivot point.


D

AliG

Re: Too high VTF?
« Reply #19 on: 30 Jun 2008, 03:38 am »
You set your VTF to what? higher or lower?  :scratch:

After all this talk, I got  inspired.   I set my VTF and wow what a nice difference!  Clearer and with less trebble sibilance.  I can now crank up the volume.  Surface noise is much better too!

Bob