Turntable Question

[dougg]

Hello
Been reading this site awhile and really enjoy it. Good People and no Fights.
I have a Harmon Kardon T20 Turntable i just Bought, Great shape and very good sounding.
My question is it has a Strobe grid to fine tune the Speed. It says to use Flouresent light to read Gauge. I have used Two different ones and a couple of LED's and it doesn't work ? My Wife and i have the speed adjusted by our ears and everything is fine. I would like to use the Strobe Guuge just to check.
Any suggestions as to get it to work ?
Thanks
Dougg

 

[Adam]

Hi, Dougg.

Would you please clarify what you mean by "it doesn't work"? Do you mean that no matter how you adjust it, the markers don't appear to be stationary?

Thanks.

 

[dougg]

Correct Adam

The Markers are supposed to look as not moving under Floursent Light at proper Speed. As i stated i have tried Two different Floursent Lights and a couple of LED's. The Turntable was Made in 1984 perhaps newer Floursents are Different?
My Wife and i have it Set by Ear at < 2 O'Clock with 12 O'Clock as center of Adjustment. Adjustment Range is about 8 O'Clock to 4 O'Clock
Thanks
Dougg

 

[TLS Guy]

Hello
Been reading this site awhile and really enjoy it. Good People and no Fights.
I have a Harmon Kardon T20 Turntable i just Bought, Great shape and very good sounding.
My question is it has a Strobe grid to fine tune the Speed. It says to use Flouresent light to read Gauge. I have used Two different ones and a couple of LED's and it doesn't work ? My Wife and i have the speed adjusted by our ears and everything is fine. I would like to use the Strobe Guuge just to check.
Any suggestions as to get it to work ?
Thanks
Dougg

Was this a unit made for another market, with a different AC frequency?

If that strobe, can not be made to seem stationary under incandescent, or fluorescent light, that is best by the way, then either the speed of the turntable is wrong, or that turntable is gray market, and built for another region. The strobe needs to be largely illuminated with artificial light and day light excluded as far as possible.

If it was built for another region, then not only will the strobe not work, but the turntable may very well be running at the wrong speed also.

If you can't get the strobe markings to appear stationary, then something is wrong, no ifs or buts.

The strobe woks, because lights flicker with the AC frequency, so the spacing, of the bars are designed to appear stationary at the correct speed at the designed AC mains frequency. USA has 60 Hz, many other regions have 50 Hz.

 

[Adam]

Based on some reading about fluorescent light flicker, it's entirely possible that your lamps are not the same as those that this strobe were designed to work with.

If you are using lamps with two bulbs, try removing one of the bulbs. If I interpreted the article correctly, the paired lamps are intended to eliminate strobing effects. One bulb by itself might still give you the intended strobe frequency.

BTW, I'm just trying to interpret what I just read - so I'm no expert!

 

[TLS Guy]

Based on some reading about fluorescent light flicker, it's entirely possible that your lamps are not the same as those that this strobe were designed to work with.

If you are using lamps with two bulbs, try removing one of the bulbs. If I interpreted the article correctly, the paired lamps are intended to eliminate strobing effects. One bulb by itself might still give you the intended strobe frequency.

BTW, I'm just trying to interpret what I just read - so I'm no expert!

I would use an incandescent bulb, that is what I use, actually currently it is a halogen, but that is an incandescent bulb. There will be no confusion then from related circuitry. If you can not get the strobe marks to appear stationary, then purchase a strobe disc, like the Merril on this site.

If you can not get the Merril disc, or a disc like it, to appear stationary, then your turntable is running at the WRONG speed.

 

[dougg]

Thanks everybody

No lights i have work, LED, Incadesent or Floresent. Maybe the New type Electronic Ballast is a Problem.
The Harmon Kardon Strobe disc that came with the Table has a Grid for 50 and 60 Hrz. I do think the Turntable is in the Ballpark with My Tuning by Ear. I will purchase the Merril Strobe Disc and Light and go from there.
Again Thanks
Dougg

 

[TLS Guy]

No lights i have work, LED, Incadesent or Floresent. Maybe the New type Electronic Ballast is a Problem.
The Harmon Kardon Strobe disc that came with the Table has a Grid for 50 and 60 Hrz. I do think the Turntable is in the Ballpark with My Tuning by Ear. I will purchase the Merril Strobe Disc and Light and go from there.
Again Thanks
Dougg

If you have both discs you don't need to buy another one.

Put the 60 Hz disc on the turntable. Flood the disc with light from a table lamp or trouble light with an incandescent bulb. If you can get the ring of the speed the turntable is set to, to appear to stay stationary, then your turntable is OK. If you can't get them to stop still, then your turntable is no good, despite what your inherent sense of pitch tells you. Very few are blessed with perfect pitch.

This is a very low tech situation, and you can easily decide the issue.

I have been doing this with turntables for over half a century. This system is fool proof and can not lie. A stroboscope is very easy to use, and it is hard to foul it up.

My strong hunch is that your turntable is seriously defective. When you are satisfied you have carried out this test correctly, then you have to accept the result. This is not debatable.

 

[Adam]

Seriously defective or not, if it sounds fine - isn't that all that matters? If the turntable speed is off a bit, will it damage the records?

 

[TLS Guy]

Seriously defective or not, if it sounds fine - isn't that all that matters? If the turntable speed is off a bit, will it damage the records?

If he has just a little creep of the ring bars one way or another, that is one thing. However if he can't even make out the bars, then the speed is way off, and so is his sense of pitch. If it is fast, by that amount, it will damage the discs. Really it should be played close to the correct speed other wise his sense of pitch will become very aberrant, and that is not a good thing for a life time of listening.

 

[highfigh]

No lights i have work, LED, Incadesent or Floresent. Maybe the New type Electronic Ballast is a Problem.
The Harmon Kardon Strobe disc that came with the Table has a Grid for 50 and 60 Hrz. I do think the Turntable is in the Ballpark with My Tuning by Ear. I will purchase the Merril Strobe Disc and Light and go from there.
Again Thanks
Dougg

Unless you have a test disc with calibrated frequencies on the tracks, I wouldn't bother setting the speed by ear. They made a lot of music (and non-music) fit onto vinyl records by speeding the tape playback while mastering. Some changed pitch in the course of one song instead of between two different ones.

 

[dougg]

One more thing to try

I have given some thought to the Old Belt being Strecthed or worn as to the cause. I do have a belt ordered and hope it will solve the Problem. I have the Service Manuel and was planning some Cleaning and Re-Lube when the Belt arrives.
Thanks for the Help and Sensiable thoughts about my Tuning by Ear.
Dougg

 

[dougg]

Turntable fixed!

The belt was Stretched. New belt got the Strobe Grid working.
Again, Thanks for the Advice.
Dougg

 

[Adam]

Thanks for the update, Dougg! I always like reading how things ended up.

Glad that it's working for you now, and it seemed like a fairly inexpensive solution.

 

[TLS Guy]

The belt was Stretched. New belt got the Strobe Grid working.
Again, Thanks for the Advice.
Dougg

Thanks for the follow up! A turntable is really simple, the moving parts any way, a chassis, belt, motor and platter. Obviously any one of those failing is a serious problem to proper function of the unit, as you found out. I'm glad you have a properly functioning unit now. Our senses can be deceiving can't they?

As an aside you really need no more proof that expensive wire, tweaks, etc., recommended on the basis of listening test are bogus. You have to have some science and measurement.

This thread may prove useful next time there is a bogus tweak post!