Wow & Flutter Meters

  • Thread starter Thread starter miroslav
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miroslav

miroslav

Cosmic Cowboy
Wondering if anyone here has used any particular models to adjust their capstans?

I just picked up this Fidelipac unit on eBay for like $20. :)

Fidelipac01.jpg


Fidelipac02.jpg



Main reason I got is because I also have a spare capstan motor for my MX-80, and it's a newer one than what is on my machine currently, and it might be just a pinch even quieter than mine, though my stock capstan is running fine for now.

Anyway...I tried the new capstan motor out on the deck, but noticed that there was a small amount of flutter on playback...which is normal, since the motor has electronic dampening adjustment trims that need to be fine-tuned via the Capstan Contorl PCB in the back of the deck...but you need a Wow & Flutter meter to do that.
I also have a spare Capstan Control PCB...so I figured I would leave the stock motor and control PCB as one set...and then drop the "new" motor in and spare control PCB and set them up as another set. That way, if ever the need, I can simply switch out both motor and control PCB...which is maybe a 20 minute job.

I have yet to try this Fidelipac meter...but I did plug it in and it appears to be working OK. It is certainly a much more simpler/streamlined Wow & Flutter meter than many of the other units I've seen for sale on eBay, and I was curious if anyone here was familiar with this or other units. The more involved units usually have multiple measuring/metering options...most of which I don't need. This Fidelipac has exactly the options my MX-80 manual calls for...so hopefully it will be a breeze using it.
 
That one you have is very similar to one I used a lifetime ago in a studio where I worked. I don't even own one now because if I can't hear wow and flutter it's not there, and the only thing I can do for wow and flutter on the Tascam 8-track I have is adjust tape tension and pinch roller pressure to spec... or replace the pinch roller and/or capstan drive belt. If none of that helps I throw the machine away and buy another one. :)
 
Beck said:
That one you have is very similar to one I used a lifetime ago in a studio where I worked. I don't even own one now because if I can't hear wow and flutter it's not there, and the only thing I can do for wow and flutter on the Tascam 8-track I have is adjust tape tension and pinch roller pressure to spec... or replace the pinch roller and/or capstan drive belt. If none of that helps I throw the machine away and buy another one. :)
Click to expand...

:D

Fortunately....the MX-80 has a Wow & Flutter calibration procedure that adjusts the capstan motor...so I won't need to throw it out! ;)

Once I realized that the new motor would need to be fine-tune with a W&F meter...I then also decided to get all the tools I need for a complete mechanical calibration. So now I have the W&F meter, a spring scale, my scope and Loftech Test Set unit. I only need to get my hands on a Tenelometer...and I'll be able to do the full factory mechanical and electronic setups.
 
So I tired out the W&F meter on my deck last night. It's pretty straightforward with this unit as there are only a couple of choices.

My MX-80 manual calls for the 0.1% resolution, which is the top end of the scale, and this W&F also has a .5% scale choice (swee pics).
Trying it out on the stock capstan/control PCB setup...at 30ips I was seeing a 0.003% deviation and at 15ips a 0.004% deviation....so I think I'm OK with that! :D
The manual doesn't tell you what "numbers" to shoot for, it only says to go for the smallest (best) reading. On this capstan motor/control PCB setup I didn't want to even touch the trim pots to see if I could improve on the reading, but when I get a chance I will drop the spare capstan motor and control PCB into the deck, and use that as my calibration testing setup.
The manual says to first completely turn all the trim pots counterclockwise to "0"...then 15 turns clockwise to put the trim in it's center position, as these are 30-turn trims. So I didn't want to disrupt the existing capstan motor/control PCB by doing that, though I'm sure at worst case I would have been able to put everything back to where it was...it's just safer experimenting with the spare motor/PCB. :)

I can't figure out how the DRIFT is supposed to be tested...? The scale is a +/- with "0" at center, but not sure what kind of signal you need to feed it from the deck...???...thought there is no call for drift measurements in the MX-80 manual and I don't have a manual for this W&F meter. I did look in a manual for a different brand/model meter...but they too don't really describe clearly how you actually test the drift. I don't think it's that important/relevant for my MX-80, as I'm sure they would have included in the calibration process if it was...and I'm betting that the other steps in the manual take care of all the rest of the mechanical adjustments, so the W&F is the only thing I need this meter for...to set the capstan motor dampening.

Anyway...I'm just waiting for the arrival of a Tentelometer that I just scored on eBay...and then I will go back and do the complete mechanical and electronic calibration of the deck. It's not the T2-H20-2, which is Tentel's suggested model for 2" tape. The one I got is the T2-H15-UM, which is one of their "special" models, and it does come with the calibration weight, so I can easily calibrate it for my 2" tape...plus, the probes are also long enough for 2"tape. I think the only reason it may not work for some 2" decks is if they require higher scales. The T2-H20-2 goes up to 600 grams, while the T2-H15-UM only goes up to 425 grams, but my MX-80 only calls for 320 grams, so I'll be at the upper end of the scale, but still within workable limits. I scored the T2-H15-UM for about $75 shipped! Supposedly it's like-new, minimal use. Hopefully it's not whacked out.
Oh...as a sidenote, I tired calling Tentel to ask if the T2-H15-UM was OK to use...and their phones are no longer connected, as as it was discussed a short while ago, it looks like Tentel has closed it's business (though the website is still up). :(

Up to this point, I've only done the basic checks of the mechanicals on the MX-80, as everything looked to be in pretty good spec, and the previous owner said he already did them...but now that I will have all the tools...I can actually do each step in the manual, so I figure it's good to at least make this one initial check of the mechanicals before I start using the deck regularly...though I've already done the complete electronics setup, and am recording a song with it already...just as my first test song with the MX-80. So far, it sounds nice and the deck is running smooth. I'm quite surprised at how quiet it is, and I honestly don't see any need for NR even at 15ips! :cool:
 
Yaewo said:
You don't really modify wow and flutter. If it is way out of wack you substitute devices, engines, flywheels, capstans and touch paint rollers. The flywheel keeping dish forced attach can impact this studying. You need a 3 khz check record.
Click to expand...

Mmmmm...my Otari MX80 deck has variable capstan damping adjustments that are done with a Wow & Flutter meter using 3150 Hz. :)
 
Just out of curiosity, do you require a test tape with 3150hz or can you feed the machine that frequency and do the adjustment while listening off the repro head?
 
No test tape....you feed the tone generated from the W&F meter and rec/play it, while feeding the output back from the deck to get a reading of how far off it is.

The W&F check I did on my MX80 with its current hardware showed that it was WELL below the minimum acceptable reading according to the Otari manual.
I have a rebuilt spare capstan motor, and when I tried it on my machine, the W&F was audible. I also have spare cards for the capstan circuit, so at some point I will install both and use the W&F meter to adjust the capstan for optimal W&F...that way I have a ready-to-go spare setup if the current motor ever goes on me.
I may just swap anyway, as the rebuilt motor is slightly quieter, but it's not much of an issue even when I'm recording with the machine right there in the room. I would have to put a mike right next to it for the motor/machine noise to be picked up. It's actually a very quiet machine....
 
thanks for the info (and glad to hear your machine spec-ed out nicely). I was curious because there's a 3m/mincom wow/flutter meter for sale in a radio shop in my neighbourhood.
I had noticed that MRL sell 'flutter tapes' but it's good to know that they're not required for at least some wow/flutter meters.
 
I know some decks call for the use of a W&F tape (my Fostex G16 does), but I was talking about my Otari MX80, which doesn't...it calls for a W&F meter.
I have a W&F tape for the G16...but have never used it. I got it used and it's old tape with some SSS, so I just didn't bother with it.

Why some call for tape and others a meter may come down to format, machine design and how the testing/calibration is done on a given deck....?
 
miroslav said:
I know some decks call for the use of a W&F tape (my Fostex G16 does), but I was talking about my Otari MX80, which doesn't...it calls for a W&F meter.
I have a W&F tape for the G16...but have never used it. I got it used and it's old tape with some SSS, so I just didn't bother with it.

Why some call for tape and others a meter may come down to format, machine design and how the testing/calibration is done on a given deck....?
Click to expand...

you can also do this nowadays with a computer to replace the meter.
 
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