DIY Alignment and Calibration

OK, I asked a question about voltmeters, I got this response:

A good AC voltmeter that can read down to 20 mv and has a bandwidth of 150Khz.

Please pardon me for being confused, but I don't know how to look for such a thing. "How do I search for a voltmeter with these specifications?" is a question that I can't answer.

Can someone point me in the right direction by posting a product link? I'll really appreciate it.
 
OK, I asked a question about voltmeters, I got this response:



Please pardon me for being confused, but I don't know how to look for such a thing. "How do I search for a voltmeter with these specifications?" is a question that I can't answer.

Can someone point me in the right direction by posting a product link? I'll really appreciate it.

I have an HP 403B. It gets the job done.

Otto
 
IMHO 150kHz bandwidth is overkill for doing an alignment. Jeff, what I think you want to look for is a voltmeter that is rated from 20Hz to 20kHz with limited error within that range. Any of the Fluke 83/85/87 meters will do nicely for that and are pretty plentiful on the used market. Any of the analog meters mentioned above will do too, but if you get a meter that has a rating in the "audio" band range it'll work for you too. You can download manuals for the Fluke meters on their website to confirm bandwidth.

If you are having bias issues then having higher bandwidth is important because bias tone is typically 100kHz, 150kHz or even 250kHz. But if you are having trouble there then its time to have a scope and such. That's my limited personal experience.

BTW everybody evm1024 turned me on to TrueRTA, a freeware analyzer/scope/meter for PC...the coolest freeware program like this I have ever seen. It'll help folks that are on a budget pinch for sure or don't need such utilities frequently and can't justify springing for hardware counterparts.

One thing to add about using sync or repro heads. It depends on the design of the machine. As a rule the repro head is better, but Tascam broke that rule with a few of their decks. Machines like the 38 and 48, use the same part number for both sync and playback heads. So, you don’t get the same advantage by using the repro for playback as you would with a machine that has a specially designed Repro head.

Yep...and others followed suit. 58 is the same way. Only need met and advantage gained on such sytems is having the repro head there for on-the-fly bias adjustment and other diagnostics. It becomes little more than a convenience feature...nice one though.
 
try jameco

Jameco sells a number of meters. This link is to the spec sheet of one of the meters that they resell (they have a nice selector as well)

You can see the spec under the "AC volts accuracy" heading 5% for the 10 to 20 KHz range....

http://www.jameco.com/Jameco/Products/ProdDS/1581214.pdf

I'm not recommending this meter (it does look nice) it was just the first one that I get the specs from.

Regards, Ethan

Here is the interactive selector:
http://www.jameco.com/webapp/wcs/st...& Supplies / Test & Measurement / Multimeters
 
OK, I asked a question about voltmeters, I got this response:



Please pardon me for being confused, but I don't know how to look for such a thing. "How do I search for a voltmeter with these specifications?" is a question that I can't answer.

Can someone point me in the right direction by posting a product link? I'll really appreciate it.

If you have a 2 head deck like TSR-8, MSR16, or MSR24 the easiest way to set the bias is by adjusting the trim pot for the bias circuit voltage, In the case of the TSR-8 it is 35 mv at 150Khz. A 3 head deck is easier to adjust because you monitor the rise and fall of a 10Khz tone on the decks meters. I have a Fluke 8060A, an HP 3400A, HP 400D tube job, HP400E, and HP400EL. I bought them all on an e-bay binge one weekend. The best one is the Fluke 8060A it was one of Flukes first digital meters. I actually have 2 and they both read the same voltage together within .0001v. The Fluke 8060A can do it all. The other HP's are all analog ac powered. Sometimes it is better to watch a needle instead of digits. Check e-bay and goodluck!
VP:eek:
 
BTW everybody evm1024 turned me on to TrueRTA, a freeware analyzer/scope/meter for PC...the coolest freeware program like this I have ever seen.

What's the difference between their "levels"?
I see that only the TrueRTA level 1 is freeware...the other levels are not...but they are not too expensive.
I'm just wondering if Level 1 gives you all that you need for alignments and basic analysis.

This one that I posted earlier is total freeware, and I liked how it worked overall.

Visual Analyzer

http://www.sillanumsoft.org/
 
OK, it's one of those rare nights where I have access to a computer for the entire evening. My computer broke down almost three months ago and I just really haven't had any desire to replace it... ironic, considering that I'm a web programmer...

Anyway, I'm moving along in a number of projects. I'm about ready to start ordering some things off the Web. I wanted to run this by everyone here before I make the purchase:

250 nWb/m MRL tape for a TASCAM 34b. Is this right??

I think this is what the manual says but I want to be 100% sure.
 
OK, it's one of those rare nights where I have access to a computer for the entire evening. My computer broke down almost three months ago and I just really haven't had any desire to replace it... ironic, considering that I'm a web programmer...

Anyway, I'm moving along in a number of projects. I'm about ready to start ordering some things off the Web. I wanted to run this by everyone here before I make the purchase:

250 nWb/m MRL tape for a TASCAM 34b. Is this right??

I think this is what the manual says but I want to be 100% sure.

That is the standard in the US more or less. If I were buying a new MRL I would get a 250 nWb/m .

Plus you can "adjust" the readings that you get to calibrate at pretty much any flux level. I'm answering in your other post too.

--Ethan
 
This def needs to be a sticky, a reference and added to continually...

.....great work guys!:)
 
Oscilloscope

And, for the oscilloscope. I want to have a hardware oscilloscope. And, I know nothing about oscilloscopes.

So, I'm going by what I *do* know, which is basically whatever TASCAM tells me to do in its manuals. In the back of my TASCAM 34b manual, in section 2 under "Essential Test Equipment Required", I see this:

Oscilloscope: General Purpose

So I'm assuming this means that any oscilloscope will do. Ehh? Right?

OK, so how about this one? It's the cheapest one that I can find, new, since I don't know how to buy a used oscilloscope: Velleman PPS10. It retails around $150 on the Web. Keep in mind that I'm not going to get into oscilloscope-intensive hobbies or professions any time soon, so "Just Enough Oscilloscope" is right for me.

What do you guys think? Last night I tackled the multimeter issue (I ended up buying a used Fluke 87 for about $90 on eBay), tonight I bought a MRL tape (7.5 ips and 15ips NAB 355 nWb/m 1/4" tape), and tomorrow I'd like to pick up the scope.

I'm glad this thread is sticky!
 
And, for the oscilloscope. I want to have a hardware oscilloscope. And, I know nothing about oscilloscopes.

So, I'm going by what I *do* know, which is basically whatever TASCAM tells me to do in its manuals. In the back of my TASCAM 34b manual, in section 2 under "Essential Test Equipment Required", I see this:

Oscilloscope: General Purpose

So I'm assuming this means that any oscilloscope will do. Ehh? Right?

OK, so how about this one? It's the cheapest one that I can find, new, since I don't know how to buy a used oscilloscope: Velleman PPS10. It retails around $150 on the Web. Keep in mind that I'm not going to get into oscilloscope-intensive hobbies or professions any time soon, so "Just Enough Oscilloscope" is right for me.

What do you guys think? Last night I tackled the multimeter issue (I ended up buying a used Fluke 87 for about $90 on eBay), tonight I bought a MRL tape (7.5 ips and 15ips NAB 355 nWb/m 1/4" tape), and tomorrow I'd like to pick up the scope.

I'm glad this thread is sticky!

Cute! However, it doesn't look to be a dual input, dual trace scope. The main reason you buy a scope to work on tape machines is to measure the phase angle of the signal from two different channels when aligning playback and record heads. You need two inputs, two probes and a dual trace scope to do that. That would be the main reason I wouldn't buy it for this purpose. Still... very cute.

Cheers,

Otto
 
Here's my general purpose scope...$70 on craigslist:

IMG_1386_1_1.JPG


BUT, keep in mind that free PC software like TrueRTA will work for basic azimuth adjustment.
 
Azimuth, the alignment of the heads being perfectly parallel with the tape is done on a dual trace O-scope. If the head is not straight the channels will be out of phase with each other especially at high frequencies.
VP
 
Just a heads-up: A friend of mine and I are embarking upon calibrating our tape machines, ourselves. He has an adequate oscilloscope and I've got... a lot more spare time than he does :)

I picked up a Fluke 87 digital multimeter, and he also acquired an audio oscillator. The oscillator in my M-520 would have sufficed, but it's nice to have a dedicated unit. Plus, it doubles as a fun instrument if you're into sine waves.

I imagine that we'll be calibrating our machines sometime in the next month, and I will post more here when this happens.
 
Ooooh

I can see it now. Instead of jamfest we can have cal(ibration)fest.

Pick a city and we all descent on someones house and spend a long weekend calibrating decks. Bring your own or use someone else's.

Actually, I think that ATR Services does hold a seminar more or less like that.

If anybody is even in the PDX area I'd be happy to toss their deck on the bench and walk through their first calibration.

Do keep us informed.

Regards, ethan
 
Quick update:

I'm going to calibrate my 1/2" 8-track this week. I'll post information here and on my blog!
 
Thanks sweetbeats! I would like to get my TEAC A-3340S Calibrated and aligned. I don't know much about it and I have no testing gear...
 
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