MS-16 story

RRuskin said:
I think you are confusing operating level with bias setting. I know of no analog tape that is/was spec'd for a +9 over-bias setting. I also doubt that the erase and record heads would be happy having that much current going through them. I suggest you find out what the set-up requirements are for whatever tape you intend to use before modifying your machines.
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Nope, not confusing MOL with bias settings. Perhaps did not state it well.

A 185 nW/m tape will require a certain bias level. A +3 tape will require about 3 dB more bias level to be properly biased. Ditto +6 and +9 tapes. In other words bias levels track MOL. We are talking absolute bias level here not relative level (ie 4 dB overbias).

Most decks that I have run across that were speced for 456 will not output a bias signal at a level sufficient to achieve the required bias signal with a +9 tape to bias it properly.

I should have written "...allows proper bias WITH a +9 TAPE while moving the pot TO the middle of its range"

Regards, Ethan
 
Ethan,

I have a spare used Hirose 60-pin male connector (no hood) and the metal locking ring that accompanies the connector in the panel-mount application. Have no need for it. Let me know if you'd like it for spares.

Check this out...interesting that the Seller says the mod for the MS-16 from 15-30ips is a jumper setting...
 
sweetbeats said:
Ethan,

I have a spare used Hirose 60-pin male connector (no hood) and the metal locking ring that accompanies the connector in the panel-mount application. Have no need for it. Let me know if you'd like it for spares.

Check this out...interesting that the Seller says the mod for the MS-16 from 15-30ips is a jumper setting...
Click to expand...

I don't doubt the jumper for speed selection especially in later versions of the servo/control board. I had planned on looking for that jumper.

You know I wold not find it too unusual if the 58 had that option....

Thanks for the offer of the connector. I'm good so far.

Regards, Ethan
 
Be aware that the 'jumper' may be soldered - not like a jumper on a computer motherboard. My 42B manaul talks about being 'jumpered' for IEC or NAB equalization, but on locating this jumper points I found they were all soldered.



AK
 
sweetbeats said:
this out...interesting that the Seller says the mod for the MS-16 from 15-30ips is a jumper setting...
Click to expand...


Very interesting. I have never been able to find one person that knew how to change the speed of a MS-16. Guess I have now. Anyway, I have read more than once that it is basically useless at 30 ips.
 
Wonder why it would be 'useless' at 30ips? Maybe it can't be properly calibrated at that speed? Higher tape speed should improve the quality of the recorded tracks, as a general rule.



AK
 
sweetbeats said:
Ethan,

I have a spare used Hirose 60-pin male connector (no hood) and the metal locking ring that accompanies the connector in the panel-mount application. Have no need for it. Let me know if you'd like it for spares.

Check this out...interesting that the Seller says the mod for the MS-16 from 15-30ips is a jumper setting...
Click to expand...

analogkid said:
Wonder why it would be 'useless' at 30ips? Maybe it can't be properly calibrated at that speed? Higher tape speed should improve the quality of the recorded tracks, as a general rule.



AK
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I don't know the answer. http://www.endino.com/graphs/
 
hey ethan and cjacek,
thanks so much for taking a look at the heads.
I took your advice and ordered a roller from terry witt.
i posted a question about the bias cap upgrade over at the electrical audio forum as there seems to quite a few technical-minded ms-16 users how hang out there.
here the link to the thread. no responses so far:
http://www.electrical.com/phpBB2/viewtopic.php?t=37031
 
Jumper...yeah I kind of figured it was a solder-link jumper...

Pete, ditto the comments on the headstack from me. Pics are a little hard to tell...that trick with the index card is great. Never tried scanning like Ethan said, but boy that would do a nice job of showing how the tape has been wearing on the heads (zenith-related wear patterns). I might just pull the stack off of my parts 48 and try that! So a good face-on shot shows the wear pattern, and an overhead shot kind of at an angle shows what the profile looks like.

AK, yeah, check out the Endino article...When you see the response curve of the MS-16 at 15ips, it is pretty clear why there are negative comments on the sound quality at 30ips. It would depend on the program material of course, but the response curve more or less moves up an octave when you double the speed and that puts the dips and drop-offs at the wrong places...

Ethan, post up if you find anything about that jumper...do you think that would be on the control board? It sure would be interesting if the 58 could do that as well...looking at Pete's headstack shots it is interesting...the MS-16 is kind of in-between the the 58 and 48...not sure what if anything of interest that indicates, but the head-cover and capstan are 48-ish, no scrape-filter ala 58 but three guides as opposed to the 48's 2 guides...tension arm design is akin to the 58 as are the amp cards...just gets my mind working for no reason at all...:)
 
Between cruises

I'm expecting to get the parts (thanks talldog) this week to move forward with my MS-16.

I have to replace some bad chips and get it all tested before moving forward onthe mods.

Replacing the cap for bias is a mo brainer. Just needs testing.

The reproduce amplifier is quite nice. It uses a low noise matched pair monolithic FET for the input gain stage. This drives a differential bipolar transistor pair. This allows for direct coupled (no caps) input stage that is low noise.

Being direct coupled you can get a large DC offset which tascam counteres with a DC servo amp (think Jensen Twin servo and Hardy MPC1). one IC for EQ and one for LF EQ as well. All in all 3 of the 4 opamps in the channel card could use an upgrade. I'm planning on replacing the 4558 with LT1358 and adding decoupling caps. Plus some upgrades in quality of the feedback resistor and EQ caps. More on that later. The 4th 4558 does not need to be replaced (U4) as that it is used for driving the meters and peak LED.

Looking at the capstan drive circuit I see a PLL motor speed control. Speed change to 30 ips cold be achieved by a change in the pulse divider network (half the pulses per rotation means twice the speed) or it could be in the uP that controls the PLL. In any case I would expect to see a single jumper that changes the speed. I'll look for that next time I have the control board exposed. As far as that goes you could make it run at 7.5 ips (but why?).

The few notes on cap and IC changes are all that I could find on the net. I did talk with Jim Williams and got a small pointer. In any case I do plan on making some mods and posting a cookbook on what I did.

I'm in the midst of a research cruise and have a pleasure cruise planned soon so getting time is difficult. I tend to vanish for hours to days when there are fires to put out cruise wise.

Regards, Ethan
 
Talldog said:
Hey Ethan,

I just pm'ed you. I have the arming board and the dbx jumpers with my parts deck if you want 'em. I also have a manual that I could copy but it is pretty big and has some large fold out drawings. Anyone out there got an aq 65 remote laying around?

Ken
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Ken,

I just turned up a AQ65 on Sleezebay. Hope you see this quick because it ends in a few minutes and has no bids.http://cgi.ebay.com/TASCAM-AQ-65-AU...ryZ15199QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Danny

PS: please don't outbid me on the OTHER item for the machine.
 
crap. I was out and missed it. I would have bought it. Thanks for the heads up Dan. What was the other part that you were bidding on?
 
Talldog said:
crap. I was out and missed it. I would have bought it. Thanks for the heads up Dan. What was the other part that you were bidding on?
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sweetbeats said:
Danny, was the "other" part the headstack?
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Ken, Sorry you didn't get that one. It had no bids until I posted it here. It ended 20 minutes before the amplifier.

Cory,

It was the MS-16 amplifier cabinet with all the cards in it. I can't believe it could even be found by most searchers. The guy that sold it didn't know what it was for or what it fit. He thought it was meters only. It was not listed as Tascam. It had no bids on it until the last few minutes. The seller started the bidding at 49.00. In the last couple minutes a couple of bidders showed up. I put in a snipe bid at 136.00 in the last 6 seconds and it sold for 137.00. I was highly ticked because I knew that in all likelyhood whoever I was bidding against found out about the stuff here. Be careful guys.

Danny
 
snipe, snipe, snipe away

Sniping is the only way to bid on eBay. That is the name of th game and anybody who puts bids in early and tries to stay on top is a fool. I should add that I love fools when I have things for sale.

I' don't duke it out - I would rather sit back about half a mile with a 50 cal...

Pick your highest price and put it in in the last few seconds. Then good luck to you.

I have been watching that auto-locator since the first day. Just because there were no bids did not mean that people were not interested. It did go for quite a bit over what I was willing to spend on it so no loss to me. Don't get me wrong.

I would suggest that if you find something that may be of interest to someone on this list that you (not YOU but all of us) send a PM to them.

Just remember what happened with all that tape (406). I paid the guy for some as did many of us who saw the auction. Then it got posted and someone most likely not of this list went and offered more than the existing sales (or so we think). And thus - so sorry - I really did not have the tape. Here is your money back.

Regards, Ethan
 
evm1024 said:
I would suggest that if you find something that may be of interest to someone on this list that you (not YOU but all of us) send a PM to them.

Regards, Ethan
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Ethan,


Yep that is good advice.


Danny
 
So, Pete, just for my own education, what has led you to seek a replacement for C42 (i.e. how do you know it needs to be replaced, or otherwise upgraded)?
 
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