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So you think you want to play with tape: An Otari Story
So you think you want to play with tape: An Otari Story
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Old 22nd July 2019, 02:35 AM   #181
kevinkr is offline kevinkr  United States
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So you think you want to play with tape: An Otari Story
The price of the LM4562 seems to have increased since I last checked. It's now at $1.39 at 40 pieces.
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Old 22nd July 2019, 02:38 AM   #182
dotneck335 is offline dotneck335  United States
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Originally Posted by anatech View Post
LM4562 for 1.11 each? Did I miss something? Where? I'm going to get me some! -Chris
LM4562NA/NOPB Texas Instruments | Mouser
Note that the quantity required for that price ($1.11) is 100. But I think it's the best bargain in the history of DIY audio!!
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Old 22nd July 2019, 02:48 AM   #183
dotneck335 is offline dotneck335  United States
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Hi dotneck335, Yes, Millmax are also very good.
Gold is a soft metal that wears away very easily. The thicker coating will survive more IC changes than the flash type. If you aren't going to replace these ICs again, why are you even looking at sockets? If you are, why are you considering the flash type finish? -Chris
Good points. My inclination towards sockets is the years of troubleshooting where a socketed IC is a god-send, especially on a PC board that's ~40 years old and probably won't take TOO much soldering on. I'm thinking that at this point, the Mill-Max sockets with gold flash are good enough. I really don't plan on doing any swapping; if I WAS planning that, I would go with the thicker gold. But I think the flash will withstand a few changes, and I need the $$ for the hundreds of capacitors I'm gonna need. Now, for you working stiffs, $25 is nothing; but for us old retired farts on a small fixed income, it IS relevant.
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Old 22nd July 2019, 04:01 AM   #184
anatech is offline anatech  Canada
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So you think you want to play with tape: An Otari Story
I am retired, not by choice either. I'm basically up a creek, you know the one.

What I would do if I were you is just solder the darned things in except for the early stages where you may want to try another op am type for lower noise. I don't think there is any point in replacing many of the NE5532 chips (does it use those? I'm making an assumption).

I used to work on tape machines professionally where some users wanted to improve performance once the gear was out of warranty. Of course, even under warranty was okay as long as they brought the machines in to us. It was safer to wait for the warranty to expire and that is what we recommended.

-Chris
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Old 22nd July 2019, 05:24 AM   #185
dotneck335 is offline dotneck335  United States
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I don't think there is any point in replacing many of the NE5532 chips (does it use those? I'm making an assumption).
-Chris
No, the Otari I have used a HA12017 for the head preamp and NJM4559s for everything else. If it DID have NE5532s, I'd leave 'em be, as I still think that is a fine opamp. But NJM4559s are really only slightly improved 741s (which suck), and the Hitachi chip, although fairly low noise, is slow, has horrible PSRR, and an order of magnitude more distortion than an LM4562.
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Old 22nd July 2019, 03:44 PM   #186
kevinkr is offline kevinkr  United States
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So you think you want to play with tape: An Otari Story
Mine have a mix of 2043, 4560 and an oddball from Matsushita in the MX-50 that I have not identified other than that it's a bipolar type rather similar to the 4560. They might be a wee bit better than what dotneck found in his machine but not by much. They are all deratives of the 741. The 5532 is probably a substantial improvement parametrically speaking, whether this results in any audible improvement is hard to guess. I'm surprised at how good the MX-50N actually is.
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Old 22nd July 2019, 08:01 PM   #187
anatech is offline anatech  Canada
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So you think you want to play with tape: An Otari Story
I think the 4560 is a FET front end, isn't it? Nope, the 4560 is an improved 4558 (dual 741). There was a Japanese op amp in this series that was J-Fet. I just can't remember which one it is.

By all means, pop every single one of those out! It will make a difference with the entire lot changed out.

-Chris
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Old 23rd July 2019, 12:11 AM   #188
kevinkr is offline kevinkr  United States
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So you think you want to play with tape: An Otari Story
The MKIII-2 is a comparatively easy test bed. I'm feeling really leery now about doing the op-amp mod on the MX-50N and that is because it's by far the best sounding tape deck I've ever owned and it easily outperforms my 5050s so I am starting to wonder if I might just actually succeed in making it sound worse. It is modified by only a little - the original machine did not have Muse caps in it, other than that and one simple mod to the LF comp circuit it is completely stock.
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Old 23rd July 2019, 12:41 AM   #189
anatech is offline anatech  Canada
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So you think you want to play with tape: An Otari Story
Hi Kevin,
When I modify a piece of equipment, I generally find that the highs are more "clear". If you look at a good FFT, the junk in the mid to high frequency ranges is greatly diminished. Personally, I don't feel you are in any danger of making your machine sound worse. You will probably reduce the background noise a bit, the distortion numbers will come down a little bit (perhaps even by 6 dB). There was one bit of kit where the distortion improvement was 20 dB, but that was low hanging fruit. A power amp designed and built by a modifier who used to work at Hafler. Some of you will know who I mean.

In short, I doubt very strongly that you would make it sound worse by applying sensible modifications (maybe) and using parts more suited to the task that we have today. I do think that you know what you are doing and this little bit of self doubt will completely evaporate once you hear your updated machine. In other words, just approach this as you would a good customer's machine and you will be a happy man. Besides, you have an RTX. Do before measurements, then after each major change to ensure you remain on track. You will then be able to attribute each improvement (or not) with the things you changed.

-Chris
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Old 23rd July 2019, 01:11 AM   #190
dotneck335 is offline dotneck335  United States
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Originally Posted by kevinkr View Post
The MKIII-2 is ........by far the best sounding tape deck I've ever owned and it easily outperforms my 5050s....... It is modified by only a little - the original machine did not have Muse caps in it, other than that and one simple mod to the LF comp circuit it is completely stock.
Interesting....WHY do you think that it sounds better? Does it have superior heads? Or is there something else in the audio circuit path that makes it better?
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