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Author Topic: Otari MX-5050 mods, impressive!  (Read 20384 times)

Offline Gkar

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Otari MX-5050 mods, impressive!
« on: November 29, 2010, 12:28:24 PM »
while I know most are oriented towards getting these machines with docb's tube preamp (and something I want to do after I get the finances straight), I have been talking with a studio person who gave me several upgrade options to the stock SS preamp.  I have done a few of them and the results were quite an improvement.  So for those who may be interested in these tips, let me know and I can post here, if that is OK...
"Music possesses far richer means of expression, and it is a more subtle medium in which to translate the thousand shifting moments in the mood of a soul." - Tchaikovsky

Offline jcmusic

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Re: Otari MX-5050 mods, impressive!
« Reply #1 on: November 29, 2010, 02:22:49 PM »
while I know most are oriented towards getting these machines with docb's tube preamp (and something I want to do after I get the finances straight), I have been talking with a studio person who gave me several upgrade options to the stock SS preamp.  I have done a few of them and the results were quite an improvement.  So for those who may be interested in these tips, let me know and I can post here, if that is OK...
We're all eyes my friend!!!

Jay
Redpoint Model D TT/Soundsmith Sotto Voce Cartridge Otari MX 5050 BII/BH Tube Repro deHavilland Model 222
 Ah Njoe Tjoeb 4000, Rogue Magnum 99, Korneff 45 SET Amp, Klipsch K-Horns Bass Bins/2" Tractrix Horns 2" BMS Drivers, Vintage Tubes.

Offline Gkar

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Re: Otari MX-5050 mods, impressive!
« Reply #2 on: November 29, 2010, 10:02:38 PM »
OK, the first thing I did was shotgun all the 'lytic caps in the power board, that made a difference in the sound quality that was somewhat expected, clearing this up a bit, please note, my 5050 was in really nice shape having been in a studio that, along with 3 others, did ADC.  So this one had been used very little, and changing the caps I expected would help a bit, and it did, and was a good idea if for no other reason than to provide a bit of insurance for longevity...

however, where things really improved was a suggestion, quite strongly given, that the metallized film caps in the 18V rails that feed the audio sections, be replaced with film and foil caps.  I'm in the camp that wonders about the changes caps make to gear, not sure I buy all that PIO, film/foil, etc., etc., stuff.  Well, my mind has been changed!  The difference was immediate and is improving over time, and was not subtle to my hearing, deeper soundstage, clearer instruments, you could really hear those violin strings against the bows, much fuller sounds.  Tapes that were really good took on a vividness that was amazing, some tapes that were marginal, like the Phase 4 recordings, sounded so much better, and some that were OK were not so hot.  There are 14 of these caps in the rails and I used some 192P caps that fit pretty well in the smallish spaces.  Would be interested in hearing from someone else that does this upgrade to confirm, I still cannot believe the difference it made.  There were other suggestions that I will get to as well...
"Music possesses far richer means of expression, and it is a more subtle medium in which to translate the thousand shifting moments in the mood of a soul." - Tchaikovsky

Offline Listens2tubes

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Re: Otari MX-5050 mods, impressive!
« Reply #3 on: December 01, 2010, 09:31:05 PM »
This is very interesting to me. All the caps on the control pcb of my BII-2 are leaky, I will be replace them with Nichicon Muse and FG cans. I just checked my HD and only the first 1000uF/50v is leaky but all will be changed as well. Now on to the audio section, sweet! I like this tweaking, I'm warming up the iron.
Neal - Ampex Fineline F-44, 3 - Otari MX5050BII-2, Revox A77 Mk II , Teac A 4010s, 4070, Sony TC102A, Magnecord 1020, Systemdek IIX/Dynavector Karat 17D2MKII, CEC CD3300 CDP, K Works NanoMax DAC, Van Alsine Transcendence Eight+ tube preamp, Dynaco MkIV amp pair, Paradigm Reference Studio 100 v1

Offline Gkar

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Re: Otari MX-5050 mods, impressive!
« Reply #4 on: December 02, 2010, 08:24:33 AM »
Neal, when you get the PS done, give it a good listen, then replace the 18v rail bypass caps with film/foil caps, these caps on the board are milk chocolate colored, shiny, and about the size of a chicklet.  Let me know how it sounds after that mod.  Unless I have completely gone bonkers, this will improve the stock sound tremendously.  As I noted early, I am somewhat dubious about the change of capacitor types making any difference whatsoever to sound in gear, but after doing exactly this to my 5050, I feel I have to eat my words and rethink my position on the cap thing...
"Music possesses far richer means of expression, and it is a more subtle medium in which to translate the thousand shifting moments in the mood of a soul." - Tchaikovsky

Offline Listens2tubes

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Re: Otari MX-5050 mods, impressive!
« Reply #5 on: December 02, 2010, 07:46:37 PM »
It will take some time before I can get all this done. Please clear some things up for me. You used Vishay-Sprague 192p caps on the audio board. These are Polyester axial film/foil caps, ie: orange drops, yes? Did these replace or bypass the choc crickets?

OK, this is impressive, so... what's the next step in this excellent project?
« Last Edit: December 02, 2010, 07:48:10 PM by Listens2tubes »
Neal - Ampex Fineline F-44, 3 - Otari MX5050BII-2, Revox A77 Mk II , Teac A 4010s, 4070, Sony TC102A, Magnecord 1020, Systemdek IIX/Dynavector Karat 17D2MKII, CEC CD3300 CDP, K Works NanoMax DAC, Van Alsine Transcendence Eight+ tube preamp, Dynaco MkIV amp pair, Paradigm Reference Studio 100 v1

Offline Gkar

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Re: Otari MX-5050 mods, impressive!
« Reply #6 on: December 02, 2010, 10:46:13 PM »
Neal, they are not orange drops, but a small film/foil I found at Mouser that would fit, probably because they are low voltage, ie., 80v.  I am guessing that other types of film/foils would also work, preferably non-inductive type, what I chose was something that would fit easily the space.  You could try some other types as well, Parts Express sells their own brand, Dayton, of tin foil and film that is supposed to be better than any of the aluminum foil and film caps and they are cheap, around $.70 each, they are a bit big, but I may give them a try at a latter time, their construction of polypropylene is superior to mylar used in the 192P, and tin foil is rated as better than aluminum.  As far as the other mods, I have not gotten to them, but I will post John's email for all to see...
"Music possesses far richer means of expression, and it is a more subtle medium in which to translate the thousand shifting moments in the mood of a soul." - Tchaikovsky

Offline Gkar

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Re: Otari MX-5050 mods, impressive!
« Reply #7 on: December 02, 2010, 10:49:20 PM »
HI Randy,
          yes, pretty big improvement. I can't understand why so many do think it will do much.
 
You also have similar caps on the audio control card; one card over from the two audio cards. Not sure why, but Otari used better quality caps on the control card than they did on the audio cards.
 
Have you bypassed the interstage coupling caps yet?
 
On the power supply rail caps you replaced, you can also experiment with values. OE values are 6 0.1uf metallized film. One one of my decks I have 6x 0.1uf film and foil, and on the other, I used 3 different values; 0.47uf, 0.22uf and 0.015uf. for each side. Gives a fuller sound.
 
 
The other thing you can do is replace the full wave bridge in the base of the power supply (bottom section below the cards). with a EDI soft recovery bridge of same voltage and current rating.
 
the fast recovery bridge will remove another layer of haze.
 
http://www.edidiodes.com/pdf/Bridges/xPIR.pdf
 
 
Beyond that, you can get into replacing the shunt resistors on the audio cards with vishay bulk foil (see attached file and link), but I would not do those until you have bypassed the coupling caps first.
 
Also, not sure what you are feeding the output of the Otari into, pre amp, etc, but adding bypass caps to the power supply of your pre and power amp will also open up the sound, remove grunge, and improve imaging. Does not matter what the brand is, very, very few manufacturers use them.
bypass caps can take an Adcom amp, from barely listenable to quite listenable. Their earlier amps had a lean and edgy sound, especially the 555 and Mk2 versions. Adcom used chrome plated steel bus bars for the ground plains. Tossing that junk out and replacing with copper buss bars and adding bypass caps transforms the sound of those adcom amps.
 
 
 
 
 http://www.datasheetcatalog.org/datasheet/vishay/vsr.pdf
 
 
john
 
"Music possesses far richer means of expression, and it is a more subtle medium in which to translate the thousand shifting moments in the mood of a soul." - Tchaikovsky

Offline Gkar

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Re: Otari MX-5050 mods, impressive!
« Reply #8 on: December 05, 2010, 07:08:50 PM »
just as an indication of the improvement the cap job, did, while I have been going through some of my tapes, on in particular always bummed me as dull and rolled sounding (Schubert Symphony 7, Skrowaczewski/Minneapolis, Mercury ST-90272) has been transformed by cap upgrade.  Now, this tape is full, clear, vivid and open, a real nice sounding recording that earlier I would have placed in the poor sound box, now it is with the excellent tapes!  And the change is not from more highs present, it is just more clear and vivd sounding, and thus, more present and enjoyable to listen to...
"Music possesses far richer means of expression, and it is a more subtle medium in which to translate the thousand shifting moments in the mood of a soul." - Tchaikovsky

Offline Listens2tubes

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Re: Otari MX-5050 mods, impressive!
« Reply #9 on: December 14, 2010, 06:30:54 PM »
Randy have you tried the higher value caps on the power supply rail 6 as stated in John's email. If so, which caps where, if you'd be so kind? Want to finalize my Mouser order.
Neal - Ampex Fineline F-44, 3 - Otari MX5050BII-2, Revox A77 Mk II , Teac A 4010s, 4070, Sony TC102A, Magnecord 1020, Systemdek IIX/Dynavector Karat 17D2MKII, CEC CD3300 CDP, K Works NanoMax DAC, Van Alsine Transcendence Eight+ tube preamp, Dynaco MkIV amp pair, Paradigm Reference Studio 100 v1

Offline Gkar

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Re: Otari MX-5050 mods, impressive!
« Reply #10 on: December 20, 2010, 11:08:41 PM »
HI, Neil, not yet, ran into a problem with a cable and am awaiting my mouser order for the Molex pins to fix said connector.  I should note that John was talking to me about the Otari MTR-10, he is a studio engineer and has a couple of these, an earlier thread with Steve Koto noted that these decks are fairly easy to get and cheap as well, they are more along the lines of a true studio machine.  I did get one, but it needed (needs) some work to get it up to its best operation, that is what I am in the process of doing.  However, the mods John mention are also applicable to the Otari MX5050 series, and that is the machine I replaced the power supply bypass caps on that made such a difference, night and day to my ears!  I plan on getting another MTR-10 and run both cap mods, the straight 0.1 mfd mods and the varied values mod and listen to the difference, going by what John has told me in the emails, the varied values mod is probably what I will eventually stay with.  I also note that the 0.1 mfd caps can be a bit of a trick to get in a small enough size, mouser and digi-key don't carry the 192Ps any more but I was able to get a stock in the 0.1 value.  In looking into various capacitor reviews and such, I have noted that there may very well be other film/foil caps available in sizes that would work as well, I believe Sonicaps makes fairly small 0.1 mfds, there are some film/foil caps of quality construction that will fit in the spaces...  feel free to contact me for any questions you have [email protected]
"Music possesses far richer means of expression, and it is a more subtle medium in which to translate the thousand shifting moments in the mood of a soul." - Tchaikovsky

Offline Listens2tubes

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Re: Otari MX-5050 mods, impressive!
« Reply #11 on: December 28, 2010, 08:52:27 PM »
I used Nichicon KZ and FG caps in the power supply. Soon to install Vampire chassis mount XLR sockets for in & out. Also have Vampire male and female cable XLR plugs to make up some IC's. Preamp end will have ETI Copper Bullets. Considering Mogami 2534 (4 x 24ga w/shield) or Cardas 4 x 24ga with shield. With either I will use the shield as in a balanced cable, having a ground wire from the shield popping out of the back of the Eichmann plug, to attach to the chassis ground lug.

If this seems way off or anyone has an opinion about wire let me know.

 
« Last Edit: December 28, 2010, 09:16:47 PM by Listens2tubes »
Neal - Ampex Fineline F-44, 3 - Otari MX5050BII-2, Revox A77 Mk II , Teac A 4010s, 4070, Sony TC102A, Magnecord 1020, Systemdek IIX/Dynavector Karat 17D2MKII, CEC CD3300 CDP, K Works NanoMax DAC, Van Alsine Transcendence Eight+ tube preamp, Dynaco MkIV amp pair, Paradigm Reference Studio 100 v1

Offline ironbut

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Re: Otari MX-5050 mods, impressive!
« Reply #12 on: December 29, 2010, 12:34:31 PM »
I've also used Nichicon caps in the PS when I haven't been able to get the right size Panasonic ED or EE. In these applications, I just go with what's easier to source and/or cheaper.

Regarding the cables, Mogami mic wires are fine but I've always thought that Cardas is better. I don't see any reason for using the 4x conductor when you can just use 2x and use the shield for the third ground wire (pin #1). That's the conventional way. You're probably smart to have the shield/ground hang out rather than connect it to the barrel of the RCA. Sometimes you have to fool around with how an XLR to RCA is grounded between two components. Sometimes it's better to have the ground/shield connected together at the RCA end and sometimes not. It's best to experiment before you solder.
BTW, if you've never worked with Cardas wire, you should do some searching around regarding tinning. I have a solder pot that I use for tinning Cardas.
steve koto
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Offline Listens2tubes

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Re: Otari MX-5050 mods, impressive!
« Reply #13 on: December 29, 2010, 07:28:04 PM »
Hi Steve, I used the Cardas 33ga. tonearm wire from cartridge clips to Copper Bullets and a solder pot is a key to burning the enamel off. As for the 4 conductor wire, I like the idea of 2 twisted pairs for IC's. Though the characteristics of the balanced 2 conductor/sheild cables should be the same.
Neal - Ampex Fineline F-44, 3 - Otari MX5050BII-2, Revox A77 Mk II , Teac A 4010s, 4070, Sony TC102A, Magnecord 1020, Systemdek IIX/Dynavector Karat 17D2MKII, CEC CD3300 CDP, K Works NanoMax DAC, Van Alsine Transcendence Eight+ tube preamp, Dynaco MkIV amp pair, Paradigm Reference Studio 100 v1