TC-750 Phono Pre-Amp (Continued)

Discussion in 'Vinyl Nutjob World: Turntable and Related Gear' started by purr1n, Oct 6, 2015.

  1. gaspasser

    gaspasser Flatulence Maestro

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    I am a super newbie when it comes to all of this...
    I need some help in understanding how to hook up the SOLA HD PS. I am looking at pictures available and need additional guidance please, specifically how to I hook up the inputs and outputs. This will be my first project so please be kind, thanks.

    EDIT: see below!
     
    Last edited: Nov 19, 2016
  2. gaspasser

    gaspasser Flatulence Maestro

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    IMG_0189.JPG image.jpg

    Since I didn't have anyone willing to assist, I decided to follow the pictures from @JoshMorr the best I can.

    Please let me know if there is anything fatally wrong.

    EDIT: I plugged it in and other than a couple of sparks (J/K :rolleyes:) it works.

    Initial impressions: Holy SHIT! This thing is crazy good. I have not heard my turntable like this. Plankton galore and I am hearing A LOT of details through the entire spectrum that I just didn't hear before. This is with SOLA HD PS and stock TC-750LC.
    Next I need to figure out which small capacitors to use. I would like to stay small so I can use the stock case. Advice, please? WIMAs?

    Update: I took Marvey's advice earlier in the thread and ordered Audyn caps from Parts Express and I will get to work now that @powermatic hooked me up with a free soldering station!
     
    Last edited: Nov 19, 2016
  3. JoshMorr

    JoshMorr Friend

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    Yoooooo - my bad, for some reason auto thread updates on this weren't popping up for me. I should have been around to give you some better info, but looks like you managed to get it sorted out. I always have the same sparks / shorts fear when plugging in a project for the first time.

    Great job on the LPS. Your electrical tape trick will surely keep you safe and free of shorts. I will forever be amazed at the value of this power supply.

    Excited for your impressions when you update the TC-750. Its amazing how replacing some critical junk caps with decent ones, and adding a basic power supply can completely change the sound of this lil pre. It been a while, and i did all mods at once, but my bet is on the low end taking a major improvement once you swap out caps.

    Looking forward to updates!
     
  4. gaspasser

    gaspasser Flatulence Maestro

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    I ended up doing everything suggested and removed the attenuator after I broke it trying to get the board out of the case. I completed the mods and I get sound but it is very low volume, which I assume has to do with not having anything to bypass attenuator. I just purchased 1M resistors but have no idea how (what direction, etc) to solder in. Please help @OJneg
     
  5. OJneg

    OJneg The Most Insufferable

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    You need to add some jumper wires that's all. the 1 Meg is actually the pull down resistor IIRC
     
  6. mrflibble

    mrflibble Friend

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    I just received my TC-750 today. Looking to use a better power supply with it. According to the rear of the unit it is 15V DC, is this correct? The supplied walwart does look totally inadequate.

    I'm not confident about messing around with power supply electronics, so I was thinking about buying an enlcosed 15V 1.5A linear power supply from Swagman Lab. Would this give me a good result, comparable to using the SOLAHD? Would it still be beneficial to remove the power filtering capacitors from the unit when using the Swagman?

    Many thanks
     
  7. mrflibble

    mrflibble Friend

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  8. purr1n

    purr1n Desire for betterer is endless.

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    It's the same unit, probably a different board revision. No idea on Swagman labs PSU. Can't vouch for it, but most likely better than that stock compact switcher.

    The Swagman PSU is expensive. Seems dumb to pay for this to use on a $40 phonostage unless you plan on modding the phonostage further.

    Better off with used Sutherland or RSA phono for $550.
     
  9. mrflibble

    mrflibble Friend

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    Thanks for the suggestions Marvey, but I don't think the Sutherland or RSA are available in the UK.

    There is another linear psu (CenSe D1) available for £50 or less (it is 15V 1A) which could be a good choice. I was alternatively considering a Musical Fidelity V90 or Schiit Mani, would the TC-750 with a linear PSU such as the Swagman / CenSe be superior to these phonostages?

    Off topic: This guy really likes the Schiit Mani (It won his phono shootout):

     
  10. purr1n

    purr1n Desire for betterer is endless.

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    Out of those compared, the Mani is competitive. There is a lot of overpriced stuff out there.
     
  11. mrflibble

    mrflibble Friend

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    I blew up my TC-750 today. I hot plugged the linear power supply I have and there was a spark. Now the left channel no longer works :oops: I'm guessing one of the transistors got fried as there is not much else to fry on the board (no IC's).

    Interestingly, I had another look at the board and DC12v is printed next to the power input on the board. Yet, on the case it says 15v. Weird. I was using a 15v PSU. I read on another forum (a German one with Google translate) about modding the TC-750 and the guy used a 12v PSU and that the being 3v short was not a problem.

    http://www.hifi-forum.de/viewthread-26-12713.html
    http://www.hifi-forum.de/viewthread-26-6619.html

    The moral of the story is don't let a penguin play with your phonostage, they cannot be trusted! |\/|

    Luckily, I bought it second hand for very little money. I suppose I could try replacing the transistors but probably not worth it?
     
  12. vinylpancakes

    vinylpancakes New

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    All I can say about this phono stage is that I don't know why I would ever look at anything else. One day I would love to see how this ranks against the best of the best.

    I made every change to this board bit by bit, over a few months span to see how it changed. It was a good experiment that turned out to be amazing. I didn't keep notes while doing so, so unfortunately I'm not going to be able to recall every minute detail from each change.

    The one thing that I regret was not trying hard enough to join SBAF sooner. I did try though, but my account kept getting deleted upon creation. I was going to ask if anyone else had other suggestions for caps instead of the already tried jantzen caps. I went with them anyways and no regrets.

    I ended up still using load caps. I bought a handful of every single ceramic cap from PE. I'm sitting at 47pf currently. Any higher I get distortion in the mid to high range (or the trailing end of notes if that's even possible. I apologize but like I said I didn't keep notes and it's been a while.) If I blank it out I get no audio. If I go with let's say a 4.7pf, I seem to lose the punchiness of this phono stage. I know my interconnects are part of the load for this. I'm just a little disappointed I couldn't get rid of them like the others on here. I run a Ortofon Blue.

    Sorry about the bad pictures. My TT sits in a very dark corner so I needed to use the flash. Not pictured is the sola power supply that was recommended in this thread. I keep the phono stage in a cardboard box for now. I have my eye on a few enclosures but just haven't gotten around to it.

    [​IMG]

    [​IMG]
     
  13. JayC

    JayC Resident Crash Test Dummy

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    I have a basic question - the stock power supply can 12V and 0.5A, but the sola power supply does 12V and 3.4A. Is there a specific reason for picking this model? I see some of the other ones, like the 12V 1.7A one showing up a little cheaper to me shipped to Germany and was wondering if it was a viable option..

    (I ordered the 3.4A version a couple weeks ago but it turned out to be DOA, so now I'm looking for another one)
     
  14. purr1n

    purr1n Desire for betterer is endless.

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    The 3.4A version sounds better than the 1.7A one. No idea why, other than the bigger one has two transistors and is heavier. Two and heavier is better than one and lighter.
     
  15. JayC

    JayC Resident Crash Test Dummy

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    I finally got my Sola LPS, and I plugged everything in, but it didnt work. I figured it was DOA, but just got my hands on a multimeter and see that it is outputting 12.22V DC all the way upto the TC750. But I still do not hear sound and do not see the red LED on the TC750 light up.

    I went back to the stock power adapter and things work fine (red LED lighting up and all)

    Anyone have this happen to them? Or possibly know whats wrong here? I'd appreciate any help here
     
  16. JoshMorr

    JoshMorr Friend

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    This is a long shot, but is polarity reversed?
     
  17. JayC

    JayC Resident Crash Test Dummy

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    HAHA, the exact thought occurred to me right after I posted since there was nothing else I had left unchecked. I had gone based on the markings on the stock supply and made connections at first, now used the multimeter everywhere and guess what? The marking on the power adapter/cable of the power adapter is reversed! I double checked, swapped the connections on the Sola LPS and viola! :D

    Whew, ive never had this happen before and cant imagine how this happened at the production line.. But now I can finally sit back and enjoy!

    EDIT: HOLY SHIT. This is what you guys have been talking about! I now totally get analog! I did before, but it was more about the tactile experience and a small difference in dynamic range. Now its a whole different world altogether! I thought I'd never really have to pick my jaw off the floor again as I did the first time I really heard good sound - this did it. Tons of details I've NEVER heard before, you have to hear it to believe me. I'm still shaking my head
     
    Last edited: May 17, 2017
  18. JayC

    JayC Resident Crash Test Dummy

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    I got rid of the power conditioning caps on the TC750 and tried it out, everything seems fine but I see that having the metal lid off and keeping it close to the Sola's transformer makes it hum. Problem is solved when you move them apart a couple inches and throw on the full case.

    Another weird thing now is that this happens everytime I unplug the Sola PS and leave the amp on:


    Of course now I'll have to be more careful and turn off the amp before the Sola PS, but this is pretty odd considering noone else has had this happen to them
     
  19. PoochZag

    PoochZag The Shadow knows - Friend

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    That happens to me too!

    I didn't know the component, I often have a wifi interference problems with certain tubes and cheap RCA cables, so I just wrote it off as related to that. But yeah it's only with my vinyl rig and speakers (LSR305) so must be the TC750
     
  20. JayC

    JayC Resident Crash Test Dummy

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    Okay this makes me feel better, I thought it was just me somehow. It seems to be related to the removed power conditioning caps though, because I am pretty sure this didn't happen yesterday..

    I also ended up ordering 4 Mundorf EVO Oil caps (2 x 10uF and 2 x 3.9uF) last night - they didnt cost much and I was getting a little lost in Audyn's catalog.. I now need to find a soldering station :p

    Question - Is there a reason people here stick to film caps (like the Jantzen superior) rather than oils like this apart from the potential longer life?
     
    Last edited: May 19, 2017

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