Sony TC500a Teardown questions!

Discussion in 'Tube Audio' started by nick parkin, Jan 8, 2019.

  1. nick parkin

    nick parkin AK Subscriber Subscriber

    Messages:
    413
    Greetings all

    This is my fourth Sony TC-500a teardown, and in the past I would give the transformers to my friend and we would split the cost, and I would keep the coral holly baskets. Now however, I will be keeping the transformers and corals, which this tc500a does have (I've had some tc500a's with the corals already removed).

    This TC500a is a gem and I'm sad to tear it down. All of the original cables and connections are in their original boxes, and it includes an original manual, as well as a manual labeled "tape talk", which defines all of the tape deck terminology. there is even some tape deck lubricant that has never been opened.


    Ive got my corals, and I have what appears to be a TamRadio power transformer. Can anyone help me verify that this tranny is a TamRadio? I saw another one on ebay that is exactly the same that is listed as a TamRadio but I just want to be sure. Does anyone now anything about this transformers sound if it indeed is a TamRadio? Does a power transformer really affect the sound that much? I know the output transformers do but ive heard all about the TamRadio transformers.

    I am going to harvest the output transformers as well after I go to the gym.

    Is there anything else worth harvesting that might be worth something from the reel to reel besides the tape reading head (I forgot the terminology, I better look in my "tape talk" booklet)?

    IMG_0778.JPG IMG_0779.JPG IMG_0782.JPG IMG_0785.JPG IMG_0786.JPG IMG_0787.JPG IMG_0793.JPG
    IMG_0796.JPG
     

     

    Please register to disable this ad.

  2. Squidward

    Squidward Scrappy Mod Staff Member Moderator

    Messages:
    4,626
    Location:
    Bikini Bottom (Ann Arbor, MI)
    I believe the OPTs have a 5K primary with 8 ohm and 600 ohm secondaries. I've always wondered if they'd make a good headphone amp off of the 600 ohm winding.
     
  3. FlaCharlie

    FlaCharlie AK Subscriber Subscriber

    Messages:
    670
    Location:
    Gainesville, FL
    I see the literature you got with it includes a schematic. Here are the specs for the transformers, as listed in the Sams Photofact.

    Sony R2R Trans Specs.jpg

    I just checked a list of manufacturer codes but TamRadio (Tamura) was not listed so maybe they didn't label their transformers with a code. If Sony regularly used them as a supplier that's probably what they are. Perhaps there are some vintage Sony experts who know for sure.

    I wouldn't get too hung up on their pedigree. Whoever made them, they will do fine as the basis for building an RH84. Use the 6CA4 rectifier that's in the Sony. You could even use the original output tubes (6AQ5s) if you wanted.

    As a few of us have told you in your other thread, PT's don't have a "sound". The design of the rest of the power supply can influence the sound, mostly in a negative way if it is either a wimpy design that doesn't provide enough filtering or if you go overboard and use too much filtering. There are numerous variations that will work well. There is no single "best" or "magical" design so don't overthink it. If you build a PS based on the original schematic, which is a C-L-C, you'll be fine. If you have room, use film caps instead of electrolytics. The Panasonics work well and are somewhat less expensive. If you use lytics, use 105 degree rated caps that have the highest hour rating you can find (probably 10,000 hrs). Panasonic, Nichicon, Cornell-Dublier are all fine.
     
  4. nick parkin

    nick parkin AK Subscriber Subscriber

    Messages:
    413

    Thank you both for your insight. I measured the Output transformers with my volt meter and I have found three windings with the following measurements

    2 ohm
    1.8 Mega Ohm
    280 ohms


    This does not seem close to what is listed. The OPT's have a 600 ohm label on them. is the impedance different when current is running through it? Can anyone explain this?
     
  5. FlaCharlie

    FlaCharlie AK Subscriber Subscriber

    Messages:
    670
    Location:
    Gainesville, FL
    Don't worry about your readings. They're different because resistance and impedance are different things. Here is the portion of the Sams showing the OT and the color of the wires. Take a look at the factory schematic, it should show the same.

    Sony OT.jpg
     
  6. gadget73

    gadget73 junk junkie Subscriber

    Messages:
    37,335
    Location:
    Southern NJ
    1.8M doesn't make sense unless the transformer winding is open or the connection is just crusty.
     

     

    Please register to disable this ad.

  7. nick parkin

    nick parkin AK Subscriber Subscriber

    Messages:
    413
    Ill double check it, it may have been 1.8K.

    is there anything on the reel to see that may be worth salvaging?
     
  8. FlaCharlie

    FlaCharlie AK Subscriber Subscriber

    Messages:
    670
    Location:
    Gainesville, FL
    When I said not to worry I was talking about the difference between the resistance readings and the nominal impedance specs. Gadget is correct in saying that 1.8 meg is too high.

    When you measure again, get readings from both of the OTs and identify which windings give which readings. Are they both consistent?

    What resistances are listed on your factory schematic? Are they the same as the ones from the Sams?
     
  9. Dandy

    Dandy Super Member

    Messages:
    4,590
    Location:
    North West, UK
    Are you harvesting the parts to resell, or are you going to build with them? And what is significant about the Corals? I've not seen a teardown like this before.
     
  10. s-petersen

    s-petersen Scott Subscriber

    Messages:
    4,715
    Location:
    Middletown,New York
    Coral holly baskets? what are those?
     
  11. nick parkin

    nick parkin AK Subscriber Subscriber

    Messages:
    413

    I will be selling the tape head and reel to reel face plate. (To any mods, I am not advertising my sales as no one in this forum happens to need a tc500a head.) Other than that I took the I/O plastic cover that has the labels for the inputs and outputs and I am going to cut it into nice square pieces and use it to lable my “input” and “speaker output” on my new amp.

    As for the coral holes baskets, they are a superb sounding 4” full range driver. You wouldn’t think 4 inches could please somebody but wowza these things sound stunning. Here is a link to one guys reviews. There are two pairs up for sale on eBay right now but I already own 6 pairs so I’m good. (Any mods reading, I am not selling the ones on eBay and am not promoting my selling of any items)


    Coral link
    http://www.glowinthedarkaudio.com/coralholey.html
     
    Last edited: Jan 10, 2019 at 6:53 PM
    Dandy and s-petersen like this.

     

    Please register to disable this ad.

  12. FlaCharlie

    FlaCharlie AK Subscriber Subscriber

    Messages:
    670
    Location:
    Gainesville, FL
    Nick - Did you re-measure the OTs? Results?

    As far as other parts to salvage . . . tubes of course, especially the 12BH7, and any higher wattage resistors from the PS. They may not be useful for this build but could come in handy for subsequent projects.
     
  13. nick parkin

    nick parkin AK Subscriber Subscriber

    Messages:
    413
    Unfortunately I already threw out the resistors. They were soldered to a point to point wiring board. I saved the tubes, and I might save the sockets as well.

    As for the output trannys i measured the values and got 380 ohms, 210 ohms, and 2 ohms. I think the wacky reading from the first time was because the voltmeter measured the resistance across my body because I held the leads on with my fingers.


    As for the build, I am waiting to stock up on some cash so I can buy a new chassis as the one o have now is 4” x 10” and 1.5” deep and it is wayyyy to small to house the new transformers and capacitors I need. I am going to do walnut sides and use finger joints to join the wood together
     
  14. Squidward

    Squidward Scrappy Mod Staff Member Moderator

    Messages:
    4,626
    Location:
    Bikini Bottom (Ann Arbor, MI)
    Re-using the sockets on these things isn't a bad idea, it's not like there's been a lot of tube rolling that occurred. If the tubes are original it's likely they were put in at the factory and never messed with again. I'd inspect them for corrosion, but mechanically I'd bet they're just fine.
     
  15. gadget73

    gadget73 junk junkie Subscriber

    Messages:
    37,335
    Location:
    Southern NJ
    There is a joke to be made here. Just sayin'.
     
  16. FlaCharlie

    FlaCharlie AK Subscriber Subscriber

    Messages:
    670
    Location:
    Gainesville, FL
    The only resistor worth saving is the big brown one that's visible in one of your pics, located next to the PT and mounted upright. Its a 600 ohm 10w wirewound. While I've used sockets from stuff like this before, sometimes it's more trouble than it's worth, especially if they are riveted in and there's very little space to work on them. If they're screwed in, no problem. But if you have to use a Dremel to grind the rivets it can be a pain. Once they're out, you still need to de-solder whatever is left on the pins so it ends up being pretty labor intensive. If you've got the tools, the time, and you're on a tight budget then go for it.

    A couple of cheap chassis suggestions . . . run down to Target or Walmart and look in their kitchen supply section. They sell bamboo boxes that are designed as drawer organizers to put silverware in. Another option is to go to a thrift store and find a fairly deep wooden picture frame. Replace the glass with a sheet of aluminum as the top plate. Aluminum baking pans work fine too. I forget his name, but there was a guy some years back who sold amps built on baking pans. He gained a bit of a following, I believe.

    I built a PP 6B4G amp with OTs from a Sansui 1000A on a big institutional strength baking pan that I found at a flea market. The aluminum is at least 1/4" thick and just the pan weighs maybe 8 or 10 lbs. Probably came from a school cafeteria. Yeah, I'm all about scrounging!
     

     

    Please register to disable this ad.

  17. 6DZ7

    6DZ7 Super Member

    Messages:
    2,258
    Well, obviously you've never had a 1.86 oz. Snicker's Bar.

    Get it?
     
    Last edited: Jan 11, 2019 at 9:46 AM
  18. nick parkin

    nick parkin AK Subscriber Subscriber

    Messages:
    413


    The tubes are all original NEC tubes and look to be in good shape. The sockets look great as well and have no corrosion.

    I want to built the RH-84 chassis similar to the one on the Glow in the Dark Audio blog. I’m not very artistic or creative so I’m okay with not making my own chassis design because it won’t look as good as this one I just love the simplicity and the Contrast between the wood and the aluminum.

    Here is a photo of it.

    AF1CFED1-C315-4E94-8B42-908BE32AED12.png

    I’m pretty sure it’s walnut wood for the sides. Can anyone confirm this and can anyone approximate it’s dimensions? I was thinking the footprint is 6x10 but it seems like it could even be 7 x 12. Any insights?

    I joined the website it was originally sold on—Audiogon — in an effort to contact the original builder who sold it. I am horrified with the Audiogon website as i immediately saw some hookup cables for sale for $3000, as well as fancy botique amplifiers that I’ve never heard of that probably have 1000% profit margins. (I really hate the “botique” Hi-Fi scene as well as overpriced hookup cables)

    Anywho before I get off track, can anyone approximate the dimensions? I love the aspect ratio of that amp and the General aesthetic and layout.
     
  19. FlaCharlie

    FlaCharlie AK Subscriber Subscriber

    Messages:
    670
    Location:
    Gainesville, FL
    Sure, reuse the sockets. It looks like you have the four 9-pin sockets you need if you go with 6BQ5s. It'll just take a bit of work to get them out and cleaned up. The tubes won't be useful for this build unless you decide to use 6AQ5s instead of 6BQ5s.

    I'm not sure what kind of wood was used on that. Find a local source and pick something that looks nice. Size? Hard to say. Again, just build it in a chassis whose dimensions appeal to you. Or you might contact the Glow in the Dark guy and ask him to measure it. Maybe he'll also be willing to send you pics of the inside so you can see how the builder did the layout. I agree, it is a very clean looking amp.

    Unless you plan on having a top plate custom made, I'd look at the standard sizes available from Hammond or similar chassis sources. If you go with wood for the sides you can just order what Hammond refers to as the bottom cover for their aluminum boxes. Order one for the top and one for the bottom if you want it to be fully enclosed. They have holes predrilled around the edges so it's easy to screw them to the wood. Of course, you'll need to cut holes in the top for the PT and the sockets.
     
    gadget73 likes this.
  20. nick parkin

    nick parkin AK Subscriber Subscriber

    Messages:
    413
    all hte leads are clipped and it should be easy to clean the old solder off. I tried contacting the guy on glowinthedarkaudio and he has not gotten back to me yet, however i believe he sold it as ive found two listings where this amp has sold.
     

Share This Page