Desperately Seeking Susan......or, a Scott 299C/D/LK72 power transformer

Discussion in 'Tube Audio' started by Wharfcreek, Apr 16, 2018.

  1. Wharfcreek

    Wharfcreek AK Subscriber Subscriber

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    I fear I may have just made a huge error in purchasing an old LK72 sans iron.....thinking I had both output transformers and a power transformer. In looking at what I thought was the proper PT, it turns out it's no where close. It's a 'stand-up' mount, vs a chassis mount.....and doesn't even have Scott ID numbers on it. How I made this error I dunno......... dumb I guess! But, at least I DO have the OTs. So, if anyone has any suggestions on where I might go to acquire a proper PT, I'd really appreciate the pointer!! Many thanks, WC
     

     

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  2. triode17

    triode17 Well-Known Member

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    Try Heyboer Transformers in Chicago. They made a Scott LK48 power tranny. for me a few years ago and did a great job, cost, $100.
     
  3. Wharfcreek

    Wharfcreek AK Subscriber Subscriber

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    Ah..... I know the Heyboer folks........ however I'm not sure the 'Chicago' part is correct! I believe they're actually located in Grand Haven, Michigan. I discovered this quite by accident, but it's where my mother grew up, and where my Grandparents lived until their passing. I used to spend summers there as a kid....the 'shores of Lake Michigan....'. Quite the place. My grandfather was a 'city' employee and was the superintendent of the Water Pumping Station that supplied water to both Grand Haven as well as the City of Grand Rapids. I'm pretty sure Heyboer and crew are located somewhere within the 'city of GH'....though I've never actually been there. When you got your transformer, did you have to supply an old one for a 're-wind'......or did you just buy an 'off the shelf' unit? I'm just wondering if they still have all the specs on hand?? In any case, thanks for the tip. If no one here has one collecting dust on a shelf, I'll contact Phil Heyboer and see if he can still supply one.

    Many thanks, WC
     
  4. arts

    arts Super Member

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    Didja smoke your breakfast that day?:rflmao:

    Sorry mate,couldn't resist,I'll let myself out.......
     
  5. Wharfcreek

    Wharfcreek AK Subscriber Subscriber

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    More like drank my lunch and dinner...........
     
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  6. Tom Bavis

    Tom Bavis Audiophool Subscriber

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    Looks like you need part number TR13-3 (unless it's an LK72B, in which case it's TR13-3-2 - don't know how it differs). Wasn't in Sams, so I can't give you their mis-estimate of ratings... B+ is 425V from a 5AR4, at about 150 mils idle.
     

     

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  7. Wharfcreek

    Wharfcreek AK Subscriber Subscriber

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    Hey Tom. I'll bet there are some Scott 'experts' here on AK that might know that difference! I'm wondering if the A and B is the difference between brown face and gold face? I'll take a look at the Scott web site and see if there's anything there that might add some further veggies to the soup!

    Thanks for that info Tom. I hadn't thought to even check that! Good direction!!

    Tom D.
     
  8. s-petersen

    s-petersen Scott Subscriber

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  9. Wharfcreek

    Wharfcreek AK Subscriber Subscriber

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    Well, I just checked the H H Scott Web Site....which has Schematics for both LK-72 A and B posted. There are some differences, but pretty minor. I did catch what I think might be an 'error' on the LK-72 A schematic. It shows a B+ voltage right at the first stage of the power supply filter.....after R206, of 425 VDC. However, when that same circuit line reaches the CT of the Output transformer, it's suddenly been 'increased' to 475 volts. I think that's a mis-print, as the 'B' model has 462V 'in' at the CT, and 458 at the plate. So, only a 4 volt drop through the OT. The 'A' schematic shows the plate voltage 'out' of the OT as 420V.....or 5 volts less than the 425 shown at the PS. Hence my belief that the 475 shown at the CT is a mis-print.

    Anyway..... I think that a PT from any 299 C/D/LK-72/233 would probably work.......though some adjusting might be necessary. Will be interesting to see what I end up with when the amp actually arrives. It's a 'brown' face......so I'd guess the 'A' version.

    On another note, the 'B' schematic shown on the HHS site has a note in the lower right corner under the LK-72B title that designates the Schematic as being Drawing # LK-72-C. Wonder what that's all about???

    WC
     
  10. Dandy

    Dandy Super Member

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    Didya find Susan in the end?

    ... on my way out to talk to Arts.

    Back to the topic. Are you doing a sympathetic restoration or a rat rod rebuild?
     
  11. Wharfcreek

    Wharfcreek AK Subscriber Subscriber

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    Hey D,

    Still can't find Susan!! I did send a note to Phil Heyboer at the suggestion of Triode above. Haven't heard back from him yet. I'm also going to send a note to Jaymanae (sp?) here on AK......as at one point he had indicated to me that he had enough iron to sink a battleship.......or maybe it was 'build' a battleship!....lol At any rate, at this point I'm still on the hunt. As to the question of 'purpose' for the amp, it's really just another 'resurrection' project. I saw the complete chassis on ebay with a bid of about $50, and I 'thought' I had all the needed transformers. So, I put in a $80 bid for the thing and won it for about $75 plus $20 for shipping. Thinking I had all the iron, I was thinking I could just 'install' it all and maybe bring the amp back from the dead. Of course, 'Murphy's Law' has come into play.....and now I'm going to be stuck with a 'dead amp' due to no power transformer. I'll still go ahead and put my output transformers in it...... and I'll keep trying to find a proper PT. Maybe I'll find some other unit that will both 'fit' and supply the needed sources. Guess we'll see. In the mean time........ I continue the hunt!!

    Tom D.
     
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  12. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    Tom; When Heyboer built a new P.T. for my MPX-100, they built a new one, based on the specs I gave them from the SAM's as they didn't have them for the MPX-100. They usually build a new one from pre-existing specs in house. I think the guy who I dealt with was ARLEN. I know it started with an "A", but not sure of the name but that one sticks for some reason.

    Larry
     
  13. Wharfcreek

    Wharfcreek AK Subscriber Subscriber

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    Hey Larry,

    Yea, I think you're right about the 'first time around' stuff for them. I've become pretty familiar with the company, mostly because of what I wrote above. I called there after I found out they were located in Grand Haven, Michigan.....and asked to talk to ... " the owner".. and got introduced to Phil Heyboer. We had about an hour long conversation that had nothing to do with Transformers. When we did finally 'talk iron'.... I had a Fisher X-100 output transformer that needed to be 'cloned'. I sent him the bad one that was actually 'functional' on one side of the center tap. What I got back in return was a transformer that worked across the entire primary, but had the spec of just 'half' of what it should be. Seems they'd measured across the one good half, and used that spec for the entire primary. Upon notifying Phil he immediately requested the old one back. 'fixed it right', and built me a second one 'at no charge'. Somewhere I'd found another X-100 OE unit......and I sold off the other set of OTs to another AKr who installed them in his X-100 with perfectly satisfactory results. After that, I've purchased a few more transformers from Heyboer, and found that they do have certain ones available from past repairs where they've kept specs on file. But, they've not been 'targeted' to the Hi Fi world....and done more to build units that were for either industrial use, or with major clients in the musical instrument amplifier world. All that said, their willingness to 'try' to help in a 'hi-fi' need is commendable! They're a great company! Now all I have to do is hope they have done a repair in the past and will have the spec data on hand. Or, just find a good one!!

    Hope you're doing well Larry! See you at Jim's hopefully!!

    Tom
     
  14. Wharfcreek

    Wharfcreek AK Subscriber Subscriber

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    Just a quick update: I heard back from Phil at Heyboer. He actually makes 2 Power Transformers for Scott units; one listed as a replacement for an LK-72, and one listed as a replacement for the 299C. What he couldn't tell me was: What's the difference? He indicated he was going to go back and find out. In the mean time, he wondered if I had the 'specs' for the needed unit? While I actually do not have 'specs'.....I did send him a link to the H H Scott web site where all the Scott Schematics are posted. I figured he and his engineers might be able to look at the schematics and figure out needed requirements better than I can. But, if anyone happens to have any actual 'specs' for an LK-72 A transformer....please let me know. Many thanks, Tom D.
     

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