What do I have here?

Discussion in 'Shock Brother's DIY Amps' started by Ripdoozer, Dec 27, 2016.

  1. Wally

    Wally Telefied Ad Free Member

    Posts:
    33,945
    Joined:
    Mar 17, 2003
    Location:
    Lubbock, TX
    "Widowmaker"?? well, this is not an "American 5" circuit without a power transformer; but if RipDoozer is married, he almost made a widow of his wife. IMho, rip should consider that being able to pick his butt up after finding himself on the floor a 'free pass'. Even with an amp that is properly grounded, one will always want to check that other equipment is not waiting to put one at risk. B.B. King was in the long term habit of making contact to the mic with his guitar strings---while NOT touching any ground point on the guitar---to check for such dangers. That is a crude but effective way of keeping one's self somewhat safe. A meter is a good tool to have to check such things. A wall circuit checker is an inexpensive safety tool, imho.....one would like to know how the AC socket in the wall is wired. Less than $10 will tell you that...carry it wherever you go. There is one outlet in this building here that I do NOT use because that checker told me that it is improperly wired. IT is not my building, it is not in a position that I want to use anyway, and there are many other properly wired circuits to use. I checked those sockets before I moved stuff in here.
     
    24 track likes this.
  2. tubeswell

    tubeswell Friend of Leo's

    Posts:
    2,374
    Joined:
    Jul 1, 2008
    Location:
    NZ
    A 3-wire mains cord should fix the problem of electric shocks - as long as there is nothing else wrong with the amp.

    But the electrolytics should definitely be replaced with 'equivalent value' new ones.
     
    JuneauMike likes this.
  3. 24 track

    24 track Doctor of Teleocity Silver Supporter

    Posts:
    14,622
    Joined:
    Nov 6, 2014
    Location:
    kamloops bc
    I came across a pepco with no power transformer but the company was kind enough to give a schematic on how to install one for my amp, the components in RipDooozers definately look Tech worthy to have it checked out properly to insure no corroded contacts and wiring and the the components are all stable for nearly 70 year old amp. thanks for getting back to me.
     
  4. Mr Ridesglide

    Mr Ridesglide Tele-Afflicted Silver Supporter

    Posts:
    1,928
    Joined:
    Dec 11, 2009
    Location:
    Bloomington, MN
    Rip - are there any techs in Austin? few up here in the cities if you wanted to take it in somewhere. I'd do it for you, but I'd be hesitant to work on something that is that cool - just in case i did something not so smart.... and made it worse!!
     
  5. keithb7

    keithb7 Friend of Leo's

    Posts:
    4,817
    Joined:
    Jan 9, 2010
    Location:
    Western Canada
    Here's one I had on my bench. I thought the back panel was a remake. I guess not.

    [​IMG]

    [​IMG]

    Sounded awesome cranked up!
     
  6. CV Jee Beez

    CV Jee Beez Tele-Holic

    Posts:
    662
    Joined:
    Nov 24, 2016
    Location:
    Duarte, CA
    You could clean all the contacts with some D-Limonene and then rinse w/ isopropyl. Kind of get all the dirt out. My Supeo was in a garage for years and all I did was clean up the circuit this way, replace the speaker wire, fix a short on the lead from the cone to terminal, and replace tubes. 2 years later , going strong.
     
  7. zook

    zook Friend of Leo's

    Posts:
    2,479
    Joined:
    Aug 6, 2003
    Location:
    Cochise, AZ
    When everything had only 2 prong cords back in the 60's it was common practice to check the polarity between the PA and the Amp by quickly touching the mike stand while touching the guitar strings to see if there was a shock. It was not necessarily a big shock, but enough to know to reverse one plug, or else switch the ground switch. Most of us lived :)
     
    robrob likes this.
  8. Recce

    Recce Friend of Leo's Silver Supporter

    Posts:
    2,632
    Joined:
    May 3, 2016
    Location:
    Northern Alabama
    What you are saying is if you swap out everything that makes it special you would like it. You can only have original 50's by leaving it alone. I agree with the folks that say take it to a tech and have it checked, cleaned and problems corrected.
     
    Last edited: Dec 29, 2016
  9. Ripdoozer

    Ripdoozer Tele-Meister

    Posts:
    142
    Joined:
    Sep 8, 2015
    Location:
    Austin, MN
    So, I assume I can't just run the wires in reverse...Yes, I decided to just replace the cord for now....Then at least it will work so I can tinker on from there. But I've seen, in multiple locations that the fuse should be wired on the hot side (black). But this amp has other things wired to the fuse as well. So, if the black wire went to the fuse, that would mean the white wire would go to the switch/pot? It can't be that simple can it? If it's not that simple, can I just desire it the way it was (neutral to fuse and hot to switch)?... with the addition of the ground obviously....

    Please try to refrain from telling me that I made a mistake by taking this action. I will probably end up taking it to someone, but I just wanted to get it into safe, working order so I can mess with it until I can take it to someone. Thank you.
     
  10. tubeswell

    tubeswell Friend of Leo's

    Posts:
    2,374
    Joined:
    Jul 1, 2008
    Location:
    NZ
    Phase/Active ('hot') wire from mains cable goes to mains fuse holder tip terminal (very important!). Ring terminal of mains fuse holder goes to main switch terminal. Other main switch terminal goes to one of the PT primary ends (doesn't really matter which).

    Neutral/return wire from mains cable goes to other end of PT primary winding. Use an insulated screw clamp terminal to join wire ends.

    Earth wire from mains cable gets clamped, then soldered, to a ring terminal, which is lok-nut* fastened to its own dedicated chassis bolt, to make a secure electrical contact with the chassis.

    *ny-lock fastening nuts are the best.
     
    Doctorx33 likes this.
  11. Robster

    Robster Tele-Afflicted

    Posts:
    1,002
    Joined:
    Feb 14, 2009
    Location:
    Marietta, GA
    You can also find that amp as the Silvertone 1340. You may have a schematic in the bottom of it. Mine was from 1954 and still sounded great with all original components.
     

    Attached Files:

  12. beezerboy

    beezerboy Tele-Meister

    Age:
    69
    Posts:
    308
    Joined:
    Sep 7, 2016
    Location:
    AK
    ya... what he said. cut the old cord off & put it in a bag so someone can return it to original if they want.
     
  13. robt57

    robt57 Telefied Ad Free Member

    Posts:
    23,749
    Joined:
    Feb 29, 2004
    Location:
    Portland, OR
    Is that like the early Danelectro with only a PT and no OT with AC where DC should be to be safer? If I worded that right.
     
    bparnell57 likes this.
  14. Ripdoozer

    Ripdoozer Tele-Meister

    Posts:
    142
    Joined:
    Sep 8, 2015
    Location:
    Austin, MN
    Hey everyone. I swapped out the cord for a proper 3 pronger. Someone had been in there and really messed some stuff up. I moved the fuse to the hot lead and removed a weird jumper wire that was running from the fuse to one of the tube pins. It was messed up. It works very well now. Tomorrow night I will (very carefully) test it with our rehearsal p.a.! Now, I can work on updating the electrolytics.
     
    tubeswell likes this.
  15. Wally

    Wally Telefied Ad Free Member

    Posts:
    33,945
    Joined:
    Mar 17, 2003
    Location:
    Lubbock, TX
    Best of luck with it. I personally would not put the amp to use like that in its condition. YMMV.....but if it ceases to function, then cross your fingers. and...sometimes stress in a circuit doesn't exhibit total failure but rather can compromise components so that they might still 'work' but not yield full and healthy results....meaning that one might just miss knowing that an amp is less than it should be.
     
    Doctorx33 and Tremade like this.
  16. Bill Moore

    Bill Moore Tele-Afflicted Silver Supporter

    Posts:
    1,137
    Joined:
    Feb 2, 2012
    Location:
    Silver City, New Mexico
    That type of shock was common back in the day! Even after the mandate for grounded recepticles, most venues were still just 2 prong. (Even in the 80's, I would find venues with 3 prong recepticles, that were not grounded, or even wired incorrectly!)
    The standard procedure was to get the PA, (if you had one), set up for the lowest noise, (like Wally said). Then while holding your guitar, touch the mic with the back of your hand, if you got a tingle reverse your amp plug, (or flip the "ground" switch, if you had one). Sometimes you had to put up with a little more noise in your amp to keep the PA quiet!
     
    Wally likes this.
  17. Ripdoozer

    Ripdoozer Tele-Meister

    Posts:
    142
    Joined:
    Sep 8, 2015
    Location:
    Austin, MN
    In the last sentence of my post I mentioned that I was going to update the components. Just gonna test my work on the new cord tomorrow since that is where the initial shock happened.
     
  18. tubeswell

    tubeswell Friend of Leo's

    Posts:
    2,374
    Joined:
    Jul 1, 2008
    Location:
    NZ
    You may well find you need to replace the old electrolytic caps. In old e-caps, the electrolytic compound between the plates breaks down with age. Over about 10 years old, they get progressively more unreliable. This can manifest in various symptoms, such as more hum (motor-boating), or at worst, complete failure (filter cap short) which can destroy your power transformer (if this happens to the reservoir cap). This would be a bugger to replace in a vintage amp. Replacing the filter caps is the lesser of two evils - in terms of 'interfering with the original mojo' - in this regard. New filter caps will also make it work better/more reliably. And these days you can get filter caps in 'vintage' values, so there's no excuse.
     
    Doctorx33 and boredguy6060 like this.
  19. Ripdoozer

    Ripdoozer Tele-Meister

    Posts:
    142
    Joined:
    Sep 8, 2015
    Location:
    Austin, MN
    Yep. Again, no need to explain. I am going to replace them.

    I wonder if there's a "parts list" of sorts that would itemize the components, or would I have to build one from the schematic. Hmmmm
     
  20. tubeswell

    tubeswell Friend of Leo's

    Posts:
    2,374
    Joined:
    Jul 1, 2008
    Location:
    NZ
    What's written/stamped on the outside of the cap can? (Usually has numbers like '40-20-20' or something like that - these are usually uF values). The voltage rating is also important. (You want a voltage rating the same or higher than the rating stamped on the can, and higher than the peak voltage seen by the caps at startup*)

    * clip your red VDC meter lead onto the reservoir cap +ve pole tab and the black lead onto the ground return pole when you start the amp up, and watch what the VDC reading rises upto a few time when you switch the amp on and off and on again etc. The reading will rise initially and then dip back down again to idle voltage as the heaters kick in.
     
    Last edited: Jan 3, 2017
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.


  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.