Results 1 to 19 of 19

Thread: 50's Danelectro Tube Tremolo (Vibrato) circuits, Octal tube, which?

  1. #1
    Senior Member
    Join Date
    Sep 2006
    Posts
    598
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    13

    50's Danelectro Tube Tremolo (Vibrato) circuits, Octal tube, which?

    For those familiar with those type of amps, which octal tube did they tend to use for the trem circuit?

    0 Not allowed! Not allowed!

  2. #2
    Supporting Member
    Join Date
    Apr 2009
    Location
    NY, NY
    Posts
    1,234
    Thumbs Up/Down
    Received: 13/0
    Given: 79/0
    Rep Power
    12
    they used the 6au6 in some but it's a 7pin tube.

    0 Not allowed! Not allowed!

  3. #3
    Old Timer
    Join Date
    Jun 2007
    Posts
    5,096
    Thumbs Up/Down
    Received: 83/0
    Given: 54/0
    Rep Power
    19
    Are you asking out of curiosity or are you trying to find out what tube goes into a specific amp?

    0 Not allowed! Not allowed!

  4. #4
    Senior Member
    Join Date
    Sep 2006
    Posts
    598
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    13
    It's a specific amp, but there is 0 info nor a schematic. It's a Wabash Deluxe from the 50s. It came in dead with the tubes in the wrong sockets, wrong tubes, etc.

    I figured out what tube type went where by testing the pin out, new caps , new star ground and a few other things and I got it working again, but the Vibrato tube is some sort of Octal power tube with standard 6L6/6V6/etc. type pin out, 2=H 3=P 4=G2 5=G1, I have no idea what specific tube. In any case it isn't working, and its not an optocoupler type setup, it's all done with that tube like many others did with smaller tubes.

    I'd be willing to bet it is a Valco, it is not dissimilar to some Harmony and other amps I've seen, so I figured there would be some Valco/Dano expert who might have an idea.

    Not sure on the Rectifier either. It came in with 6V6s (in the wrong slots) and a 5Y3. It doesn't bias anywhere close to correct, nor are the DC heaters on the preamp tubes, which are drawn from the bias tap correct, with those tubes, but it biases correctly with the right heater voltages (series heaters) with 6L6s, and the PT doesn't get hot from the current draw so that seems right. 5Y3 in a 6 tube amp with 6L6s....don't think so. Not sure what would have been correct for it though; 5U4 draws a lot of current, GZ34 would raise the voltage quite a bit. There may be some vintage rectifier I don't know about with that pin out that is supposed to be there.

    0 Not allowed! Not allowed!

  5. #5
    Old Timer
    Join Date
    Jun 2007
    Posts
    5,096
    Thumbs Up/Down
    Received: 83/0
    Given: 54/0
    Rep Power
    19
    So the trem tube is for the low freq osc? Is the socket wired for a single or dual section tube?

    0 Not allowed! Not allowed!

  6. #6
    Lifetime Member Enzo's Avatar
    Join Date
    May 2006
    Location
    Lansing, Michigan, USA
    Posts
    31,719
    Thumbs Up/Down
    Received: 1,602/7
    Given: 0/0
    Rep Power
    54
    he said it was wired for an octal power tube like 6L6.

    Try various power tubes there and see. 6V6, 6K6. Doesn't seem like 6L6 would be used, but try it.

    0 Not allowed! Not allowed!
    Education is what you're left with after you have forgotten what you have learned.

  7. #7
    Senior Member
    Join Date
    Sep 2006
    Posts
    598
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    13
    Single. As I noted, heater at 2, anode 3, 91ohm resistor between anode and G2 at pin 4, G1 at pin 5. Power comes in at the screen grid, so the plate voltage is lower.

    I traced the thing tonight, looks like this tube functions in conjunction with a 6SJ7 to produce the vibrato effect across the coil of the field coil speaker. Has to be really, the rest of the amp is isolated from it. I tested all the resistors, caps, pots, grounds, everything is within tolerance and functional, at least on the meter.

    I'll see if I can scan and post my crappy hand drawn schematic of the trem circuit.

    I only have the common tubes on hand. I'll see if I can get my hands on some less common vintage octals with that pin out. I was hoping someone would have seen similar to narrow it down, there were a few Valcos I found pics of on the web that at least had a family resemblance to the control layout. I've seen some references to some of them using a 6SN7 and a 6SJ7 together, but the pin out is wrong for the 6SN7.

    Rectifier: GZ34 is a no-go, voltage too high and bias is off, not to mention it makes the amp noisy. 5U4 also a no go, the heater current makes the PT get hot. It seems happy and quiet with the 5y3, so for now its staying in unless I find out about some higher current ability, rare, vintage recto tube with the same pin-out and voltage multiplier.

    0 Not allowed! Not allowed!
    Last edited by wizard333; 09-19-2014 at 06:34 AM.

  8. #8
    Old Timer
    Join Date
    Jun 2007
    Posts
    5,096
    Thumbs Up/Down
    Received: 83/0
    Given: 54/0
    Rep Power
    19
    Quote Originally Posted by wizard333 View Post
    I traced the thing tonight, looks like this tube functions in conjunction with a 6SJ7 to produce the vibrato effect across the coil of the field coil speaker. Has to be really, the rest of the amp is isolated from it.
    I've not seen that before. Interesting, fluctuate the magnetic field to produce tremolo. Cool. Keep us informed.

    0 Not allowed! Not allowed!

  9. #9
    Senior Member
    Join Date
    Sep 2006
    Posts
    598
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    13
    Crappy hand drawn Schematic below:

    Click image for larger version. 

Name:	WabashDeluxeTremSchematic_zps5dea647d.jpg 
Views:	531 
Size:	43.6 KB 
ID:	30648

    0 Not allowed! Not allowed!

  10. #10
    Senior Member
    Join Date
    Jul 2012
    Location
    The 26th state
    Posts
    589
    Thumbs Up/Down
    Received: 0/0
    Given: 1/0
    Rep Power
    8
    If you want, email it to me and I'll try to post it. gui_tarzan@yahoo.com

    0 Not allowed! Not allowed!
    --Jim


    He's like a new set of strings... he just needs to be stretched a bit.

  11. #11
    Senior Member
    Join Date
    Sep 2006
    Posts
    598
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    13
    So does anyone know of an amp with a similar setup to the schematic I posted, maybe one with a schematic and tube chart available? Anything jump out as to what tube it might be or why it might not work? I tested all the resistors/caps/pots all appear to be functional within their parameters.

    0 Not allowed! Not allowed!

  12. #12
    Supporting Member Jazz P Bass's Avatar
    Join Date
    Dec 2008
    Location
    Wernersville, PA
    Posts
    12,828
    Thumbs Up/Down
    Received: 449/2
    Given: 236/0
    Rep Power
    25

    0 Not allowed! Not allowed!

  13. #13
    Member
    Join Date
    Sep 2010
    Location
    Roxboro, NC
    Posts
    50
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    9
    The earlier Gibson GA-40's used a 6V6 and half of a 6SN7 in the Tremolo.

    I had to make a new drawing, in order to troubleshoot one of mine ('54), and I've attached that drawing.

    Jack
    Attached Files Attached Files

    0 Not allowed! Not allowed!

  14. #14
    Senior Member
    Join Date
    Sep 2006
    Posts
    598
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    13
    6SJ7 maybe.
    No, wrong pin out, see above.

    I did try a 6v6 but it didn't work. I can't find any non working components either. Do you remember what you saw change at the pins when the controls were manipulated, voltage wise?

    0 Not allowed! Not allowed!

  15. #15
    Senior Member
    Join Date
    Sep 2006
    Posts
    598
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    13
    Click image for larger version. 

Name:	WabashDeluxeTremSchematic_zps8de714cc.jpg 
Views:	193 
Size:	43.6 KB 
ID:	30880

    Updated/corrected schem attached. I honestly don't know how this would work, but that is how it is wired.

    0 Not allowed! Not allowed!

  16. #16
    Senior Member
    Join Date
    Sep 2006
    Posts
    598
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    13
    The other thing is that, since the trem section is on one side of the field coil, what tube goes in V6 makes a big difference in the strength of the magnetic field generated by the coil and hence the volume of the amp. The more current draw, the more voltage across the coil, the stronger the field. A 6v6 leaves almost no clean headroom and a volume not much above conversational levels; a 6L6 gives reasonable volume with some clean headroom. Neither make the trem work.

    This amp, alone among anything I've ever seen, seems to absolutely require a certain tube set to work at all. Wrong power tubes = wrong load which throws the heater voltage on the preamp tubes way off, bias on the power tubes way off (since the DC preamp tube heaters are connected to the bias, which in turn is connected to everything else). Can't substitute rectifier tubes either, only a 5Y3 makes the thing work right. Obviously there is some tube that will make the trem work when inserted at V6, since there are no bad parts in that circuit. Anything else won't cut it.

    The other odd thing is, though it is clearly a fixed bias, grounded cathode amp with dissipation around 70% at idle with various 6L6s in the power sockets, it acts a lot like a class A amp in that Ia drops when not at idle, and never goes above idle current.

    0 Not allowed! Not allowed!

  17. #17
    Member
    Join Date
    Mar 2010
    Posts
    234
    Thumbs Up/Down
    Received: 2/0
    Given: 5/1
    Rep Power
    10
    Silvertone 1333 uses 6SJ7 for tremolo. No field coil speaker....

    0 Not allowed! Not allowed!

  18. #18
    New Member
    Join Date
    May 2008
    Location
    GA
    Posts
    2
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    0
    Quote Originally Posted by wizard333 View Post
    For those familiar with those type of amps, which octal tube did they tend to use for the trem circuit?
    I would bet that the tube in question is the 6Y6G. Its pinout matches your amp's wiring and is what was used in the Danelectro Maestro field coil tremolo circuit from the early 50's along with a 12SJ7 for the oscillator circuit, but Danelectro also used the 6SJ7 as the oscillator valve in other amps of the mid-50's that had a 6.3V heater winding rather than a 12.6V winding.

    What is the rest of your amp's tube complement?

    0 Not allowed! Not allowed!

  19. #19
    New Member
    Join Date
    Apr 2019
    Posts
    1
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    0
    Hello Wizard 5years ago you had this thread going, I just found and purchased a 56 Wabash Deluxe and am trying to figure out the trem circuit and also what is correct speaker load since mine has a non original speaker in it. If you are still on this forum or if anyone else can help it would be most appreciated....thx!

    0 Not allowed! Not allowed!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Bought a tube tester and need 9 pin adapter for octal tube socket
    By kka in forum Maintenance, Troubleshooting & Repair
    Replies: 2
    Last Post: 04-02-2012, 05:34 AM
  2. Half Tube Tremolo/Vibrato?
    By Natman in forum Maintenance, Troubleshooting & Repair
    Replies: 1
    Last Post: 01-27-2010, 08:55 PM
  3. Simple octal tube socket question
    By Chevy in forum Maintenance, Troubleshooting & Repair
    Replies: 6
    Last Post: 02-15-2009, 06:46 PM
  4. 50's Baldwin tube amp
    By baddog in forum Conversion Projects
    Replies: 8
    Last Post: 10-22-2008, 04:55 PM
  5. Need suggestions for 50's tube amp debug
    By vortex in forum Repair and Restoration
    Replies: 3
    Last Post: 12-14-2006, 10:07 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •