Home Forums GuitarPCB Build Support Sunn Model T Switching (solved)

Viewing 17 posts - 1 through 17 (of 18 total)
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  • #3274
    Sasan
    Participant

    Hi there,

    I’m new here an hope I don’t start a topic about something that has been discussed before.

    I saw in the building docs of the Sunn Model T that the switch changes from Normal (top) over Brite (middle) to Both (bottom).

    How do I change the setting that I have BOTH in center position and the other twos on top/bottom?

     

    Thanks in advance & regards

    #3275
    Cybercow
    Moderator

    Sasan – with the appropriate On-On-On toggle switch, the wiring diagram shown on pages 2 & 3 of the Sunn-T build document demonstrates the connection setting so “center” is engaging both the “brite” and the “normal” channels. When I built my Sunn-T, I followed that diagram and “both” is in the ‘center’ position of the On-On-On toggle switch.

    #3277
    wilkie1
    Moderator

    +1 Cybercow!  When this circuit was developed, we found that there are different switch patterns found with ON-ON-ON switches.  We suggest you use your DMM meter to test the particular switch you are using to validate the switch pattern it has.

    The desired operation is to have BOTH channels active in the center switch position.

    #3279
    Sasan
    Participant

    Hi Cybercow, hi Wilkie1,

    thank you both for your quick reply. This answer is even better.

    I got confused a bit by the graphic of the switch in the building documentation. Here it looks as if Normal is the top switch position, brite the center one and both the bottom one

    thanks again for your help

    #3280
    wilkie1
    Moderator

    The labels shown for the BRITE, IN and NORMAL are the destinations for those wires.  Sorry if that was confusing.  The dark blue lines represent the switch contacts positions when the switch is in the center position.  This is valid for many switch types.  Others may vary.  That is why I suggest you validate your particular switch before wiring.

    #3284
    Cybercow
    Moderator

    Sasan – If you look at the diagram at the bottom of page 2, you’ll note the BLUE lines in each of the three depictions of the switch, represent the switch’s internal connections in each of its 3 positions.  In the image at the top of page 3, (like the last image you posted), the blue lines on the switch shows the switch in its “center” position. Some times the details are a devil. 😉

    Glad you sussed it out. The Sunn-T is a useful circuit. I was using mine just last night at a gig. Just wanted to add a small bit of the kind of OD sound the Sunn-T can deliver.

    #3334
    Sasan
    Participant

    Hi friends, I don’t think the blue/green lines are confusing. Rather the picture description on the one that I’ve inserted in my last post.  Maybe you could add a box which states something like „switch position center: both in“ instead of the „center [picture] both“.

    #4058
    mybud
    Participant

    Greetings all: Just built the Sunn-T, and it sounds great. Mild settings are especially useful to my ears.

    However, I’ve run into the same switching issue as Sasan (earlier posts regarding non-functioning centre position). I did test the wiring with a DMM and thought it (the switch, that is) corresponded exactly with the build document layout, but no. No sound in the centre position and other options working fine. I could do this by hit and miss but don’t want to mess it up. So could anyone kindly advise a step-by-step solution to some my problem?


    @Sasan
    : I seem to recall that you solved this by swapping some wires? Would you mind giving me a bit more detail?

    Best to all and thanks for a great forum (and circuit).

    Marc (South Africa)

     

    #4059
    Sasan
    Participant

    Hi Marc,

    I just mirrored the wiring for the Switch horizontally.

    So basically, the two white wires are on the left, the red one on the right and the connection from middle left to bottom right. Would flip the image for you but i‘m on my phone and dont find an option to mirror images.

     

    Hope this helps

    #4198
    mybud
    Participant

    Hi all: Thought I’d provide some feedback (no unintended) on my adventures with the switch. I tried Sasan’s mod first, flipping the wires along the vertical. Please see above. This makes sense because the switching pattern (in the middle position) is asymmetrical. That was my a-ha moment!

    But sorry to say same effect, no sound in the middle position. I then rewired it as per Barry’s diagram above. Same story. It crossed my mind that an alternative arrangement might be to use an ordinary DPDT to give the option of choosing between normal and brite channels, but not both, but now I’m kind of determined to resolve this particular option (i.e. all options available).

    I then redeployed my trusty Fluke DMM and lo and behold, the switching pattern for this particular one (MTS-2 from Tayda) appears to be different, as follows:

    1                   4

    2                   5

    3                   6

    Centre position (1 connects to 2, 5 to 6)

    Switch up (2 connects to 3, 5 to 6)

    Switch down (1 connects to 2, 4 to 5)

    If anyone has the patience to help with us, it’ll be greatly appreciated. I’m afraid it has me beat; I can’t get two options to work but not three.

    Best to all and many thanks in advance, Marc

    #4204
    wilkie1
    Moderator

    With your switch in the position you have described:

    Jumper lugs 1 to 5.  Connect the IN wire to lug 5.  Brite to lug 6.  Normal to lug 2.  Now you  will have normal operation with center position connecting both channels.

     

    #4211
    mybud
    Participant

    Thanks again, wilkie1. Problem solved.

    #4718
    Anonymous
    Inactive

    Hi all. Rather than starting a new thread, I’ve tagged in to this one. I getting a very faint sound out of the center channel.  The two other positions seem fine, but have less gain than expected. I’ve reflowed all the connections to no avail. I have a multimeter, but I’m not sure how to check the voltages at different switch positions  any advice? Thanks

     

    #4726
    Barry
    Keymaster

    The Crash Course Guide on the Guides Page will show how to take voltages.

    #4738
    Anonymous
    Inactive

    So take voltages of each transistor in all 3 switch modes? Each switch position reads the same: Q1- 6.9, Q2- 8.25, Q3- 8.04, Q4- 9.76

    #4740
    Billy
    Moderator

    Your green jumper should go from middle right to bottom left yours looks like it goes from top right to bottom left on the DPDT switch

     

    #4745
    Anonymous
    Inactive

    I can confirm it is wired middle right to bottom left. Just looks wrong in the pic from the angle.

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