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Problem: TL-404 & Selector switch

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Hi guys,
Finishing up my headphone amp/preamp today and I think I have run into a problem. Since Doc just finished his preamp/headphone amp with the TL-404's, I hope he can chime in.
The TL-404's are autoformers. The problem I have is with the output selector switch I am using. It is a Seiden 32SG selector switch which Bent Audio used to stock and now Brian Cherry at DIY Hifi supply is stocking. It is a 6 position switch. Let me describe the switch for you. The first wafer has two solderable tabs, supposedly the left and right channel. Let's call these the "output tabs" The second wafer has 24 solderable tabs. Before I soldered the individual wires from the 500 ohm, 200 ohm, 50 ohm, 10 ohm and 4 ohm sections of the TL-404 to the switch I of course checked which tab on the Seiden switch corresponded to which position using my multimeter. Mind you the ground tab on the TL-404's and the 5K tab are already soldered to the respective areas. Only 12 of the 24 solderable tabs on the second wafer actually worked when I checked with my multimeter (which makes sense since its a 6 position switch). Now everything was fine when I did this and there was no continuity(on the second wafer) with any one of the 24 solderable tabs with each other, only with the respective "output tabs" on the first wafer, so that I knew which position and which one of the 12 working tabs corresponded to which "output tab" and to which channel.
Ok?
When I soldered the TL-404 tabs to the corresponding tabs on the switch and then checked for continuity I was in for a surprise. Every one of the 12 tabs that I soldered (i.e. both channels) is now continuous with one another as well as both TL-404's. Is this because the TL-404 is an autoformer and I should be using a different kind of switch?
I really want to make sure of this before I flick the power switch!
Best,
Anand.

Follow Ups:

Re: Problem: TL-404 & Selector switch - Doc B. 11:18:57 05/10/04 (3)
Hi Anand,
I don't have firsthand experience with a Seiden switch. We used Electroswitch switches in the big headphone amp, and they are more standard than what you describe, in that the wiper (what you are calling output) terminal for a given deck is on the same deck with the "input" terminals.
When you say that the ground tab and the 5K tab on the TL-404s are soldered to the respective areas, you mean that the ground tab is connected to signal ground, and the 5K tab is connected to the parafeed coupling cap, yes?
Then the "output" (wiper) terminal of the switch goes to one of the + terminals ( L, tip or R, ring) on the headphone jack, yes?
Do you also have the - terminal of the headphone jack connected to signal ground?
- Re: Problem: TL-404 & Selector switch - AnandR 13:40:27 05/10/04 (2)
  Answers:
  The ground tab on the TL-404 is connected to signal ground, and the 5K tab is connected to the parafeed capacitor.
  The wiper(s) of the switch go to the L and R positive terminals on the Neutrik Headphone jack, and the ground jack or negative terminal is connected to signal ground.
  I have a feeling, that because my multimeter is on the 'continuity' position that it is beeping everywhere since we are dealing with autoformers that are connected to ground (as they should be). The only terminal that does not have continuity with anything else is the 5K terminal with the parafeed cap (makes sense). So I guess maybe all the beeps I am getting are just normal. I am figuring that no matter what switch you use, this will be the case for all of them since there is no separate primary/secondary for the autoformers. Did you check continuity like I did?
  Let me know...
  AnandR.
  - Re: Problem: TL-404 & Selector switch - Doc B. 16:37:03 05/10/04 (1)
    OK, Anand and I talked this thru and everything is A-OK. Yes, you will get a continuity checker to beep at every step on the switch if on end of the DMM is attached to the "output" terminal. This will also happen if you wire a multi tap transformer secondary to a switch, it isn't just the the case with an autoformer.
    A more useful test might be to connect the black lead of the DMM to signal ground and connect the red lead to the output terminal of the switch. Then set the meter to the lowest ohms scale. You should see a very low reading, like 0.1ohms at the 4 ohm position, and the readings should increase ever so slightly as you switch up to the higher impedance taps, since you are adding more turns of wire each step and hence increasing the DC resistance of the coil. At the 500 ohms tap you will see the highest reading.
    - Re: Problem: TL-404 & Selector switch - AnandR 06:46:21 05/11/04 (0)
      Here are the readings I got Doc:
      500 ohm tap: DC resistance of 10.6 ohms
      200 ohm tap: DC resistance of 6.4 ohms
      50 ohm tap: DC resistance of 2.4 ohms
      10 ohm tap: DC resistance of 0.3 ohms
      4 ohm tap: DC resistance of 0.1 ohms
      Both channels were exactly the same, off by maybe 0.1 ohms at the worst.

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