Split Stack & T100S

[iamkrash]

Is the TS-100 available

[assquatch20]

Is the TS-100 available

Nah not enough interest. Had some guy up north offer me maybe $200-250 because he insisted scratchy pots would need replaced instead of cleaned. The tubes in it are worth that much. I'll let my kids sell it when I'm gone. I'm 33 so hopefully it'll be awhile.

[rnolan]

Hey assquatch20, you could (if you wanted to) repurpose the T100S as a very nice HiFi amp.  Freq response is 10Hz-20KHz.

[assquatch20]

Hey assquatch20, you could (if you wanted to) repurpose the T100S as a very nice HiFi amp.  Freq response is 10Hz-20KHz.

I'm sure it would be great for that but I think I might have it looked over and put it back to work for some occasional gigs. Really just needs the pots cleaned though. Wired a 12x12 wall of cabs up as two 8 ohm loads so I can run it with all kinds of amps.

[Kazinator]

Really just needs the pots cleaned

Could it be that there is DC flowing through the pots from the tube grid? Even clean, new pots will scratch if there is DC.

The pots are decoupled from DC on the amp input via 10 uF nonpolar caps. But they are DC grounded, and directly connected to the tube.

If a measurement shows DC on the pots, or the R16 grid resistor, one thing to try might be to insert a capacitor between the pots and ground, to make them AC grounded (like pots always should be in most designs).

I.e. you never do this:

Code Select Expand

  IN --||-------+
                |
                >
                >
                > <----- OUT
                >
                >
                |
                |
                V

where OUT could be a potential source of current, like a tube grid or transistor base, etc.

You want this:

Code Select Expand

  IN --||-------+
                |
                >
                >
                > <----- OUT
                >
                >
                |      OK, no DC across pot
               ---
               ---    AC ground
                |
                V

or this:

Code Select Expand

  IN --||-------+
                |
                >
                >
                > <---||-- OUT
                >
                >
                |      OK, no DC across pot
                |
                |  DC ground, but decoupled from IN and OUT
                V

At least two out of the three paths to the pot have to block DC.

[rnolan]

Hey Kaz, good to know, and thanks for that, though I suspect a good clean and all will be good.  Over the years (many of them) my B200s pots got a bit scratchy, a decent clean, they are all good (for another 20  years). I suspect it's much the same for a T100S.

But hey, as you say, if that doesn't fix them...