Putting a buffer into a tube driver.. Help please

[msurdin]

I have a tube works 911 tube driver. I am building the IC buffer off GGG (i heard this is a decent buffer..any comments on it?) I want to be able to turn on the pedal like normal but when the TD is on the buffer comes on with it (I dont want the buffer to always be on).

Thanks For your help
Matt

[shredgd]

The Tube Driver already incorporates an IC buffer at the beginning of its circuit, you don't need another one.

[msurdin]

I was talking to pete cornish and he was telling me how he still put a buffer into the TD and it kept it from getting muddy and keeps it on the bright side..
Would building one into it hurt it at all? Would it do what cornish said?

Thanks

[shredgd]

Actually my DIY Tube Driver has even got too much treble...
Pete Cronish is an effect guru, but I can't get the point in adding a buffer right before a buffer!
However you might build the buffer anyway and give it a try. I suggest you to try it without putting your hands into the Tube Driver, at first, that is in front of the pedal, so you can then decide to incorporate it into the pedal or not.

[msurdin]

Alright. I will do that. How do I then wire it into it so it is turned on/off at the same time as the TD?

[shredgd]

As far as I know, the Tube Driver's own input buffer is always on, so you can't put a circuit in front of it and have it turning on and off with the original footswitch. Unless you put your new buffer after the TD's own buffer, but I don't think this would address the same purpose you were talking about, you cannot do it (it would require replacing the footswitch with a 3PDT one and making the whole pedal true bypass).
In both cases, you should have a look at the GGG schematic for the TD and make your mind (in front new buffer always on vs. buffer in the middle of the circuit on/off). Keep in mind that R4 is actually two 680k resistors in series in your pedal, because the point between the two is where the signal is taken (from the end of the first 680k) to the footswitch and from the footswitch back to the circuit (to the second 680k). So what is there before the first 680k is the input buffer of the TD.

In the case you decide to add the buffer in front of the circuit (always on), I've never owned an original Tube Works 911, however, as you are going to make a series connection, you simply should follow the signal (wire) coming from the input jack, unsolder it (probably at the input jack end of the wire is a better idea than at the board end), take your buffer and solder it in between, that is you connect the wire you just unsoldered to the output of the buffer and you solder a new wire from the input jack to the input of your buffer.
This is very simple, but now you have the problem of the alimentation. The Tube Driver works with a +15v/-15v power section: 30v would probably be a bit too much for your buffer, even though the buffer inside the circuit is already powered that high. You might, instead, use the +15v and ground, but you should be able to find out the +15v paths in the board (ground is not a problem, the ring of one of the jacks would be fine).

[Ben N]

If you read Cornish's essay on buffering vs, true bypass, one of the reasons he gives for usig buffers is tomaintain an even level and quality signal throughout, without being subject to imedance mismatches whe you switch in or out this or that effect. In other words, part of the point is to have it on all the time. Now, that is not the only approach, of course. But you should look into that before building a buffer just to switch in/out along with your tube driver, in addition to the one that is already there.

hth,
Ben