DIP switches on preamp

[BassLife77]

I was thinking about building this preamp kit but the high and low pass filters are controlled by DIP switches on the board. so there is no immediate control over the tone while the preamp is in a box. Can the DIP's be substituted with switches or pots that can be mounted on the box? Can the 1M trimpot be substituted with a 1M rotary pot so I can control the volume more easily?

[line6man]

I'm not sure why you would want something like that in a bass?

I would just use rotary switches to select the capacitor values.

[SpamBot]

I'd be wary of the current draw of two tubes. Even with subminiatures, you have two of them, and an IC to power.

[slyjoe]

I think the OP said it was going in a box, so in that case, with an external 9v supply, the current draw may not be an issue.

The volume can be replaced with a pot. The problem may be finding appropriate switches. There are a total of 8 combinations for the low pass, and 16 for the high pass.

Other than that, no problem.

[BassLife77]

Originally Posted by line6man

I'm not sure why you would want something like that in a bass?

I would just use rotary switches to select the capacitor values.

I was gonna put it in an enclosure. according to the instructions the C4 cap has to be substituted with a 0.22uf if the preamp is used for electric bass. since the previous mini-tube enclosure I built sounded so great I'm gonna give this a try. but those DIP switches and the 1M trim pot are useless if they are in a box. I was thinking maybe some DPDT type switches or pots could be used in their place.

[BassLife77]

Originally Posted by slyjoe

I think the OP said it was going in a box, so in that case, with an external 9v supply, the current draw may not be an issue.

The volume can be replaced with a pot. The problem may be finding appropriate switches. There are a total of 8 combinations for the low pass, and 16 for the high pass.

Other than that, no problem.

yes, they are 4 way DIP switches. never had to deal with those

[line6man]

Originally Posted by BassLife77

I was gonna put it in an enclosure. according to the instructions the C4 cap has to be substituted with a 0.22uf if the preamp is used for electric bass. since the previous mini-tube enclosure I built sounded so great I'm gonna give this a try. but those DIP switches and the 1M trim pot are useless if they are in a box. I was thinking maybe some DPDT type switches or pots could be used in their place.

If this is going to be in an enclosure, you can just use eight SPST switches.
Or why not just get the DIP switches mounted outside of the enclosure?

[BassLife77]

Originally Posted by line6man

If this is going to be in an enclosure, you can just use eight SPST switches.
Or why not just get the DIP switches mounted outside of the enclosure?

I thought about 8 SPST switches but I thought it might be cumbersome to have so many switches on one box. could I get the same results with some 4PDT mini toggle switches?

[i_got_a_mohawk]

8 SPST switches would give you the capabilities of the 2 x 4DIP switches. If you were to use a couple 4PDT switches, you would only have the option of all on or all off. (ie the electrical equivilant of turning all the switches on one of the 4DIP switches to on or off).

[line6man]

Originally Posted by i_got_a_mohawk

8 SPST switches would give you the capabilities of the 2 x 4DIP switches. If you were to use a couple 4PDT switches, you would only have the option of all on or all off. (ie the electrical equivilant of turning all the switches on one of the 4DIP switches to on or off).

Yep. 4PDT will only give you a total of four options.

Why no use two rotary toggle switches?

[BassLife77]

Originally Posted by line6man

Yep. 4PDT will only give you a total of four options.

Why no use two rotary toggle switches?

didn't think of rotary, that sounds like a better option. how would I wire those to the board? I'm trying to teach myself electronics, huge learning curve.

http://www.electronics-made-easy.com/
I knew I should have took those electronic classes in school

[line6man]

Originally Posted by BassLife77

didn't think of rotary, that sounds like a better option. how would I wire those to the board

The biggest thing about the rotary switches would be getting all the options. Ideally, you would want a 4P16T switch to do all 16 options, but it would probably be really difficult to find such a thing, and it would be quite large with 68 solder terminals!

You might have to settle for fewer than 16 options.
You could easily do any 6 options, but I'm not sure whether you could find rotary switches with more positions.

I can do diagrams for whatever rotary switch options you come up with. Just let me know what you decide to do.

[JackANSI]

Originally Posted by line6man

The biggest thing about the rotary switches would be getting all the options. Ideally, you would want a 4P16T switch to do all 16 options, but it would probably be really difficult to find such a thing, and it would be quite large with 68 solder terminals!

You might have to settle for fewer than 16 options.
You could easily do any 6 options, but I'm not sure whether you could find rotary switches with more positions.

I can do diagrams for whatever rotary switch options you come up with. Just let me know what you decide to do.

You could try a Binary Coded Decimal (BCD) switch (with a 4-bit output) since you have a common and 4 independent choices.. You'd only have 5 connections to make to the switch..

like:
http://www.elexp.com/t_bcd.htm

But its going to probably be hard to find a panel mount rotary one..

[BassLife77]

holy crap I didnt know this was going to be this advanced. I think I'll mount the DIP's on top of box and run wires to the board. that will save me a lot a headaches, time, and money. thanks for the suggestions!