Any reccomendations on using the tube head with bass guitar. I am currently building the tube head and am thinking on using it as a preamp or compressor.

Most likely you won't have to change anything to get a satisfactory preamp. Something I always do with PAiA preamps is replace all of the signal capacitors with higher quality film caps or, in the case of high value electrolytics, Nichicon or similar audio grade electrolytic capacitors. You probably don't need to modify any of the values yet, I'd get the thing up and running with the stock values replaced first.

You may want to increase C12 and C22, this prevents any of the switching noise from the charge pump getting into your tube circuit. 47uF to 100uF is more preferable if you can fit the parts. Also, a mod I always do is to run the tubes off of filtered DC. Here is a link that shows you what to do (scroll to the bottom of the page): http://www.paia.com/ProdArticles/tmpmod.htm

Hey Cliff! Thanks for your response.

A neat thing about kits is it isn't so intimidating getting in there and making changes. A parts substitution is one of the least foolproof modifications and it adds some "me".

I've posted a response as to TubeHead w/bass guitar over in the Q/A section too. I always like to recommend building the kits as is first, then making changes. It is flat across the full range 20-20k so it is happy with bass as input. Try it too, without the changes suggested in the manual for input impedance/gain. In my opinion it's better without, particularly when the channels are series connected. The dc to tube filament mod as shown the Tube MicPreAmp is best left off TubeHead. The new filter capacitor currents will introduce hum that wasn't there. Also, in Tube MicPreAmp, the mod was developed when a Made in China tube was stocked and it really made a difference: With the current Sovtek stock, the change is not so beneficial. One more note as to dc to the tubes--about 8v is the right amount.

Any differences by changing capacitors in TubeHead will only likely be noticeable with test equipment, then, adjustments or the op-amp gains are likely to minimize these.

--sl