Tube design

[tomtom]

It's a nice design but I wonder why you use an IC, make it an all tube design !

 Just my two cents, sorry.
 Tom

[william]

The original design is based off the Mesa Boogie Tremoverb's preamp.  People keep reminding me that there are possible error's in the values of the Tremoverbs schematic, but I'm prepard to try differnt values to get what I'm looking for.  

As to why I'm using an op-amp, its because the original Tremoverb design has a tube for gain, this tube as far as I can tell produced no distortion.  This can be achived with an inexpensive IC.  This means that instead of having three tubes with one being only half used, I can have only two, and an op-amp.  I plan to find a good value for the gain of the Op-amp, and then permenatly set it with a resistor.  The rest of the cirtcuit is very close to the orange channel of the Tremoverb.

The choice of IC is mostly because thats the first Dual Op-amp I found in ExpressSCH.  I will use a TL072 when I actually build it.  

I've ordered the parts friday, and expect them to arrive soon.  Then I will know just how large the pedal is.  If its too large, it becomes a rack-mounted pre-amp.

Thank you for your time.

William

[Jay Doyle]

William,

The input opamp stage looks fine if it is supposed to be inverting, but right now it is non-inverting, and if you want any gain you need to put a resistor and cap to ground off of the inverting input.

Could be that the symbol is just upside down though...

Jay

[william]

I checked what you were saying and it is correct.  I have updated the Schematic to the suggested change.  The change was made with refrence to this page.  http://ourworld.compuserve.com/homepages/Bill_Bowden/opamp.htm

I also noticed some errors in the PCB I had planned to make, and fixed that as well.  I'll update with more information when I get the parts.

William