boost

[1878]

Hello Everyone...

Need some opinions. I'd like to build a simple, 1 knob power boost to drive a Digitech RP7 fitted with an Electro Harmonix 12AX7. Here's the criteria:

1. It has to be able to link up with my 9v daisy chain.

And that's it.

I'd prefer something with a little dirt rather than completely clean, but again, I'm open to suggestions.

Thanks in advance

[shredgd]

Go with the Electro Harmonix LPB2: simple, yet very effective.

One word about your application, though: your Digitech pedalboard, as any other solid state device, will distort unpleasingly with a booster in front of it (the fact it features a 12AX7 doesn't change things: it's got solid state stages before and after the tube).
If you put the booster after it, instead, you will have a useful boost for solos, and you'll drive the input of your amp harder to give you some more grit. However, you might also get the same result by working with the Digitech's output volume (similarly, you usually don't need a boost for solos with digital pedalboards, as you can simply save extra patches with a bigger output volume for solos).

Giulio

[1878]

Thanks for the reply...

I've run my double muff before the RP7 and it's handled it ok. I know what you mean about the 'unpleasantness' though. I'll only be giving it a gentle push so I'm hoping I'll get the desired effect. I'd stopped using the RP7 until I changed the valve. It's amazing what one good quality component can do !!

Thanks again.

[MikeH]

Boosters can range from clean and brittle (MXR micro amp) to soft and dirty (AMZ mini booster).  It's hard to say which type (if any) will hit the preamp of your multi fx in the most pleasant manner, so you really ought to bread board a couple to find out.  A good middle of the spectrum boost (and perhaps the best place to start) would be the AMZ mosfet boost, or a zvex SHO, in my opinion.

[DougH]

I would build an NPN boost over the LPB. But try a number of them on your breadboard and pick which one you like best.

[suprleed]

I would try Tim Escobedo's Utility boost.  It's simple and flexible in that it allows for different transistors.  I've tried both a 5089 BJT and a J201 JFET.  The 5089 is dirtier/rougher, while the J201 is a little smoother.  A darlington is also possible but I've never tried it.  Throw a socket in there and experiment w/ trannies to your hearts content.

For what it's worth, I often use my boost in front of my Digitech RP250 with decent results (and it doesn't even have a 12ax7).  It doesn't work on every setting, but I've found that boosting a few of the clean tube amp models yields pretty good results.  I know purists are rolling there eyes here, but hey its all I got for now.  The dirty channel on my SS amp sounds like a metal file on a cheese grater, so boosting the digitech into the clean channel is a definite improvement!  Whatever sounds good to you is key.

[shredgd]

I would build an NPN boost over the LPB. But try a number of them on your breadboard and pick which one you like best.

The LPB actually is an NPN boost... Maybe you were thinking about the Microamp, which uses an IC?

Giulio

[MikeH]

Either way- Boosters generally contain so few components that it's not expensive to buy the parts for say 10, and breadboard them all.  Then just box up the one you like best/that does what you're looking for.  And all of the extra parts you'll have left over are VERY common and can be used in hundreds of other builds.

[1878]

Thanks for the replies.

I've just run the double muff/RP7 combo again. I really pushed it this time and it wasn't good. I'm thinking of building another parallel universe and sticking that in front of it. I'll probably just end up using the RP7 for modulation and delay. It's quite poor in some aspects, but you can 'get the horrible' if you really try.

Cheers.

[snoof]

I would build an NPN boost over the LPB. But try a number of them on your breadboard and pick which one you like best.

The LPB actually is an NPN boost... Maybe you were thinking about the Microamp, which uses an IC?

Giulio

I think Doug is referring to Gus's NPN boost.  the beginner project.  I like Gus's over the LPB as well.