Booster: Micro Amp vs Mosfet

**jorgemg1984** · 03-26-2012, 08:09 AM

Hi there!

I have a Fromel Shape EQ pedal that I love bue it does not have a boost knob which is very handy in EQ pedals - first I like hitting solid state amps with a little clean boost, second if you cut too much mids or bass you end up loosing a lot of volume. And my jazzmaster ultralight is not so loud at 8 ohms...

So my tech is going to check the idea of adding a boost circuit to the pedal if there's enough space inside for the board and the footswitch.

Does anyone here has experience with the MXR Micro Amp or a Mosfet booster like this one?

AMZ Mosfet Booster Guitar Effect

Do you have any prefference for a neutral / linear booster that does not color your sound?

Thanks!

**monkmiles** · 03-26-2012, 09:45 PM

I'm a big fan of FET and Mosfet boosts. But they tend to color a tad in a similar fashion to tubes. I have an Xotic EP booster that I really like...fat sounding and small. The ZVex SHO is a good one too and there are builders who make clones in those tiny enclosures to save on space. Used to have a Fulltone Fat Boost 3 that was good too. There's others that have caught my eye like the Keeley Katana.

**jorgemg1984** · 03-27-2012, 05:56 AM

Thanks for your input, I was told by a forum member who really knows this things the Micro Amp should be more neutral than the Mosfet booster - but the tube saturation sound makes me curious

I think both the EP and the SHO will colour my sound too much (and maybe the Mosfet too so there's a chance I end up with the Micro Amp)

The Fulltone and the Keeley seem great but I need something with an available schematic so my tech can do the circuit... does the mosfet color your sound too much? thanks!

**monkmiles** · 03-27-2012, 07:00 AM

Yes, a FET boost will color your tone more than something like the micro boost. In my opinion, I don't think FET boosts color the tone "too much". Mosfet and jfets are both types of FET transistors and found in a bunch of boosts and overdrives these days because of their tube or amp like feel. But they are not completely transparent...which is what many like about them.

I have a lot of experience with pedals. Lots and lots of pedals through the years but mostly in a rock or fusion style of play. I don't use pedals for straight jazz. My pedalboard for rock these days has about 7 pedals including a couple FET pedals. It was a magical tonal moment for me when I first tried a jfet driven overdrive because I had only used tubescreamer opamp overdrives previously.

The AMZ mosfet boost is found in the Catalinbread Super Chili Picaso among being a huge influence to other FET boosts.

Another non FET boost to look at would be the one by MXR/CAE. And of course the old EHX LPB.

Lots of good info and opinions on pedals like these on thegearpage.net effects forum.

**jorgemg1984** · 03-27-2012, 07:27 AM

Wow lots of info, thanks! I will take the pedal to my tech today and let's see what he tells me... do you think the CAE is very different from the regular Micro Amp? The Mosfet tube feel really appeals to me

I read some things on TGP as I usually do but I have two problems with that forum 1) when someone asks about a pedal (in this case a clean boost) you get tons of answers which one advocating a different pedal is the absolute best ever made (usually obscure and expensive) 2) I don't find reviews there very accurate usually... but it's a greater forum to gather info!

Thanks again,

**mangotango** · 03-27-2012, 09:24 AM

I use a Carl Martin Hydra pedal. it's a fairly clean +15db boost that will give me a big enough lift to stand out from the band without my having to fiddle with the volume control, or colouring the sound too much (though there is a knob on the pedal that will allow you to control the amount of grunge that you add

) .

**jorgemg1984** · 03-27-2012, 10:24 AM

Ok back from the tech! He will order a very small pcb and then we will decide between one of the boost circuits, probably the mosfet one. The pcb is very small and he said the pedal has space for it, a knob, a foostswitch and even a dedicated led to the boost

Can't wait to have it back... thanks for the help guys!

**monkmiles** · 03-27-2012, 10:37 AM

Originally Posted by jorgemg1984

do you think the CAE is very different from the regular Micro Amp?

I haven't actually played the CAE, so I can't say. This thread at a DIY forum seems to have links to schematics of both or at least some talk about them: mxr microamp vs amz mosfet booster

Originally Posted by jorgemg1984

Ok back from the tech! He will order a very small pcb and then we will decide between one of the boost circuits, probably the mosfet one. The pcb is very small and he said the pedal has space for it, a knob, a foostswitch and even a dedicated led to the boost

Can't wait to have it back... thanks for the help guys!

Very cool. Yea, these should be simple/small circuits. I play around with modding here/there, mostly wah pedals though since they're easy to mod. I did attempt to build my own jfet boost that I found a pcb and schematic on...but I screwed it up somehow and then decided I should just concentrate my time on playing pedals rather than trying to put one together!

**jorgemg1984** · 03-27-2012, 10:57 AM

Thank god I am completely unable for those tasks... I think I would be modding things all the time

This way I control myself and let that work for my tech! I will tell you how it all went.

**jorgemg1984** · 04-18-2012, 12:14 PM

Update: my tech build a LPB-1 boost and instaled it in my Shape EQ - it's working great when i scoop the mids! He was able to add an extra footswitch and led and also got the same knob as the other ones so the pedal looks stock

Fromel should really add a boost to that pedal. it's very simple and it's kind of important in EQ pedals. This turned a good pedal in an excellent one.

Thanks for the help!

**monkmiles** · 04-20-2012, 10:17 PM

Awesome. Share a pic if you have one. Any particular reason you went with a LPB-1 for the boost? I'm sure it's a good choice, just curious.

**jorgemg1984** · 04-21-2012, 08:49 AM

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ImageShack® - Online Photo and Video Hosting

It really looks stock...

The reason for going with the LPB-1 is curious actually. My tech ordered stuff from Musik Ding because it's pretty cheap and I had told him I wanted the Mosfet Booster; He made a mistake and ordered the LPB-1 so he did a second order for the Mosfet. He then installed it and for some reason it didn't work well: loud pop when turned on; huge earth noise in my pedalboard; the pot did a loud scratch noise when moved; etc... He said let's try the LBP-1 just for fun and... it worked great! I am still curious about the Mosfet but since this one worked so good... it's staying!

**iim7V7IM7** · 04-21-2012, 10:23 AM

Hi,

I have experience with two "clean boost" pedals; 1) Lizard Leg Effects "Flying Dragon" (Lizard Leg Effects - Flying Dragon Boost)
and 2) Xotic Effects "RC Booster" (RC Booster).

Flying Dragon: This is a FET based clean boost that provides up to 13 dB of boost. It is the most transparent, non-compressed boost that I have heard. The company's slogan is "your sound, just more" and that is exactly what it does.

RC Booster: Is an opamp based clean boost with a very useful +/- 15 dB bass and treble EQ. It ever-so-slightly compresses your signal so you can tell when it is on. The EQ controls are extremely useful in particular for rolling off highs and controlling bass output.

I recommend both depending on your application.

Best,

Bob

**jorgemg1984** · 04-21-2012, 10:48 AM

Hi Bob, thanks for your input but the problem is already solved

I needed a small circuit to add to my EQ pedal and the LBP-1 circuit did it very good! On my other pedalboard the Para DI is doing the trick for me.

I am currently waiting for a pedal with a full of mods Tube Scream and a stock RC Booster indepent of each other. I am using the RC Booster adter the TS and also after my RAT to better manage their volume (stacking it basically) and specially to EQ them to my taste. I can report when I have it.

**Insufferable_Rhythm** · 04-21-2012, 02:58 PM

Originally Posted by jorgemg1984

The reason for going with the LPB-1 is curious actually. My tech ordered stuff from Musik Ding because it's pretty cheap and I had told him I wanted the Mosfet Booster; He made a mistake and ordered the LPB-1 so he did a second order for the Mosfet. He then installed it and for some reason it didn't work well: loud pop when turned on; huge earth noise in my pedalboard; the pot did a loud scratch noise when moved; etc... He said let's try the LBP-1 just for fun and... it worked great! I am still curious about the Mosfet but since this one worked so good... it's staying!

"Der HardOne"? A pull-down resistor at the input would have solved the pop. The scratchy noise is completely normal for this circuit. "Huge earth noise" can be more elusive, but he probably just needed to "reflow" his ground joints.

**jorgemg1984** · 04-21-2012, 03:07 PM

Yes, exactly that one. Hmm good to know all those things, I will tell him that because he told me he had a use for that booster on other project. For me the LBP-1 worked so well I will keep it as it is!

**Insufferable_Rhythm** · 04-21-2012, 03:29 PM

Can the boost be activated independently, or only when the Shape EQ is also activated?

Just wondering because the LBP-1, while a fine circuit for driving an amplifier into distortion, has a very low input impedance and will load down your pickups.

**jorgemg1984** · 04-21-2012, 03:32 PM

It can be activated independently, I just use it if I need it.

Really? Funny, it seems to be working good, gives me a lot of boost without distortion and I am not noticing any special change in my sound.

**Insufferable_Rhythm** · 04-21-2012, 03:35 PM

It could be less noticeable with a darker tone. Also, if you have any pedals on before it (or buffered bypass pedals), the issue would be negated.

**jorgemg1984** · 04-21-2012, 03:51 PM

I have pedals before it, maybe that's why I am not noticing it. They are all true bypass but were ON when I used them. Funny thing the Shape EQ has a switch between true bypass and buffer, if I ever use it as a standalone pedal I should use it buffered then.