why is SHO super hard on your amp?

[ampgeek]

Sorry..I should have mentioned that I was envisioning putting this "pipe dream" right at the entrance of the PI (~45VDC) and upping everything to a 50'ish VDC rating. Power from a voltage divider somewhere off of the B+rail.

I now see that this is more akin to the recovery stage of a Klein-ulator than a re-adaptation of a simple stomp box booster.

Thinking that the best approach will be to tell the amp owner to leave something on his guitar volume pot whenever he anticipates kicking in the clipping circuit mid song!

Thanks as always guys!
Dave O.

[eniam rognab]

EP Booster http://s21.photobucket.com/user/reverwe ... c.jpg.html
What FET types are recommended for Q1?

maybe try a J201 if you have one handy. also an MPF102 will probably work... might sound shitty though.

i like using 2SK117 fets in stomp boxes.

i forgot to mention (probably unnecessarily) that the pinouts of these fets are different and are not drop in replacements for each other. particularly the 2sk117, i have to bend the leads around each other to fit the proper pinout on my circuit boards...

anyway carry on.. im all for this thread morphing into whatever you guys wanna talk about...

[eniam rognab]

Howard Dumble built the same thing into the amp itself and provided it with a footswitch labelled "PAB" (Pre Amp Boost). Tell your buddies its your Dumble mod.

Cheers,
Ian

this has me thinking though....

got a schemo? cause ill build it! i aint afraid!! and turn it up!

STORTION!!!

[martin manning]

Howard Dumble built the same thing into the amp itself and provided it with a footswitch labelled "PAB" (Pre Amp Boost).

Not exactly. The PAB is a tone stack lift. Dumble's JFET booster was accessed via a separate input jack that sent the guitar signal to the FET, just like putting a pedal in front of the amp. Look at any of the Dumble schematics in the files section.

[ampgeek]

Check the "Dumble Files" section of the Amp Garage index for all of the Dumble style amp files that you could ever need.

The PAB is a switch that lifts the tone stack from ground and provides a significant boost with a modest change in tone (depending on your tone settings of course).

Many D-style amps have an FET input channel that might provide some inspiration here. I have excluded that from the two builds that I have done.

Cheers,
Dave O.

[ampgeek]

LOL Beaten to the punch by a minute or two.

Thanks for confirming MM!!
Dave O.

[eniam rognab]

i did just this after posting



noooooooob alert!!!!

thanks guys

engineers are sooo smaht!!

[eniam rognab]

Howard Dumble built the same thing into the amp itself and provided it with a footswitch labelled "PAB" (Pre Amp Boost).

Not exactly. The PAB is a tone stack lift. Dumble's JFET booster was accessed via a separate input jack that sent the guitar signal to the FET, just like putting a pedal in front of the amp. Look at any of the Dumble schematics in the files section.

u da man martin, u da man ampgeek.

you guys (hugs)

[ampgeek]

Rock on fellow, former, I assume, New Englander!!

I am a displaced NH native (by way of Boston) living in San Diego for the past ~17 years.

Cheers,
Dave O.

[eniam rognab]

Rock on fellow, former, I assume, New Englander!!

I am a displaced NH native (by way of Boston) living in San Diego for the past ~17 years.

Cheers,
Dave O.

NICE! i loved living in sandy eggo! my wife graduated from UCSD, during which time we lived in north park and la jolla. i have lots of dish network friends down that way!!

miss that ocean here in sacramento, but we have some pretty amazing rivers!!

[Structo]

What?

A Super Hard On is "Hard On" a amp?

[jaysg]

Dumble's JFET booster was accessed via a separate input jack that sent the guitar signal to the FET, just like putting a pedal in front of the amp. Look at any of the Dumble schematics in the files section.

Some people think the David Lindley bits on Jackson Browne albums are through the JFet input. Sounds like it to me. I have built a couple AMZ MosFet Boosts and it's a similar sound. Please correct me, if I've got the wrong end of the stick...again.

[EtherealWidow]

Here are a couple of mods for the SHO. http://revolutiondeux.blogspot.com/2012 ... n-sho.html

[eniam rognab]

Here are a couple of mods for the SHO. http://revolutiondeux.blogspot.com/2012 ... n-sho.html

hey that looks familiar!!

love that website, wasted MANY hours there... and here...

at the bottom of the page is the Landgraff clean boost. Looks like NTE does make and equivalent mosfet. NTE490.

although i havent had much luck with NTE components... high on price, low on quality.... what else is new?

[davent]

In place of the BS170 you can also use a 2N7000, pinout is reversed.

Couple SHO boards.
[IMG:640:480]http://i216.photobucket.com/albums/cc305/davent/IMG_2635.jpg[/img]