C*rr*m Mod?

[vh junkie]

Yeah... I'm still on the case!
Starting by putting in some protection for the OTX!
Here is part of the schematic for a 100w JCM900. It shows the fusing used there for one half(pair) of the power tubes.


I could find no fuse holder assemblies that seemed small enough to fit in the space I wanted.
So I made one. Bend the terminal strip tabs over and solder the fuse holders in place.


Here it is installed.
Left side of the fuse goes to ground via jumper to the center lug.
Right side goes to our 1ohm bias sensing resistors.
One end of these resistors were pulled from the lugs on the tube sockets and go to the fuse.
The red wire/connector in the center is a tip jack connected directly to the plate on the tube pair on this side.
This will be repeated on the other side. The "****** resistors" will be connected between the two tip jacks.
If this doesn't work out the tip jacks will be replaced by bias pots dedicated to each side.

[mr.twistyneck]

Bravo! I'm gonna go get some popcorn.have fun!

[plexified]

I'm gonna say chris merrum is brilliant , super cool and winds some of the best

iron , being a fucking rocket scientist that works for nasa and deparment of defense .

That being said, vh5150 you absolutely crack me up , love your prescence bro .

So anyway this mod sounds killer and can kill you !

I 've used this mo and the variac as attenuator and I say it fucking slays !

Don't kill yourself , its 500volts direct current . you can't let go ...sizzzzlllleeee pop

[plexified]

VHjunkie....you gonna try this? I remember(barely) when Evil Kenevil tried to jump the Grand Canyon in that rocket thingy. Everyone said not too.....but noooooo....he had to do it..... hmmmmmm kinda also reminds me of that coyote strapping an ACME rocket to his ass.....ah, that didn't work out too well either.

I am still laughing my ass off thank you !!!!

[plexified]

Bravo! I'm gonna go get some popcorn.have fun!

wow , popcorn is a start .

trying the mod ?

a good pair of steel toed work boots , at least a pair of polorized safety glasses , oh and

velcro wristband to earth or ground , a carbon fibre lead fleeced flac jacket and of course

a quality halon multi purpose extinguisher for hot times at ridgemont high !!!!

[vanhalen5150]

I just moved, If I can find my SM57 amongst the rubble pile I now denote as the "shock and awe" room I'll post a pre/post clip today.

[vh junkie]

Roller skates on his feet! Acme rocket on his back!
So you tried this with your sovtek 50? What resistance did you like?

[vanhalen5150]

It sounds pretty good but its frightening when you see the tubes acting like jet engines. Im advising people who value your tube amp to NOT try this. I tried a 4k,3k and a 1k. I stood on a plastic milk crate. My girlfriend had some friends over and they are like " why are you with him"? Her response was " I'm not sure".

[Maverick]

Icce picks

[vh junkie]

Ok, Maverick votes for sounds like Ass... Twisty and Plexified are in the plus column! VanHalen5150 is trying to explain to his girlfriend why he's playing the guitar wearing gloves and standing on a milk crate!; but gives it a pretty good!

Hmmm!

[vanhalen5150]

Very short clips. Just experimenting. Listening to these now I can hear the fear. Bad timing with sweating hands. If you saw how these were recorded you'd understand. I looked like the Karate kid standing on a pier post. I was thinking more of becoming BBQ rather than musical abilities.
Just through a SM57 in front of the cab, no real mic placement perfection. Charvel with a JB. THD hotplate. Definately something to work with. The amp had no where close to this much gain, but does sound good on its own. Getting the right resistor to match the amp would be a challange. Variable resistor? I can see how this mod could be refined in ways to be very good actually. As you go down in value's it's very evident that your tubes are going to melt. But hey, where are the limits if you dont give it a go.
More follow ups this week, If I have the nerve.

[vh junkie]

I can hear the fear!

I love it!

[Dunkmop]

How loud did you have the amp set at? You probably wouldnt need the hotplate in there, would you?

It really does sound like the amp is about to explode lol, but does sound good

Maybe too over the top.

[vanhalen5150]

The amp was all on 10. I think I actually need to go up in values not down. I need to try it with the volume set at 2-3 as well. Things you think of after the fact.

[vanhalen5150]

I had some small copper aligator clips on pin 3's, with just a touch of solder to keep them from falling off. Should I have shrink wrapped those? Picking up signals? Most likely.