First Trainwreck Express build, This Amps Going Metal \m/

[martin manning]

Dave, I think there are a couple of problems with your PPIMV schematic. The 2M2 safety resistors have to go from the pot wipers to the bias supply to get 220k to Vbias when it's maxed, and you also have the terminal numbers flipped on one pot- the way you have it one side is maxed when the other is at min. I don't know if there is any real standard, but I think the CW lug is most often labeled 3.

[Colossal]

Dave, I think there are a couple of problems with your PPIMV schematic. The 2M2 safety resistors have to go from the pot wipers to the bias supply to get 220k to Vbias when it's maxed, and you also have the terminal numbers flipped on one pot- the way you have it one side is maxed when the other is at min. I don't know if there is any real standard, but I think the CW lug is most often labeled 3.

Oh man! Good catch Martin; I appreciate it. That was bad QC on my part. I whipped that drawing out rather quickly and didn't take the time to compare it to the photo for accuracy. I corrected the drawing and reposted. Good thing Hobbs hasn't tried it yet I added the shielding icons as well to the shielded runs to the grids.

[HobbswheresCalvin]

IIIITTSSSS ALLLLIVVVEEE

after a few mistakes fixed, its alive.

i had wired the power tube resistors R20 and R21 to the wrong lug, had them wired in with the diodes going to ground. popped a fuse even on the variac

after we fixed that. realized one of the sets of diodes on the power tube was wired in the wrong direction. Fixed that those 2 were probably done at the very end of my night the first night i was building. i essentially built the amp in 2 days but had to wait to get the filter caps to wire them in and finish this sexy beast

we first tried some older USA made fender tubes that tested really high, Fenders. with some GT 34s in the power stage. sounded good. but the tube in the first stage was microphonic so i changed it out for one of the high grade substitute mesa tubes, the SPAX7, the one with the heat shring tubing around it. worked like a champ

these tubes are all for the time being, my coworker is an amp tech and were gunna go thru all of his NOS tubes and see what works the best.

i may have to go thru some solder joints in the preamp stage. it seems when i smack the amp around a little it kinda crackles a bit, we are going to change a few tubes and see if that doesnt fix the problem because alot of the noise im hearing seems to be coming from the tube choices.

but so far i love it.

O and you guys were saying its loud. well FUCK how can ANYONE LIVE AT THIS VOLUME. haha im going to definitelly do the PPIMV mod, but am going to test it as it at band practice tonight. the clarity and the sustain on this amp. and the responsiveness....man i cant say enough. i even noticed some nuances with my guitar volume and tone controls. its so clear i can hear the inconsistencies with my volume sweep. it tends to dive at the end. it could be because the carbon has been wiped away from play, but im definitelly going to change it out.

thanks for all your help guys, and ill be back

time to go play some METAL \m/

[RJ Guitars]

Congrats! Looking forward to the practice report. 2 days is a pretty fast build time for an Express even if you didn't sleep much. can't wait to hear the clips and maybe even see it on stage with you. rj

[HobbswheresCalvin]

Cabinet hasnt been made yet, but it will happen soon. have to recover from the funding i have already put into this project

Thinking a Bubinga Shell with an Ebony Front, Most likely going to do a design thru the front and add some lighting to the inside of the cabinet to give it some real sense of life. but im stoked that tis come this far

[HobbswheresCalvin]

Good thing Hobbs hasn't tried it yet I added the shielding icons as well to the shielded runs to the grids.

haha glad i saw this conversation on this post before i tried it as well, just checked it because i saw RJ had posted.

going to start working on this next week most likely, for now ill enjoy the pureness of it

[HobbswheresCalvin]

so ive got an audio file for you guys, its not the best quality but it does show how responsive the amp is. recorded in our rehearsal spot tonight during practice.

the amp was making all sorts of noise when i had anything plugged into it. then after a little while i guess it "broke" itself in. and sounded pretty good, this was recorded halfway thru practice, i had unplugged my saturator distortion and line 6 m 13, im pretty sure it was the m 13 that was making a bunch of noise, but anyways, when i plugged straight in, the amp seemed to like me alot more.

the tone was incredible. so clear and cut so well. i dont have too much problem with the amount of bass response and the el 34s are definitely a good choice, over the 6v6s

i have the amp almost fully cranked and some of th treble pulled out with the smaller brite cap in the circuit. presence control is very responsive and i think besides a few bugs its great.

a little hiss but it seems like its the first tube stage. well see what a mullard or tungsol does for that

Thanks again

[fishy]

Congrats on your build. Always a good feeling.

Interesting clip.....not heard an Express clip like that before.

Plugging stuff into the front end of an Express does not seem to result in much success from my experience and what I have read.

[HobbswheresCalvin]

haha, ya i am trying to go where no guitarist has gone, trainwreck + metal.

overall it went well, super clean and easy to play on. i did not fight for my tone at all with the amp, and the little guy even overpowered my bandmates 5150

[leadfootdriver]

Cool!

[HobbswheresCalvin]

I figure, i might as well post this here as well

Amp sounds great, got a little hiss coming from the first channel but with how loud im pumpin it, its expected. Got it up around 3 oclock. Sounds monstorous,

Going to order the parts for the ppimv tomorrow hopefully, as well as the parts to turn my presence into a presonance knob. The highs are very strong with this one and im just not finding much use out of the presonance top range, i use the smaller bright switch and thats enough for me.

I dont need the Master Volume for practice, but for bedroom use......its a must,

We put svetlana EL 34s in it, and it loves em. I have so far a mullard that rates around 1300 on both sides and a tad that rates at 1650 in the second position, and a new jj in the phase inverter socket, liking it thus far, thanks you guys for all your help

Ill post some more clips now that i have some knobs on it to judge my settings and a clearer idea of the tone i am getting out of it.
They will be metal of course. Fast and heavy.

[Colossal]

Got it up around 3 oclock. Sounds monstorous,

Going to order the parts for the ppimv tomorrow hopefully, as well as the parts to turn my presence into a presonance knob. The highs are very strong with this one and im just not finding much use out of the presonance top range, i use the smaller bright switch and thats enough for me.

I dont need the Master Volume for practice, but for bedroom use......its a must.

The master will change the tone slightly but at 12'oclock (and with the gain at 3 o'clock) you will probably really like the tone; really heavy and tight. Glen K. suggested turning the bright switch off for a bit more heaviness (which I do 99% of the time). Also, try backing off on your guitar's tone knob slightly; that will thicken the sound.

[HobbswheresCalvin]

Ya i figured it will change it a bit, thats ok as the amp has such a big sweep of tones, im sure i can find one that works. For practice with the drummer, im going to leave the master wide open as well as live, because theres no point. Our drummer plays so hard. I can turn the amp to full bore and still hear even his kick.

Hes a metal drummer but the way he decribes it he plays harder then he does fast...and with as many cymbal and stick breaks ive seen from him. I believe it

This amp doesnt lie its hilarious. now everyone hears my fuckups in practice, not just me. Its great as well as i noticed my guitar volume is a little toasted. When i turn it all the way up theres a drop in volume and tone. And if i back it off to 80% it sounds great again.

[Reeltarded]

Awesome dooder! I love the ppimv as a tone selector, you will find it good for finding the right blend of feedback. I normally place mine just loud enough to compete with a snare, and then work the tone settings out from there, around 7 with most amps.

Nice rig!

What tap os your NFB on? I used to use the 4 tap, but with the ppimv it is better on the 16 and ride the edge of it.

[HobbswheresCalvin]

Well i am using the 4 ohm impedence with my cab, and have the NFB on the 8 ohm as in the layout, havent messed with the way its typically wired yet. I almost dont want to change it considering how good it sounds, i did change the first preamp tube back to the high grade mesa i had, the mullard exploded, i think it was mainly due to how tight the sockets were to begin with and i changed its position a few times. Was a bitch to get it out. But the mesa tube is alot less reactive to hits against it with a chopstick so i kinda like it more and sounds a bit better to me. Not as mucb midrange and a little bit more glassly sounding.

But ill probably order parts for the ppimv and presonance controls soon.

And will be ordering the cabinet soon. Not going to go traditional there though