Z-28-ish

[Drew.12345]

Hello,
Just finished up my Z-28ish build with some mercury magnetic iron I had lying around from another failed project. With some help from a couple Amp Garage members this thing is up and running and I couldn't be happier. Such a wealth of knowledge available here and such williness to help fellow members succeed. You guys are great!
I had a heck of a time getting the bias circuit just right but everything is as it should be now- Thanks guys.
Hats off to the the doc for this little circuit... this is amazingly simple and yet sooo effective.
This is my take on the Z-28 as I have wanted this amp for several years. I am really impressed by the Docs work and designs and I would love to own the full Z line. The new Z-Wreck is amazing! IMHO I think he makes some of the best amps on the planet and I hope to contribute to his work by purchasing from him soon.
I really love the breakup and volume level on this amp. I especially like the way I can set the tone stack up for easy pickin' and smooth clean tone and then crank a couple knobs and get overdriven tube heaven. I REALLY love the raunch I get out of this thing with my tele.
Sorry for the rambling here are some pics.
Camera pics were about 6meg so I saved as PDF to reuce this

Drew

[surfsup]

RED! very cool. Nice work..

[Drew.12345]

Red always makes the iron sound better!
LOL

[Drumslinger]

Congrats on your new build Drew!

[Luthierwnc]

IMHO, this is an amp design that really works well with a Dumbleator active loop inserted just before the phase inverter. Take a look on the Dumble Discussion page to follow-up. The loop is a single tube active buffer that uses a cathode follower to get the impedance down for the FX and then runs the signal through a normal gain stage to bring the levels back up (or more).

My experience with this design is that the first gain stage is so well thought out that putting a raunchbox before the input just makes it sound like every other amp in the world. By putting a little hair on after the tone recovery stage it doesn't mess with the mojo to that point. Even without using any effects it adds a little richness to the tone and is very scaleable. Not a difficult project (at least, easier than the one you just made). Not very expensive either. Food for thought, Skip

[Colossal]

Drew,

Great looking build, congratulations. What kind of music are you playing through the amp?

[M Fowler]

Congrats Drew, nice build.

[Drew.12345]

Luthierwnc,
Nice idea! I actually have Nik's c-lator (dumble-ator clone). Im going to look into this and give it a whirl. Could prove very effective as this amp seems to take pedals quite well.
Thanks

Colossal,
Thanks- I love this amp. I'm a huge paisley fan so some of his riffs always come out. I find myself playing tom petty or stone. I like this amp so much because of the chunky rhythm tones I get when I crank it.
Sadly.... not much of a lead player.

Mark,
I couldn't have done this without you.
Thanks once again

Andrew

[DR.Z]

Nice job Drew.
Gut shot looks good.

DR.Z

[Drew.12345]

Wow! Thanks Doc!
Im a huge fan of your work! It is an excellent amp and your design is brilliant.
Thanks for what you do...I hope to get the real thing one day.. or maybe a Route 66... So many great amps and so little time.

Drew

[Lynxtrap]

That preamp is phenomenal! I just had to try it in my Fender. It might be on it's way to become an "icon" as K O'C would call it. Not my Fender but the Z preamp, that is

[Luthierwnc]

Drew.12345;

If you have the loop, you probably have the rest of what you need still lying on the bench. Run your send from the center lug of the volume and the return to the top of the inverter. That is a lot of enemy territory so be sure to use coax on at least the send run. With that big bright cap I don't think you have to worry about losing capacitance.

I've been messing with pentode front-ends (mostly 5879s) for a long time and I can't think of a single application -- other than Dumble-style amps themselves -- that benefits more from the active loop before the inverter. It just seems to breathe. I've done it with higher-gain amps but it gets lost. Run your time-based effects in the loop and your grinders before the jack.

A word of warning or at least a recommendation to research it more -- you need line-level loop effects that don't suck tone or you need to look at a parallel mixer like a Minimix. I just have a cheap TC G-Sharp (hundred bucks shipped) that works great but there are some suckage devices out there that don't play well with others.

Fun project. I'll bet it works with most of your guitars too, sh

[wsaraceni]

looks great. i've been kicking around what to do with my half built express and think I'm going to try this preamp in it this weekend and next week. have a few ef86s coming (hopefully one isn't microphonic). do you know the voltages on the ef86? I'm assuming ill have some things to change since I'm not going with the z28 power section and bias, ill be using the stock express el34 power amp