Okay, rebuilt the entire thing from the ground up. But I killed the 68nF cap in Figure 3. Replaced it with a spare 47nF I had laying around (closest thing I had) and the circuit didn't work at all. Finally figured out that Figure 3 was giving me the trouble. Replaced the cap with a 30uF cap...

My trimmer is behaving poorly.

Thanks for all the help guys. I'll go back and triple check everything and look at the grounding. Keep the ideas coming!

Hey all. This isn't my first build, but I'm currently attempting the "Infinity Universal Preamp" for my bass guitar. And it ain't going too well. My building has always been a mess, but it works. So far, I've gotten audio to output, but it's incredibly distorted and there's a ton of hum. The hum...

Nope. Either they are from different eras (and thus different production designs), or they aren't the same tube.

Unplug the device before you do this.

Quote: Originally Posted by Uncle Erik Eh, who cares? There are better ways to learn about headphones. Though maybe one of the organizers for CanJam 2010 should drop an invite to Apple execs. Their products are deeply entwined with headphones - it would be good for them to come to a...

But you can usually tell when one is on its way out. Distortion and channel imbalance are two good indicators that a tube is dying.

Quote: Originally Posted by rds I thought the RA-1 uses Solens... I think it did. Maybe he just wanted different caps. Solens don't seem to get the best rap in capacitor reviews.

Last time I checked out the project's thread, it sounded like the beta builds were blowing transistors or something.

Thanks for the link. It looks like that's exactly what I need.

Oh. Oops. When you say crude, does that imply a bad design, or a non-optimal, yet still on par, way of doing it? But what's the opamp doing, then? And why can't I just bypass this all with a +18V regulated power supply? Isn't that what this is doing?

My next project is going to be the Infinity Universal Guitar Preamp for use with my bass. The designs call for a dual rail PSU that supplies +9 and -9 volts. See the 5th page of this: http://www.techniguitare.com/projets...ms-V1.1-En.pdf How come I can't just use a PSU that supplies +18...

Expect them to last a while, but plan on having a spare. That's what I do. Just like transistors, tubes can and do have failures. Fortunately, it is much easier to replace a bad tube than a bad transistor.

Yep, there shouldn't be a difference unless you use a wire that is too thin for the current going through it. But for headphone purposes, you'll be fine with whatever kind of wire you choose.

Check out this project. Could probably be easily modified to have two outputs, one in stereo for headphones, and one in mono for a power amp input. Infinity: an universal guitar preamplifier!

Hmmm, I live in the STL area. This is a little far for me to drive (4 hours), but if the timing works out, I may be in the area. I'll keep checking to stay up to date, but don't count on me being there.

I get a 404 message when I try the last link.

WHAT!??!?!?! I must be living under a rock! It's good to hear that AIC will be putting out a new album.

Ever consider that the noise is actually part of the recording? Perhaps the microphone distorted a little when she sang louder.

DIFFERENCE: 1+ vs. MKI+. 1+ is a desktop amp that uses a hybrid design. MKI+ is a totally solid state portable amp.

WANT! Vacuum Tube Chess Set

But jeez is it expensive. I went fishing for a week in Ignace, and we ran out of milk. A gallon of milk cost me almost $7!

Quote: Originally Posted by Gatto D&D is only fun if you're playing with crazy people... if you're character isn't almost dying ever session and you don't leave at least one city in ruins by accident then you're doing it wrong. I think settlers is that kind of game too, if nobody is...

^ Yep.