More PI experimentation

[misterwhizzy]

In the PI slot of my Jet City, I had a JJ ECC803S, which was a pretty decent sounding tube. I hate the short-plate JJ's with a passion, but the long-plate one sounds pretty good, and they seem to make good power tubes, so I was using it, and it worked pretty well. I had recently got frustrated, though, by a lack of note clarity and headroom.

So I dropped in my Amperex 12AU7, and it makes a good bit of difference. The amp opened up quite a bit and actually seemed to thicken up. It's counterintuitive to say that a lower gain tube could thicken the sound, but that's what my ears tell me. It's also quite a bit clearer, especially with the added distinction between strings. And the harmonic content seems much more involved now. When I play a chord with the D and G strings, I really hear some top end harmonics that didn't ring out before. I really like the fact that I seem to be getting the best of both worlds with plenty of gain, plenty of definition, and plenty of thickness.

The only downside, which still doesn't make sense to me, is that there was a bit of a volume drop. I thought the PI was designed to be a unity-gain amplifier, so it seems like dropping the gain wouldn't change that, unless that gain factor was dependent on the gain of the tube, which it most likely is. Of course, if the PI was clipping, that wouldn't matter much. Now I'm just rambling. Anyways, I can't remember why I pulled this out to begin with, but I'm happy it's back to where it was.

 

[Funkfingers]

Re: More PI experimentation

The phase inverter is designed to be a unity gain amplifier, provided that it is running the intended valve/tube.

Your choice of a superior quality valve/tube, whilst improving some sonic qualities of the amplifier, has taken it off spec.

 

[glassman]

Re: More PI experimentation

Once you go "U"...nothing else will do!

 

[misterwhizzy]

Re: More PI experimentation

Once you go "U"...nothing else will do!

A wise man once told me the same thing!

The only downside is I'm losing a bit of compression on the clean sounds so my lousy picking technique has reared its ugly head. I don't think that's the fault of the amp.

Seriously, though, Jerry, thanks for all your help. You're a great resource, and, as far as I can tell, a great guy as well.

 

[glassman]

Re: More PI experimentation

The only downside is I'm losing a bit of compression on the clean sounds so my lousy picking technique has reared its ugly head. I don't think that's the fault of the amp..

Hey Will...I'm heavy handed and have terrible picking technique. I used to be very self-conscious about it. I alway turned the guitar over to my customers to give a freshly repaired amp a run through until one of my highly talented regulars told me he wanted me to do it. I did and procedded to appoligize for my inaccuracy and he stopped me. He said: "I was listening to what you were playing, not how you were playing...you got your own style dude and I respect that". I realized that he was right...guitar playing isn't a competition and we all gotta enjoy what we bring to the table. My personal amp is the most unforgiving amplier that I have ever played...I like it that way. If I can hear my own slop, I can work on it. Will...I'd be willing to bet that you are the only one that thinks you have lousy picking technique...everyone else is probably listening to what you are playing.

and, as far as I can tell, a great guy as well.

It's so hard to tell what we are like on the internet...I try to be the same person on here as I am in real life.