New Liverpool - Judy Jean

[Gibsonman63]

C-EC40X3-525
Capacitor - Electrolytic, 40/40/40 µF @ 525 VDC
Three section FP type electrolytic capacitor. Each section is 40 µF, rated at 525 VDC.

From AES. The other one is 20/20/20 @ 525.

[Colossal]

Very cool that you paralleled the input Gibsonman. I hate to waste a good triode I paralleled the input on a Rocket build and it sounded great and very quiet too.

[ChrisM]

What filter caps, look old.

[passfan]

Try and isolate from the feedback by disconnecting from the OT tap to eliminate that part of it. It sounds like a time lag from the time you play a note to the time you hear the ghosting.

[Gibsonman63]

Try and isolate from the feedback by disconnecting from the OT tap to eliminate that part of it. It sounds like a time lag from the time you play a note to the time you hear the ghosting.

Still there and the amp still sounds great other than the ghosting on really high notes. I double checked the color code for the OT and I am on the correct tap for global negative feedback.

I don't know if I am getting used to it or if it starting to diminish a bit. I will be able to measure AC ripple on my power supply in a couple of days when my Fluke arrives. The can caps make for a clean build, but could it be that they aren't the best choice for this amp? The ghosting is always about the same note regardless of what note I play, which is making me suspect the power supply. Some notes are ok and some get cancellation.

For most of what I play, it wouldn't be noticable, but there are a couple of things. The lead to "All Right Now" for example. The the last few notes are fairly high on the higher strings. The listener may not notice it in the mix, but the feel is different playing it when the notes don't sustain well.

[selloutrr]

so is it ghosting or boosting / cutting notes do to phase cancellation?

If you are running multiple speakers make sure they all fire the same direction. I'd look at the phase inverter on out to the OT of the amp if you are getting a cancelling of notes.

[passfan]

You know I had a chance to spend the afternoon swapping tubes through mine and I was surprised at how well a 12au7 performed in V1. It allowed me to run the gain up even more while maintaining a cleaner overdrive and cuts down on the hiss a ton. I noticed with certain tubes, such as RCA and telefunken, that my upper frets didn't sing as well as some of the lower ones. EI's seemed really fuzzy, a 12ax7 Mullard was palatable. The best sounding 12au7 was an older Sylvania out of a Conn organ. If you find something for certain wrong let me know.

[Gibsonman63]

Thanks guys. I put the 1.5K screen resisters back in. I seem to get just a little more hair with those.

I'll try swapping some tubes around later tonight and see what happens.

I'm pretty sure my speakers are firing the same directon. I've used this particular cabinet for a long time with a lot of different heads. It's only really high notes, and just some of them because it is adding the same pitch all the time.

VVR is great in this amp. No difference in tone or drive at all. The only difference is that you move less air.

My board should be back in action next week and I will be able to post some clips.

[zambo]

try disconecting the cathode bypass cap.

[Gibsonman63]

I'll give it a try and report back over the weekend. I had a band session with it the other night and it works really well in the mix as long as you are playing rock and roll. It's definitely a differenct animal from the Express.

I have been playing with the brighter of the two bright swtich settings. I was thinking that if I tweak the coupling caps to voice the amp just a hair brighter, I may get attenuate some of the ghosting as well.

[rooster]

You might want to try breaking the Presence control ground off from the Vol/Tone control ground path. Give it, the Presence control, it's own ground. If you are going for the KF look, certainly get that .1 cap ground to the other side of the Presence control pot.

Also, as I look at your pics and focus on the grounding of the Presence Control, I see another ground wire coming off the board? What the heck is that wire attached to? Whatever it is I am pretty sure you don't want it there.

It is a good looking build, BTW.

[Gibsonman63]

Rooster,

By presence control ground are you talking about the ground tab for the pot or the ground through C10 and R14.

The ground coming off of the board is labled bias on the layout. It picks up a ground between R17 and R18. Did I miss something there or are we talking about a different ground?

[rooster]

Well, let me explain then. Cut that ground buss wire off after it finishes with the bass pot. The extended buss wire then (what's left in the Presence comtrol area), just unscrew it and replace it with a solder lug - attach your Presence ground here, skip the ground lug that is on the Presence pot. The 220K resistors, yes, attach them there also. (I was drifting into Express land there for a moment.)

It just needs a different ground path, that's the suggestion.

BTW, most ghosting things are typically involved with lower frequencies, so when you said it's a higher frequency thing, you need to look at the Presence control.

[Gibsonman63]

Actually the ghosting is lower frequency, but it is only noticable when you play a higher note.

[rooster]

Oh, I see. Well, I still think you might want to consider the new ground for the Presence control, but your call, no worries.

As to the ghost note event in a Class A EL84 quad, it's highly reported. Notably the G string above the 12th fret, FWIW.

When you considered additional filtering, I think you were on target then. Do you have a quality 47uf/450VDC cap around? If you do and you want to pursue this, PM me.