V30 Ghost notes

[Chuck H]

This might sound wierd but...

I've been working on two combo amps. Both have ghost notes in the upper registers. Both amps are very similar in size. both amps use a V30. Both amps do not have ghost notes when plugged into an external cabinet. One uses EL84s and the other 6L6s.

Are V30's just particularly sympathetic to preamp tube resonant frequencies or something??? Anyone else have this problem?

Chuck

[pdf64]

I think you are experiencing cone cry, it's related to lightweight vintage type speaker cones, see below. Both my V30s from the mid 90s exhibit this, so much so that I reconed 1 of them, but without improvement. My Celestion Gold is bad for it also, though my Blues seem fine.
I recently fixed a Boogie Maverick from the late 90s with a pair of V30s, and those were fine. Speakers are a bit of a black art. Try the amps with a different speaker which has a more sturdy cone material.

Hope that helps - Peter.


From webervst.com

Cone Cry, Ghost Notes, Edge Yowl
Context: I replaced that speaker because it had too much cone cry.
Description: As the speaker cone is vibrated by the voice coil, it can generate frequencies of its own that may be strong enough to be audible along with the intended note or signal from the musical instrument. These notes or tones may or may not be harmonically related to the intended note, and in some cases may be either higher or lower in frequency than the intended note. This usually means that the voice coil is driving the cone so hard that it is overcoming any damping and is essentially out of control. Sometimes manufacturers use huge magnets and loose spiders so they can win the 'sensitivity ratings' contest, but the result is a system that is difficult to control. Edge yowl is the term used to describe sounds that occur when the surround resonates, imparts energy back into the cone, and generates tones and notes that may or may not be harmonically related to the intended note.

[tubeswell]

Cone cry doesn't have to be bad - Depending on when it occurs (i.e. if it only happens when you whack the strings hard) you can use cone cry somewhat with your playing style. In addition, I note that the Weber site infers that cone cry is associated with undoped speakers. So if you don't care for it but want to keep the speakers and don't mind if you alter them, you could get some lightweight model aeroplane dope and apply it sparingly around the cone rim with a small sable brush. If you are going to do this make sure the speaker is lying flat on its back while the dope dries. Beware that model aeroplane dope comes in different grades of strength - it is usually applied in order to tighten fabric or paper surfaces to improve surface smoothness, so it dries and shrinks to get the tension. The stonger it is, the more it shrinks as it dries, and if it is too strong or applied too generously, it could warp the cone a bit (I'm not saying that it will - depends on how much you slap on).

(It is also handy for repairing cones that aren't irretrievably damaged, if you apply it sparingly with a patch of some lightweight tissue paper across the tear)

[Chuck H]

I hadn't considered cone cry. But being as these are two very different amps in very similar cabinets, that alone says something for it. I suppose the next thing to try is plugging either amp into the others speaker to see if the problem still exists. If it does, it's cone cry.

The V30 is already doped. I probably won't be doping it more. And finding a more appropriate speaker won't be easy. This is the third speaker I've tried in the amp. And the first one that sounds good. UUUHHG!?! I'm gonna have to go into the used speaker business.

Chuck

[TD_Madden]

Warehouse Guitar Speakers - Veteran 30.