Pentode/Triode...WTF???

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cellardweller

cellardweller

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I'm sure I knew at one time, vaguely, what this meant...

I have an ampeg vt120. I would like to be able to take it from it's present output of 120w down to 60w for recording purposes. Let me detail the switchs/knobs on the back, because if anyone can give info on these they will be awarded 86 sluts...um... err..., oh, I mean virgins in the afterlife... :D

"Pentode/Triode" switch
"Low damping/High damping" button
"presence" knob
"60w/120w" switch

What is "damping?
How do I safely switch it to 60w without changing the ohm rating(or how do I compensate correctly?)?
What is "pentode/Triode"?

Please help me. I've been battling my horrible tone for years now, and I'm ready to burn down my house, so I can buy new equipment.

In prone supplication I implore thee for help!!! :( :o
 
cellardweller said:
What is "damping?
Click to expand...
Damping controls how the speker will react to the amp. More damping tightens the sound up.

cellardweller said:
How do I safely switch it to 60w without changing the ohm rating(or how do I compensate correctly?)?
Click to expand...
The impedance shouldn't change, all you are doing is turning off 2 of the power tubes. The cabinet is what determines the impedance.
cellardweller said:
What is "pentode/Triode"? :o
Click to expand...
This is the way the tubes are hooked up, one will give you more (and different) distortion than the other.
 
The impedance shouldn't change, all you are doing is turning off 2 of the power tubes. The cabinet is what determines the impedance.
Click to expand...

The only thing that lead me to wonder, and assume it may be different from this, is the fact that it is a self-contained amp that has approx. 6 different cab inputs (with differing ohm ratings). That is, the "built-in" speaker has a 1/4 that you have to manually disconnect/reconnect. Besides the obvious usage of another cab, I thought that maybe this was because of an ?impedance? difference when switching this...?

I guess the only remaining quesiton then would be, is there any reason that the "presence" knob is next to, and kinda 'bracketed' with the damping switch? Are they in some way dependant on and/or drastically affected by one another???
 
Both presance and damping are feedback circuits. They will have an effect on one another but how much depends on the design, so I don't know in your application.
The different output jacks are for using external speakers. If you add a cab and still use the internal one, you have to change where the internal speaker is plugged in.
 
Thanks Farview, I've tried all possible combinations of eq/gain on the face of the amp, so if I can't find a better sound from the above listed buttons/knobs/switches, which are located on the back of the amp, I guess it's time to get different tubes.
 
How old are the tubes? What don't you like about your sound? If you can describe it maybe I could point you in the right direction.

Normally the presence control is on the front of the amp, I wonder why they put it on the back.
 
Tubes are relatively new, they are Sovtek 5881's, (and Sovtek 12ax7a's I think).

Hmmm, how to explain... I don't really know how to explain it! I can't get a decent tone for distortion. I always begin with low/mid/high around 12 o'clock and work from there.

I guess it's too "thin" sounding? Lifeless... hard to find adjectives for this!

The most unfortunate thing when trying to narrow down the source of my nasty funk is the fact that my preamps suck, my room leaves much to be desired, and I'm still very much a novice n00b to mic placement etc...

I guess thin/lifeless is as good as I can put it in words. Let me go listen and see if words can serve me better after....

*edit* oh yeah, presence on the back. I've always thought that was strange myself. Never seen another amp like this before. Not sure if I said it, but the presence knob is right next to the damping switch, on the back.

Your patience is appreciated!
 
If you have a 57, point it at the spot that the dust cover (the circle in the middle of the speaker) meets the cone.
Set the amp for pentode, turn the tone controls all the way up the damping on and the presence at 5. Turn the pregain until you have the distortion you want, then back it off one.
Try that and tell me what you don't like about it, we can keep doing this until we hone in on a good sound. What kind of sound are you going for?
 
Setting it to triode will also lower the power/headroom of the amp.
 
Yes, I have a 57. Not to split hairs here, but isn't "the circle in the middle of the speaker" the cone? :confused:

I'll have to verify the damping, but I think this is as I have been trying it...
 
The big circle is the cone, the small circle in the middle of the cone is the dust cover. It is the thing that covers the voice coil.
 
um, yeah.... I knew that.
Seriously thanks for setting me straight.

Sorry for the lag in response there, especially due to the generous nature of your offer, but I was preoccupied with family last night (as usual).

Sound I am looking for... I'm actually not picky, what kills me is that I can get (what sounds to me like) many "good" tones from my amp, but either my mic placement or something in the chain is just slaughtering it (I'm guessing pre's).

Well I guess, in a perfect world, I could settle for that "master of puppets" guitar sound :D .
But seriously, in retrospect, now that I think about it, I always thought that I had my own sound, until I found that sound unattainable through recording, and now I am just trying to get any sound that doesn't sound like arse... thicken it up by recording it twice, maybe throw in a "clean" track to thicken/fill it out. I feel like a woman because I'm just never happy! :p

If I had to narrow it down to one band, of whom you may not have heard, that I'd LOVE to have the guitar tone of, it would be the Hypocrisy release titled "Abducted". There are a couple of "clean" songs on there that also sound good to me, but I am mainly referring to his distortion...

Lemme think about this... see if I can come up with a better, more commonly known example...
 
The master of puppets sound is really thin. If I remember right, everyone was using ADA preamps at that point, not tube stuff. The other thing is that those sounds have the mids scooped AFTER they were recorded. The mids have to be recorded and then scooped in the mix. And Justice For All was a more extreme example of this. When you cut the mids out in the mix, it sounds like there is more distortion than there was. You probably have way too much gain.
I will have to dig up that Hypocricy album and listen to it.
 
Farview said:
Set the amp for pentode, turn the tone controls all the way up the damping on and the presence at 5. Turn the pregain until you have the distortion you want, then back it off one.
Click to expand...

Already set to pentode, high damping, presence @ 5, tones were @ 5.

Should I have the 120w/60w, set to 60w? Would this allow me to overdrive the tubes at lower volumes, and be of no consequence?
 
cellardweller said:
Already set to pentode, high damping, presence @ 5, tones were @ 5.

Should I have the 120w/60w, set to 60w? Would this allow me to overdrive the tubes at lower volumes, and be of no consequence?
Click to expand...
I haven't found that it does it at lower volumes so much as the tubes just distort more. Power tube distortion is different sounding than preamp distortion, combining the two effectively is the key. Turn the tones to 10 and tell me what you don't like about the sound. This might take a while to get done this way, I have to be on a plane tonight.
 
Yes, I apologize for my lack of time of late... Every time that I get down there, everything plugged in, turned on, tuned up, there is some place I have to go, or something else I have to do....

I'm unclear about your last answer, the 60w setting would be less desirable? You are saying this may give too much power tube distortion, as opposed to cranking the tone knobs for preamp dist, correct or no?

Sorry for my density,
Thanx for the patience...
 
It all depends on the sound you are after. You have a lot of choices to make with this amp. Marshalls are much easier, you crank it up and it sounds like it does. There is no better or worse, it all depends. I want to start with the tones all the way up as a starting point because that is as far as you can go, we will back things off from there. I have never used that amp, so I am relying on your description of the sound at the settings I suggest to help you get the sound you want.
This might fail miserably, but we can try.
 
I guess one VITAL detail I've left out, is the fact that I've been using a boss MT2 for distortion. I ran through channel "A" last night (tried with and w/o my pedal) , and attempted to get a "usuable" sound, and absolutely could not. "A" would only produce shitty sounding fuzz , with wierd mid-range to it...

Here's how the channels and their controls are labeled:

A- gain, high(pull low boost), super mid, level
B- gain, level
C- gain, low, mid, high


I'm stuck using "c" with the help of my CRAPPY (for recording) Boss MT2 (metalzone), because "C" has the actual tone control. The other two channels just sound HORRIBLE!!! With pedal, without pedal, no matter the amount of knob tweaking... just plain old shitty...
I cannot crank the gain on "C" loud enough to produce any distortion (w/o pedal), without blowing myself out (and probably the speaker).

NOTE: All of the above was attempted with damping/presence/tone/etc as you suggested.
 
Does channel B use the same tone controls as channel c?
I listened to Hypocrisy yesterday. The sound they have is pretty 'metal zone-y'. The problem comes in when you try to mic that sound. You need a lot more bass than you think. It gets taken out in the mix, but part of the sound is the speakers and power tubes crapping out under the strain of it. Back the distortion on the metal zone off so the distortion is more grainey than smooth, that should help.
I haven't really been a fan of Ampeg since they came back in the late 80's (except for bass amps) they are owned by the same company that make Crate amps and they share circuit design (like the super mid control or shape as it is called on the Crates) Their philosophy is all about making stuff that sounds good in your bedroom, unfortunately that kind of sound rarely mics up very well.
 
Nope. C channel tone controls only work for "C" channel.

I'm finding that no matter what I think it sounds like, the mic hears it totally different (der :o ). I didn't have chance to record my experiments last night, only phuck with about 300 different settings-

which brings me to this question-

What difference will the mic be able to discern between low/high damping?
I know that "More damping tightens the sound up." is probably as good of a description that words can convey, but I hope you don't mind me asking again anyway. I know that I should just experiment and find out for myself, but to be honest, this amp is beginning to absolutely kill my desire to even play anymore!!!! It is actually depressing!!!!!

Okay waa and boo hoo session is over... sorry.
I'll try again tonight...
 
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