#1
Hey ya'll, pretty tired at the moment so bare with me cause my wording will probably be shit. but anyways...

so i have this old 80's 60 watt peavey vtm head that i bought used and it's my first tube amp ever and i don't even really know that much about them. i've always used solid state. when i tried it in the store with an emperor 4x12 it sounded loud as F*CK on 3. so i took it home and i use all the heads i own with 450 watt 6x10 bass cabs. i bi-amp'd it with another 50 watt solid state head i own it didn't seem anywhere as loud as it. so i've been thinking and researching a lot about why it isn't as loud. i've been thinking either it has worn out power tubes. i don't know if they're the originals and i don't know if they've been replaced and when. lately when i really turn it up the volume will drop in and out. i think maybe because i have played bass through it really cranked up before and that might have worn the tubes out even more. my other theory is that the head doesn't have enough power to drive those speakers in the cab. i recently tried out a guitar at my local shop through a 100 watt jcm 800 with a mx412a cabinet and i swear it pushed so much more air and has so much more volume and a much better bass response. maybe cause it was a 100 watt head pushing speakers with a lot lower db rating than the ones in my bass cab? maybe it's both old tubes and the cabinet? i don't know. if someone can help me figure out why i'm experiencing this problem. it'd be greatly appreciated. thank you.
Last edited by disfigured-scum at May 7, 2014,
#2
Definitely sounds like power tubes, especially with the sound cutting in and out.
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#3
The tubes may have unseated during transit too. Pull 'em out and plug 'em back in.
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#5
Quote by Cathbard
The tubes may have unseated during transit too. Pull 'em out and plug 'em back in.



...with a dose of dry contact cleaner (NOT oily WD40 stuff) I might add.

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#6
Speaker impedance could also be a cause of power drop. Check the amp and speaks are set for the same impedance.
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#7
Quote by disfigured-scum
Hey ya'll, pretty tired at the moment so bare with me cause my wording will probably be shit. but anyways...

so i have this old 80's 60 watt peavey vtm head that i bought used and it's my first tube amp ever and i don't even really know that much about them. i've always used solid state. when i tried it in the store with an emperor 4x12 it sounded loud as F*CK on 3. so i took it home and i use all the heads i own with 450 watt 6x10 bass cabs. i bi-amp'd it with another 50 watt solid state head i own it didn't seem anywhere as loud as it.


Lots of options (besides power tubes). One, the speakers in the 4x12 might have been more sensitive (efficient) than the 10s in your bass cabinets. Two, the impedance presented to the amp by the 4x12 might have been lower than it was by the bass cabinet (you said "cabs," so are you using more than one?). When you say you "bi-amped" it, what are you talking about?
#8
i'll clean out the sockets and see if that helps in any way.

yes the impedance does match for both the head and cab. they're 8 ohm.

i too think the speakers in that emperor cab were more sensitive causing it to sound a lot louder because they were designed for guitar and not bass. the impedance on both the emperor and my cabinet are both 8 so i don't think that's it. the marshall cab i tried with that jcm was rated for 16 so that's another thing that makes me think that it might be the speakers. when i use that cab with my acoustic 450 it sounds alooooot better because i think that head is loud enough to drive those speakers in my bass cab. i still think i should l replace the tubes in the head though cause of what i described earlier with the volume drops when cranked and such. also no, i'm only using one cab with the peavey. i just said 'cabs' cause i own 2 of the same cabs, but i'm not using them both at the same time. the 'bi-amp' thing... i meant i was using 2 amps at once with an A/B box with one signal going to the 50 watt SS amp and the other going to the peavey.

i think i'm gonna take the peavey to a shop and try it out with a bunch of different guitar cabinets and high wattage bass ones like mine to see if that is the case. all in all i think i might just end up buying an actual guitar cab to go with it.
Last edited by disfigured-scum at May 8, 2014,
#9
Quote by disfigured-scum
no, i'm only using one cab with the peavey. i just said 'cabs' cause i own 2 of the same cabs, but i'm not using them both at the same time. the 'bi-amp' thing... i meant i was using 2 amps at once with an A/B box with one signal going to the 50 watt SS amp and the other going to the peavey.

i think i'm gonna take the peavey to a shop and try it out with a bunch of different guitar cabinets and high wattage bass ones like mine to see if that is the case. all in all i think i might just end up buying an actual guitar cab to go with it.


Speaker sensitivity can make a pretty big difference; I have one set of speakers that are rated at about 102 dB, another that are rated at around 95 dB. Each reduction of 3 dB is like halving the power of the amp, so with those particular lower efficiency speakers, it's almost as if the amp were putting out a quarter of the power. Those old 104 Acoustics used Eminence speakers, as I recall, but I don't know what kind of efficiency we're talking.

Bi-Amping usually suggests that you've got a crossover before the amps, with one amp handling highs, the other handling just lows. I'm not sure what special name you'd give to simply sending the signal to more than one amplifier would be (if any).