alright rackmount guys, educate me on power amps

[drew_half_empty]

ok, well, i decided for live situations, due to my never ending quest for bone crushing volume, I'll just get a seperate power amp & run it with the bassman pre amp

so heres what I want

+300 or more watts
+LOTS of options, it'll be solid state so i'm prolly gonna need to tweak the crap out of it to get my tone
+under $500

I'm not sure about impedance, see, the bassman is 4 ohms, but sounds best plugged into an 8 ohm cab, so I guess if it was 4/8 switchable that'd be cool, but i'm not sure if you can mismatch impedance on power amps, is that safe?

 

[Jag513]

Re: alright rackmount guys, educate me on power amps

Can't help you with solid state suggestions, but I can answer your last question. Do NOT mismatch impedance with solid state circuitry. Transistors just don't behave the same way tubes do. A tube amp may sound great with a mismatched impedance, but a solid state amp'll bust. Through half the resistance, a transistor will try to put out twice the power. That will fry the amp.

Just out of curiosity, how is a 50 watt tube amp not loud enough?

 

[drew_half_empty]

Re: alright rackmount guys, educate me on power amps

well, at all the local venues, micing is not an option

ok so in order to do this, i'd hafta convert the bassman to 8 ohms?

what all does that entail?

 

[drew_half_empty]

Re: alright rackmount guys, educate me on power amps

http://www.carvin.com/products/dcm.php?ItemNumber=DCM1015&CID=PWA

this one looks pretty good, what do you think?

 

[the guy who invented fire]

Re: alright rackmount guys, educate me on power amps

if you are just gonna use the Bassman for the preamp it does NOT matter what the impedence is...The impedence of the power amp is all that will matter. Also...tube amps are FAR more forgiving of mismatched impedences that SS amps are...I would strongly advise against mismatching a SS amp's impedence.

If you want to do all this...just pickup up a good SS power amp, and enough cab(s) to make it happen.

 

[some_dude]

Re: alright rackmount guys, educate me on power amps

When you do this, make sure you still have a load on your Bassman....so either a cab or some type of loadbox.

Other than that, run the output of your slave out or effects loop out to the power amp. I suggest 300w as a minimum....with solid state it's better to run a 1000w amp at 2.5 on the volume than it is to run a 300w amp at 8 or 9.

 

[drew_half_empty]

Re: alright rackmount guys, educate me on power amps

yeah, the cab is gonna be 8 ohms

so is it safe or not to go bassman (4 ohm) preamp - 8 ohm power amp - 8 ohm cab?

i dunno how much the power amp affects tone, but for these purposes, is that EQ kind of a necessity?

I don't wanna sacrifice great tone for volume, i mean, right now i'd give my tone about a 9, and i could stand it going to about 8, maybe 7, but no lower than that

 

[some_dude]

Re: alright rackmount guys, educate me on power amps

yeah, the cab is gonna be 8 ohms

so is it safe or not to go bassman (4 ohm) preamp - 8 ohm power amp - 8 ohm cab?

The Bassman's impedance doesn't matter....you're going strait off the preamp, not the (Bassman's) power amp.

BTW - Did you take note of the part where I said you'll need a load for your Bassman....if you didn't, go back and read it, if you fail to do that, you'll blow the output transformer in your Bassman (big $$$ repair).

i dunno how much the power amp affects tone, but for these purposes, is that EQ kind of a necessity?

It might be...the only way to know for sure is to try it first.

I don't wanna sacrifice great tone for volume, i mean, right now i'd give my tone about a 9, and i could stand it going to about 8, maybe 7, but no lower than that

You WILL going to be sacrificing tone for volume. A better option would be micing into the PA.

 

[Jag513]

Re: alright rackmount guys, educate me on power amps

Yeah, it's safe. It's only the power amp that deals with impedances. Since the preamp just feeds the power amp, you'll be fine.

A solid state power amp will reproduce tone extremely faithfully. It won't alter tone like a tube power amp will. My suggestion to you is to record something from the preamp out of your Bassman. If you have a good computer soundcard, go through there. Or through a mixer/4-track, etc. with the EQ flat. That is how your amp will sound through a solid state power amp with a flat EQ (except through your cab which will impact the sound too...). If you like that, you can either just leave the EQ on the power amp flat or look for something else without an EQ. I'd suggest just getting that one with the EQ if you're happy with your preamp tone, since if you ever want it there's a very flexible EQ on that.

 

[drew_half_empty]

Re: alright rackmount guys, educate me on power amps

BTW - Did you take note of the part where I said you'll need a load for your Bassman....if you didn't, go back and read it, if you fail to do that, you'll blow the output transformer in your Bassman (big $$$ repair).

well, what exactly is a load box & how much are they?

I'm gonna hafta have a tech do some work on the bassman anyways, so would there be a way to like wire a switch or something in so i wouldn't have to do that?

 

[the guy who invented fire]

Re: alright rackmount guys, educate me on power amps

well, what exactly is a load box & how much are they?

I'm gonna hafta have a tech do some work on the bassman anyways, so would there be a way to like wire a switch or something in so i wouldn't have to do that?

all you need is a 4 ohm "dummy load". You have to have it, and if you do not use one you will have to get a new output transformer.

 

[drew_half_empty]

Re: alright rackmount guys, educate me on power amps

well, i have a little 1x12 cab, so assuming i set the volume on the bassman itself low enough to not really be able to hear it, i guess it'd be fine

 

[some_dude]

Re: alright rackmount guys, educate me on power amps

well, i have a little 1x12 cab, so assuming i set the volume on the bassman itself low enough to not really be able to hear it, i guess it'd be fine

That'd work perfect.

 

[the guy who invented fire]

Re: alright rackmount guys, educate me on power amps

just so I know...where on God's grey Earth do you think you are gonna use 300 watts of power?

 

[some_dude]

Re: alright rackmount guys, educate me on power amps

just so I know...where on God's grey Earth do you think you are gonna use 300 watts of power?

It's solid state......

the point isn't to use 300w....it's to have 300w of headroom. Maxing out a SS amp sounds like ass, it's far better to have too much than not enough.

 

[the guy who invented fire]

Re: alright rackmount guys, educate me on power amps

It's solid state......

the point isn't to use 300w....it's to have 300w of headroom. Maxing out a SS amp sounds like ass, it's far better to have too much than not enough.

Im quite aware of all that but my point is that 300 watts is just pure overkill!

 

[some_dude]

Re: alright rackmount guys, educate me on power amps

Im quite aware of all that but my point is that 300 watts is just pure overkill!

Strange....I consider 300w barely enough.

 

[drew_half_empty]

Re: alright rackmount guys, educate me on power amps

ok, last question (i think)

on that power amp, it says the inputs and speaker out are 1/4"

and well, i need 1/8"

assuming i got an adaptor, would it work fine?

 

[Quencho092]

Re: alright rackmount guys, educate me on power amps

1/8 inch? isnt that mini phone plug?

Most good PA's use good old twist on wire clamps w/ banana plug inserts. For speaker cable wire just get anything thick, unshielded, and decently priced.

Best tone solution IMO-get a small mono tube preamp or SS preamp, an SM57 and a mic stand. Put mic in front of cab, set the preamp for max headroom and a tad compression. run this out to the PA input. Run PA to big rig speakers.

getting a dummy load, and/or doing surgery on your amp to get a preamp out will likely suck your tone and make your power tubes blow out quicker.

 

[Hellion]

Re: alright rackmount guys, educate me on power amps

First of all, you DON'T need 300 watts of SS power. My current guitar rig uses a Marshall 8008 which is a solid state power amp. It puts out 80 watts a side, and even that is overkill. QSC makes a single rack space PA, I think the 1810, which puts out about 75 watts at 4 ohms, but I've run it with an 8-ohm stereo cab with no problems forever, so it was putting out around 35-40 per side, which is a god's plenty.

Secondly, no, you don't need an EQ if you're getting the tone you want from your Bassman. Power amps are designed to reproduce faithfully what is put into it. But the thing is, if you're going to use a rack mounted PA, why not just get a decent preamp for it as well? Line 6's POD or Tech 21's SansAmp are both excellent sounding preamps.