Guitar head/power amp setup?

XVX · #1 09-01-2011, 01:17 AM

Been reading these forums forever, finally time for my first post. Forgive me if it's a little long-winded.

I play bass in a fast, noisy punk band. I'm usually broke, so have to make due with whatever I can occasionally afford/borrow for shows. Currently, I'm playing out of an all tube B-52 guitar head. AT100 I think it's called. I play with a lot of distortion, and am actually really happy with the tone I'm getting out of this thing; enough low end to pull through the rest of the noise, the problem is it's just not loud enough for shows. Works great for practice, but I'm usually turning it up to 10 for shows, and it's just shy of the perfect volume. Currently playing out of an ampeg 412. Most of the shows we play are at small venues/houses, and nothing gets mic'ed. My question is this: if I bought a decent power amp, would it be possible to connect the head from the line out to the PA (making sure to still have a load going from the head) and still get a similar sound? I love the sound I'm getting, just need more power, and not sure if using a separate power amp would degrade the tone at all? Also, I've got an ampeg 8x10 sitting in a garage I've been itching to use, but haven't bothered for the same reasons, head just isn't pushing enough umph. Would this setup work with the 8x10? I know I could just get a bass amp, but I'm happy with the tone I'm getting, just feel like I need more power. And money is limited. Your thoughts, fellow TB'ers?

JimmyM · #2 09-01-2011, 01:26 AM

Yep. You can get DI's that go between the speaker out and cab. The Radial JDI and JDV do and maybe one other, and both Countryman DI's do. If you have to DI with a tube amp, it's the best way to go. Using a big tall cab also helps.

ZachM · #3 09-01-2011, 01:40 AM

First thing I would do would be to try the amp with the 810; you'll have more speaker area with it than the 412, and if you are just a little shy of the volume that you want right now, that might put you over the edge.

As far as your other question goes, if your amp has a preamp output, there's no reason why you couldn't send that line to a power amp... But if your tone is really coming from cranking the amp to it's limits, the preamp-out solution will not get you the power tube distortion that is happening, so it won't sound quite the same. But you could get a DI to go between the speaker and the head, which could then be run to a power amp, which might be your best bet.

JimmyM · #4 09-01-2011, 01:44 AM

A quality mic is the best bet, but a speaker DI is a really good second best.

XVX · #5 09-01-2011, 02:03 AM

I've tried it out with the 8x10 several times, and same problem. And the amp sounds good at practice played through the 4x12 at about 4, so it's not only when it's cranked all the way.

And I'm still fairly new to all of this, not too familiar with DI's. So the chain would be bass>head>DI>cab>power amp? I'm confused what the role of the speaker DI is, exactly.

Sartori · #6 09-01-2011, 05:12 AM

Also, remember, even if you're getting most of your volume from the external power amp, if the guitar head is a tube amp, it still has to be connected to a speaker cab.

JimmyM · #7 09-01-2011, 09:24 AM

Quote:

Originally Posted by XVX

I've tried it out with the 8x10 several times, and same problem. And the amp sounds good at practice played through the 4x12 at about 4, so it's not only when it's cranked all the way.

And I'm still fairly new to all of this, not too familiar with DI's. So the chain would be bass>head>DI>cab>power amp? I'm confused what the role of the speaker DI is, exactly.

It puts the sound of the entire amp and not just the preamp into the DI. Makes a difference. Most folks run them into the PA and don't bother with adding a power amp, but I suppose if it has the right input, you could do that signal chain with the power amp as well.

XVX · #8 09-01-2011, 11:57 AM

I'm still a bit confused as to how I'd set this all up. I know if I'm just going amp-power amp-cab I have to use the preamp out/line out, and still have a load connected. With the speaker DI, can I go from the speaker out of the amp, into the DI, then power amp-cab? That way I wouldn't have to worry about separate loads. Also, the three above mentioned speaker DI's are all around $200, which is a bit out of my budget. Any suggestions for cheaper ones that'll still get the job done?

I think my starting point will be getting a decent power amp first, and trying out my original idea with the 8x10, and seeing how the tone is. If it's noticeably weaker, then I'll look into the DI.

JimmyM · #9 09-01-2011, 12:16 PM

Nope, you have to always have a speaker load on the tube amp, even with a DI.

But anyway, I think your starting out idea is a sound idea. You may like it with just the pre going into the power amp, and it's a lot less unwieldy.

runmikeyrun · #10 09-01-2011, 02:39 PM

I play through a peavey 100w windsor guitar head. Even with an 8x10 it still wouldn't give me enough volume for basement shows. I ended up going with a 2x15 and 8x10. Those got too heavy so now I just run through a pair of 4x12s. Seems to do the trick.

If you run your amp's preamp out from the effects loop into a power amp you won't need a load on the tube amp. Plugging into the preamp out shunts the signal and no signal goes to the head's power amp. You will get a different tone though, because part of your tone is power amp distortion and frequency response of the speakers. If you have a PA at practice for the singer, trythis... plug your preamp out into the PA and then run the PA through your 4x12. If it sounds good, go with the power amp setup.

Personally, I wired in a line out jack off the output jack of my amp. I can plug this into a direct box at a club. I still need to run a speaker cabinet though.

Keep in mind you'll be looking at getting a big power amp if you want a noticeable volume increase. My backup rig is a 500w pre/power setup and it only sounds a little bit louder than my 100w windsor. You'll need to look at least 700w if not 1000. Your ampeg 4x12 will def blow with that, so you're also going to have to look at getting two new cabs.

XVX · #11 09-01-2011, 03:44 PM

My head has no preamp out, only line out. Is this much different? Is there a way to set this up without needing to worry about a load on the tube amp?

I'll try running through the PA at practice, good idea. It's just a little 200w one, but it should give me a better idea of the tone I'd be getting. And I've been searching around and have found some decent deals on what seem to be the more favorable power amps. Crown, qvc, carvin, etc. 1000w+ bridged @4ohms. I've also got the 8x10, should be able to handle that no problem, right?

Sartori · #12 09-01-2011, 05:45 PM

No, there is no way to do this without connecting the tube head to a speaker load. It's a tube head. It has to have a load on it.

coreyfyfe · #13 09-01-2011, 06:50 PM

Quote:

Originally Posted by runmikeyrun

Plugging into the preamp out shunts the signal and no signal goes to the head's power amp. You will get a different tone though, because part of your tone is power amp distortion and frequency response of the speakers.

No signal is going to the power amp but if it's out of standby and voltage is being applied to the tubes you need to have a load on the head otherwise you're just going to blow the output transformer.

runmikeyrun · #14 09-01-2011, 07:26 PM

Quote:

Originally Posted by coreyfyfe

No signal is going to the power amp but if it's out of standby and voltage is being applied to the tubes you need to have a load on the head otherwise you're just going to blow the output transformer.

I stand corrected, and apologize for the bad info. Would he be able to pull the power tubes and be ok?