New Episode: Will it work? Should I do it?

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Sound as good as you play
Member Since: Dec 23, 2008

1 - I've been reading recently about small tube guitar amps, rated anywhere from 1 watt to 15 watts, which are able to produce nice tone at relatively low volume.

2 - The manual for my Behringer DI100 says it can accept guitar amp speaker outputs to +48dBu.

3 - Can I run the speaker output from one of those small tube amps through the DI100, pass the "thru" signal to the amp speaker, with the balanced DI output to my FOH console?

4 - Will this setup accurately capture that nice tone so that it can be part of the FOH mix?

My thinking is that this might be a viable means of getting a nice guitar tone out into FOH, while keeping stage volume down. I'm currently micing the guitar amps, which works well, but I'd try the DI route if I thought it would work well. My lead guitar guy agrees that lower stage volume will help our sound and he's been looking at the small tube amps.

Thanks for any input.

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I am not a crook's head
Member
Since: Mar 14, 2003


Mar 01, 2009 01:43 pm

You don't want to run an amplified signal through anything but a speaker cabinet. The voltages are WAAAY too high for anything but a speaker or dummy load to handle. It would fry that DI box in a heartbeat.

If you're wanting to run a direct signal from an amp to the PA system, you'll have to use the line out from the amp. A lot of amps have a direct output from the preamp section of the amp. Then you can send that either through your DI box or to a line input on your mixing console.

And you will certainly not get the good tube amp sound by going direct into the board. The desirable element of the tube amp sound comes from the amp's power section, not the preamp section. When you send a DI out of an amp, it bypasses the power section and sends a signal from the preamp.

Keep micing the amp, its the best way to capture the true character of the amp. If you want to run direct, get a modeller.

Czar of Midi
Administrator
Since: Apr 04, 2002


Mar 01, 2009 04:57 pm

Agree with Tadpui on the sound of the amp. I have a little Epiphone Valve Jr. amp that is modded. It is a 5 watt class A single ended tube amp and it can go from mild to full on scream. Although with the mod's on it can get extremely loud through the single 12" cabinet it can also get a very good growl at a very respectable volume. Taking a direct line out from the amp will not yield that same sound as miccing the speaker cabinet will.

Sound as good as you play
Member
Since: Dec 23, 2008


Mar 02, 2009 10:45 am

If you've seen any of my other posts, you already know I don't give up on these little schemes of mine without pushing back just a little. No disrespect intended .... it's just that I'm trying to really understand why some things work and some don't.

What made me think that tapping the speaker signal might work was stuff like the following (excerpted from an article explaining DIs at soundonsound.com):

"Sometimes it's desirable to take a DI feed from the speaker output of an amplifier, and both active and transformer DI boxes can do this, as long as they are fitted with an input designed to accept speaker-level signals. Amplifiers' speaker outputs carry signals of several tens of volts, while line-level signals are usually only around a couple of volts, so it's evident that plugging a speaker signal into a line-level input would overload it massively, probably to the point of causing damage. Mic inputs are designed to accept signals of typically only a few thousandths of a volt in amplitude, so the effect of plugging in a speaker signal would be even more serious than in the case of the line input. DI boxes with speaker input jacks should also have thru connectors allowing connection to either the original speaker or to a dummy load. The DI output signal will be at either mic or line level and can be fed to the appropriate console input."

Am I misunderstanding this?

Thanks for your patience.

Prince CZAR-ming
Member
Since: Apr 08, 2004


Mar 02, 2009 11:24 am

There are schematics out there in inet land for taping signal out from a speaker. You have to design it for your amp wattage, and speaker impedance (ohms). I think i saw it on ax84 somewhere, but it's been quite a while, and i can't find it easily now =/.

So technically, yes, you can tap signal out from your speakers, but just not by plugging it directly into a DI box. DI box wants to see LINE or INST level signal, as mentioned in your quote. Not speaker level, which is generally rated in watts.

Sound as good as you play
Member
Since: Dec 23, 2008


Mar 02, 2009 11:52 am

Here are the parts of the quote that I'm focusing on:

"Sometimes it's desirable to take a DI feed from the speaker output of an amplifier, and both active and transformer DI boxes can do this, as long as they are fitted with an input designed to accept speaker-level signals."

and

"DI boxes with speaker input jacks should also have thru connectors allowing connection to either the original speaker or to a dummy load. The DI output signal will be at either mic or line level and can be fed to the appropriate console input."

Behringer says the DI100 can handle:

"Direct connection of speaker outputs with ratings up to 3,000 Watts."

My reading says that the DI100 is capable of handling the amp input, as described in the article excerpt.

Thanks again.


The Czar of BS
Member
Since: Dec 31, 2007


Mar 02, 2009 11:53 am

There are some DI's that will let you run an amp level signal to them.

I believe that a Countryman FET85 has a switch for amp signals.

The only thing is, the sound will not anywhere near what the amp is doing.

A speaker is reactive. And will change impedance at certain frequencies. An active or passive DI will not. So, you will not get the same characteristics for the DI.

Plus the cabinet is also playing into the resonance game as well. So, you will get the warm signal from the tube. But not any of the sound of the amp it's self.

Micing the cabinet is still the best way to get the sound that the guitar player has on stage.

Prince CZAR-ming
Member
Since: Apr 08, 2004


Mar 02, 2009 12:03 pm

I'd say go for it. The first quote you mentioned is the same thing i said: if there's circuitry to handle it.

The second one is also very similar.

So, if the DI100 says it'll handle speaker outputs, then have fun!


I am not a crook's head
Member
Since: Mar 14, 2003


Mar 02, 2009 12:24 pm

I wasn't aware that there was such a thing as DI box that could accept amplified signals. Well slap my fanny and call me Seabiscuit.

Still, I'd just stay with micing the amp. All the cool kids are doing it.

Czar of Turd Polish
Member
Since: Jun 20, 2006


Mar 02, 2009 01:18 pm

Hehe, the seabiscuit line got a genuine chuckle from me :)

Sound as good as you play
Member
Since: Dec 23, 2008


Mar 02, 2009 02:51 pm

To be honest I just wanted to string this along until Rob said that yes you can do it, but no it won't sound good [same as for my last bad idea].

The more time I spend with this stuff, the more I learn that there's a reason why things are done one way and not the other.

Thanks for all the input.

The Czar of BS
Member
Since: Dec 31, 2007


Mar 02, 2009 04:03 pm

I'm such a kill joy!

Czar of Midi
Administrator
Since: Apr 04, 2002


Mar 02, 2009 09:34 pm

So Doug, you didn't catch the last line of my post then did you??


Quote:
Taking a direct line out from the amp will not yield that same sound as miccing the speaker cabinet will.


I thought that was what you were after, but didn't stretch it out as Rob did. But he is a much better kill joy then I.

producer
Member
Since: Dec 07, 2006


Mar 02, 2009 09:56 pm

I think posted something about these types of DI boxes a while back. i used to have a Hughe's & Kettener Red Box which by definition was a DI box...heck it even looked like one...only it was bright red...and it took speaker load from your amp and leveled it out for the mixer with a speaker passthru. It was always a nice sounding unit - but only shined when mixed with the cabinet Mic. I guess im just being redundant...but it wasnt a great standalone solution. But if you can find one on ebay, its worth trying out, i believe they are discontinued. Or maybe the Behringer is just as good too, have not used it to comment.

Sound as good as you play
Member
Since: Dec 23, 2008


Mar 03, 2009 08:15 am

Noize - You just can't match Rob when it comes to p***ing all over every last glowing ember of hope that I might have had.

Czar of Midi
Administrator
Since: Apr 04, 2002


Mar 03, 2009 08:59 pm

True, I'm usually dancing around the edge of the subject. I'm not good at just coming out and stating the obvious sometimes.

The Czar of BS
Member
Since: Dec 31, 2007


Mar 03, 2009 09:05 pm

My wife would like to add... Imagine living with him.

Not sure what that's suppose to mean? =P

Czar of Midi
Administrator
Since: Apr 04, 2002


Mar 04, 2009 08:59 pm

Ouch, she'd get along dandy with my wife then it sounds like.

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