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What do you do if your amp dies at a gig?


solo4652
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Countryman on my pedalboard. I don't take a back up head, so I wouldn't dream of gigging without a DI box. Of course, if the band just had speakers on sticks for vocals and no 'proper' pa then I'd be stuck.

Curious to hear what happens with your Behringer. My guitarist has the guitar version and other than the fact that it HATES phantom power, it gets used quite regularly when he doesn't have his amp or can't be bothered to mic it.

Edited by Jack
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[quote name='JPJ' timestamp='1395403992' post='2402064']
+ 1

Just a thought, but how many of us double as the bands sound man? I do in our band, how many more?

[/quote]

Yep, me too! I have the mixer next to me throughout the set for monitor tweaks. And I send a bit of upper frequency DI to the PA, in case the amp dies I can bring in the rest of the bass quickly.

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Just been looking at the preamp schematic for my SWR SM400 and it would appear that the DI would work even with the head switched off as it's just passive components (in parallel with an opamp) betwixt the input socket and the 'direct' routing for the XLR out. wouldn't be balanced, but it [i]might just[/i] pass signal…

You've got me curious now, I'll try it later on in the week… <_<

Edited by paul_5
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Sounds to me that this was a "f*** me, the amps gone down where's the thing with the doobry wotsit plug it in quickly ah sh*t it doesnt work bollox"kind of situation that could have been avoided if you had tested and set the unit up prior to actually needing it. : )
The BDDI is usually reliable though the psu input tends to burn out leaving you needing a battery.
Hope you get it sorted.

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@Monkyman

Well, no, that's not what happened. We were at rehearsal and the guitarists combo died. I had the BDDI with me so I decided to try out my disaster-recovery plan while guitarist used my head/cab rig. Try as we might, we couldn't get any useful volume for my bass by using the BDDI without an amp. This made me think about what I'd do if my head went down at a gig. That was last week. This week, we rehearsed in a different room with a different PA. The crappy speakers immediately started to distort when I used the BDDI as a preamp.
I've sort of given up with the BDDI now. Instead, I'll buy a back-up head, I think.

Edited by solo4652
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Happened to me recently with my Ampeg valve amp. I went straight into the desk with a DI. Sounded rotten but got us through. Turned out it was shoddy electrics in the venue ( a stable) and there was nothing wrong with my amp....phew!

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To get shot of the Powerblock distortion, you either need to make up a little lead to run from the ring (I think) of the effects send/return to both CD ins or use a stereo-to-phono adaptor and a single phono to twin phono lead:


You need to go from the correct side of the adaptor - that's easy to determine, you either get a noise or silence. This bypasses the "speaker sim" distortion bit.

Edited by tauzero
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[quote name='solo4652' timestamp='1395862590' post='2407392']
@Monkyman

Well, no, that's not what happened. We were at rehearsal and the guitarists combo died. I had the BDDI with me so I decided to try out my disaster-recovery plan while guitarist used my head/cab rig. Try as we might, we couldn't get any useful volume for my bass by using the BDDI without an amp. This made me think about what I'd do if my head went down at a gig. That was last week. This week, we rehearsed in a different room with a different PA. The crappy speakers immediately started to distort when I used the BDDI as a preamp.
I've sort of given up with the BDDI now. Instead, I'll buy a back-up head, I think.
[/quote] sorry to be pernickety - but it's unlikey to be a flaw in the speakers that the BDDI brought up. Either the BDDI is broken or something else is set wrong- but probably in between the BDDI and the desk. My guess again is that something wasn't set right on either the gain input - any line/mic level button - or something with the Eq on the desk causing the problems.

Otherwise - this is cheap and I can almost guarantee it will work to get a bass into the PA

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Oh gawd, I'm getting so confused now. This is an interesting thread on Talkbass: http://www.talkbass.com/forum/f36/di-recommendations-behringer-ultra-di-di100-606401/ " You don't want a DI, because 90% of the time they do not boost! That's not what a DI is for."

Can I check my BDI-21 at home without a desk to see if it's working? If I plug my bass into the BDI "IN" and then run an XLR from the BDI into my Compact, should I expect to get some giggable volume? I'll go and try it now while my missus is at the stables and report back...


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I have a couple of Tech21 boxes for this sort of thing - the VT BassDI and the 3 channel BDDI

RRP is expensive but for some reason they just don't hold their value used so they can be found pretty cheap.

Usually use the VT as it's a bit smaller

Edited by fretmeister
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[quote name='solo4652' timestamp='1396000918' post='2408775']
Oh gawd, I'm getting so confused now. This is an interesting thread on Talkbass: [url="http://www.talkbass.com/forum/f36/di-recommendations-behringer-ultra-di-di100-606401/"]http://www.talkbass....i-di100-606401/[/url] " You don't want a DI, because 90% of the time they do not boost! That's not what a DI is for."

Can I check my BDI-21 at home without a desk to see if it's working? If I plug my bass into the BDI "IN" and then run an XLR from the BDI into my Compact, should I expect to get some giggable volume? I'll go and try it now while my missus is at the stables and report back...
[/quote][quote name='solo4652' timestamp='1396000918' post='2408775']
Oh gawd, I'm getting so confused now. This is an interesting thread on Talkbass: [url="http://www.talkbass.com/forum/f36/di-recommendations-behringer-ultra-di-di100-606401/"]http://www.talkbass....i-di100-606401/[/url] " You don't want a DI, because 90% of the time they do not boost! That's not what a DI is for."

Can I check my BDI-21 at home without a desk to see if it's working? If I plug my bass into the BDI "IN" and then run an XLR from the BDI into my Compact, should I expect to get some giggable volume? I'll go and try it now while my missus is at the stables and report back...
[/quote]

A passive DI box is not a pre-amp, and certainly not a power amp!

Go back to basics. The signal chain for a backline rig is:

Bass --> pre-amp --> power amp --> speaker cabinet

If you want to go through the PA, the signal chain is:

Bass --> DI box (producing a balanced signal through an XLR cable --> mixer pre-amp --> power amp --> PA cabs

You can do all sorts of things with different types of DI boxes, including (with some types) boosting the signal, but a bog-standard passive DI box won't boost, amplify or change the signal other than to convert it from a 1/4" jack unbalanced signal into an XLR balanced signal.

That allows you to plug the signal into a PA channel strip intended for use with vocal microphones. Strips like that include a powerful and (usually) pretty reasonable pre-amp.

Alternatively, you can plug your bass into a DI box using a 1/4" jack instrument cable as usual, and then run another 1/4" jack instrument cable to one of the line level channel strips on the PA. Strips like that include a less-powerful but (usually) pretty reasonable pre-amp.

IMHO the ONLY way you can test this stuff at home is if you have some sort of mixer at home with you. You can't test a DI box by plugging it into your backline.

Given how cheap rehearsal room time is (even in London most places charge roughly £10 an hour) why don't you just set aside the first hour of your next rehearsal specifically for equipment testing and working out which settings do what?

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:blush:

I just knew I'd end up with egg on my face with this. I'd misunderstood what the BDI in particular, and DI boxes in general are for. It will come as no surprise to anybody (apart from me, obviously) that the BDI won't drive a speaker without going through some sort of power amp. I've just tried it at home.
Back to my original concern for disaster recovery options. I'll get a back up head. That way, if my cab goes pop, I can DI from the head into the desk (maybe via the BDI), and if my head goes pop I can switch to the spare head with my existing cab.

Don't shout at me please - my eyes glaze over quickly when I read up about balanced/unbalanced signals, pre-amps, power amps, gain etc.

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I've had a similar problem. I depped for a friends band and they put everything through the PA. So he said, don't bring your amp to the rehearsal, you won't need it. Being a sceptical type, I did leave the combo at home, but took an Ampeg Portaflex head just in case. As the bass player I was depping for also set up the PA (surprise!) nobody at the rehearsal had a very clear idea how it worked. So, bass through DI produced no usable volume and, surprisingly, bass into Portaflex, XLR line out into desk didn't either. We tried different channels, including one that was working with the keyboard, changed leads, turned every knob on the board, still not enough. So, after a couple of hours of barely being able to hear what I was playing, I said my amp was coming to the gig whether they liked it or not. Unfortunately, I never got to the bottom of what the problem was.
After the gig my mate said "It was great having you here tonight, when the regular bassist plays, I can never hear him."

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I've lost count of how many gigs I've done using just my bass, MXR M80 and the PA. Even if I take an amp, we take a feed from my pedalboard into the PA. There are problems in the system (broken equipment, user error, mismatched levels) somewhere if you can't get a great sound from just the sansamp into the desk. The same goes for you spinynorman, the DI on your portaflex is specifically made to do just what you asked it to, it should work and if it doesn't it's broken.

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  • 3 weeks later...

Interesting to read. Personally, I carry a spare head. Never had to use it, thankfully. But this was triggered with a gig, where the output pot on my head broke. It was either off or full volume! Needed to carefully control the volume from the bass, but got through it. So got a spare head. Doesn't take up alot of space in the car, so don't mind taking it with me.

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