[blacksuede58]

Ok, I haven't actually attempted this yet, because I'm leery of
unknown consequences. So I'm just asking, here...

So when I record my band's gigs, I'll usually just plant a mike in
front of my bassist's cab. A couple times I've run a TS cable out of
the unbalanced DI jack in the back of his amp, and gone into a line
input on the mixer. No problems.
But, he does have a balanced XLR DI output back there, as well.

The issue is... I'm going into a Mackie 1604VLZ, where the phantom-
power is global-- one switch on/off across all 16 XLRs. And I need it
on, for the condensers I'm using for drum overheads.

This is probably a no-brainer-- but there's no way I'm jacking a DI
from a bass amp into a phantom-powered XLR without asking somebody
knowledgeable first!

So, tag-- you're it. And thanks in advance.

M.

[David Gravereaux]

On 11/01/2010 05:21 PM, blacksuede58 wrote:
Ok, I haven't actually attempted this yet, because I'm leery of
unknown consequences. So I'm just asking, here...

So when I record my band's gigs, I'll usually just plant a mike in
front of my bassist's cab. A couple times I've run a TS cable out of
the unbalanced DI jack in the back of his amp, and gone into a line
input on the mixer. No problems.
But, he does have a balanced XLR DI output back there, as well.

The issue is... I'm going into a Mackie 1604VLZ, where the phantom-
power is global-- one switch on/off across all 16 XLRs. And I need it
on, for the condensers I'm using for drum overheads.

This is probably a no-brainer-- but there's no way I'm jacking a DI
from a bass amp into a phantom-powered XLR without asking somebody
knowledgeable first!

So, tag-- you're it. And thanks in advance.

M.


Shouldn't be a problem if the following is true:

1) The output is designed to drive a 1200 ohm load (a mic input) at a
reference level of about 400mVrms (-10dBu). Max input level of a
microphone input is assumed to be no less than 4Vrms (10dBu) according
to AES-X152. Use the pad function if needed.

2) There is no DC resistance from either pin 2&3 to pin 1. This is true
of a transformer as used in DI ...unless it is one of those $20 pieces
of junk from China. For some reason, they connect pin1 to the center
tap of the secondary which will dissipate 1/3 watt across the 1/4 watt
6K81 phantom summing resistors and destroy them.

Active outputs "should" have DC blocking caps.
--



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[Jay Ts[_2_]]

blacksuede58 wrote:
Ok, I haven't actually attempted this yet, because I'm leery of unknown
consequences. So I'm just asking, here...

It's good to ask here, but the best place to ask is
the manufacturer of the bass amp. It's easy to say
that a product like that "should" be compatible with
phantom power, but a call or email to the manufacturer
can result in a definitive answer. (Or at least, it
"should". ;-)

Before doing that, get the name of the manufacturer
and exact model, and see if you can find an owner's
manual online at the manufacturer's website. That
might get you a quick answer.

Since you didn't tell us the exact model of the product,
there's no way anyone can be sure to give you accurate
information -- there are all sorts of dodgy products
that have been sold, including things that almost no
one has ever heard of.

Jay Ts

[Mike Rivers]

On 11/1/2010 8:21 PM, blacksuede58 wrote:

A couple times I've run a TS cable out of
the unbalanced DI jack in the back of his amp, and gone into a line
input on the mixer. No problems.
But, he does have a balanced XLR DI output back there, as well.

The issue is... I'm going into a Mackie 1604VLZ, where the phantom-
power is global--

This is probably a no-brainer-- but there's no way I'm jacking a DI
from a bass amp into a phantom-powered XLR without asking somebody
knowledgeable first!

This is a question for the (unspecified) manufacturer of the
amplifier. Whether there's likely to be a problem or not
depends on how that XLR direct output is wired.

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff

[Doum]

blacksuede58 écrivait news:241e31e1-d453-4969-
:

Ok, I haven't actually attempted this yet, because I'm leery of
unknown consequences. So I'm just asking, here...

So when I record my band's gigs, I'll usually just plant a mike in
front of my bassist's cab. A couple times I've run a TS cable out of
the unbalanced DI jack in the back of his amp, and gone into a line
input on the mixer. No problems.
But, he does have a balanced XLR DI output back there, as well.

The issue is... I'm going into a Mackie 1604VLZ, where the phantom-
power is global-- one switch on/off across all 16 XLRs. And I need it
on, for the condensers I'm using for drum overheads.

This is probably a no-brainer-- but there's no way I'm jacking a DI
from a bass amp into a phantom-powered XLR without asking somebody
knowledgeable first!

So, tag-- you're it. And thanks in advance.

M.

You could go from the balanced XLR connector on the bass amp to the
balanced "line" in on the Mackie using a cable with a female XLR connector
at one end and an 1/4" TRS connector at the other end, that way you will be
sure you won't damage anything and you'll have the balanced connection you
want. Phantom power is not applied to the balanced 1/4" inputs on the
Mackie.

The cable should be wired this way TRS tip to XLR pin 2, TRS ring to XLR
pin 3 and TRS sleeve to XLR pin 1.

HTH

[Mike Rivers]

On 11/2/2010 10:51 AM, Doum wrote:

You could go from the balanced XLR connector on the bass amp to the
balanced "line" in on the Mackie using a cable with a female XLR connector
at one end and an 1/4" TRS connector at the other end

It's true that the line inputs have blocking capacitors to
keep the DC phantom power off them, but that XLR output on
the amplifier might (most likely is) be at mic level so that
it functions as a DI.

Again, this is something that's unique to the amplifier.

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff

[Gareth Magennis]

"Mike Rivers" wrote in message
...
On 11/2/2010 10:51 AM, Doum wrote:

You could go from the balanced XLR connector on the bass amp to the
balanced "line" in on the Mackie using a cable with a female XLR
connector
at one end and an 1/4" TRS connector at the other end

It's true that the line inputs have blocking capacitors to keep the DC
phantom power off them, but that XLR output on the amplifier might (most
likely is) be at mic level so that it functions as a DI.

Again, this is something that's unique to the amplifier.

--


I had a Bass combo in for repair just last week where these blocking caps
were both swollen and obviously damaged, even though they were rated 63v.
This wouldn't be the first time I have come across this problem either - not
sure how this happens with 48v phantom. ???

So yes, careful with that phantom.



Gareth.

[Doum]

Mike Rivers écrivait -
september.org:

On 11/2/2010 10:51 AM, Doum wrote:

You could go from the balanced XLR connector on the bass amp to the
balanced "line" in on the Mackie using a cable with a female XLR
connector
at one end and an 1/4" TRS connector at the other end

It's true that the line inputs have blocking capacitors to
keep the DC phantom power off them, but that XLR output on
the amplifier might (most likely is) be at mic level so that
it functions as a DI.

Again, this is something that's unique to the amplifier.


We don't know what amp the OP has but I own a Roland CUBE 100 bass amp
( http://www.roland.com/products/en/CU...ASS/index.html )and I just
tried the XLR "DI" connector to one "line" input on a Yamaha MG32/14fx
console and I had to engage the PAD switch (-26 db) and put the trim a bit
below 0 to get a workable level on the console, so that tells me the XLR
output on the Roland amp is definitively not mic level and is even quite
hot.

So I think my suggestion is good and if the OP amp XLR out is mic level, he
should be able to boost the signal with the trim control on his Mackie.

This of course can vary from one amp to another.

[blacksuede58]

On Nov 2, 8:07*am, Mike Rivers wrote:

This is a question for the (unspecified) manufacturer of the
amplifier. Whether there's likely to be a problem or not
depends on how that XLR direct output is wired.

Yes that's definitely true... but seeing as said bass amp is about 23
miles from here, and said bass player is remarkably dodgy about
diligent replies to email and other avenues to a quick (i.e., tonight)
answer about the make/model of his amp, I can't Google up any info.

But actually, you guys have given me the ballpark answer I was looking
for: DI into a phantom-powered XLR *is* a possibility... but fraught
with real peril if everything isn't perfect. So you know what? Screw
it-- I'll stick with the unbalanced quarter-inch DI out to mixer line-
in cable. It's always a short run amp to mixer-- we're just a
barband, so the board is never more than 15 feet away-- and haven't
had any noise or signal-loss problems. It just works, so why mess with
it?

Still, I was curious about it and you guys helped out (and also, have
made me glad I hadn't just plunged ahead and blindly jacked that DI
cable in). Thanks!

M.

[Bill Ruys[_2_]]

"blacksuede58" wrote in message
...
Ok, I haven't actually attempted this yet, because I'm leery of
unknown consequences. So I'm just asking, here...

So when I record my band's gigs, I'll usually just plant a mike in
front of my bassist's cab. A couple times I've run a TS cable out of
the unbalanced DI jack in the back of his amp, and gone into a line
input on the mixer. No problems.
But, he does have a balanced XLR DI output back there, as well.

The issue is... I'm going into a Mackie 1604VLZ, where the phantom-
power is global-- one switch on/off across all 16 XLRs. And I need it
on, for the condensers I'm using for drum overheads.

This is probably a no-brainer-- but there's no way I'm jacking a DI
from a bass amp into a phantom-powered XLR without asking somebody
knowledgeable first!

So, tag-- you're it. And thanks in advance.

M.

There seems to be a lot of worry warts around here. You should be safe as
houses. The truth is, if the DI out is transformer based, it will be fine.
Dynamic mics look like a transformer load anyway (just a coil on a
diaphragm). And if it's active, the design engineers should be lined up
against a wall and shot if phatom power presents a problem. It will almost
certainly be capacitively coupled.

So my advice would be to ignore the old women replying and just plug it in
and get on with your life.

[David Gravereaux]

On 11/02/2010 06:58 PM, Bill Ruys wrote:
So my advice would be to ignore the old women replying and just plug it in
and get on with your life.


Agreed. If it hums, lift pin1. If the level's too hot, use a pad.
There's more important things to worry about.

--



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[geoff]

Soundhaspriority wrote:

To avoid a "misunderstanding", use an isolation transformer:
http://www.bhphotovideo.com/c/produc...ormer_for.html

You'll never have to say you're sorry.

You will with my Buzz DIs - they're phantom-powered !

geoff

[Gareth Magennis]

"Bill Ruys" wrote in message
...
"blacksuede58" wrote in message
...
Ok, I haven't actually attempted this yet, because I'm leery of
unknown consequences. So I'm just asking, here...

So when I record my band's gigs, I'll usually just plant a mike in
front of my bassist's cab. A couple times I've run a TS cable out of
the unbalanced DI jack in the back of his amp, and gone into a line
input on the mixer. No problems.
But, he does have a balanced XLR DI output back there, as well.

The issue is... I'm going into a Mackie 1604VLZ, where the phantom-
power is global-- one switch on/off across all 16 XLRs. And I need it
on, for the condensers I'm using for drum overheads.

This is probably a no-brainer-- but there's no way I'm jacking a DI
from a bass amp into a phantom-powered XLR without asking somebody
knowledgeable first!

So, tag-- you're it. And thanks in advance.

M.

There seems to be a lot of worry warts around here. You should be safe as
houses. The truth is, if the DI out is transformer based, it will be
fine. Dynamic mics look like a transformer load anyway (just a coil on a
diaphragm). And if it's active, the design engineers should be lined up
against a wall and shot if phatom power presents a problem. It will
almost certainly be capacitively coupled.

So my advice would be to ignore the old women replying and just plug it in
and get on with your life.




VERY few backline amps I have ever dealt with have transformer based DI
outs. The only one I can remember off hand is a Mesa Boogie, and I'm not
100% sure on that, actually.


Gareth.

[Mike Rivers]

On 11/2/2010 9:58 PM, Bill Ruys wrote:

There seems to be a lot of worry warts around here. You should be safe as
houses. The truth is, if the DI out is transformer based, it will be fine.

Agreed, but you don't know if it is. It would be a good
idea, but an expensive one, and unless this is a boutique
amplifier, I suspect that there's no transformer in there.

People who make microphones know how to power (and not
power) them. But those same people don't make instrument
amplifiers. Assume nothing.

So my advice would be to ignore the old women replying and just plug it in
and get on with your life.

It sounds like he's taking the path of getting on with his
life and using what he knows works rather than trying
something new and with some (albeit small) risk without
sufficient information.

Will you bring him a replacement bass amp when it blows up?

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff

[Peter Larsen[_3_]]

Bill Ruys wrote:

There seems to be a lot of worry warts around here. You should be
safe as houses. The truth is, if the DI out is transformer based, it
will be fine. Dynamic mics look like a transformer load anyway (just
a coil on a diaphragm). And if it's active, the design engineers
should be lined up against a wall and shot if phatom power presents a
problem. It will almost certainly be capacitively coupled.

Not all circuit designers have grasped the concept that coupling caps need
to be rated for what can be encountered on the outside of the box, some just
look at what their own psu provides and rate the caps in accordance.

So my advice would be to ignore the old women replying and just plug
it in and get on with your life.

There are to safe bets: mic in front of bass guitar loudspeaker and tranny
coupling. Various other options have been mentioned that will work fine in
some contexts.

Kind regards

Peter Larsen