[John Williamson]

adam79 wrote:
I was just over at Radio Shack and they had a 680 ohm, 1/2 watt, 5%
tolerance resistor. Will this one work just as well, or is the wattage/
tolerance too high?

The higher power isn't a problem, except that it will be bigger, so
harder to fit in. It may also be a carbon film resistor, which will be
slightly noisier (In theory, you may or may not notice the difference.)
As for the value, try it, and try a 560 ohm too, and see which sounds
better.

--
Tciao for Now!

John.

[PStamler]

On Aug 28, 9:39*pm, John Williamson
wrote:
adam79 wrote:
I was just over at Radio Shack and they had a 680 ohm, 1/2 watt, 5%
tolerance resistor. Will this one work just as well, or is the wattage/
tolerance too high?

The higher power isn't a problem, except that it will be bigger, so
harder to fit in. It may also be a carbon film resistor, which will be
slightly noisier (In theory, you may or may not notice the difference.)
As for the value, try it, and try a 560 ohm too, and see which sounds
better.

Yeah, the physical size may be a problem. The Mouser 698 ohm will be
fine, also 681 ohm. And I do like metal films for their low noise and
stability.

Oh, do solder the resistor into the male XLR connector rather than the
female; it's a bit roomier.

Peace,
Paul

[Scott Dorsey]

Bill Graham wrote:

Thanks.....that explains why I have never heard of anyone wrecking his
dynamic mike by accidently plugging it into a phantom powered mike input
jack.....This in the face of the usual rule....."If something can screw up,
it will"....:^)

Every once in a while you'll still encounter T-power, which is differential
across the two inputs... and that will occasionally damage dynamic mikes.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[adam79]

On 8/20/10 9:12 AM, Scott Dorsey wrote:

You CAN go wrong with one, by getting the 421 Mk II which is not actually
a 421 at all and really is a different microphone designed to look like a
421. Stay away from that.

But the real original 421 is a good mike on just about everything. And the
441 is just as good!
--scott

Is there a way to tell the difference between the two visually? If I'm
buying the mic used (probably on eBay, unless anyone has a better
suggestion), I want to make sure I'm getting the original version..
instead of just taking the seller word.

I haven't had the chance to use the MD421, and the mic rental place only
has the Mk II. Is the 421 as good on bass amps as the RE20?

Thanks,
-Adam

[Scott Dorsey]

adam79 wrote:
On 8/20/10 9:12 AM, Scott Dorsey wrote:

You CAN go wrong with one, by getting the 421 Mk II which is not actually
a 421 at all and really is a different microphone designed to look like a
421. Stay away from that.

Is there a way to tell the difference between the two visually? If I'm
buying the mic used (probably on eBay, unless anyone has a better
suggestion), I want to make sure I'm getting the original version..
instead of just taking the seller word.

It says so on the nameplate.

I haven't had the chance to use the MD421, and the mic rental place only
has the Mk II. Is the 421 as good on bass amps as the RE20?

Yes, but it's different and needs more careful placement. The variable D
mechanism on the RE-20 allows you to get away with all kinds of stuff you
cannot with a regular mike.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[adam79]

On 8/28/10 11:36 PM, PStamler wrote:

Yeah, the physical size may be a problem. The Mouser 698 ohm will be
fine, also 681 ohm. And I do like metal films for their low noise and
stability.

Oh, do solder the resistor into the male XLR connector rather than the
female; it's a bit roomier.


I took a picture of the resistors I bought at Radio Shack:
http://members.toast.net/adam79/resistor.jpg. Can you tell by the pic if
they are the metal film ones? Also, this is where I connect the
resistor: http://members.toast.net/adam79/mic1x.jpg, right?

Thanks,
-Adam

[Don Pearce[_3_]]

On Mon, 30 Aug 2010 01:45:15 -0400, adam79 wrote:

On 8/28/10 11:36 PM, PStamler wrote:

Yeah, the physical size may be a problem. The Mouser 698 ohm will be
fine, also 681 ohm. And I do like metal films for their low noise and
stability.

Oh, do solder the resistor into the male XLR connector rather than the
female; it's a bit roomier.


I took a picture of the resistors I bought at Radio Shack:
http://members.toast.net/adam79/resistor.jpg. Can you tell by the pic if
they are the metal film ones? Also, this is where I connect the
resistor: http://members.toast.net/adam79/mic1x.jpg, right?

Thanks,
-Adam

Is the Radio Shack part number on the pack anywhere? That would be
more helpful.


And yes. Connect the resistor between blue and red. The best way is to
fold one of the leads over so it ends up parallel to the other. The
resistor will then sit nicely in there parallel to the wires. To
prevent shorts, strip some of the insulation off a piece of spare wire
and slip it up over the longer resistor lead.

I have to say the red lead does not look too well soldered right now.
I would expect the solder to spread round both sides of the tag. You
can attend to that while you are putting the resistor in. Meanwhile,
that empty hole in the tag makes anchoring the resistor wire very
simple.

d

[Arny Krueger]

"adam79" wrote in message
net
On 8/28/10 11:36 PM, PStamler wrote:

Yeah, the physical size may be a problem. The Mouser 698
ohm will be fine, also 681 ohm. And I do like metal
films for their low noise and stability.

Oh, do solder the resistor into the male XLR connector
rather than the female; it's a bit roomier.


I took a picture of the resistors I bought at Radio Shack:
http://members.toast.net/adam79/resistor.jpg. Can you
tell by the pic if they are the metal film ones? Also,
this is where I connect the resistor:
http://members.toast.net/adam79/mic1x.jpg, right?

AFAIK RS sells only carbon film resistors in this packaging. They are
suitable for your application.

[adam79]

On 8/30/10 7:57 AM, Arny Krueger wrote:

AFAIK RS sells only carbon film resistors in this packaging. They are
suitable for your application.


You're right. I looked up the part number and it's listed as a "680 ohm
1/2W 5% Carbon Film Resistor.

-Adam

[Scott Dorsey]

Mike Rivers wrote:
The other is that connecting or disconnecting
a mic with phantom power applied can cause a voltage spike
that the input to the mic preamp stage sees. Today most mic
preamps are made idiot-resistant with the use of clamping
diodes on the input to keep the spike from getting higher
than the power supply voltage. But some people believe that
those diodes affect the sound so they're not present in some
designs and I suppose that some have been removed.

This is now a solved problem. (Well, it's always been a solved problem
since you could always just use a transformer for isolation, but this time
it's been solved without them).

Clamping diodes to the rails don't affect the sound. Zener diodes to ground
affect the sound. The key to the whole clamping to the rails thing is that
the diode is absolutely completely turned off and adds no nonlinearity
(only capacitance) under normal situation.

The problem is that making clamps to the rails work reliably and effectively
is nontrivial, so people are inclined to supplement them with zeners. But
some folks at THAT did a really nice analysis of the whole situation.

http://www.thatcorp.com/datashts/AES127-000183.pdf

This really is the absolute coolest thing to come out of last year's AES
show.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[geoff]

adam79 wrote:
On 8/26/10 12:50 AM, John Williamson wrote:

On Ralph's website, the resistor part number is PENN-1600.25

You missed this off the end of the URL somehow.

This resistor is the one you need to solder netween pins 2 and 3
inside the XLR connector as discussed earlier in the thread.


I got it! I was checking my XLR mic cables and the connectors don't
seem to unscrew from the cable. There's a Philips head screw on the
connector, but when I unscrew it, I can't seem to get the connector
off the cable. Am I doing something wrong? Here's a picture of the
connector: http://members.toast.net/adam79/XLR.jpg

Also, I'm not sure if this question was already answered, but are
there XLR adapters out there that have the resistor built in (so I
don't have to permanently modify my cables)? If so, is there a name
for this particular adapter?

No. You need to put the resistor in yourself. Unless somebody is selling
them ready-made where you are, like I am in New Zealand (at nominal charge)
!

But really, you get the bits and it's a few minutes' work.

geoff

[geoff]

O - tyhadam79 wrote:
On 8/26/10 6:42 AM, Mike Rivers wrote:
adam79 wrote:

Also, I'm not sure if this question was already answered, but are
there XLR adapters out there that have the resistor built in

Not exactly the answer you were looking for, but I answered that
there were people who will custom make one for you, but it is not
available as a commercial product.

I actually found a commercial product that does this:
http://www.markertek.com/Audio-Equip...ml?SES-XLR-ISO.


NO - that transformer is an isolagting transfoirmer that will still reflect
the 'too high' impedence of the mixer input to the mic.

At $20 it's too expensive; I'm just gonna buy a pack of those
resistors and do the mod myself. Does this improve the sound quality
of all mics, or are some impartial to the mod? It can't hurt the
quality, only make it better, right?


No. Every mic will have it's own interaction with a particular load. Mics
already optimised for 1500-2500 ohm inputs may have their performance
diminished.

geoff

[geoff]

adam79 wrote:
On 8/26/10 4:42 PM, Mike Rivers wrote:
adam79 wrote:

I actually found a commercial product that does this:
Sescom/SES-XLR-ISO

No, it doesn't do the same thing. It's a transformer, not a load
resistor. It's a problem solver, but not for this problem.

Some mics will sound worse when loaded by 600 ohms. Some won't sound
any different. This particular gizmo, with the resistor value as
calculated based on the input impedance of your preamp, is unique to
the SM57. That's why the recommendation is to make a plug-in
"adapter" so you can use it or not.


I'm starting to get a bit confused. My original question was about
what the mic rental guy told me: certain mics, like the RE-20, were
made with the assumption that they would be connected to a mic-pre
with a transformer. Consequently, you don't get the most out of the
mic when using it with a pre-amp absent of a transformer.

That was opinion, not fact. And is unrelated to this particular effect.

Does this "gizmo" for the SM57 relate to the topic above, or is it an
unrelated mod that makes the SM57 sound better? If it does relate to
the topic, how do you figure out what ohm resistor you need for a
particular mic?

If it doesn't relate, does the Sescom/SES-XLR-ISO
solve the transformerless pre-amp issue?

No. Search the 'Recording Magazine' article.

geoff
Thanks,
-Adam

[geoff]

John Williamson wrote:
Bill Graham wrote:
How about the phantom power delivered to a condenser mike? There are
an awful lot of chassis out there that only deliver 18 Volts or less
to mikes that were designed to accept up to 50 volts or so.....I
often wonder how their performance suffers from a starved phantom
power supply......Any thoughts on this?

Depending on the mic, anything from perfect functioning to reduced
capacity to reproduce loud sounds to a total failure to function, via
an increased self noise.

Mic will specify what their operating phantom voltage is, just as mixers
should specify what voltage they output.

Many condensor mics are fine down to 12v, like the various C414 (IIRC).

geoff

[Ty Ford]

On Thu, 26 Aug 2010 22:13:11 -0400, Mike Rivers wrote
(in article ):

adam79 wrote:

Just one quick question.. The "desired load" for a mic isn't something
that's listed in the specs, it's a value that is determined by trial and
error, right?

Right. Sometimes you'll find an "impedance" in a mic's
specification but this usually doesn't tell you anything
useful about how to get the best performance from it.



I don't know what the preamps in the old Peavy board at 8x10 here in
Baltimore had for input Z, but SM58s sounded great through it with no added
resistors.

Regards,

Ty Ford


--Audio Equipment Reviews Audio Production Services
Acting and Voiceover Demos http://www.tyford.com
Guitar player?:http://www.youtube.com/watch?v=yWaPRHMGhGA