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General Discussions => The Lab => Topic started by: Diaultras on November 05, 2019, 10:49:20 AM

Title: XLR(m) to XLR(f) Bleeder Resistor
Post by: Diaultras on November 05, 2019, 10:49:20 AM
Hello

I need to protect IC gear down the line of a tube compressor.  The 100 CM from Rapco Horizon is expensive.
As I have xlr barrels I’m planning just to do it myself.

Where to solder the 100K resistor?
Pin 2 to Pin 1? 
This will change the output impedance?
Pro and Cons?

Thanks for advice.
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: Khron on November 05, 2019, 12:08:06 PM
What exactly are you trying to achieve, and why / how?
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: pucho812 on November 05, 2019, 01:34:42 PM
I am not sure what he is asking other then he wants to connect 2 pieces of gear together, one has IC chips and one is a tube compressor.  Looks like he is planning to use 100CM rapco if that is even a part number? or he is using 100CM (around 3 feet)of length of cable.  Either way he will be fine if he just wires up a cable between then gear and is done unless there is a puzzle piece missing.
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: RuudNL on November 05, 2019, 01:49:53 PM
As long as the tube equipment has a transformer (balanced) output, I don't see a problem when connecting this output to semiconductor (IC) equipment.
But when the tube equipment has an unbalanced output (capacitor from plate or cathode to the output) I can imagine that you are a bit worried.
In the last case you should first get an idea of the maximum output level of the tube device.
I could imagine that two zeners in series (with reverse polarity) would short out most unwanted high voltages.
In general, IC equipment will survive a voltage of + or - 15 Volts on the input.
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: Diaultras on November 05, 2019, 01:52:02 PM
What exactly are you trying to achieve, and why / how?

Here:

https://www.rapcohorizon.com/product/155/d-box-terminator
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: Diaultras on November 05, 2019, 01:58:03 PM
As long as the tube equipment has a transformer (balanced) output, I don't see a problem when connecting this output to semiconductor (IC) equipment.
But when the tube equipment has an unbalanced output (capacitor from plate or cathode to the output) I can imagine that you are a bit worried.
In the last case you should first get an idea of the maximum output level of the tube device.
I could imagine that two zeners in series (with reverse polarity) would short out most unwanted high voltages.
In general, IC equipment will survive a voltage of + or - 15 Volts on the input.

Yes it has balanced outputs, but without bleeding resistor at the output tranny.

Will the zeners do not affect sound or impedance?
Any idea what value would work?
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: RuudNL on November 05, 2019, 02:10:31 PM
If there is an output transformer, there are no zeners or resistors needed IMHO...
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: pucho812 on November 05, 2019, 03:24:52 PM
o.k. I got it....

that d-box you link is a DMX terminator and under DMX terminators.
It's for DMX applications.
"DMX is a lighting control protocol which allows users to have ultimate control over their lighting needs. ... DMX originated as a way to set the bar for lighting manufacturers to build fixtures that would all be compatible with each other, instead of having individual control stations for each set of lighting"

DMX cables can come terminated with 3 pin xlr's...

Now what two boxes do you wish to connect together.  if both are pro audio manufactured boxes, you will be fine without any special things.

Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: Diaultras on November 05, 2019, 03:34:04 PM
If there is an output transformer, there are no zeners or resistors needed IMHO...

Thank you RuudNL. I heard that it would.  If I want to do what rapcohorizon do, where is located the 100K resistor? Pin 2 to Pin 1?
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: Diaultras on November 05, 2019, 03:39:44 PM
o.k. I got it....

that d-box you link is a DMX terminator and under DMX terminators.
It's for DMX applications.
"DMX is a lighting control protocol which allows users to have ultimate control over their lighting needs. ... DMX originated as a way to set the bar for lighting manufacturers to build fixtures that would all be compatible with each other, instead of having individual control stations for each set of lighting"

DMX cables can come terminated with 3 pin xlr's...

Now what two boxes do you wish to connect together.  if both are pro audio manufactured boxes, you will be fine without any special things.

Thank you for commenting, Pucho!

This:

"In certain instances, equipment using “retro” and “vintage” design topologies may damage DC-coupled input stages, like those used by Dangerous Music and other high-end pro audio manufacturers. This occurs specifically when the manufacturer does not modernize the output stage to be compatible with the transistor/IC world of today."

I just want to know if the solution of 100K resistor will work. I have a mastering vintage tube compressor and I am worried. Otherwise I will have to adapt a 5W bleeding resistor at the B+ to ground (ohm law willing).
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: ruffrecords on November 05, 2019, 03:50:37 PM
Thank you for commenting, Pucho!

This:

"In certain instances, equipment using “retro” and “vintage” design topologies may damage DC-coupled input stages, like those used by Dangerous Music and other high-end pro audio manufacturers. This occurs specifically when the manufacturer does not modernize the output stage to be compatible with the transistor/IC world of today."

This sounds like marketing speak to me. Who exactly said this?

Cheers

Ian
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: Diaultras on November 05, 2019, 04:05:09 PM
This sounds like marketing speak to me. Who exactly said this?

Cheers

Ian



https://www.gearslutz.com/board/high-end/1021142-shadow-hills-mc-dangerous-gear-killer.html
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: moamps on November 05, 2019, 06:05:23 PM
Where to solder the 100K resistor?
You can use here two resistors, from pins 2 and 3 to pin 1. They are used just for discharging a static voltage on secondary vs. ground.
@pucho812
DMX termination is 120ohms  between  pins 2 and 3.
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: pucho812 on November 05, 2019, 07:26:38 PM
You can use here two resistors, from pins 2 and 3 to pin 1. They are used just for discharging a static voltage on secondary vs. ground.
@pucho812
DMX termination is 120ohms  between  pins 2 and 3.

yes o˚. but the rapco device he pointed to is listed under a DMX terminator on their website.   which I was just pointing out that might not be what he wants.

as wouldn't worry about it until it's a problem
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: RuudNL on November 06, 2019, 03:21:38 AM
Of course you can do anything you want.
But it is not needed and it won't cause any problems...
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: ruffrecords on November 06, 2019, 04:37:20 AM


https://www.gearslutz.com/board/high-end/1021142-shadow-hills-mc-dangerous-gear-killer.html

Gearslutz is not exactly renowned for accuracy. I notice the guy from dangerous is reported as saying:

I
Quote
f any of your outboard that you wish to connect to Liaison has a
“floating output,” a qualified tech. can add what are referred to as
“bleeder resistors” to the transformer outputs. Parts cost about 15-
cents!

Must be a very poor design if it cannot cope with a floating output.

This is very strange because at the dangerous web site they say:
Quote
Audiophile-grade components are used throughout the LIAISON’s 100% passive analog relay switching system,

Which is by definition floating.

Cheers

Ian
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: [silent:arts] on November 06, 2019, 05:54:45 AM
Cool. All my gear can be claimed as potential dangerous gear killer  ;D
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: ruffrecords on November 06, 2019, 07:10:44 AM
Cool. All my gear can be claimed as potential dangerous gear killer  ;D
Good idea. I think I will add a notice to all my tube mixers to to say "Do not use with gear made by Dangerous due to their inability to cope with professional standard signals"

Cheers

Ian
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: RuudNL on November 06, 2019, 04:10:46 PM
 ;D
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: abbey road d enfer on November 06, 2019, 06:18:50 PM
"In certain instances, equipment using “retro” and “vintage” design topologies may damage DC-coupled input stages, like those used by Dangerous Music and other high-end pro audio manufacturers. This occurs specifically when the manufacturer does not modernize the output stage to be compatible with the transistor/IC world of today."
Let's be frank: this is pure marketing BS. If a piece of gear leaks current, it is defective, and as such should be fixed before being put in service. Installing 100k resistors is NOT a substitute for recapping.
I hate people who exploit the credulity of the public.

Quote
I just want to know if the solution of 100K resistor will work. I have a mastering vintage tube compressor and I am worried.
Did you check if it's leaking? If not you don't have to worry, if yes, fix it.

Quote
Otherwise I will have to adapt a 5W bleeding resistor at the B+ to ground (ohm law willing).
That won't help a potential leakage issue in any way. Who suggested that stupidity?
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: john12ax7 on November 06, 2019, 07:45:06 PM
Is this definitely not a problem? I've seen guitar tube amp output transformers do some strange things when the secondary is not grounded.

It would seem prudent to make sure than any connection the user sees can never develop any high voltage.
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: abbey road d enfer on November 07, 2019, 02:43:48 AM
Is this definitely not a problem? I've seen guitar tube amp output transformers do some strange things when the secondary is not grounded.

It would seem prudent to make sure than any connection the user sees can never develop any high voltage.
That's a totally different subject. Tube amps can oscillate when not loaded, but we're talking about low-level  equipment, where this type of malpractice would result in a level that would not be dangerous for any kind of decently designed SS stuff.
And anyway, a pair of 100k resistors would not do anything about it.
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: gyraf on November 07, 2019, 03:08:09 AM
Sounds to me like someone had a QC problem once - that they sucessfully blamed on someone else... :-)

/Jakob E.
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: moamps on November 07, 2019, 04:14:17 AM
It isn't normal nor professional that the floating output has inherent static charge, in the first place.
Second, obviously THAT has problems with a batch  of input receivers 1246, which are rated to withstand of 1kV charge at the input.

"Because the 1240-series devices are input
stages, their input pins are of necessity connected to
the outside world. This is likely to expose the parts
to ESD when cables are connected and disconnected.
Our testing indicates that the 1240-series devices will
typically withstand application of up to 1,000 volts
under the human body ESD model."

So IMHO blaming only Dangerous company isn't correct and sounds to me as an usual GS BS.

P.S.
I serviced recently a well known almost new console where about 50  BJTs in CCSs for LED VU meters was faulty or erratically working depending on the temperature. So I believe that the QC on parts level (and there are a lot of fakes on the market) is a much bigger problem right now.
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: abbey road d enfer on November 07, 2019, 04:45:30 AM
Second, obviously THAT has problems with a batch  of input receivers 1246, which are rated to withstand of 1kV charge at the input.

"Because the 1240-series devices are input
stages, their input pins are of necessity connected to
the outside world. This is likely to expose the parts
to ESD when cables are connected and disconnected.
Our testing indicates that the 1240-series devices will
typically withstand application of up to 1,000 volts
under the human body ESD model."
For me it's not a sign that they have a problem, it just shows they have taken care of ESD, as any decent manufacturer should.
 THAT simply acknowledge the fact that ANY input can be subject to hazardous voltages, and that they have taken the necessary steps to make sure their parts are capable of withstanding voltages that are higher than what is a typical in normal life.

The quotation from GearSlutz is not a proof either that there is a problem with Dangerous Music products; more probably the vagaries of an ill-informed idiot.
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: Diaultras on November 07, 2019, 07:28:57 AM
Thanks everyone for taking the time  to comment. 
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: abbey road d enfer on November 07, 2019, 08:20:45 AM
o.k. I got it....

that d-box you link is a DMX terminator and under DMX terminators.
It's for DMX applications.

Why someone has associated this product with tubes is beyond me. I've never seen a vacuum tube DMX driver.  Using vacuum tubes there is nonsense. And I seriously doubt its usefulness in a DMX connection.
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: pucho812 on November 07, 2019, 01:44:30 PM
Why someone has associated this product with tubes is beyond me. I've never seen a vacuum tube DMX driver.  Using vacuum tubes there is nonsense. And I seriously doubt its usefulness in a DMX connection.

maybe there is a typo on the website or someone was listening to the marketing department vs engineering department?
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: Gold on November 07, 2019, 02:09:34 PM
The chief designer for Dangerous is not a rube. He has decades of experience as a studio tech as well as a designer. Sounds like there is some confusion somewhere.
Title: Re: XLR(m) to XLR(f) Bleeder Resistor
Post by: Monte McGuire on November 07, 2019, 08:19:57 PM
Why not take the actual tube device and a voltmeter and see what DC or AC voltage appears between pin 2 and pin 1 and also pin 3 and pin 1. I doubt you'll see some random kilovolt of death, but regardless of theory and what's supposed to happen, you can actually measure what is actually happening right now with that specific piece of equipment.

Why assume anything when you can get a $5 meter and measure whether there's "death" emanating from an output jack? Once you see nothing there, then you can just connect the device with a simple cable and be happy.