+20 dB boost and TX EQ on by default - should be off

David Decoons, wo2x

I did a database reset today and of course the +20 dB boost and TX EQ were on by default. I feel these should be off by default.

Comments??

Dave, wo2x

np2g

Agree with that .

Tim - W4TME

The default setting for the mic inputs (BAL/Mic) normally require the mic preamp (+20 dB boost) which is why it is on by default.  The LINE input on the 6700 and 6500 has it turned off by default and cannot be enabled since it is expecting that you are using a line level input rather than the much lower gain that come from microphones.

David Decoons, wo2x

I find with my setup and working with several 6000 series users we get better results with the +20 dB off. The preamp in the Flex is not as good as an external preamp (if needed). Seems to add unwanted distortion, even when keeping the peak indicator in the yellow. Processor on and in Normal setting. For the included hand mic I would agree it needs the extra amplification. But to each their own. That's what makes the radio "Flexible". Dave, wo2x

Bryan Rambo W4WMT

You say the 20dB mic pre is permanently disabled for "LINE" input mode (XLR in the back) on the 6500? Hmmm, I run the mic pre that way all the time. Seems to work FB. 73 de W4WMT

Tim - W4TME

Using the XLR input is how I have my StudioProjects tube mic preamp connected and I select LINE for the input mode.  it does work FB.

David Decoons, wo2x

I am not near the radio right now. So you are saying when using the rear XLR you select Line instead of Balanced?? What is the difference?

I have it set to Balanced with the +20 dB off driving it with the W2IHY 8 band EQ and EQ Plus. I get outstanding audio reports.

Thanks
Dave, wo2x

Bryan Rambo W4WMT

No, you are right!!! I don't know what I was thinking :-)

np2g

OK
 Since this +20DB is a bulk setting. (Non Adjustable) if you think you need it do you really need +20DB. Whatever happened to being able to measure this  and give this input the correct values ? 

Boosting the input up to some where you do not need and then killing it in the next setting is just bad operations. 

An example 

Say you need +12DB  using That +20DB well  the rest is just excess and can result into Over driving , clipping.  **** audio SO  

IF  Flex makes this +20  DB boost Adjustable (Now that,s the idea)   I would suggest one could use it . Until then Mine is OFF .

This is why any/all usable  Preamp,s  has a variable control on it .

NOT all knobs to the right . 

And this +20  still should default to off .So anyone who is so inclined to use it must make the decision . And if you turn it on  Let persistence remember if you are so inclined.

Ian1

Tim Just to be clear I am under the impression when running Balanced microphone cable from back input i selected Bal? My Heil PR40 needs the 20db turned on so for me the default on works. Ian

David Decoons, wo2x

I've been using Balanced but Tim mentioned Line. I do not hear a difference between Balanced or Line. Maybe Tim can explain the difference.

Ian1

Tim page 124 does state use XLR with back Bal connection. Like David asks whats the difference?

Ian

Tim - W4TME

David,

Electrically, there is no difference between the XLR connector and the 1/4" TRS on the back of the 6700/6500. So you can physically connect your outboard equipment/balanced mic to the rear of the radio by either the XLR or 1/4" input.

For audio connections in general, the XLR is primairly used to connect a balanced microphone (low gain input device) to the radio and the 1/4" TRS is used for connecting line level (higher gain) audio inputs. Since both low and high gain input devices can be connected to the radio, we wanted to provide two software settings in SmartSDR to accomidate both devices, which is BAL (for BALanced microphone) and LINE (for lie level or higher gain inputs.  When select LINE, the intent is that you have connected a high gain input so it bypasses the +20 dB mic preamp.  Selecting BAL  gives you the option to enable, and does so by default,  the +20 dB mic preamp since the additional gain is usually always needed for balanced mics.

My external tube based (mostly) class AB mic preamp has both an XLR and a 1/4" balanced output.  Since I have a box full of XLR to XLR cables, I use the XLR input on the 6700 and set it to LINE in SmartSDR because I do not need or ever want to use the internal +20 dB boost (preamp); my external preamp provides all of the mic input gain for optimal SNR.
 

Tim - W4TME

For your first question, see my response to David below.

And yes, I would expect and balanced dynamic mic connected to the rear of a 6700/6500 will benefit from the +20 dB mic preamp.

Tim - W4TME

There is plenty of digital gain range in the audio input control (slider) where you do not need a variable stepped microphone preamp (+20 dB boost).

The FLEX-6000's default audio settings are configured to work with a microphone and all mics benefit from having the mic preamp (+20 dB boost) on, so that is why it is on by default.  In most other radios you do not have the option to turn the mic preamp off; you just have the option to use a different line level physical interface where there isn't any gain preamplification applied.

Tim - W4TME

See my comments above. You are equating the physical interface (XLR and 1/4" TRS) with the BAL and LINE setting in SmartSDR.  They are not linked or associated.  You can user either physical balanced inputs (XLR or 1/4" TRS) with the LINE or BAL setting.  In the manual, we documented the most common use case which is a balanced dynamic mic with an XLR connection, connected to the XLR input on the radio and selecting the BAL as the input in SmartSDR.

David Decoons, wo2x

Thanks for the detailed explanation.

So there is no electrical difference between the TRS and XLR (which I knew) and there is no difference between Line or Balanced (if the +20 is disabled). Line automatically has the +20 dB preamp disabled and should be the recommended setting for those of us who do not need the internal preamp.

I looked in the manual and there was no reference to the Line setting and I was unaware of it's use.

Learn something new, a good day!

Dave, wo2x