Adjusting gain on Jubilees / Electro-voice dx38

[PrestonTom]

Hey Jubilee owners that use the Electro-voice DX38: How are you adjusting the gain/volume for your 4 channels of amplification?

 

1. CD player analog output to 2 channel pre-amp then to DX38 then to amplifiers

or 

2. CD player digital output  to DX38 to a 4-channel pre-amp then to amplifiers

or 

3. CD player to DX38 then to amplifiers and use "gain setting" on the DX38 itself to adjust the level?

 

Please fill me in on the details,

-Tom

 

 

 

[Chris A]

Digital player digital output (PS3, BDP-103, or computer, etc.--via HDMI) or analog output (phonograph or MP3 player)

 

--to A/V preamp (overall channel delays and relative channel gains set using room correction software and/or REW/calibration mike)

 

--to Dx38 (XLR to XLR)

 

--to two stereo amps (XLR to XLR)

 

Chris

Edited May 16, 2016 by Chris A

[Coytee]

Sources:  SACD player, DVD player and DTV  All going into

 

Peach via RCA inputs.  Peach RCA outputs going to Dx38 inputs via RCA/XLR cord (hard wired with appropriate ends, no adapter)

 

Dx38 outputs to Crown K2's input (XLR/XLR)

 

Crown output to a big smile on my face.

 

 

I have the Crown's dialed down to around 25% of their gain.  Kills any hiss and can still turn it up a bit.  If I ever want to let it thump as per my reputation, I can simply dial the K2's up to almost whatever I want.  I however, will hear some spittle from across the room if I do this (until the volume pushes you out of the room, masking the noise)

[PrestonTom]

Thanks Chris, So it looks like the pre-amp accepts either a digital or analog input and you use the pre-amp prior to the DX38 to adjust gain.

 

In my application, I would be using an analog pre-amp (probably). Doing this prior to the DX38 means and extra D-A conversion to get it to the DX38 and feed the DX38 A-D converter an attenuated signal (so I would not be using all the bits on the ADC). In the old days (before dithering and oversampling and more than 16-bit converters), we always worried about quantization noise if the input voltage was small. This is the problem I am conceptualizing with using a 2-channel pre-amp.

 

I have looked at 4 and 6 channel  pre-amps(to use after the DX38) and have not been excited by any of them, although a 4-channle potentiometer would probably work fine ... need to think it through. Things are simpler since I only use digital as a source.

[PrestonTom]

So Richard (Coytee): it looks like you are using "method 1"

This has the advantage of a 2-channel pre-amp but the disadvantage of an "extra" D-A conversion and giving the DX38 a "small" voltage and not using all the bits in its A-D converter. 

 I am guessing "method 1" is widely used.

Thanks,

-Tom

[Chris A]

My setup is a HT, two channel, three channel, and 5.1-music system. 

 

The Dx38 crossover apparently only has two analog inputs and an AES/EBU "controller" port. I'm using the two Dx38s in my system--one for bi-amping the center K-402 multiple entry horn, and the other bi-amping the surround Cornwalls.  The two Crown Xti-1000 amps each have a DSP front-end to EQ the horn subs.

 

However, the Yamaha SP2060 that I'm using on the Jubs has an AES/EBU input port for data that can be used if your upstream preamp has an AES/EBU output channel--thus eliminating an analog connection to the crossover.

 

Chris

Edited May 16, 2016 by Chris A

[PrestonTom]

Thanks Chris: I am assuming the DX38 can take a consumer digital signal (S/PDIF) through its digital input (AES/EBU) and do the necessary bit and sampling rate conversion.

The Yamaha is interesting. I do not see many deals on them however.