What to do if DAC's analog preamp output is too high

[marc412]

Hello, If I have a DAC with an analog preamp module that outputs 11.8 vrms, may I know if lowering the volume of the preamp would technically lower the vrms output to the amplifier? There is no DAC preamp bypass in the setup.

If so, if I volume match my DAC to another DAC without a preamp on the same amplifier, can I say that the vrms output to the amplifier is roughly the same? Ideally, I imagine I would want to attempt to lower the output to 4vrms

Main goal that I am trying to accomplish is to reuse the dac with the 11.8 vrms to a headphone amplifier, any thoughts?

 

[RayDunzl]

Which DAC?

 

[Blumlein 88]

How about the models and names of the amp and DAC and the headphone amp you intend to use. That way we can look into specs and maybe be of help.

Also looks like a new member so welcome to ASR.

 

[marc412]

Which DAC?

How about the models and names of the amp and DAC and the headphone amp you intend to use. That way we can look into specs and maybe be of help.

Also looks like a new member so welcome to ASR.

The DAC in question would be Holo Audio's Spring 3 KTE with Preamp module, and the amplifier would be a Cayin HA-300b

And thank you for the welcome!

 

[RayDunzl]

I don't see an "owner's manual".

My DAC has jumpers to choose the maximum output voltage.

An interim solution could be to reduce the digital level by 15.3dB taking 11.6V max out down to 2V

Next I might whip up a passive attenuator if digital volume control wasn't making me happy enough.

 

[Blumlein 88]

Well your amp has an input sensitivity of 400 mv or .4 volts. OTOH, your DAC controls volume via switched resistors with 84 1db steps in the preamp module. So you will want to never put the volume above -30 db and everything should be fine. You'll still have 54 db of volume control which should be plenty. I'd like to know more about the preamp circuit and where volume control is done for certainty, but I do believe you can just lower the volume and suffer no bad consequences.

Mark -30 db as a max level. You may run into cases where you'd like to go slightly past it for very low volume sources. In any case you'll be okay as most of the time you'll be even below -30 db on the volume control.

 

[RayDunzl]

Yeah, forgot to consider the amp input sensitivity...

As for digital volume attenuation...

Software volume control - does this affect sound quality in a negative way?

I asked Cambridge Audio about this for their Evo, and they said the volume is internally analogue. They may well have been making it up though! I know other kit does volume in DSPs. Yes, there are chips that offer analog volume control with digital control. Your AVR is full of them.

www.audiosciencereview.com

 

[marc412]

I don't see an "owner's manual".

My DAC has jumpers to choose the maximum output voltage.

An interim solution could be to reduce the digital level by 15.3dB taking 11.6V max out down to 2V

Next I might whip up a passive attenuator if digital volume control wasn't making me happy enough.

Well your amp has an input sensitivity of 400 mv or .4 volts. OTOH, your DAC controls volume via switched resistors with 84 1db steps in the preamp module. So you will want to never put the volume above -30 db and everything should be fine. You'll still have 54 db of volume control which should be plenty. I'd like to know more about the preamp circuit and where volume control is done for certainty, but I do believe you can just lower the volume and suffer no bad consequences.

Mark -30 db as a max level. You may run into cases where you'd like to go slightly past it for very low volume sources. In any case you'll be okay.

Thank you both, so I can summarize lowering the preamp volume will suffice?

 

[Blumlein 88]

Thank you both, so I can summarize lowering the preamp volume will suffice?

Yes.

 

[RayDunzl]

Thank you both, so I can summarize lowering the preamp volume will suffice?

(Old man slaps forehead for not thinking a preamp would have a volume knob.)

Ok, I'll go back to fantasizing about my other hobby now.

Do I want to order a LAK-17B or something else, or not?

Enjoy your headphones!

 

[marc412]

A thought that I have, please educate me if it is a mistake, is if the amplifier is expecting about 4vrm optimally on XLR, and my DAC's preamp RCA out is less hot at 5.8 vrms (vs XLR's 11+), would it make sense for me to also alleviate the issue by using a RCA to XLR cable?

Especially since I read that the amp's "balanced input will transform to single-ended through a pair of input transformer".

Edit: forgot to mention why I don't go RCA to RCA, its because the amp would be expecting 2vrms apparently


EDIT 2: if you stumble upon this in the future, the answer is it depends on the amp, but safer to not do this at all, I asked the distributor