Passive preamp for speaker protection

[Petrushka]

Not passive, but this is what I am trying out.

Amazon.com

Independent volume control for four amps. I’m using two.

 

[rdaow]

Hey there whaardahl,

No need for anything additional…I own the Wiim Amp and, in their WiiM Home mobile control app, there is a setting for max gain; Devices > Gear Icon > Audio Settings > Volume Limit. A setting around 70% will result in plenty of gain without killing any transducers.

Being a software developer - I don't trust any software

 

[AaronJ]

I use this, don't knoe if it measures fine but subjektive-acustically it doesn't change anything
Besides: great small company with fantastic customer support even in the EU

OL Switcher _ Shop JDS LABS

OL Switcher is the solution to your input/output woes, enabling you to route your audio where needed, without fumbling with cables. OL Switcher is a 2 input, 2 output, passively attenuating preamp. Connect a DAC, connect a DAP, connect a headphone amp, and your speaker system.

jdslabs.com

I second this suggestion, and it's one I use. Always always always have an analog volume control between a digital device and the amplifier section, even if the digital device does volume control. Software can malfunction, or a slip of a finger can max out volume on a slider. Ears and speakers are worth protecting.

 

[unpluggged]

Always always always have an analog volume control between a digital device and the amplifier section

No need to be so categorically imperative here. There are better ways to deal with this alleged hazard. And what about, say, analog volume controls based on relays and resistor networks? Or do you refer specifically to mechanical potentiometers?

slip of a finger can max out volume on a slider

But not on an analog slider, I presume?

Ears and speakers are worth protecting.

That's why you set levels in your audio chain so that even if you feed your speakers with a full-scale signal, their output will not exceed safe sound pressure levels. With this condition met, you don't need to worry so much about accidental volume changes. And remember, accidents can happen anywhere. For instance, somebody can by accident turn your analog knob.

And I have yet to hear about such accidental full-volume blasts except for a bug in one of Topping DACs. Well, I would just avoid crappy devices.

speakers are worth protecting.

Those speakers that are worth protecting already have necessary protections built in.

 

[Sokel]

Reed relays stepped attenuator.No annoying clicks and all the safety,joy and precision

 

[wadude]

Thanks, wadude. Helpful to hear from someone with a similar setup. I have the RCA-XLR cable from Blue Jeans Cable, which also does good work. I'm using the WiiiM's room correction, which applies parametric eq and it seems to bring + results. Would you mind sharing which brand and model of passive step attenuator you are using? Can't find many options for products let alone recommendations.

Thanks, wadude. Helpful to hear from someone with a similar setup. I have the RCA-XLR cable from Blue Jeans Cable, which also does good work. I'm using the WiiiM's room correction, which applies parametric eq and it seems to bring + results. Would you mind sharing which brand and model of passive step attenuator you are using? Can't find many options for products let alone recommendations/reviews.

Yes, it actually works! There may still be a guy on eBay, Eric Yamm, that had some nice units with a Chinese 21 step attenuator and four source selector for just over a hundred bucks. I sent one to my son and it’s really nice. I used the same step attenuator installed in a Fostex PC/1e for many years, right up to about twenty-five minutes ago. All of a sudden I’m listening to Buffy Saint-Marie through a new Goldpoint v24 that Pine Tree Audio installed in a gray version of their SP-1 box. I’m in the throws of an expectation bias induced euphoric rush.

If you haven’t seen it, the thread, “Are Passive Preamps Bad?” has lots of useful information.

 

[Chr1]

I use a Tisbury Audio Mini Passive Preamp.

Works very well for not a huge amount of money.

 

[JeffGB]

I've tried a similar setup with a passive volume controller but I wasn't happy with it. I'm using EQ and loose about 4db from my DAC output and also have horrible noise problems (radio interference from cell towers etc). After trying all kinds of things, I purchased a Schiit Magnius and it does it all. It's no longer made but has been replaced by an even better option the Midguard. You can see the superb performance in ASR reviews. The price is very reasonable by comparison to buying special cables etc and provides an excellent headphone amp, great volume control, and two gain settings. With the Midguard you can connect a single ended source and output XLR with no performance loss (the Magnius had poorer performance in single ended use). I find the low cost and great performance, along with perfect conversion of single ended to balanced with no noise, makes it a good choice. I hope I don't sound like a fanboy . It's just that I have tried everything else in a similar situation. If you aren't losing gain in EQ and your XLR conversion cable, the passive can work, at the expense of having a stable low output impedance to drive your amp. Good luck in your decision!

 

[RayDunzl]

will the 2volt output of my WiiM be passed through the volume attenuator and onto the amp as 2volts?

The method by which volume is controlled is to reduce the signal voltage going to the amplifier.

So, for all but the "wide open" case, no.

For every -6db the voltage is cut in half.

-12dB = 1/4 original voltage.

-18dB = 1/8 voltage, and so on.

 

[whaardahl]

Thanks for your correction--and thanks for not ridiculing me So at -6db the 2 volts is reduced to 1, etc.

 

[whaardahl]

Thanks to all who responded to my query! I ended up ordering a Nobsound that has an ALPS 27 potentiometer. It had very good reviews and was inexpensive. If I have any issues, I'll try another of the suggestions that I received, perhaps something with a stepped attenuator.