• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

BobWire XLR1 XLR and RCA Switcher Review

Rate this switcher:

  • 1. Poor (headless panther)

    Votes: 1 0.8%
  • 2. Not terrible (postman panther)

    Votes: 7 5.5%
  • 3. Fine (happy panther)

    Votes: 41 32.0%
  • 4. Great (golfing panther)

    Votes: 79 61.7%

  • Total voters
    128

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
45,763
Likes
254,595
Location
Seattle Area
This is a review and detailed measurements of the BobWire XLR1 XLR switcher including support for conversion from RCA. It was sent to me by the company and costs US $270.
BobWire XLR1 two channel stereo balanced XLR audio rca AB selector unbalanced switch review.jpg

As these "problem solver" boxes go, this is very attractive packaging. The big deal though is high level of flexibility and functionality. Dual methods of switching is provided to select inputs: signal level or 12 volt trigger:
BobWire XLR1 two channel stereo balanced XLR audio rca AB selector unbalanced switch review XL...jpg


The level sensitivity pots were easy to adjust unlike some recessed ones that require tiny screwdriver. The indicators in green are great as it allows you to figure out what the unit has decided to do, i.e. which input is selected.

Due to use of relays for switching, you can also use the unit backwards with one input going to two outputs (then only trigger method works).

One key application here is for "home theater bypass" where you could use this box to switch between your 2-channel and home theater processor to access the same amps and speakers.

Here is the output:
BobWire XLR1 two channel stereo balanced XLR audio rca AB selector unbalanced switch review XL...jpg


BobWire XLR1 Measurements
Let's start with loopback in Audio Precision using its balanced I/O at 4 volt to know how good we could measure:
Audio Precision APx555 Loopback Measurement.png


Routing the same signals through XLR1 generates essentially the same response:
BobWire XLR1 two channel stereo balanced XLR audio rca AB selector switch.png


There is an inconsequential rise in distortion to vanishingly small -140 dB. Noise must have remained the same for SINAD to be as good as the analyzer.

Using the RCA input incurs fair bit of penalty though:
BobWire XLR1 two channel stereo balanced XLR audio rca AB selector unbalanced switch.png


Distortion goes down a bit at lower input levels but not enough to matter.

Frequency response is flat and extended just like AP:
BobWire XLR1 two channel stereo balanced XLR audio rca AB selector switch frequency response m...png


Noise is the same as loopback in AP:
BobWire XLR1 two channel stereo balanced XLR audio rca AB selector switch input SNR measurement.png


Crosstalk was amazingly good:
BobWire XLR1 two channel stereo balanced XLR audio rca AB selector switch input channel separa...png


All of these measurements far exceed the product specs which made me read the description again, realizing then that switching is done by relays and not electronics! Still, some care has been involved to make sure that signal path is very clean. So I decided to not measure in this route anymore and focus on other aspects such as bleed from alternative channel:

BobWire XLR1 two channel stereo balanced XLR audio rca AB selector switch input bleed measurem...png


So best to turn off the non-input or at least turn its level down if you are not listening to it.

Conclusions
The XLR1 switcher is a high-function device with ability to be fully transparent to any source you through it at. While there is a good bit of premium here relative to typical boxes out there, I think it is well deserved given the full picture. In grand scheme of things, solving the integration of 2-channel and multi-channel is worth this and more.

I am happy to recommend the BobWire XLR1 balanced and unbalanced switcher. Member @BobWire has done a great job here in identifying the need and executing very well against it.

------------
As always, questions, comments, recommendations, etc. are welcome.

Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 
Hello ASR community, I am Bob from BobWire. Thank you to Amir for taking the time to test my XLR1! I was an engineer/director of product development at Parasound products for 20 years. I left to start my own business (BobWire) last year. The XLR1 is my newest product but I also do make an RCA only version (model RCA1), speaker level (model SPK1) and some audio sensing device to activate 12V triggers (model AAT1 & DAT1). Keeping signal integrity throughout the audio chain has been a top priority in all of my designs and I'm pleased to see that the XLR1 maintains this tradition! (check out my website bobwireaudio.com for more info). :)
 
Brilliant!
 
Cool but $$. Can't help thinking if Behringer made this it would be under $100.
(Bob from BobWire here) I know the topic of cost will always come up. As a very small company there would never be a way to compete on cost with someone like Behringer. Then again, they would never use the premium components needed for a truly transparent switching device. For example, the relays use gold on gold internal contacts for handling the audio signal which costs a lot more. I possibly could have gone to China to reduce costs but low production and quality don't always go hand in hand there. Because the XLR1 has fully balanced circuits, it requires twice the components as a single ended RCA switch. The XLR1 also has quad audio detection circuits. Each leg of the 2 balanced channels (left & right) has its own detection circuit. This provides extremely high (and accurate) sensitivity for the automatic switching feature but again requires twice the components.
 
The XLR1 also has quad audio detection circuits. Each leg of the 2 balanced channels (left & right) has its own detection circuit. This provides extremely high (and accurate) sensitivity for the automatic switching feature but again requires twice the components.
And that was the better option over, say, using a pair of high-impedance balanced receiver circuits with a low-power dual opamp and an inverting mixer (the single or dual transistor variety would basically do) plus just one instance of the detection circuit? The circuitry doesn't need to be low noise or distortion just as long as it loads the input as little as possible, so I might tend towards 470k or 1Meg resistors even (compensation for input capacitance likely required in feedback). Opamp wise, you could probably pull if off with an LM358 if you absolutely insist but a 4558 would probably be better.
 
Last edited:
And that was the better option over, say, using a pair of high-impedance balanced receiver circuits with a low-power dual opamp and an inverting mixer (the single or dual transistor variety would basically do) plus just one instance of the detection circuit? The circuitry doesn't need to be low noise or distortion just as long as it loads the input as little as possible, so I might tend towards 470k or 1Meg resistors even (compensation for input capacitance likely required in feedback). Opamp wise, you could probably pull if off with an LM358 if you absolutely insist but a 4558 would probably be better.

I designed a sense circuit with just 3 transistors (BC-5xx), ~32 years ago. No loading of significance with 68-100k per leg (L/R). Used it for a decade switching on and off my bedroom system and shutting it down 10 minutes after the last song finished. Could be used for switching anything in the presence of signal, even composite video.

IMG_3795.jpg


One of the last draw it, etch it, drill it, make it projects from my ferric chloride and broken drill bit era in my 20s. I only dug it out recently to make a new design for my 91yo father, so he doesn't have to worry about leaving his various systems on for weeks at a time in his "HiFi room".

IMG_3791.jpg
 
I designed a sense circuit with just 3 transistors (BC-5xx), ~32 years ago. No loading of significance with 68-100k per leg (L/R). Used it for a decade switching on and off my bedroom system and shutting it down 10 minutes after the last song finished. Could be used for switching anything in the presence of signal, even composite video.

View attachment 398206

One of the last draw it, etch it, drill it, make it projects from my ferric chloride and broken drill bit era in my 20s. I only dug it out recently to make a new design for my 91yo father, so he doesn't have to worry about leaving his various systems on for weeks at a time in his "HiFi room".

View attachment 398208
Cool. What specific transistors did you use?
 
at this point you may as well slap in a few more inputs and vol. pot.
 
Cool. What specific transistors did you use?

Two BC-547Bs, 1xBC-557, 4 diodes, 3 caps, 4 resistors and a relay.

Plug pack supplied, switched the mains via a DPDT relay. RCA inputs and an override/trigger button for manual turning on.
 
Two BC-547s, 1xBC-557, 4 diodes, 3 caps, 4 resistors and a relay.

Plug pack supplied, switched the mains via a DPDT relay. RCA inputs and an override/trigger button for manual turning on.
Very nice little package to the design. I like it.
 
Very nice little package to the design. I like it.

This BobWire product is a step up both in flexibility and price for sure. I think it will sell well. I only built mine because no such product existed in 1991. Made a few for friends who just loved not having to press lots of power switches or remember to turn off stuff.

Now anyone could look at a schematic for a typical powered subwoofer and "borrow" the auto switching section (use it for triggering, power or switchable input/outputs), although many of them are too complicated and far too unreliable. Sometimes simple is best.
 
Hello ASR community, I am Bob from BobWire. Thank you to Amir for taking the time to test my XLR1! I was an engineer/director of product development at Parasound products for 20 years. I left to start my own business (BobWire) last year. The XLR1 is my newest product but I also do make an RCA only version (model RCA1), speaker level (model SPK1) and some audio sensing device to activate 12V triggers (model AAT1 & DAT1). Keeping signal integrity throughout the audio chain has been a top priority in all of my designs and I'm pleased to see that the XLR1 maintains this tradition! (check out my website bobwireaudio.com for more info). :)
Congratulations Sir.

I wish there was more engineering oriented business driven individuals like you in this magical, but sometimes grim audio world.

I prefer exactly mid priced high quality products from smaller companies, preferably producing in the west, or at least not in a communist dictatorship.

If I ever need such solution, XLR1 is on my short list. Keep up the good work.

Cheers.:)
 
I designed a sense circuit with just 3 transistors (BC-5xx), ~32 years ago. No loading of significance with 68-100k per leg (L/R). Used it for a decade switching on and off my bedroom system and shutting it down 10 minutes after the last song finished. Could be used for switching anything in the presence of signal, even composite video.

View attachment 398206

One of the last draw it, etch it, drill it, make it projects from my ferric chloride and broken drill bit era in my 20s. I only dug it out recently to make a new design for my 91yo father, so he doesn't have to worry about leaving his various systems on for weeks at a time in his "HiFi room".

View attachment 398208
I too miss the days of relay/logic, and when you could get surplus NIB telephone and other heavy duty (military spec) relays for next to nothing... I liked those octal base ones.
Still like to hear the muted click of them in modern gear (SMSL DL100 I just installed).
Ditto ferric choride and drill bits (I grabbed a bunch of them from the local physics department...still have a few).
I wrote my own pcb designer app in basic, run on a Sinclair, and printed out on a graphite ink jet printer....ah, those were the days...) :D
 
Product idea for consideration:

XLR switcher
* 3-in-1-out flippable to 1-in-3-out
* remote control switching & auto-sense switching
 
At last, a useful little box !!;)
 
Back
Top Bottom