Interspace PCBB3 Hum Eliminator/Converter

[johnnyx]

I bought a PCB with two balanced HT-9696 600+600 ohm isolation transformers for about £15, for a valve guitar amplifier.
I was looking for some of that "transformer saturation" that "mix engineers" seem to like so much.
It boasted permalloy core and oxygen free copper wire.
I was disappointed to find that it tested very well, better than I need, and the amplifier clipped before the transformer saturated.

 

[VientoB]

My god what an embarrassing product.

 

[amirm]

I would have hoped for ASR not to deal with such s..t products.

You wouldn't know the good, without knowing the bad.

And at any rate, I have no way of judging products until I test them.

 

[xanalog]

Thanks for the review, @amirm,

Perhaps it was not worth further testing this passive (transformer-based?) RCA-to-XLR converter, but it would have been nice to get a read on both Input+Output Impedance.
If you are in the mood to test few other aliexpress specials, I have a few of these (never used, isolation baluns) hum/noise eliminators.
DM me.

"Dual Channel Audio Isolator PA-2"
Input Impedance: 600R (ac impedance)
Output Impedance: 600R (ac impedance)
Frequency Response: 20Hz- 20kHz (< 0.3db ref 1kHz)
Fixed Loss: <0.7db (ref 1kHz 1V RMS)
----------------------------------------

TIANCOOLKEI - RCA to XLR 600Ω:10K boost audio preamplifier
Isolation boost multiple: 600Ω:10K
Potentiometer: 10k/50K(default 10K)
Measured frequency response: 20Hz-120KHz attenuation <-1.6dB

 

[ErVikingo]

Jensen are great

 

[Eulipian]

This is a review and detailed measurements of the Interspace/Hive PCBB3 3.5mm unbalanced to XLR balanced converter/"hum eliminator." It was kindly drop shipped to me. This model is superseded by PCBB4 which costs US $151.
View attachment 555969
I was impressed by the very nice feel of the silicone cable bringing out the 3.5mm jack, ready to plug into a computer in live scenarios. Usually we see RCA jacks. There are options to lower level (pad), convert to mono and lift ground.

Interspace PCBB3 Converter Measurements
I start with my usual 1 kHz tone at 2 Volts:
View attachment 555970
The unit is passive which I assume it means it has a transformer. As such, the worst performance is at lower frequencies, not 1 kHz:
View attachment 555971

It saturates at just 0.15 volt and logarithmically gets worse as frequencies get lower. But need not be this bad as we see from measurements of the Jensen ISO-MAX CI-1RR competitor:

I couldn't even run the PCBB3 at 20 Hz due to its distortion going through the roof:

View attachment 555975

Frequency response is uneven as well:
View attachment 555974

Crosstalk is good enough:
View attachment 555976

Conclusions
Yes, we expect such "solution boxes" to provide adequate performance but it can't be so bad that it hurts the eye! The company should at least document the specs so you know what you are buying.

Our focus is high performance and as such, I can't recommend the Interspace PCBB3. Suggest spending a few more dollars to get the Jensen and its higher end competitors.
-----------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Another addition to the door stop collection.

 

[pablolie]

Like others stated... I am not quite sure why these fringe products need to even be considered for testing. I'd be far ore curious about old DACs to help establish how they compare against today's crop.

 

[amirm]

I am not quite sure why these fringe products need to even be considered for testing.

You have a ground loop and have tried everything but it won't go away. These things are a solution for that especially since they convert unbalanced to balanced.

 

[pablolie]

You have a ground loop and have tried everything but it won't go away. These things are a solution for that especially since they convert unbalanced to balanced.

Clearly not this particular one :-D
We all know the simple approaches to solve ground loop issues - which IMO should really not happen these days. I personally have had not an issue with ground hiss in years immemorial, which makes me often wonder why others encounter them still.

 

[amirm]

Last ground loop I had was with my subs in my theater. Tried running them unbalanced with cables already in the walls and hum was everywhere. Resorted to balanced cable laying on the floor to resolve it.

 

[xanalog]

Last ground loop I had was with my subs in my theater. Tried running them unbalanced with cables already in the walls and hum was everywhere. Resorted to balanced cable laying on the floor to resolve it.

Have you tried any risers for those balanced cables?

 

[Steve Dallas]

Like others stated... I am not quite sure why these fringe products need to even be considered for testing. I'd be far ore curious about old DACs to help establish how they compare against today's crop.

This forum has a diverse audience. I am a former live sound engineer and owned a project studio for several years. It is interesting to see how some problem solver devices similar to the ones I used actually perform and answer questions like, "Was Radial worth the extra outlay?" My intrigue is similar to yours but in a different domain. I rather enjoy these little tangents away from the normal fare.

Clearly not this particular one :-D
We all know the simple approaches to solve ground loop issues - which IMO should really not happen these days. I personally have had not an issue with ground hiss in years immemorial, which makes me often wonder why others encounter them still.

"I don't know anyone who voted for Nixon!" Just because you have not had an issue with them in your little bubble does not mean others do not battle them frequently. I recently had to solution two of them in my home studio. One was solved by a Radial Stage Bug and the other by an iFi USB isolator. And my house is new construction with proper wiring. It happens all the time.

 

[Tell]

I wonder why people that don't even know USE CASE OF THIS are feeling the need to chime in with their opinions....?
This is used in cases where sound quality is NOT THAT IMPORTANT. Like connecting a smartphone to a PA system and not having everyone in room loose their hearing and it does exactly that just fine.
Last I checked PA and live performances were not what I would call "state of the art HIFI".

Tell me you haven't heard a PA without telling me you haven't heard a PA.

 

[Kraken2109]

There're some weird views here that quality doesn't matter in live sound situations. I guess a lot of people are still used to crap PA that you might find in a village hall or a school.

If you look at what the actual state of the art is (e.g. d&b, L'acoustics) you'll see that there are some incredible PA systems out there.

I'd actually love to see Amir review some high end PA speakers and amplifiers.

 

[Mnyb]

It least someone is interested otherwise these wont show up in amir's mail ? so someone have gone trough the trouble of donating this device . So it's gets tested kind of the ethos of this site ? don't you think

So if your grumpy about the "wrong" device getting tested flood amir's inbox with interesting hardware

 

[NicolasGr]

It least someone is interested otherwise these wont show up in amir's mail ? so someone have gone trough the trouble of donating this device . So it's gets tested kind of the ethos of this site ? don't you think

So if your grumpy about the "wrong" device getting tested flood amir's inbox with interesting hardware

exactly, we all benefit from people who drop ship and send gear to be tested.

- Oh, another Dac, ANOTHER headphone,
etc?"

- yes, thank you very much

 

[amirm]

It least someone is interested otherwise these wont show up in amir's mail ? so someone have gone trough the trouble of donating this device . So it's gets tested kind of the ethos of this site ? don't you think

So if your grumpy about the "wrong" device getting tested flood amir's inbox with interesting hardware

FYI there is a flood of products here waiting to be tested. Went to look for an item that I need to test right away and in the process, landed on these two interspace devices that were sent back in December of last year! The owner has kindly waited and waited so I figured it was time to get the testing done.

 

[EXIF68]

What the hell????
Such a device is not worth to be tested.
LG Walter

 

[xanalog]

FYI there is a flood of products here waiting to be tested...

So, I guess I should not ask you if you'd be interested in a review of the Sennuopu DS-M12 (8-channel automotive DSP).

It's offered by an aliexpress seller, and is equipped w/a wired controller/display (amps, BT, opto, 2xUSB), @~$300.

 

[Cbdb2]

I’d find it really interesting to see a test of one of those cheap AliExpress DRV134 dual-channel unbalanced-to-balanced board modules for comparison. It costs less than €10 including shipping, and I’ve had good experiences with it so far.

View attachment 555993
View attachment 555994

Does it eliminate ground loops?