Question

Hello,

Quick question about the Presonus Eris E7 XT 7" Active Studio Monitors.

I've seen some reviews  & opinions online that mention the speakers have quite a loud constant buzz, even with no source plugged into them. Is this something you're aware of? There's a lot of BS on the internet so just checking with those who know!

Thanks so much,

Chris

Answer 1

I have a pair of the Eris E7 XT monitors and I can confirm that they have a very annoying power-mains related low frequency "hum".

I have digged into this in order to find the root cause and see what can be done in order to get them to work without any kind of low frequency hum.

I found that the reason for the LF-humming is due to the mains transformer which power the internal amplifiers. The transformer is of the "conventional" E-type (not a toroid transformer) and therefore emits/leaks a significant level of magnetic field outside the transformer. The low-level signal conditioning electronics, which are implemented on a PCB of its own (carrying the input connectors, potentiomters etc), picks up  some of this magnetic field and translates it into an electrical signal, the HUM, which is in sync with the power mains frequency. 50/100Hz in my case. This signal is then fed into the internal amplifiers (one for the woofer and one for the tweeter).

Unfortunately, there is no easy way to get rid of this magnetic field nor to shield it off, as the design/implementation is what it is...

On one of my speakers, so far, I have split the complete internal amplifier module into two separate parts. One containting the power transformer with the mains connector, voltage selector and mains switch and the the other part is the 2 internal power amps incl. the input signal board, rectifiers, voltage regulators and heat sink. The transformer part can now be put in a greater distance from the internal electronics (in a separate box). I now have to use an electrical 5 core cable to connect the two separated modules, carrying two "low-voltage" AC-voltages and a common AC ground reference. all taken from the secondary (safe) side of the transformer.

I can confirm that the result of this is a complete noise free monitor without any hum, working as expected.

I belive that this mains hum problem, must either be a design glitch by the Presonus design team or a painful mistake by the manufacturing team, selecting a low quality transformer, maybe with a poor iron core or a bad coil winding principle, producing a too high magnetic leakage.

So, it would be nice if someone at the Presonus team gave their view on this matter.

Regards,

Ingvar
Leksand, Sweden

Answer 2

Hello!

I am considering buying a couple of Eris E7 XT's and so I'm wondering about the buzzing issue. Are there any updates regarding this issue? Did victordruslawski learn anything new?

Jakob

Answer 3

Before I start I would like to let anyone who stumbles upon this thread to know that my original post was removed (not by me and you can see an evidence my post was here as jakobbreinholt was following up on my original post), which tells me some individuals from PreSonus don't like when there is not just issue's exposé from Ingvar, but also me even stating a range of SNs which are faulty (yes, this is a fault). Now, it is possible speakers from affected batches are being refurbished, however from my recent experience I can tell you that our local PreSonus distributor did not offer any repair for my pair I purchased about a month ago and consequently returned as both were from affected range and were unacceptable to be used as bookshelf/desk speakers which is what they are supposed to be used as. They did, however, reach out to me about a week ago offering me a pair of some they did refurbishment on (as in they installed the service kit, which I believe, is provided by PreSonus directly), but in my case I kindly

So, again, for anyone shopping for these and being worried if theirs are affected, here is, again, a range of faulty SNs EX7D20010030-EX7D21020999. As stated from PreSonus rep in my support request, later batches are not affected and should have upgrade transformers, which shall have buzzing suppressed or removed completely. I will be purchasing a pair from one of the retailers next week and I will then report my findings. I hope, jakobbreinholt, that this also answers your question.

Answer 4

Hey there, does anyone know what year those speakers were made that include the problem? I recently ordered some and then found this feed. Does anyone know what year the EX7D20010030-EX7D21020999 were made to know if my batch was affected? Thanks!

Answer 5

hi.

i have a same issue too. no jack and there is a buzz sound at e7 xt. i cut the gain off but two of them still buzzing. what is the solution? i think presonus have fix this products that we have... is there any progress or solution ?